WorldWideScience

Sample records for bridge strengthening condition

  1. Field tests of Fibre Bragg Grating sensors incorporated into CFRP for Railway Bridge strengthening condition monitoring

    DEFF Research Database (Denmark)

    Täljsten, Björn; Kerrouche, Abdelfathe; Leighton, J;

    2008-01-01

    This paper reports results obtained from an unusual situation in structural monitoring – a ‘test-to-destruction’, measuring strain using a series of fibre Bragg gratings (FBG) sensors on a decommissioned concrete Railway Bridge in Örnsköldsvik, Sweden. The study formed part of the FP6 EU funded...... the study, the FBG sensors were continuously monitored, allowing the incremental increases in the strain to be seen and through the yield point of the carbon composite reinforcement. The sensors were able to follow the resulting induced changes in strain of over a range in excess of 4000µε. The measurements...... reinforcements used in remedial repair and for monitoring better the performance of existing bridge structures....

  2. Strengthening of a railway bridge with NSMR and CFRP tubes

    DEFF Research Database (Denmark)

    Täljsten, Björn; Bennitz, Anders; Danielsson, Georg

    2008-01-01

    Strengthening of structures with CFRP is today considered an accepted method to upgrade concrete structures. In this paper two different CFRP strengthening systems are combined to give extended service life to a Swedish double-trough-double-track railway bridge, constructed in concrete with a 10...

  3. Carbon fiber-reinforced polymer strengthening and monitoring of the grondals bridge in Sweden

    DEFF Research Database (Denmark)

    Täljsten, Björn; Hejll, Arvid; James, Gerard

    2007-01-01

    strengthened. The strengthening methods used were CFRP plates at the serviceability limit state and prestressed dywidag stays at the ultimate limit state. The strengthening was carried out during 2002. At the same time monitoring of the bridge commenced, using LVDT crack gauges as well as optical fiber sensors....

  4. Effects of CFRP Strengthening on Dynamic and Fatigue Responses of Composite Bridge

    Directory of Open Access Journals (Sweden)

    Kittisak Kuntiyawichai

    2014-01-01

    Full Text Available This paper investigates the effect of CFRP strengthening on dynamic and fatigue responses of composite bridge using finite element program ABAQUS. Dynamic and fatigue responses of composite bridge due to truck load based on AASHTO standard are investigated. Two types of CFRP strengthening techniques, CFRP sheets and CFRP deck, are applied to both the damaged and undamaged bridges. For the case of damaged bridge, two through-thickness crack sizes, 3 mm and 6 mm in depth, are assumed at midspan of the steel girders. Furthermore, effects of the number of steel girders on the dynamic and fatigue responses are also considered. The results show that the maximum responses of composite bridges occur for dual lane cases. By using CFRP as a strengthening material, the maximum stress and deflection of the steel girders reduce and consequently increase the fatigue life of the girders. After introducing initial crack into the steel girders of the composite bridges, the fatigue life of the bridges is dramatically reduced. However, the overall performance of the damaged composite bridge can be improved by using CFRP, albeit with less effectiveness. Therefore, if cracks are found, steel welding must be performed before strengthening the composite bridge by CFRP.

  5. Strengthening an in-service reinforcement concrete bridge with prestressed CFRP bars

    Institute of Scientific and Technical Information of China (English)

    Hai-long WANG; Wei-liang JIN; David J.CLELAND; Ai-hui ZHANG

    2009-01-01

    Carbon fiber reinforced polymer(CFRP)bars were prestressed for the structural strengthening of 8 T-shaped rein-forced concrete (RC)beams of a 21-year-old bridge in China.The ultimate bearing capacity of the existing bridge after retrofit was discussed on the basis of concrete structures theory.The flexural strengths of RC beams strengthened with CFRP bars were controlled by the failure of concrete in compression and a prestressing method was applied in the retrofit.The field construction processes of strengthening with CFRP bars-including grouting cracks,cutting groove,grouting epoxy and embedding CFRP bars,surface treating,banding with the U-type CFRP sheets,releasing external prestressed steel tendons-were introduced in detail.In order to evaluate the effectiveness of this strengthening method,field tests using vehicles as live load were applied before and after the retrofit.The test results of deflection and concrete strain of the T-shaped beams with and without strengthening show that the capacity of the repaired bridge,including the bending strength and stiffness,is enhanced.The measurements of crack width also indicate that this strengthening method can enhance the durability of bridges.Therefore,the proposed strengthening technology is feasible and effective.

  6. Failure Load Test of a CFRP Strengthened Railway Bridge in Oumlrnskoumlldsvik, Sweden

    DEFF Research Database (Denmark)

    Täljsten, Björn; Bergström, Markus; Carolin, Anders

    2009-01-01

    The results obtained when performing a load test to failure of an existing structure are valuable when assessing calculation models, updating finite element models, and investigating the true structural behavior. In this paper a destructive testing and monitoring of a railway bridge in Örnsköldsvik...... using carbon fiber reinforced polymer (CFRP) rectangular rods epoxy bonded in sawed up slots, e.g., near surface mounted reinforcement. The strengthening was very successful and resulted in a desired shear failure when the bridge was loaded to failure. The load-carrying capacity in bending...... for the unstrengthened and strengthened bridge as well as the shear capacity was predicted with Monte Carlo simulations. The particular calculation presented showed that there was a 25% probability of a bending failure instead of a shear failure. Monitoring showed that the strengthening reduced the strain in the tensile...

  7. Repair and Strengthening Assessment of Existing Bridges Based on Time-Dependent Reliability Analysis

    Institute of Scientific and Technical Information of China (English)

    孙晓燕; 黄承逵; 孙保沭

    2004-01-01

    The strategy on repair and strengthening of existing bridges based on time-dependent reliability was analyzed with the maximum expected benefit as the objective function. A sample of risk-ranking decision was illustrated based on updated inspection information with 35 survival age. The effect of improvement of live loads and difference of repair methods on time-dependent reliability of existing bridges are considered. The results show that the decision method can be used in real project, with the cost of failure consequence and the risk of failure considered.

  8. Cyclic Load Responses of GFRP-Strengthened Hollow Rectangular Bridge Piers

    Directory of Open Access Journals (Sweden)

    Junfeng Jia

    2014-01-01

    Full Text Available This study investigated the seismic behavior of glass fiber reinforced polymer (GFRP strengthened hollow rectangular bridge piers. Cyclic testing of reinforced concrete (RC piers retrofitted with GFRP was carried out under constant axial loading and lateral bending. The failure characteristics, flexural ductility, dissipated energy, and hysteretic behaviors, were analyzed based on experimental results. A simplified GFRP-confined concrete model is developed by considering effective strength coefficient and area distribution ratio of GFRP sheets. The results indicate that the failure modes and damage region would be changed and the ductility and dissipated energy of the GFRP-strengthened hollow rectangular bridge piers were improved greatly but not much improvement for the lateral load capacity. The analytical results of the force-displacement hysteretic loops based on the GFRP-confined concrete model developed in this paper agreed well with the experimental data.

  9. Cyclic Load Responses of GFRP-Strengthened Hollow Rectangular Bridge Piers

    OpenAIRE

    Junfeng Jia; Qiang Han; Zigang Xu; Dongjie Zhang

    2014-01-01

    This study investigated the seismic behavior of glass fiber reinforced polymer (GFRP) strengthened hollow rectangular bridge piers. Cyclic testing of reinforced concrete (RC) piers retrofitted with GFRP was carried out under constant axial loading and lateral bending. The failure characteristics, flexural ductility, dissipated energy, and hysteretic behaviors, were analyzed based on experimental results. A simplified GFRP-confined concrete model is developed by considering effective strength ...

  10. GFRP seismic strengthening and structural heath monitoring of Portage Creek Bridge concrete columns

    International Nuclear Information System (INIS)

    Located in Victoria British Columbia (BC), Canada, the Portage Creek Bridge is a 124m long, three-span structure with a reinforced concrete piers and abutments on H piles. The bridge was designed prior to the introduction of current bridge seismic design codes and construction practices. Therefore it was not designed to resist the earthquake forces as required by today's standards. The bridge is on a route classified as a Municipal Disaster Route scheduled to be retrofitted to prevent collapse during a design seismic event, with a return period of 475 years (i.e., an event with 105 probability of exceedance in 50 years). Conventional materials and methods were used to retrofit most of the bridge. The dynamic analysis of the bridge predicted the two tall columns of Pier No. 1 will form plastic hinges under an earthquake resulting an additional shear to the short columns of Pier No. 2. A non-liner static pushover analysis indicated the short columns will not be able to form plastic hinges prior to failure in shear. The innovative solution of Fiber Reinforced Polymer wraps (FRPs) was chosen to strengthen the short columns for shear without increasing the moment capacity. The FRP wraps and the bridge were instrumented as one of 36 demonstration projects across Canada sponsored by ISIS (Intelligent Sensing for Innovative Structure) Canada, federally funded Network of Centers of Excellence, to access the performance of FRP and the use of FOS (Fiber Optic Sensors) for Structural Health Monitoring (SHM). The two columns of the bridge pier were strengthened with GFRP (Glass Fiber Reinforced Polymer) wraps with eight bi-directional rosette type strain gauges and four long gauge fiber optic sensors attached to the outer layer of the wraps. In addition, two 3-D Crossbow accelerometers are installed on the pier cap above the columns and a traffic web-cam mounted above the deck at the pier location. The data is collected through high sped internet line to an interactive web page

  11. Bridge Condition Assessment Using D Numbers

    Directory of Open Access Journals (Sweden)

    Xinyang Deng

    2014-01-01

    Full Text Available Bridge condition assessment is a complex problem influenced by many factors. The uncertain environment increases more its complexity. Due to the uncertainty in the process of assessment, one of the key problems is the representation of assessment results. Though there exists many methods that can deal with uncertain information, however, they have more or less deficiencies. In this paper, a new representation of uncertain information, called D numbers, is presented. It extends the Dempster-Shafer theory. By using D numbers, a new method is developed for the bridge condition assessment. Compared to these existing methods, the proposed method is simpler and more effective. An illustrative case is given to show the effectiveness of the new method.

  12. Fuzzy Based Decision Support System for Condition Assessment and Rating of Bridges

    Science.gov (United States)

    Srinivas, Voggu; Sasmal, Saptarshi; Karusala, Ramanjaneyulu

    2016-06-01

    In this work, a knowledge based decision support system has been developed to efficiently handle the issues such as distress diagnosis, assessment of damages and condition rating of existing bridges towards developing an exclusive and robust Bridge Management System (BMS) for sustainable bridges. The Knowledge Based Expert System (KBES) diagnoses the distresses and finds the cause of distress in the bridge by processing the data which are heuristic and combined with site inspection results, laboratory test results etc. The coupling of symbolic and numeric type of data has been successfully implemented in the expert system to strengthen its decision making process. Finally, the condition rating of the bridge is carried out using the assessment results obtained from the KBES and the information received from the bridge inspector. A systematic procedure has been developed using fuzzy mathematics for condition rating of bridges by combining the fuzzy weighted average and resolution identity technique. The proposed methodologies and the decision support system will facilitate in developing a robust and exclusive BMS for a network of bridges across the country and allow the bridge engineers and decision makers to carry out maintenance of bridges in a rational and systematic way.

  13. Fuzzy Based Decision Support System for Condition Assessment and Rating of Bridges

    Science.gov (United States)

    Srinivas, Voggu; Sasmal, Saptarshi; Karusala, Ramanjaneyulu

    2016-09-01

    In this work, a knowledge based decision support system has been developed to efficiently handle the issues such as distress diagnosis, assessment of damages and condition rating of existing bridges towards developing an exclusive and robust Bridge Management System (BMS) for sustainable bridges. The Knowledge Based Expert System (KBES) diagnoses the distresses and finds the cause of distress in the bridge by processing the data which are heuristic and combined with site inspection results, laboratory test results etc. The coupling of symbolic and numeric type of data has been successfully implemented in the expert system to strengthen its decision making process. Finally, the condition rating of the bridge is carried out using the assessment results obtained from the KBES and the information received from the bridge inspector. A systematic procedure has been developed using fuzzy mathematics for condition rating of bridges by combining the fuzzy weighted average and resolution identity technique. The proposed methodologies and the decision support system will facilitate in developing a robust and exclusive BMS for a network of bridges across the country and allow the bridge engineers and decision makers to carry out maintenance of bridges in a rational and systematic way.

  14. Repair and strengthening of R/C bridges degraded by environmental actions and pollution

    OpenAIRE

    Benedetti, Andrea; Donchev, Ted; Pelà, Luca

    2012-01-01

    Many bridges all around the world experience very hard environmental conditions, and due to the irregular maintenance effort, show different problems of cracking, concrete cover detachment and steel reinforcement wear and corrosion. In general, as a consequence of the polluted rain wetting, the problem is more evident in vertical structures than in the horizontal ones, and serious problems can arise when the piers and columns are very tall. In recent times, the solutions offered by composite ...

  15. Analysis of resonance mechanism and conditions of train bridge system

    Science.gov (United States)

    Xia, H.; Zhang, N.; Guo, W. W.

    2006-11-01

    In this paper, the resonance mechanism and conditions of train-bridge system are investigated through theoretical derivations, numerical simulations and experimental data analyses. The resonant responses of the bridge induced by moving trains are classified into three types according to different resonance mechanisms: the first is related to the periodical actions of moving load series of the vertical weights, lateral centrifugal and wind forces of vehicles; the second is induced by the loading rate of moving load series of vehicles; the third is owing to the periodically loading of the swing forces of the train vehicles excited by track irregularities and wheel hunting movements. The vehicle resonance is induced by the periodical action of regular arrangement of bridge spans and their deflections. The resonant conditions are proposed and the corresponding resonant train speeds are determined. The application scopes of resonance conditions are discussed. The resonance of the train-bridge system is affected by the span, total length, lateral and vertical stiffness of the bridge, the compositions of the train, and the axle arrangements and natural frequencies of the vehicles. The resonant train speeds for some bridges are estimated and are compared with the critical train speeds obtained from the dynamic simulation of train-bridge interaction model or from the field measurements.

  16. Bridge Pressure Flow Scour at Clear Water Threshold Condition

    Institute of Scientific and Technical Information of China (English)

    GUO Junke; KERENYI Kornel; PAGAN-ORTIZ Jorge E; FLORA Kevin

    2009-01-01

    Bridge pressure flow scour at clear water threshold condition is studied theoretically and experimentally. The flume experiments reveal that the measured scour profiles under a bridge are more or less 2-dimensional; all the measured scour profiles can be described by two similarity equations, where the horizontal distance is scaled by the deck width while the local scour by the maximum scour depth; the maximum scour position is located just under the bridge about 15% deck width from the downstream deck edge; the scour begins at about one deck width upstream the bridge while the deposition occurs at about 2.5 deck widths downstream the bridge; and the maximum scour depth decreases with increas-ing sediment size, but increases with deck inundation. The theoretical analysis shows that: bridge scour can be divided into three cases, i.e. downstream unsubmerged, partially submerged, and totally submerged. For downstream unsubmerged flows, the maximum bridge scour depth is an open-channel problem where the conventional methods in terms of critical velocity or bed shear stress can be applied; for partially and totally submerged flows, the equilibrium maximum scour depth can be described by a scour and an inundation similarity number, which has been confirmed by experiments with two decks and two sediment sizes. For application, a design and field evaluation procedure with examples is presented, including the maximum scour depth and scour profile.

  17. STRENGTHENING OF FINANCIAL BASE OF LOCAL BUDGETS IN THE CONDITIONS OF BUDGETARY REFORM

    OpenAIRE

    Feshchenko, L.

    2011-01-01

    In article problem questions of formation of profitable base of local budgets in the conditions of financial and economic crisis, and as influence of budgetary-tax reforming on strengthening of their financial self-sufficiency are considered.

  18. Application of system-based correction factors in condition rating of steel-composite bridges

    OpenAIRE

    Casas Rius, Joan Ramon; Anitori, Giorgio; ghosn, michel

    2016-01-01

    Traditional condition rating procedures concentrate on member condition and give no consider-ation to system behavior. In this paper a methodology is proposed to modify the correction factor applied dur-ing the assignment of bridge condition rating to account for bridge system behavior. Robustness and redun-dancy concepts that have been used in the past for structural design of new bridges and for assessment of existing bridges are in this work extended to condition rating, which represents t...

  19. Bridge Management Strategy Based on Extreme User Costs for Bridge Network Condition

    Directory of Open Access Journals (Sweden)

    Ladislaus Lwambuka

    2014-01-01

    Full Text Available This paper presents a practical approach for prioritization of bridge maintenance within a given bridge network. The maintenance prioritization is formulated as a multiobjective optimization problem where the simultaneous satisfaction of several conflicting objectives includes minimization of maintenance costs, maximization of bridge deck condition, and minimization of traffic disruption and associated user costs. The prevalence of user cost during maintenance period is twofold; the first case refers to the period of dry season where normally the traffic flow is diverted to alternative routes usually resurfaced to regain traffic access. The second prevalence refers to the absence of alternative routes which is often the case in the least developed countries; in this case the user cost referred to results from the waiting time while the traffic flow is put on hold awaiting accomplishment of the maintenance activity. This paper deals with the second scenario of traffic closure in the absence of alternative diversion routes which in essence results in extreme user cost. The paper shows that the multiobjective optimization approach remains valid for extreme cases of user costs in the absence of detour roads as often is the scenario in countries with extreme poor road infrastructure.

  20. Enlarged Cross-section of The Stone Arch Bridge Strengthened by Technology Application%增大截面法加固石拱桥的技术应用

    Institute of Scientific and Technical Information of China (English)

    吴跃梓; 章劲松

    2012-01-01

    石拱桥是极具中华民族气息与特色的桥型,该桥型结构实用、美观.然而随着时代的变迁及交通运输业的发展,大量的石拱桥出现了各种各样的病害,很多桥甚至已发展成危桥.为改善交通状况,消除安全隐患,结合当前经济状况,加固利用旧危石拱桥是合理的.石拱桥加固的方法很多,结合工程实例重点阐述增大截面加固法加固石拱桥的基本原理、方法和步骤.%Stone arch bridge is a Chinese national flavor and characteristics of the bridge, the bridge type structure, beautiful and practical. However, with the change of times and the development of transportation industry, large stone arch bridges the emergence of a variety of diseases, many bridges has developed the deserted bridge. In order to improve traffic conditions, to eliminate potential safety problems, combined with the current economic situation, strengthening the old stone arch bridge is reasonable. Stone arch bridge reinforcement method, this paper focuses on the section- enlarging reinforcing method for reinforcing stone arch bridge, the basic principle of the method and steps.

  1. Discuss How to Strengthen the Quality Management of Bridge Engineering%探讨如何加强桥梁工程质量管理

    Institute of Scientific and Technical Information of China (English)

    张应赞

    2014-01-01

    At present, the bridge project is stil a very serious problem. At the same time, the quality system of bridge, the control and management of supervision department, the know-ledge popularization of bridge experts and patent protection are facing unprecedented chalenges. Therefore, this article carries on the discussion of how to strengthen the quality man-agement of bridge engineering.%目前,我国桥梁工程仍旧存在十分严峻的问题。同时,桥梁的质量体系、监理部门的职能控管、桥梁专家的知识普及和专利保护都面临绝无仅有的挑战。因此,本文对如何加强桥梁工程质量管理进行了探讨。

  2. Carbon Fibre-reinforced Polymer Strengthening and monitoring of the Gröndals Bridge in Sweden

    DEFF Research Database (Denmark)

    Täljsten, Björn; Hejll, A.; James, G.

    2007-01-01

    The Gröndal Bridge is a large freivorbau bridge (prestressed concrete box bridge), approximately 400 m in length with a free span of 120 m. It was opened to tram traffic in the year 2000. Just after opening cracks were noticed in the webs, these cracks have then increased, the size of the largest...

  3. CFRP加固受损桥墩的抗震性能试验研究%Experimental Research on Seismic Performance of Strengthening Damaged Bridge Pier with CFRP

    Institute of Scientific and Technical Information of China (English)

    吴刚; 丁明波

    2013-01-01

    以某城市立交工程为背景,建立桥墩缩尺模型,完成CFRP加固前后模型墩的拟静力破坏试验,分析研究模型墩加固前后的滞回曲线、骨架曲线、刚度退化曲线和能力耗散系数曲线.研究表明,采用CFRP加固受损桥墩,可有效恢复桥墩抗震性能,甚至得到提高,加固效果明显.%The experimental research is based on an interchange engineering of a city, where two scale models of bridge pier are built. Pseudo-static test is conducted to damage the scale model and strengthened the model with CFRP. The hysteretic curve, skeleton curve, stiffness degradation curve and energy dissipation coefficient curve of the scale model and strengthened model are analyzed. The experimental research shows that the seismic performance of bridge pier model can be recovered under the CFRP strengthening technology, and the capacity even can be enhanced The strengthening effect is obvious.

  4. NDT-based bridge condition assessment supported by expert tools

    Science.gov (United States)

    Bień, J.; KuŻawa, M.

    2016-06-01

    This paper is focused on the progress in the application of Expert Tools supporting integration of inspection and NDT testing findings in order to effectuate effective decision making by bridge owners. Possibilities of knowledge representation in the intelligent computer Expert Tools by means of the multi-level hybrid network technology are described. These multi-level hybrid networks can be built of neural, fuzzy and functional components depending on the problem that needs to be solved and on the type of available information. Application of the technology is illustrated by an example of the Bridge Evaluation Expert Function (BEEF) implemented in the Railway Bridge Management System "SMOK" operated by the Polish State Railways.

  5. Decision support system for integrating remote sensing in bridge condition assessment and preservation

    Science.gov (United States)

    Endsley, Arthur; Brooks, Colin; Harris, Devin; Ahlborn, Tess; Vaghefi, Khatereh

    2012-04-01

    Since the National Bridge Inventory (NBI) was first conducted, structural health monitoring (SHM) of U.S. bridge infrastructure has consisted largely of time and labor-intensive surveys with subjective results. In-situ and embedded sensors, while more reliable and accurate, can be costly and in many cases infeasible for SHM because they require installation in hard-to-reach places or during construction. Remote sensing (RS) technologies such as radar, electrooptical imaging and laser scanning may offer an innovative, cost-effective method of monitoring the dynamic conditions of U.S. bridges in real-time. While some RS techniques may be costly for state agencies to deploy on their own, RS imagery is available through government agencies or commercial vendors for moderate or no cost. How can disparate RS datasets be integrated with one another and with inventory data in a way that is meaningful to bridge asset management decision makers? This paper discusses the development and functionality of the Bridge Condition Decision Support System (DSS), a web-based asset management tool for bridge managers and inspectors. The DSS seamlessly merges bridge metrics from RS data with NBI inventory data allowing decision makers to compare up-to-date bridge condition metrics from multiple inputs as a time series. It enables analysis of RS and inventory data available through user-friendly web services which can also expose virtually unlimited server-side data processing. Using open-source software, the authors developed a scalable, spatially-aware bridge condition database with a fast and flexible server application programming interface (API) and a cross-browser compatible web mapping application written in Javascript.

  6. 丫髻沙大桥桥面系加固设计%Strengthening Design of Floor System of Yajisha Bridge

    Institute of Scientific and Technical Information of China (English)

    陈红

    2013-01-01

    In the light of the deteriorations (the loosening and breaking of the high-strength bolts at connections of part of the stringers and cross beams, the cracking and breaking of part of the connecting angle steels and the cracking in the welding seams at connections of part of the cross beam webs and lower flanges) having occurred in the floor system of the Yajisha Bridge (the main bridge is a three-span half-through continuous concrete-filled steel tube arch bridge with a main span 360 m) in the operation period, the causes leading to the deteriorations were analyzed and the strengthening of the floor system of the bridge was designed. According to the analysis, it was concluded that the main cause leading to the deteriorations was the increase of stress in the cross beams of the floor system and the decrease of fatigue performance of the steel structure caused by the increase of truck load. In the design, the live load criterion for the strengthening of the floor system remained unchanged and the floor system was to be systematically strengthened by adding the crack stopping holes, increasing the sections of the cross beams and longitudinal girders and changing the connecting ways of the stringers and cross beams. Finally, the safety and effectiveness of the strengthening measures were verified by the finite element calculation and tests.%针对丫髻沙大桥(主桥为主跨360 m的三跨连续中承式钢管混凝土拱桥)运营期间桥面系出现的病害(部分纵梁、横梁连接处高强螺栓松动、断裂,连接角钢开裂、断裂,部分横梁腹板与下翼缘连接处焊缝开裂等),进行原因分析及桥面系加固设计.经分析,汽车荷载增加引起桥面系横梁的应力增加,降低钢结构的疲劳性能是引起桥面系病害的主要原因.加固设计活载维持原设计荷载标准不变,通过增设止裂孔,增加钢横梁截面,增设大纵梁,改变纵梁、横梁的连接方式对桥面系进行系统加固,采用有限

  7. Aerodynamic force coefficients of plain bridge cables in wet conditions

    DEFF Research Database (Denmark)

    Matteoni, Giulia; Georgakis, Christos T.

    In this paper, the aerodynamic forces and force coefficients from preliminary static wind tunnel tests on a plain cable in wet conditions are presented. The presented results are for several different relative cable wind-angles. A comparison is made with tests in dry conditions. In dry conditions...... aerodynamic damping. Analysis of the fluctuating lift component shows the presence of “enhanced” vortex shedding at specific wind velocities – similar to what might be observed in the presence of a tripping wire......., tests were performed for wind velocities between 2 and 31 m/s, whilst in wet conditions tests were performed for the range of wind velocities where rain rivulet formation was found possible, i.e. between 8-18 m/s. For all of the tested relative cable-wind angles in wet conditions, a reduction...

  8. Reliability Analysis of Bridge Bending Component Strengthened with FRP%FRP加固桥梁受弯构件的可靠性分析

    Institute of Scientific and Technical Information of China (English)

    闫磊; 任伟

    2011-01-01

    This paper studied the bending component strengthened with fibre reinforced polymer(FRP) based on the Specifications for Strengthening Design of Highway Bridge(JTG/T J22-2008 ) with reliability method.The statistics parameters were achieved by means of Monte-Carlo method, the average value was 1. 713, the standard deviation was 0.545 and the variation coefficient was 0.318. The distributing law of reliability index considering ρ and vehicle operation state was studied. The result showed that the reliability of strengthened component was slightly lower than the code. The safety reservations of components were greater for reinforcement of larger increase amplitude load effect.%利用可靠度方法对JTG/T J22-2008中矩形截面受弯构件的FRP加固进行了研究,通过Monte-Carlo法获得了加固后构件抗力的统计参数:均值为1.713、标准差为0.545、变异系数为0.318.考虑不同p值及汽车运行状态,研究了加固后构件可靠指标的分布规律.结果表明:受抗力变异性增大的影响,构件可靠指标略低于规范的标准,加固规范对汽车荷栽提级增幅较大的构件安全设置水准较大.

  9. The brief talk of X128 shui -da line yuliang bridge strengthening engineering construction management%浅谈 X128水大线渔梁桥加固工程建设管理

    Institute of Scientific and Technical Information of China (English)

    瓦庆标

    2016-01-01

    随对我局管养的 X128水大线渔梁桥加固工程建设管理进行简单的阐述。%With the rapid development of Chinese social economy,the development of?highway transportation is also ad-vanced rapidly,and the bridge number is also increased.A large number of highway bridges?were founded in 60,70s in our province,under the function of increasing vehicle load,the technical state rapid decreased,soon the level of bridge de-veloped from class one or two to the three or four or even five,which was a threat to people's lives and property safety,and the bridge collapse accident sometimes happened.The paper mainly conduct a Simple exposition on the X128 Shui -Da line Yuliang Bridge strengthening engineering construction management.

  10. Wireless monitoring of the longitudinal displacement of the Tamar Suspension Bridge deck under changing environmental conditions

    Science.gov (United States)

    de Battista, Nicky; Westgate, Robert; Koo, Ki Young; Brownjohn, James

    2011-04-01

    In order to be able to monitor the performance and health of a civil structure it is essential to understand how it behaves under different environmental conditions. It is a well documented fact that the structural performance of bridges can be altered considerably when they are subjected to changes in environmental conditions. This paper presents a study investigating the longitudinal movement of the road deck on Tamar Suspension Bridge in Plymouth in the UK over six months. The expansion joint of the bridge deck was instrumented with pull-wire type extensometers. The data were transmitted wirelessly using commercial wireless sensor nodes and collected at a data acquisition laptop computer, which was accessible online for remote monitoring. In addition, position data of various locations on the bridge deck were collected using a Robotic Total Station (RTS). Environmental data, such as the temperature, and structural data, such as cable tension, were acquired from other monitoring systems. Conclusions drawn from a fusion of the bridge deck's longitudinal displacement with other structural and environmental data are discussed in this paper.

  11. Durability of reinforced concrete beams strengthened with fiber reinforced polymers under varying environmental conditions

    International Nuclear Information System (INIS)

    Fiber reinforced polymers (FRP) materials were adopted by the aerospace and marine industries, not only for their lightweight and high strength characteristics but also due to their tough and durable nature . As the engineering community has become more familiar with the performance advantages of these materials, new applications have been investigated and implemented. Researches and design guidelines concluded that externally bonded FRP to concrete elements could efficiently increase the capacity of RC elements. Long-term exposure to harsh environments deteriorates concrete and the need for repair and rehabilitation is evident. In order to accept these FRP materials, they must be evaluated for durability in harsh environments. An experimental program was conducted at the materials laboratory- faculty of engineering-Ain Shams university to study the durability of RC beams strengthened with FRP sheets and to compare them with un strengthened beams.The effect of gamma rays on FRP materials and concrete specimens bonded to FRP sheets were also investigated.

  12. Remote monitoring as a tool in condition assessment of a highway bridge

    Science.gov (United States)

    Tantele, Elia A.; Votsis, Renos A.; Onoufriou, Toula; Milis, Marios; Kareklas, George

    2016-08-01

    The deterioration of civil infrastructure and their subsequent maintenance is a significant problem for the responsible managing authorities. The ideal scenario is to detect deterioration and/or structural problems at early stages so that the maintenance cost is kept low and the safety of the infrastructure remains undisputed. The current inspection regimes implemented mostly via visual inspection are planned at specific intervals but are not always executed on time due to shortcomings in expert personnel and finance. However the introduction of technological advances in the assessment of infrastructures provides the tools to alleviate this problem. This study describes the assessment of a highway RC bridge's structural condition using remote structural health monitoring. A monitoring plan is implemented focusing on strain measurements; as strain is a parameter influenced by the environmental conditions supplementary data are provided from temperature and wind sensors. The data are acquired using wired sensors (deployed at specific locations) which are connected to a wireless sensor unit installed at the bridge. This WSN application enables the transmission of the raw data from the field to the office for processing and evaluation. The processed data are then used to assess the condition of the bridge. This case study, which is part of an undergoing RPF research project, illustrates that remote monitoring can alleviate the problem of missing structural inspections. Additionally, shows its potential to be the main part of a fully automated smart procedure of obtaining structural data, processed them and trigger an alarm when certain undesirable conditions are met.

  13. Wet-Strengthening of Paper in Neutral pH Papermaking Conditions

    Science.gov (United States)

    Crisp, M. T.; Riehle, Richard J.

    The ability to wet-strengthen paper is an important requirement of the paper industry because wet strength agents allow for the manufacture of a variety of paper grades and products. The most significant area of application is in the manufacture of hygiene grades of paper, including hand towels and facial tissues, kitchen towels and serviettes, and other tableware products. Another important area of application is in packaging grades, including liquid packaging board for fruit juice and milk cartons; carrier bags and paper sacks; and corrugated cardboard boxes for transportation of fruit, meat and other items. Speciality grades, such as tea bags and coffee filters, bottle labels and currency paper, and wallpaper and poster paper also use wet strength agents. In fact, any grade of paper that needs to maintain a degree of strength and integrity after becoming wet involves the application of a wet strength agent.

  14. 30t轴重下朔黄铁路桥涵结构强化技术试验研究%Experimental Study on Strengthening Method of Bridges and Culverts under 3 0 t Axle Load in Shuo-huang Railway

    Institute of Scientific and Technical Information of China (English)

    薛继连

    2015-01-01

    通过调研朔黄铁路桥涵结构的运营现状,分析30 t轴重货物列车运营条件下各种跨度桥梁运营活载效应与设计活载效应比值,提出朔黄铁路大轴重重载运输强化改造设计活载图式,开展朔黄铁路30 t 轴重货车实车综合试验,根据各类桥涵结构特点和试验结果,得出大轴重重载列车对桥涵结构的作用规律。从钢筋混凝土简支梁、普通高度预应力混凝土梁、低高度及超低高度预应力混凝土梁、桥梁支座、钢筋混凝土涵洞及框构桥和墩台基础等方面,分析了大轴重重载运输条件下桥涵结构面临的主要技术问题,研发了预应力碳纤维板强化、辅助梁强化、小跨度桥涵强化等技术,研制了新型重载支座。各强化技术与措施经朔黄铁路工程实施与强化效果验证,可提高桥涵结构承载能力,能满足30 t轴重货车运营要求。%Based on the investigation of the current operational state of bridges and culverts along the Shuo-Huang Railway,an analysis was performed on the ratio of the actual and designed live load effects on the bridg-es under the actual 30 t axle load of the freight train.The precept of the strengthening and the reconstruction of the bridges loaded under the heavy axle load was proposed.Based on a comprehensive test and the characteris-tics of the structures of the bridges and culverts,the effect of the 30 t axle load of the freight on bridges and culverts of various spans was studied.The main technical problems faced by bridge and culvert structures under the heavy haul transportation condition were analyzed in terms of reinforced concrete simply-supported girder, prestressed concrete girder with normal height,prestressed concrete shallow girder,bridge bearing,reinforced concrete culvert,framed bridge,and footing of abutment and pier.The challenge of the heavy axle load to the current bridges and culverts at service required strengthening with the

  15. Development of the applicability of simplified Henry's method for skewed multicell box-girder bridges under traffic loading conditions

    Institute of Scientific and Technical Information of China (English)

    Iman MOHSENI; A.R.Khalim RASHID

    2012-01-01

    Concrete precast multicell box-girder (MCB) bridges combine aesthetics with torsional stiffness perfectly.Previous analytical studies indicate that currently available specifications are unable to consider the effect of the twisting moment (torsional moment) on bridge actions.In straight bridges the effect of torsion is negligible and the transverse reinforced design is governed by other requirements.However,in the case of skewed bridges the effect of the twisting moment should be considered.Therefore,an in-depth study was performed on 90 concrete MCB bridges with skew angles ranging from 0° to 60°.For each girder the bridge actions were determined under the American Association of State Highway and Transportation Officials (AASHTO) live load conditions.The analytical results show that torsional stiffness and live load positions greatly affected the bridges' responses.In addition,based on a statistical analysis of the obtained results,several skew correction factors are proposed to improve the precision of the simplified Henry's method,which is widely used by bridge engineers to predict bridge actions.The relationship between the bending moment and secondary moments was also investigated and it was concluded that all secondary actions increase with an increase in skewness.

  16. Theoretical analysis of the oscillations of rotating liquid bridges under microgravity conditions

    Science.gov (United States)

    Acero, F. J.; Montanero, J. M.

    A liquid bridge can hold a significant liquid volume and provides a convenient way for its manipulation in microgravity conditions. Apart from their basic scientific interest, a liquid bridge can be considered as the simplest idealisation of the configuration appearing in the floating zone technique used for crystal growth and purification of high melting point materials. This has conferred to the study of liquid bridges a great interest not only in fluid mechanics but also in the field of material engineering. Even in space, the liquid bridge is susceptible to dynamic disturbances that may result from g-jitter, pulse-like accelerations due to a docking activity, crew movement or operation of equipment on the space station, and vibration of machines on board. These perturbations may excite oscillations of the free interface. Therefore it is important to know the natural frequencies and decay rates that characterize those oscillations. The presence of rotation in many artificial satellites and space stations provides a strong motivation for the study of its influence in the dynamics of liquid bridges. In this contribution, an analytical study of the small oscillation modes of rotating liquid columns is carried out. The analysis also includes the effect of an outer bath of similar density to that of the liquid column. However, to simplify the study, the ratio between viscous and capillary forces is assumed to be very small, so that a negligible amount of the oscillation energy is dissipated in the thin boundary layers existing at solid surfaces and fluid interfaces. The oscillation frequency ω depends on the rotation speed Ω due to the competition between the centrifugal and Coriolis inertial forces, and the restoring capillary force. If 2Ωω the motion becomes an internal wave (hyperbolic regime). The influence of the rotation speed on the axisymmetric and non-axisymmetric oscillation modes is studied in detail. The structure of the frequency spectrum as a

  17. Cross spectral energy method for damage assessment of the cable-stayed bridge under operational conditions

    Institute of Scientific and Technical Information of China (English)

    Yang Hezhen; Li Huajun

    2008-01-01

    The new cross spectral energy method (CSEM) is proposed for maintaining cable-stayed bridge safety by the measurable output-only vibration response.Damage assessment of real structures is limited by a series of problems such as unknown ambient excitation forces, errors introduced by system identification,incomplete dynamic measurements, etc.Thus the methodology based on cross spectral energy of each substructure member is derived to meet these challenges.The novel damage index does not require any modal or parameter identification technology.It can be calculated directly from vibration test data.In order to evaluate the efficiency of the presented methodology, a three dimensional (3D) actual cable-stayed bridge model with one or more damaged positions under operational conditions was studied.In order to testify the reliability of damage detection method, the response data was polluted by the random noise.It is proved that the proposed method can successfully localize all damage cases even in noisy data.With the help of examples, the CSEM can potentially be applied as a nondestructive evaluation technique (NDT) for on-line health monitoring of cable-stayed bridges with minimum disruption of its operations.

  18. Local scour around bridge abutments under ice covered condition- an experimental study

    Institute of Scientific and Technical Information of China (English)

    Peng WU; Faye HIRSHFIELD; Jue-yi SUI

    2015-01-01

    The local scour around bridge abutments has been an active research topic for many decades. But very few studies have been conducted regarding the impacts of ice cover on the local scour phenomenon around bridge abutments. A series of ice covered flume experiments were conducted in this study. The shape factors of different abutment types in the local scour were compared. Under ice cover, the shape factor for semi-circular abutments ranges from 0.66~0.71. Three different non-uniform sediments were used withD50s of 0.58 mm, 0.50 mm, and 0.47 mm respectively. Two types of ice cover, namely smooth and rough cover, were created to simulate the impacts of ice cover around the abutments. Maximum scour depth was analyzed under different conditions. The contours of the scour holes were plotted to show the bed morphology and sediment deposition around bridge abutments. An empirical relationship between maximum scour depth, densimetric Froude number and sediment size was developed.

  19. ‘We experienced a lack of tools for strengthening coping and health in encounters with patients with chronic illness': bridging theory and practice through formative research

    Directory of Open Access Journals (Sweden)

    Kristen Heggdal

    2015-11-01

    Full Text Available Background: Healthcare personnel in specialist care in Norway took the initiative to develop their practice in order to improve follow-up of patients with chronic illness. A research project was constructed that involved a close collaboration between practice and research in the development of a new, complex intervention to strengthen patients' ability to live with long-term conditions. Aims and objectives: This paper seeks to describe a part of the research process that involved the first- stage development of the intervention. The first objective is to describe how clinicians, patients and a health researcher collaborated, and to discuss the benefits of this collaborative work for improving practice. The second objective is to outline the intervention's aspects and components. Method: Three clinical sites were chosen for developing the intervention: a rehabilitation unit, an outpatient clinic and a centre for patient education. An interdisciplinary team of nine healthcare personnel and four patients engaged with the researcher(s in the formative research. A list of criteria for reporting on the development of complex interventions was applied to elaborate on intervention components. Results: An intervention was developed that entailed a person-centred approach to facilitating overall health in chronic illness. This involved a change in practice as the professionals acquired a new approach to the use of patients' capacity for health, and as patients began to function as active partners in health promotion. Conclusions: A close collaboration between clinicians, former patients and researcher was necessary for developing a theory and a research-based intervention that improved the follow-up of individuals diagnosed with long-term conditions. The intervention was designed to be applicable across diagnostic categories and in a variety of clinical settings. These patients experience a multitude of challenges that require attention in health

  20. Application of ultrasonic surface wave techniques for concrete bridge deck condition assessment

    Science.gov (United States)

    Li, Mengxing; Anderson, Neil; Sneed, Lesley; Maerz, Norbert

    2016-03-01

    Ultrasonic surface wave (USW) is a well-established technique for the performance monitoring of concrete structures. In order to investigate the capability and reliability of this technique for concrete bridge deck condition assessment, a portable seismic property analyzer (PSPA) with USW capabilities was used to assess the condition of a reinforced concrete bridge deck exhibiting visible evidence of significant deterioration. After the investigation was completed, variable thicknesses of concrete were removed from upper surface of the concrete deck by milling and hydrodemolition, with greater thickness being removed where the concrete was more deteriorated. The thickness of removed concrete during the hydrodemolition process was mapped by Light Detection and Ranging (LiDAR). A comparison of the thickness of concrete removed and the USW data indicates that there is a qualitative correlation between the USW results at each test location and the thickness of concrete removed at those same test locations. Results suggest that the PSPA, and comparable USW techniques, could be potentially effective for estimating the thicknesses of concrete that would be removed during milling and hydrodemolition, although more work is needed to study the relationship between USW and removal thickness data in order to be used for quantity estimations.

  1. Effects of processing condition on the microstructural and tensile properties of 14Cr-based oxide dispersion strengthened alloys

    International Nuclear Information System (INIS)

    Eight different oxide dispersion strengthened (ODS) steels were manufactured to investigate the influence of several processing parameters including milling temperature, rotation speed, and consolidation temperature. Microstructural evolution and resulting mechanical properties were then characterized for the different manufacturing processes. As milling temperature decreases, microstructures become finer and room temperature tensile strength increases. Lowering the consolidation temperature induces an increase in tensile strength with a decrease of ductility. The microstructure becomes homogeneous as the tensile strength increases when the milling speed increases from 100 rpm to 250 rpm. However, the improvement seems to be less effective than the adoption of a cryomilling technique. Porosity development was considerably dependent not only on consolidation condition but also on powder quality after mechanical alloying

  2. M PC复合材料加固空心板梁桥静载试验研究%Study of Static Tests for Using MPC Composite Material to Strengthen Void Plate Girder Bridge

    Institute of Scientific and Technical Information of China (English)

    谷丹丹; 孙全胜

    2015-01-01

    为研究M PC复合材料加固空心板梁桥的有效性,在某跨径13 m的空心板梁桥主梁跨中11 m范围内浇筑M PC复合材料进行加固,桥梁加固前与加固后分别进行静载试验,并采用有限元法建立加固前后主梁的有限元模型,分析加固前后主梁的挠度、裂缝和应变的变化。分析结果表明:工况1(跨中最大弯矩横向对称加载)、工况2(跨中最大弯矩横向偏载加载)下主梁加固后的挠度较加固前分别降低了13.4%、12.6%,加固后主梁的挠度明显减小;在试验过程中,加固后主梁裂缝未见明显变化,裂缝区应变水平降低,较好地抑制了原有裂缝的发展;工况1、工况2下主梁加固后的应变较加固前分别降低了13.75%、14.79%,加固后主梁受拉区应变显著降低;加固后校验系数改善率最大为13.89%,该加固方法能够有效地提高桥梁的承载力和刚度。%To study the efficiency of using MPC composite material to strengthen void plate girder bridge ,within the 11 m area of the midspan of the main girder of a 3 × 13 m void plate girder bridge ,the MPC composite material was cast for the strengthening purpose .Static tests were done before and after the strengthening ,and the finite element method was used to establish the models of the main girder before and after the strengthening ,to analyze the variation of main span deflec‐tion ,cracking and strain .The results of the analysis indicate that under two load cases (load case 1 is the transverse symmetrical loading with maximum midspan bending moment and the load case 2 is the transverse eccentric loading with maximum midspan bending moment .) ,the deflection of main girder reduces by 13 .4% and 12 .6% , respectively , compared with the data before the strengthening ,and the deflection of the main girder after strengthening is distinctively declined . During the process of the tests ,the cracking of the main

  3. Study of Static Tests for Using MPC Composite Material to Strengthen Void Plate Girder Bridge%M PC复合材料加固空心板梁桥静载试验研究

    Institute of Scientific and Technical Information of China (English)

    谷丹丹; 孙全胜

    2015-01-01

    To study the efficiency of using MPC composite material to strengthen void plate girder bridge ,within the 11 m area of the midspan of the main girder of a 3 × 13 m void plate girder bridge ,the MPC composite material was cast for the strengthening purpose .Static tests were done before and after the strengthening ,and the finite element method was used to establish the models of the main girder before and after the strengthening ,to analyze the variation of main span deflec‐tion ,cracking and strain .The results of the analysis indicate that under two load cases (load case 1 is the transverse symmetrical loading with maximum midspan bending moment and the load case 2 is the transverse eccentric loading with maximum midspan bending moment .) ,the deflection of main girder reduces by 13 .4% and 12 .6% , respectively , compared with the data before the strengthening ,and the deflection of the main girder after strengthening is distinctively declined . During the process of the tests ,the cracking of the main girder after the strengthening did not show distinct variation ,the strain level in the cracking area is decreased and the propagation of the original cracking is better curbed .In the contexts of load case 1 and load case 2 ,the strain of the main girder after the strengthening decrease 13 .75% and 14 .79% ,respectively ,compared with data before the strengthening ,and the strain in the tensile area of the main girder is obviously de‐creased .The verification coefficient is improved by a maximum rate of 13 .89% after strengthening and the method is able to effectively improve the load bearing capacity and stiffness of the bridge .%为研究M PC复合材料加固空心板梁桥的有效性,在某跨径13 m的空心板梁桥主梁跨中11 m范围内浇筑M PC复合材料进行加固,桥梁加固前与加固后分别进行静载试验,并采用有限元法建立加固前后主梁的有限元模型,分析加固前后主梁的挠度、裂缝和应变的

  4. Effect of Thermal Bridges in Insulated Walls on Air-Conditioning Loads Using Whole Building Energy Analysis

    OpenAIRE

    Mohamed F. Zedan; Sami Al-Sanea; Abdulaziz Al-Mujahid; Zeyad Al-Suhaibani

    2016-01-01

    Thermal bridges in building walls are usually caused by mortar joints between insulated building blocks and by the presence of concrete columns and beams within the building envelope. These bridges create an easy path for heat transmission and therefore increase air-conditioning loads. In this study, the effects of mortar joints only on cooling and heating loads in a typical two-story villa in Riyadh are investigated using whole building energy analysis. All loads found in the villa, which br...

  5. 侵蚀性环境下桥梁CFRP/BFRP加固后的长期性能试验%Experiment for Long-term Performance of Bridge Girders Strengthened with CFRP/BFRP Sheets and Subjected to Erosion Environment

    Institute of Scientific and Technical Information of China (English)

    孙晓燕; 董伟伟; 王海龙; 何世钦

    2013-01-01

    为了研究侵蚀性环境下服役桥梁构件采用纤维材料加固后的长期性能,对11根具有初始锈蚀损伤的钢筋混凝土梁式构件采用碳纤维布(CFRP)和玄武岩纤维布(BFRP)加固后继续退化的承载力及服役性能进行试验.通过对加固后构件进行电化学加速锈蚀和盐液浸润干湿循环模拟不同程度的后续服役性能退化,研究侵蚀性环境对CFRP和BFRP加固构件在不同后续服役期的承载力、刚度等性能影响规律,同时对比了2种加固材料的耐久性能和成本效益.结果表明:侵蚀性环境下加固后的桥梁构件承载能力评估需综合考虑钢筋锈蚀引起的承载力降低和侵蚀性环境对纤维利用效率的降低;CFRP对刚度提高显著,而BFRP加固具有更好的延性;考虑加固后长期服役性能,CFRP加固后具有较好的耐久性,而BFRP具有较高的成本效益.%To investigate the long-term performance of existing bridge girders strengthened with fiber reinforced plastics (FRP) sheets and subjected to erosion environment, the bearing capacity and service performance experiments of 11 reinforced concrete (RC) girders, which were strengthened with carbon fiber reinforced plastics (CFRP) and basalt fiber reinforced polymer (BFRP) sheets after initial corrosion damage, were conducted. Different subsequent performance degradations for strengthened girders were simulated through electrochemical accelerated corrosion together with wet/dry cycles of salt solution. The effect of environmental erosion on capacity, stiffness and other parameters of CFRP/BFRP strengthened girders in different follow-up service time was tested. The durabilities and costs of the two strengthening materials were also investigated. The results show that the capacity evaluation of bridge girders strengthened with FRP sheets should consider the effect of rebar corrosion together with the environmental reduction of FRP strengthening; the CFRP strengthening improves

  6. Thermodynamic Properties of Hard-Sphere Fluid under Confined Condition Based on Bridge Density Function

    Institute of Scientific and Technical Information of China (English)

    周世琦

    2003-01-01

    Based on the functional integral procedure, a recently proposed bridge density function [J. Chem. Phys. 112 (2000) 8079] is developed to calculate global thermodynamic properties of non-uniform fluids. The resulting surface tension of a hard wall-hard sphere interface as a function of the bulk hard sphere fluid density is in good agreement with the available simulation data. The proposed numerical procedure from the approximation of non-uniform first=order direct correlation function to a non=uniform system with excess Helmholtz free energy is of fundamental importance for phase behaviour under the confined condition due to the fact that many available simple approximations in classical density functional theory are for non=uniform first=order direct correlation function.

  7. Bridge Temporary Strengthening Method Based on Multi-Point Support%基于多点支撑的桥涵临时加固方法

    Institute of Scientific and Technical Information of China (English)

    郭瑞军

    2014-01-01

    近年来大型设备逐渐增多,且其重量远远超过了桥涵的设计荷载。为了使特种车辆安全通过沿线的桥涵,基于多点支撑原理,提出在桥涵下部增设支撑点,通过调整支撑点位置来改变桥涵的受力情况。通过分析桥梁加固前后的内力,证实了此加固方法加固效果明显,可为类似工程提供参考。%In recent years, the number of large equipments is gradually increasing, and their weights are far more than the bridge design load. In order to make the special vehicle go through the bridge safely, based on the principle of multi-point support, the article proposes to add support at the bottom of the bridge, mediate the support position so as to change the stress state of the bridge. By comparing the bridge internal forces before and after reinforcement, the results show that the reinforcement effect is obvious, and the reinforcement method can provide reference for similar projects.

  8. Muscle-strengthening and conditioning activities and risk of type 2 diabetes: a prospective study in two cohorts of US women.

    Directory of Open Access Journals (Sweden)

    Anders Grøntved

    2014-01-01

    Full Text Available BACKGROUND: It is well established that aerobic physical activity can lower the risk of type 2 diabetes (T2D, but whether muscle-strengthening activities are beneficial for the prevention of T2D is unclear. This study examined the association of muscle-strengthening activities with the risk of T2D in women. METHODS AND FINDINGS: We prospectively followed up 99,316 middle-aged and older women for 8 years from the Nurses' Health Study ([NHS] aged 53-81 years, 2000-2008 and Nurses' Health Study II ([NHSII] aged 36-55 years, 2001-2009, who were free of diabetes, cancer, and cardiovascular diseases at baseline. Participants reported weekly time spent on resistance exercise, lower intensity muscular conditioning exercises (yoga, stretching, toning, and aerobic moderate and vigorous physical activity (MVPA at baseline and in 2004/2005. Cox regression with adjustment for major determinants for T2D was carried out to examine the influence of these types of activities on T2D risk. During 705,869 person years of follow-up, 3,491 incident T2D cases were documented. In multivariable adjusted models including aerobic MVPA, the pooled relative risk (RR for T2D for women performing 1-29, 30-59, 60-150, and >150 min/week of total muscle-strengthening and conditioning activities was 0.83, 0.93, 0.75, and 0.60 compared to women reporting no muscle-strengthening and conditioning activities (p<0.001 for trend. Furthermore, resistance exercise and lower intensity muscular conditioning exercises were each independently associated with lower risk of T2D in pooled analyses. Women who engaged in at least 150 min/week of aerobic MVPA and at least 60 min/week of muscle-strengthening activities had substantial risk reduction compared with inactive women (pooled RR = 0.33 [95% CI 0.29-0.38]. Limitations to the study include that muscle-strengthening and conditioning activity and other types of physical activity were assessed by a self-administered questionnaire and that

  9. 论如何加强桥梁现场施工管理%Discussion on How to Strengthen the Site Management of Bridge Construction

    Institute of Scientific and Technical Information of China (English)

    李钦

    2013-01-01

      随着我国经济的高速发展,对交通网络体系的要求越来越高。桥梁现场施工管理技术是一项集科学性、专业性、操作性、实践性于一体的工程监管工作。本文就提高桥梁现场施工管理,提出了若干建议。%With the rapid development of Chinese economy, the demand increasingly higher for traffic network system. Co-nstruction management technology of bridge site is an organic whole set of scientific, professional, operation, practice engin-eering supervision work. This paper wil improve the bridge construction site management, and puts forward some suggest-ions.

  10. Optimization Design of Strengthening Prefabricated T-Shaped Beam Bridge:Case Study of Maintenance and Strengthening of Municipal Flyover%装配式T形梁桥加固设计优化分析--以某市政跨线桥维修加固工程为例

    Institute of Scientific and Technical Information of China (English)

    汪洋

    2014-01-01

    Taking the engineering of strengthening a simply supported T-shaped beam bridge as an exam-ple, the paper analyzes the mechanical property of T-shaped beam bridge by the finite element software named Midas Civil, as well as the changing rules of the stress of diaphragms and main beams, the structur-al improvement factor and the transversal uneven amplifying coefficient of T-shaped beam bridge with the different location of additional diaphragms. Finally, the optimal location of diaphragm is confirmed.%以简支T形梁桥加固工程为背景,利用Midas Civil有限元软件对T梁桥进行力学性能分析,总结出纵向不同位置增设横隔梁时,T梁桥的横隔梁及主梁应力、结构改善系数和横向不均匀增大系数的变化规律,从而最终确定横隔梁最佳位置。

  11. The behaviour of a floating water bridge under reduced gravity conditions

    International Nuclear Information System (INIS)

    When high voltage is applied to pure water filled into two beakers close to each other, a connection forms spontaneously, giving the impression of a floating water bridge (Armstrong 1893 The Electrical Engineer pp 154-45, Uhlig W 2005 personal communication, Fuchs et al 2007 J. Phys. D: Appl. Phys. 40 6112-4, Fuchs et al 2008 J. Phys. D: Appl. Phys. 41 185502, Fuchs et al 2009 J. Phys. D: Appl. Phys. 42 065502, Fuchs et al 2010 J. Phys. D: Appl. Phys. 43 105502, Woisetschlaeger et al 2010 Exp. Fluids 48 121-31, Nishiumi and Honda 2009 Res. Lett. Phys. Chem. 2009 371650). This phenomenon is of special interest, since it comprises a number of phenomena currently tackled in modern water science. In this work, the behaviour of this phenomenon under reduced gravity conditions during a parabolic flight is presented by the means of high speed imaging with fringe projection. An analysis of the behaviour is presented and compared with theoretical considerations.

  12. 压力性尿失禁患者液桥试验影响的研究%Study of Strengthening nursing on fluid bridge test for patients with stress incontinence

    Institute of Scientific and Technical Information of China (English)

    丁清清; 刘会范; 张瑞莉; 齐艳

    2011-01-01

    Objective To study the impact of strengthening nursing on the results and complications of fluid bridge test in the women with urodynamic stress incontinence. Methods The fluid bridge tests were competed in this study on 100 women with urodynamic stress incontinence confirmed by urodynamic study. According to the degree of nursing intervention, the cases were randomly divided into control group (only received routine nursing interventions) and experimental group ( additionally received strengthening nursing interventions) of 50 cases. The pareamenters were compared between two group including the facial expressions of pain score (FPS - R) , state anxiety inventery( S - AI) ,fluid bridge test, and incidence of febrile urinary tract infection. Results The FPS - R and S - AI of experimental group was (2 ±0. 9) and (35. 79 ±6. 97) , significantly lower than that of control group. However, the positive rate of fluid bridge test was 96% , singifcantly higher than that of control group and there was no significant difference in the incidence of febrile urinary tract infection between both groups (P = 0. 358). Conclusions Strengthening nursing intervention can improve quality of fluid bridge test for the patients with urodynamic stress incontinence and reduce the level of pain and anxiety.%目的 研究对女性压力性尿失禁患者液桥试验检查结果及并发症的影响.方法 随机选取经尿动力学检查证实为压力性尿失禁女性患者100例进行液桥试验.依据干预程度,将其随机分为实验组和对照组各50例.对照组给予常规护理干预措施,实验组在其基础上给予强化护理干预措施.记录液桥试验结果、疼痛评分(Facepain rating scale FPS-R)、状态焦虑问卷(State-Trait Anxiety Inventery,S-AI)得分和检查后2d内发热性泌尿系感染发生情况.结果 FPS-R评分和S-AI评分实验组分别为2±0.9和35.79±6.97,均显著低于对照组(2.5±0.8和43.56±9.10);实验组患者液

  13. Streambed scour evaluations and conditions at selected bridge sites in Alaska, 2012

    Science.gov (United States)

    Beebee, Robin A.; Schauer, Paul V.

    2015-11-19

    Streambed scour potential was evaluated at 18 river- and stream-spanning bridges in Alaska that have unknown foundation details or a lack of existing scour analysis. All sites were evaluated for stream stability and long-term scour potential. Contraction scour and abutment scour were calculated for 17 bridges, and pier scour was calculated for 7 bridges that had piers. Vertical contraction (pressure flow) scour was calculated for sites with overtopping floods (where the modeled water surface was higher than the superstructure of the bridge). In most cases, hydraulic models of the 1- and 0.2-percent annual exceedance probability floods (also known as the 100- and 500-year floods, respectively) were used to derive hydraulic variables for the scour calculations. Alternate flood values were used in scour calculations for sites where smaller floods overtopped a bridge or where standard flood-frequency estimation techniques did not apply. Scour was also calculated for large recorded floods at several sites. Equations for scour in cohesive soils were used for sites where streambed sediment was silt-sized or smaller.

  14. Effect of Thermal Bridges in Insulated Walls on Air-Conditioning Loads Using Whole Building Energy Analysis

    Directory of Open Access Journals (Sweden)

    Mohamed F. Zedan

    2016-06-01

    Full Text Available Thermal bridges in building walls are usually caused by mortar joints between insulated building blocks and by the presence of concrete columns and beams within the building envelope. These bridges create an easy path for heat transmission and therefore increase air-conditioning loads. In this study, the effects of mortar joints only on cooling and heating loads in a typical two-story villa in Riyadh are investigated using whole building energy analysis. All loads found in the villa, which broadly include ventilation, transmission, solar and internal loads, are considered with schedules based on local lifestyles. The thermal bridging effect of mortar joints is simulated by reducing wall thermal resistance by a percentage that depends on the bridges to wall area ratio (TB area ratio or Amj/Atot and the nominal thermal insulation thickness (Lins. These percentage reductions are obtained from a correlation developed by using a rigorous 2D dynamic model of heat transmission through walls with mortar joints. The reduction in thermal resistance is achieved through minor reductions in insulation thickness, thereby keeping the thermal mass of the wall essentially unchanged. Results indicate that yearly and monthly cooling loads increase almost linearly with the thermal bridge to wall area ratio. The increase in the villa’s yearly loads varies from about 3% for Amj/Atot = 0.02 to about 11% for Amj/Atot = 0.08. The monthly increase is not uniform over the year and reaches a maximum in August, where it ranges from 5% for Amj/Atot = 0.02 to 15% for Amj/Atot = 0.08. In winter, results show that yearly heating loads are generally very small compared to cooling loads and that heating is only needed in December, January and February, starting from late night to late morning. Monthly heating loads increase with the thermal bridge area ratio; however, the variation is not as linear as observed in cooling loads. The present results highlight the importance of

  15. Numerical Analysis of the Dynamic Response of Existing Railway Bridges.

    OpenAIRE

    Frøseth, Gunnstein Thomas

    2014-01-01

    The railway is an important part of the infrastructure in todays society and there is a need to increase the capacity and verify the existing railway network to face the challenges of tomorrow. To meet todays and the future demand set upon the railway network, there is a need to strengthen and assess the condition of existing railway bridges. This thesis focuses on numerical analysis of the dynamic response of railway bridges. First, viscous damping models are considered since they represent ...

  16. 多种加固方法应用于双曲拱桥主拱圈的提载加固%Reinforcement for Improving Bearing Capacity of A Double Arch Bridge Main Arch by Strengthen Methods

    Institute of Scientific and Technical Information of China (English)

    黄伟; 申波; 薛守宝; 梁影

    2012-01-01

    In this paper, reinforcement for improving the bearing capacity of a double arch bridge is studied. Based on the test results of a double-arched bridge of Anshun in Guizhou province, the strengthening program of the main arch is proposed. At the section of arch feet, the moment bearing capacity is improved by enlarged upper edge concrete and lower edge concrete of the section, the section is changed to box section. At the other section of the arch, the negative moment bearing capacity is improved by enlarged upper edge concrete of the section, and the positive moment bearing capacity is improved. For the deficiencies of the positive moment bearing capacity, the bonding steel plate is recommended at the arch rib of the other section. The results show that the reinforcement methods can improve load level of the bridge effectively. The construction of the bridge is convenient and can satisfy the design goals.%针对双曲拱桥的提载加固,基于贵州省安顺市木浪河大桥的检测结果,提出了在主拱圈的拱脚上缘增大截面、下缘增大截面改造为箱形断面,以提高拱脚抵抗负弯矩、正弯矩的承载能力;对其它截面采用拱背增大截面以提高抵抗负弯矩的承载能力,相应也提高了抵抗正弯矩的承载能力;对正弯矩承载能力不足的截面,采用粘贴钢板的加固方法.结果表明:采用这种提载加固的设计方法,达到了提高荷载等级的目的,同时方便施工,便于达到加固效果.

  17. Soft soil strengthening by stone columns: case of the embankment under the bridge “Moulay Youssef” (Rabat/Salé

    Directory of Open Access Journals (Sweden)

    Nehab Noura

    2014-04-01

    Full Text Available The soil is generally a heterogeneous material presenting very variable characteristics. In a general way, the main problems related to soils are: low bearing capacity, deformations under static or dynamic loads, large displacements and large settlements of soft soil where the soil moves according to a fixed ground water table. The development of soil mechanics and geotechnical engineering has led to the amelioration of a wide range of soil improvement techniques. These techniques consist in modifying the characteristics of the ground by physical action or by incorporating columnar inclusions made of highly compacted gravel or granular material into the original soil. Stone column is one of the soft ground improvement methods, applicable to a wide range of soil strata and an economical method of support in compressible and cohesive soils. However, there are many difficulties in quantitative analysis of soil column interaction due to the fact that bearing capacity and consolidation behavior of stone column-mat foundation system is affected by various parameters. In the present study, mechanism and various parameters of stone column behavior are investigated by loading tests. Also, tests results are compared to the finite element numerical modeling “Plaxis 2D” (case study: the embankment under the bridge “Moulay Youssef, Rabat/Salé”.

  18. 铁路框架桥纵横梁线路加固体系模型优化与结果评价标准研究%Model Optimization and Evaluation Standard of Railway Track Strengthening System with Longitudinal-Transverse Beams during Construction of Frame Bridge

    Institute of Scientific and Technical Information of China (English)

    彭斌; 高玉兰

    2014-01-01

    In this paper, the static calculation model of railway track strengthening system was optimized, and a three-dimensional model with longitudinal members was built involving rail, longitudinal beam, track-fastening beam, and so on; and also the influences of frame bridge and soil excavation on the strengthening system were taken into consideration. Then, by giving multiple working conditions with different parameters, a comparative analysis of numerical simulation results between the optimized model and the simplified model was carried out under each working condition. Then, comprehensively considering relevant standard codes and specifications, an evaluation standard of static calculation result of railway track strengthening system with longitudinal-transverse beams was established. Furthermore, based on simulation calculation results, the transverse beam's deflection and stresses as well as the rail's deflection were analyzed under each working condition, and the results were evaluated by using the suggested evaluation standard. The research results show that the optimized model can more accurately simulate the field working conditions, making the calculation result more reliable; and if evaluating calculation results by using the suggested evaluation standard, the evaluation conclusion will be on the safe side.%对静力计算的模型进行了优化,建立加入钢轨、纵梁及扣轨梁等纵向构件的三维模型,考虑了支撑加固体系的框构桥及开挖土体的影响;设置变化不同参数的多个工况,将优化模型与简化模型在各工况下的数值模拟结果进行比较与分析;综合考察相关规范及规定,从而建立评价纵横梁线路加固体系静力计算结果的标准。基于模拟计算的结果,分析了各工况下横梁的挠度和应力以及钢轨的挠度,并利用建立的评价标准进行评价。研究表明,优化模型能够较精确地模拟现场工况,使计算结果更加贴近

  19. Control of bridge cranes with distributed-mass payloads under windy conditions

    Science.gov (United States)

    Tang, Rui; Huang, Jie

    2016-05-01

    Operating cranes is challenging because payloads experience large and dangerous oscillations, especially when the system is suffering from wind disturbances and the large-size payload is modeled as a distributed-mass model. The payload oscillations induced by both intentional motions commanded by the human operator and by the external wind disturbances make the dynamics more complicated. This paper presents a novel combined control architecture to limit oscillations of the distributed-mass payload caused by both human-operator commands and wind disturbances. While a smoothed command suppressed operator-induced oscillations, a wind-rejection command eliminated the payload swing resulting from the wind gusts. Through simulations, a large range of system parameters and motions are analyzed to investigate the dynamic behavior of bridge cranes with distributed-mass beams and wind disturbances by using the new control scheme. Experimental results obtained from a small-scale bridge crane validate the simulated dynamic behavior and the effectiveness of the proposed method.

  20. 浅埋式桩基础钢筋混凝土拱桥桥墩防撞安全性评价与加固技术研究%Pier anti-collision safety evaluation of reinforced concrete arch bridge with shallow-buried piles and its strengthening technology research

    Institute of Scientific and Technical Information of China (English)

    吴超; 李德建; 宁夏元; 胡先春

    2013-01-01

    On the background of Yuan River bridge in Wuqiangxi,a method of pier anti-cillision safety evaluation,based on "Highway Bridge Code for Design",was put forward for reinforced concrete arch bridge with shallao-buried piles.On the basis of safety evaluation of Yuan River Bridge pier,a pier strengthening project of Yuan River Bridge in Wuqiangxi was proposed.In order to simulate the interaction of new and old concrete after strengthening of foundation,three-dimensional solid elements were adopted,where two situations of the interface between new and old concrete,i.e.,fully bonded or sliding were taken into account.The feasibility of this pier reinforcement project was studied,which can also provide reference for the similar bridge strengthening engineering.%以五强溪沅水大桥为工程背景,针对浅埋式桩基础钢筋混凝土拱桥,提出基于我国公路桥涵设计规范桥墩防撞安全性评价方法.通过对该桥的桥墩防撞安全性评价提出了相应的桥墩加固方案.采用三维实体单元来模拟基础加固后新老混凝土的共同作用,同时考虑新老混凝土接触面按完全粘结与滑动2种情况建立计算模型,对桥墩防撞加固方案的可行性进行了研究,亦可供同类桥梁加固参考.

  1. Performance Improvement of DFIG-based Wind Farm Using Multilevel Cascaded H-bridge Converter under Unbalanced Grid Voltage Conditions

    DEFF Research Database (Denmark)

    Shokri, Yunes; Ebrahimzadeh, Esmaeil; Lesani, Hamid;

    2014-01-01

    This paper presents a new configuration of doubly fed induction generator (DFIG)-based wind farm with multilevel cascaded H-bridge (CHB) converter and its control system, which is suitable not only for unbalanced grid voltage conditions, but also for small voltage sags. The proposed configuration...... of DFIG can balance the point of common coupling (PCC) voltage without needing additional DC link capacitor or energy storage unlike other configurations and methods. Consequently, the stator voltage and the other loads voltage connected to the PCC are kept constant at the nominal value. The new...... configuration improves all the DFIG signals under unbalanced grid voltage and small voltage sag conditions unlike other methods. Some of the DFIG units in wind farm require to connect the CHB converter, therefore, it is cost-effective. Matlab/Simulink is used for simulation of a 13.5-MW wind farm consisting of...

  2. Demonstration of Bridge Type Schemes for Maanshan Changjiang River Bridge Under Condition of Complicated River Pattern%复杂河势条件下的马鞍山长江大桥桥型方案论证

    Institute of Scientific and Technical Information of China (English)

    杨光武

    2013-01-01

    马鞍山长江公路大桥所处河段为分汊河段,其中左汊主桥桥址处河势条件复杂,通过对桥址处河势条件及通航要求等建桥条件的综合分析,对5种左汊主桥桥型方案(主跨2×1080m三塔悬索桥方案、主跨1 388 m两塔悬索桥方案、主跨1 180m两塔斜拉桥方案、主跨2×850m三塔斜拉桥方案、主跨1 760m单跨悬索桥方案)从航道适应性、工程经济性进行比较和论证.经过综合比选,确定马鞍山长江公路大桥左汊主桥采用主跨2×1 080 m三塔两跨悬索桥,较好地解决了深槽左右摆动引起的航道适应性问题,为大桥的顺利立项和获批创造了有利条件.%The river reaches at the site of Maanshan Changjiang River Highway Bridge are the forked reaches, of which the condition of river pattern of the reach at the site of the main bridge of the left bridge is quite complicated. Through the comprehensive analysis of the construction conditions, such as the river pattern and navigation requirements, of the site of the main bridge, five bridge type schemes (i. e. a three-tower suspension bridge with main spans 2×1 080 m, a two-tower suspension bridge with a main span 1 388 m, a two-pylon cable-stayed bridge with a main span 1 180 m, a three-pylon cable-stayed bridge with main spans 2×850 m and a single-span suspension bridge with a main span 1 760 m) put forward for the bridge were compared and demonstrated from aspects of the waterway adaptability and engineering economy. On the basis of the comparison and demonstration, it was finally determined that the scheme of the three-tower and two-span suspension bridge with main spans 2×1080 m should be chosen for the bridge. With the chosen scheme, the problem of the waterway adaptability affected by the left and right swaying of the deep channel was well resolved and the favorable conditions for the successful determining and approval of the bridge project were thus created.

  3. THE INFLUENCE OF BORDER CONDITIONS ON REINFORCED BRIDGE AND LOCOMOTIVE DYNAMICS

    Directory of Open Access Journals (Sweden)

    A. S. Raspopov

    2010-11-01

    Full Text Available In this article the effect of boundary conditions on dynamic performance of reinforced concrete span during the motion of a locomotive is studied. The critical speeds of a load motion under vertical and longitudinal construction vibrations are determined.

  4. Transforming School Conditions: Building Bridges to the Education System that Students and Teachers Deserve

    Science.gov (United States)

    Daughtrey, Alesha

    2010-01-01

    In this report the TeacherSolutions Teacher Working Conditions team--a group of 14 accomplished teachers who work in mostly high-needs schools and districts, both urban and rural, draw on current research and Center for Teaching Quality case studies to identify essential, research-based principles that must undergird sustainable and effective…

  5. Fitness yoga as modern technology of special health groups’ girl students’ psycho-physical condition and psycho-social health strengthening

    Directory of Open Access Journals (Sweden)

    Skurikhina N.V.

    2016-04-01

    Full Text Available Purpose: substantiation of purposefulness of fitness yoga application for strengthening of special health groups’ girl students’ psycho-physical condition and psycho-social health at physical culture training and recreation classes. Material: trainings were practiced twice a week in 2 groups with 20 girl students in every group. Each training session lasted 60 minutes. The following indicators were registered: pressing ups in lying position; torso bending during 30 sec. from lying on back position; rising legs up to 90 degrees angle in hanging position; long jump from the spot; forward torso bending; test for coordination. Health condition was determined by express assessment of physical health. Results: in both groups girl students’ backbone mobility increased (р<0/05. First group’s girl students demonstrated higher results in pressing ups in lying position during 30 sec. (by 7.34+1.2 times and in long jump from the spot (14.2+0.4 cm. It was noticed that fitness yoga exercises render positive influence on girl students’ psycho-emotional state, general physical self-feeling and physical condition. Conclusions: targeted fitness yoga exercises’ influences on girl-students’ organism are recommended for support and correction of their health.

  6. Understanding and simulating vibrations of plain bridge cables under varying meteorological conditions

    DEFF Research Database (Denmark)

    Matteoni, Giulia

    -scale monitoring, wind tunnel testing and theoretical modelling. An extensive wind tunnel test campaign was then undertaken in order to further understand the onset conditions and characteristics of instability in the different climatic conditions described in the literature. Tests were separated into two...... exhibits marked variations. This variation is sufficient to generate negative quasi-steady aerodynamic damping, and thus to potentialy lead to galloping instability. Passive dynamic wind tunnel tests were subsequently undertaken for a cable section model of the same type as the one tested in static......-to-peak amplitudes and aerodynamic damping, changes consistently with Reynolds number, for the tested wind angles-of-attack. In fact, for selected angles-of-attack, the response was stable thoughout the whole tested range of Reynolds number, while for other angles, negative aerodynamic damping, accompanied by large...

  7. Catalytic defluorination of perfluorinated aromatics under oxidative conditions using N-bridged diiron phthalocyanine.

    Science.gov (United States)

    Colomban, Cédric; Kudrik, Evgenij V; Afanasiev, Pavel; Sorokin, Alexander B

    2014-08-13

    Carbon-fluorine bonds are the strongest single bonds in organic chemistry, making activation and cleavage usually associated with organometallic and reductive approaches particularly difficult. We describe here an efficient defluorination of poly- and perfluorinated aromatics under oxidative conditions catalyzed by the μ-nitrido diiron phthalocyanine complex [(Pc)Fe(III)(μ-N)Fe(IV)(Pc)] under mild conditions (hydrogen peroxide as the oxidant, near-ambient temperatures). The reaction proceeds via the formation of a high-valent diiron phthalocyanine radical cation complex with fluoride axial ligands, [(Pc)(F)Fe(IV)(μ-N)Fe(IV)(F)(Pc(+•))], which was isolated and characterized by UV-vis, EPR, (19)F NMR, Fe K-edge EXAFS, XANES, and Kβ X-ray emission spectroscopy, ESI-MS, and electrochemical techniques. A wide range of per- and polyfluorinated aromatics (21 examples), including C6F6, C6F5CF3, C6F5CN, and C6F5NO2, were defluorinated with high conversions and high turnover numbers. [(Pc)Fe(III)(μ-N)Fe(IV)(Pc)] immobilized on a carbon support showed increased catalytic activity in heterogeneous defluorination in water, providing up to 4825 C-F cleavages per catalyst molecule. The μ-nitrido diiron structure is essential for the oxidative defluorination. Intramolecular competitive reactions using C6F3Cl3 and C6F3H3 probes indicated preferential transformation of C-F bonds with respect to C-Cl and C-H bonds. On the basis of the available data, mechanistic issues of this unusual reactivity are discussed and a tentative mechanism of defluorination under oxidative conditions is proposed.

  8. Bridging Mediterranean cultures in the IYS: A documentary exhibition on irrigation techniques in water scarcity conditions

    Science.gov (United States)

    Barontini, Stefano; Louki, Amina; Ben Slima, Zied; Ezzahra Ghaouch, Fatima; Labaran, Raisa; Raffelli, Giulia; Peli, Marco; Vitale, Nicola

    2015-04-01

    Brescia, an industrial city in Northern Italy, is now experiencing a crucial change in its traditional structure. In recent years in fact it has been elected as living and working seat by many foreigners and it is now one of the cities with the greatest percentage of migrants in the Country. This is an important challenge for the city and an opportunity to merge, compare and integrate different cultures to build its future. In this context some students of different Courses (engineering and medicine), belonging both to the Arabian and local community, met together and with researchers in the study team 'Al-B¯i r¯u n¯i , for culture, science and society'. The team aims at organising cultural events in which, starting from the figure of the Persian scientist Ab¯u Raih. ¯a n Al-B¯i r¯u n¯i (about 973, 1051), the contribution of the Arabian and Islamic culture to the development of the European one in the middle ages is investigated. Moving from the initial idea of the study team Al-B¯i r¯u n¯i and from the suggestions of the World Soil Day 2014 and of the International Year of Soils 2015, we built a documentary exhibition entitled 'Irrigation techniques in water scarcity conditions'. The exhibition, which stresses the importance of the irrigation techniques for the soil conservation, is focused on the idea of disseminating two main concepts, i.e. (1) the technological continuity of some water supply systems in countries, around the Mediterranean Sea, affected by similar conditions of water availability, and (2) the possibility of building environments where, due to severe or extreme climatic conditions, the sustainability is reached when the man lives in equilibrium with the nature. The exhibition, which is written in Italian and will move around in the city during all 2015, consists of about twenty posters organized into three main chapters, corresponding to three main classes of water supply systems which are common in most of the countries surrounding

  9. Effects of surface roughness and cross-sectional distortion on the wind-induced response of bridge cables in dry conditions

    DEFF Research Database (Denmark)

    Matteoni, G.; Georgakis, Christos T.

    2015-01-01

    , for varying Reynolds numbers and wind angles-of-attack. Using passive-dynamic wind tunnel tests, it is shown that the in-plane aerodynamic damping of a bridge cable section, and the overall dynamic response, is strongly affected by changes in the wind angle-of-attack. Using the drag and lift coefficients......, determined in static conditions for an identical cable model as the one used for passive-dynamic tests, the in-plane aerodynamic damping is evaluated by employing a one-degree-of-freedom (1 DOF) quasi-steady analytical model. Similarly, it is shown that regions of instability associated with the occurrence......Theoretical and experimental investigations to date have assumed that bridge stay cables can be modelled as ideal circular cylinders and that their aerodynamic coefficients are invariant with wind angle-of-attack. On the other hand it has been demonstrated that bridge cables are characterised...

  10. Generalized Fragility Relationships with Local Site Conditions for Probabilistic Performance-based Seismic Risk Assessment of Bridge Inventories

    Directory of Open Access Journals (Sweden)

    Sivathayalan S.

    2012-01-01

    Full Text Available The current practice of detailed seismic risk assessment cannot be easily applied to all the bridges in a large transportation networks due to limited resources. This paper presents a new approach for seismic risk assessment of large bridge inventories in a city or national bridge network based on the framework of probabilistic performance based seismic risk assessment. To account for the influences of local site effects, a procedure to generate site-specific hazard curves that includes seismic hazard microzonation information has been developed for seismic risk assessment of bridge inventories. Simulated ground motions compatible with the site specific seismic hazard are used as input excitations in nonlinear time history analysis of representative bridges for calibration. A normalizing procedure to obtain generalized fragility relationships in terms of structural characteristic parameters of bridge span and size and longitudinal and transverse reinforcement ratios is presented. The seismic risk of bridges in a large inventory can then be easily evaluated using the normalized fragility relationships without the requirement of carrying out detailed nonlinear time history analysis.

  11. Railroad Bridges

    Data.gov (United States)

    Department of Homeland Security — Bridges-Rail in the United States According to The National Bridge Inspection Standards published in the Code of Federal Regulations (23 CFR 650.3), a bridge isA...

  12. A Review on Strengthening Steel Beams Using FRP under Fatigue

    Directory of Open Access Journals (Sweden)

    Mohamed Kamruzzaman

    2014-01-01

    Full Text Available In recent decades, the application of fibre-reinforced polymer (FRP composites for strengthening structural elements has become an efficient option to meet the increased cyclic loads or repair due to corrosion or fatigue cracking. Hence, the objective of this study is to explore the existing FRP reinforcing techniques to care for fatigue damaged structural steel elements. This study covers the surface treatment techniques, adhesive curing, and support conditions under cyclic loading including fatigue performance, crack propagation, and failure modes with finite element (FE simulation of the steel bridge girders and structural elements. FRP strengthening composites delay initial cracking, reduce the crack growth rate, extend the fatigue life, and decrease the stiffness decay with residual deflection. Prestressed carbon fibre-reinforced polymer (CFRP is the best strengthening option. End anchorage prevents debonding of the CRRP strips at the beam ends by reducing the local interfacial shear and peel stresses. Hybrid-joint, nanoadhesive, and carbon-flex can also be attractive for strengthening systems.

  13. A Review on Strengthening Steel Beams Using FRP under Fatigue

    Science.gov (United States)

    Jumaat, Mohd Zamin; Ramli Sulong, N. H.

    2014-01-01

    In recent decades, the application of fibre-reinforced polymer (FRP) composites for strengthening structural elements has become an efficient option to meet the increased cyclic loads or repair due to corrosion or fatigue cracking. Hence, the objective of this study is to explore the existing FRP reinforcing techniques to care for fatigue damaged structural steel elements. This study covers the surface treatment techniques, adhesive curing, and support conditions under cyclic loading including fatigue performance, crack propagation, and failure modes with finite element (FE) simulation of the steel bridge girders and structural elements. FRP strengthening composites delay initial cracking, reduce the crack growth rate, extend the fatigue life, and decrease the stiffness decay with residual deflection. Prestressed carbon fibre-reinforced polymer (CFRP) is the best strengthening option. End anchorage prevents debonding of the CRRP strips at the beam ends by reducing the local interfacial shear and peel stresses. Hybrid-joint, nanoadhesive, and carbon-flex can also be attractive for strengthening systems. PMID:25243221

  14. Hydrology and modeling of flow conditions at Bridge 339 and Mile 38-43, Copper River Highway, Alaska

    Science.gov (United States)

    Brabets, Timothy P.

    2012-01-01

    The Copper River basin, the sixth largest watershed in Alaska, drains an area of 24,200 square miles in south-central Alaska. This large, glacier-fed river flows across a wide alluvial fan before it enters the Gulf of Alaska. The Copper River Highway, which traverses the alluvial fan, has been affected by channel planform reconfiguration. Currently (2012), two areas of the Copper River Highway are at risk: at Mile 38-43, the road grade is too low and the highway could be flooded by high flows of the Copper River, and at Mile 36, the main channel of the Copper River has migrated directly toward Bridge 339. Because Bridge 339 was not designed and built to convey the main flow of the Copper River, as much as 50 feet of scour occurred at the piers in 2011. The piers can no longer absorb the lateral or vertical loads, resulting in closure of the bridge and the Copper River Highway. The U.S. Geological Survey Flow and Sediment Transport with Morphologic Evolution of Channels (FaSTMECH) model was used to simulate the flow of the Copper River and produce simulations of depth, water-surface elevation, and velocity. At the Mile 38-43 area, FaSTMECH was used to analyze the effects of raising the road grade 5 feet, and at Mile 36, FaSTMECH was used to analyze the effects of constructing a channel to divert flow away from Bridge 339. Results from FaSTMECH indicate that if raising the road grade 5 feet in the Mile 38-43 area, a flood with an annual exceedance probability of 2 percent (400,000 cubic feet per second) would not overtop the highway. In the Bridge 339 area, results from FaSTMECH indicate that a design channel could divert flows as much as 100,000 cubic feet per second away from Bridge 339.

  15. Heavy Vehicles on Minor Highway Bridges

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Nielsen, Søren R. K.; Enevoldsen, I.

    Vibration of a bridge structure due to the passage of vehicles is an important consideration in the design of bridges. Further, a common problem in bridge engineering practice in these years is the upgrading of minor highway bridges (=5-20 m) to carry heavier loads partly due to a tendency...... of heavier trucks moving at larger speeds, and partly because the authorities want to permit transportation of special heavy goods at a larger part of the road net. These needs will in many cases cause the strengthening of the bridges becomes necessary. In order to keep the expenses of such strengthening...... the results obtained using the numerical models given in details in "Heavy Vehicles on Minor Highway Bridges : dynamic modelling of vehicles and bridges". The models are established using a ordinary vehicle which consists of a 48 t Scania with a 3 axle tractor and a 3 axle trailer, joined in a flexible hinge...

  16. Heavy Vehicles on Minor Highway Bridges

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Nielsen, Søren R. K.; Enevoldsen, I.

    Vibration of a bridge structure due to the passage of vehicles is an important consideration in the design of bridges. Further, a common problem in bridge engineering practice in these years is the upgrading of minor highway bridges (=5-20 m) to carry heavier loads partly due to a tendency...... of heavier trucks moving at larger speeds, and partly because the authorities want to permit transportation of special heavy goods at a larger part of the road net. These needs will in many cases cause the strengthening of the bridges becomes necessary. In order to keep the expenses of such strengthening...... the numerical models for the mathematical models of the vehicles and the bridge from which the load amplification factors can be estimated assuming that the dynamic parameters of the vehicles and the modal parameters of the bridge are known....

  17. Reinforcement and numerical analysis on the corbel of a half-through arch bridge

    Institute of Scientific and Technical Information of China (English)

    LIAO Bi-hai; WANG Yuan-han; CHENG Hong-guang; MIAO Yu

    2009-01-01

    Corbels support the crossbeams of half-through arch bridges. They are prone to cracking easily due to their characteristics and complicated loading conditions. Based on a practical diagnosis of a bridge crossbeam, we bonded steel plates onto bridge corbels to strengthen them. We carried out a numerical analysis on the effectiveness of the reinforcement by using the commercial software ANSYS. The numerical analysis shows that the stresses near the section break increased slightly, but the variation amplitude was small and all the stresses were within an allowable range. The loading test indicates that it is feasible to strengthen the corbel with vertical bonded steel plates. Therefore, the reinforcement is effective and economical. This reinforcement method is suitable for this type of corbel and can be applied in similar cases.

  18. Active Control of Suspension Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper some recent research on active control of very long suspension bridges, is presented. The presentation is based on research work at Aalborg University, Denmark. The active control system is based on movable flaps attached to the bridge girder. Wind load on bridges with or without...... flaps attached to the girder is briefly presented. A simple active control system is discussed. Results from wind tunnel experiments with a bridge section show that flaps can be used effectively to control bridge girder vibrations. Flutter conditions for suspension bridges with and without flaps...

  19. 粘钢加固损伤混凝土箱型桥墩的抗震性能Ⅱ:动力响应数值分析%Anti-seismic properties of damaged concrete bridge piers with hollow cross-section strengthened with adhering steel platesⅡ:numerical analysis on seismic dynamic responses

    Institute of Scientific and Technical Information of China (English)

    邓江东; 宗周红; 黎雅乐; 刘爱荣

    2013-01-01

    The flexibility method and the fiber model were used to numerically simulate the earth-quake dynamic response of the damaged concrete bridge piers with hollow cross-section strengthened with adhering steel plates.The performance index,such as the seismic forces at the piers bottom, pier top displacement and residual stiffness,were analyzed,and on the basis of model tests the seis-mic mechanics behaviors of the strengthened piers were comprehensively studied.The analysis re-sults show that the failure modes of the strengthened bridge piers under the earthquake actions are al-so displayed as the occurrences of plastic hinge in the superior margin of the steel plates,which coin-cides with the pier model testing results.The comparison of the seismic performances before and af-ter strengthening validates the effectiveness of the strengthening method with steel plates of making new plastic hinge.The effects of the initial damage degree,steel plate thickness and slenderness rati-os on the seismic safety degrees of the bridge piers are small.However,when the axial compression ratio is large,the seismic safety degrees decrease quickly.%针对具有初始弯曲损伤的粘钢加固混凝土箱型桥墩,采用柔度法和纤维模型,进行了系统的地震动力响应数值模拟计算,分析了地震作用下加固桥墩的地震剪力、墩顶位移、剩余刚度等性能指标,并在拟静力试验的基础上综合研究其抗震加固力学行为。分析结果表明,地震荷载作用下地震中桥墩仍然发生加固钢板上缘产生塑性铰的破坏模式,与拟静力试验结果一致。加固前后桥墩抗震性能的对比结果表明,经粘钢加固形成新塑性铰的加固方式可有效增强桥墩的抗震能力。初始损伤程度、加固钢板厚度和长细比等对加固桥墩抗震安全度的影响较小。大轴压情况下,安全度快速降低。

  20. Strengthening of Shear Walls

    DEFF Research Database (Denmark)

    Hansen, Christian Skodborg

    of the response, results in the ability to determine and characterize the two-way crack propagation, i.e. the relationship between tensile cracking in the concrete and interface debonding between strengthening and concrete. Using the load-crack opening relationship from the strengthened concrete tension member......The theory for concrete structures strengthened with fiber reinforced polymer materials has been developing for approximately two decades, and there are at the present time numerous guidelines covering strengthening of many commonly encountered structural building elements. Strengthening of in...... that describes a unit width strip of a strengthened disk. The unit width strip is named a strengthened concrete tension member and contains a single tensile crack and four debonding cracks. Analysis of the member results in closed form expressions for the load-crack opening relationship. Further analysis...

  1. Experimental Analysis on Strengthened Performance of Existing Pre -stressed Concrete Hollow Slab Bridge%预应力砼空心板桥加固性能试验分析

    Institute of Scientific and Technical Information of China (English)

    王勇平

    2012-01-01

    针对某空心板桥的病害,采用加填封端混凝土、腹板加厚、腹板黏贴钢板等加固手段以期改善其受力性能,并通过加固后的静载试验及病害跟踪检查分析等方法来评价维修加固效果,可为相应的工程实践提供有价值的参考。%For the existing hollow slab bridge disease, adopt different reinforced methods, such as filling the end hollow of slab with concrete, internal upsetting web plate, and pasting steel plates on the external web plate to improve mechanical behavior, and by carrying out static load test and follow -up disease checking to evaluate maintenance and reinforcement effect. It can provide some valuable reference for engineering practice.

  2. Developing a Traffic Management Framework for Coastal Expressway Bridges under Adverse Weather Conditions: Case Study of Rain Day in Shenzhen, China

    Directory of Open Access Journals (Sweden)

    Chenming Jiang

    2015-01-01

    Full Text Available Adverse weather can reduce visibility and road surface friction, lower vehicle maneuverability, and increase crash frequency and injury severity. The impacts of adverse weather and its interactions with drivers and roadway on the operation and management of expressway or expressway bridges have drawn the researchers’ and managers’ attention to develop traffic management frameworks to mitigate the negative influence. Considering the peculiar geographical location and meteorological conditions, the Guangshen Coast Expressway-Shenzhen Segment (GSCE-SS was selected as a case in this study to illustrate the proposed traffic management framework on rain days. Conditions categorized by rainfall intensity and traffic flow were the main precondition to make the management decisions. CORSIM simulator was used to develop the alternate routes choice schemes, providing reference for other systems in the proposed traffic management framework. Maps of (a entrance ramp control (ERC strategies; (b mainline control strategies; (c alternate routes choice; (d information release schemes, under scenarios of different volume and rainstorm warning grades (BLUE to RED, were drawn to present a reference or demonstration for managers of long-span expressway bridges not only in China, but even in the world.

  3. Precipitation of Nb in Ferrite After Austenite Conditioning. Part II: Strengthening Contribution in High-Strength Low-Alloy (HSLA) Steels

    Science.gov (United States)

    Altuna, M. A.; Iza-Mendia, Amaia; Gutiérrez, I.

    2012-12-01

    Often, Nb contributes to the strength of a microalloyed steel beyond the expected level because of the grain size strengthening resulting from thermomechanical processing. Two different mechanisms are behind this phenomenon, and both of them have to do with the amount of Nb remaining in solution after hot rolling. The first of them is the increase of the hardenability of the steel as a result of Nb, and the second one is the fine precipitation of NbC in ferrite. Three Nb microalloyed steels were thermomechanically processed in the laboratory and coiled at different temperatures to investigate the effect of Nb content on the tensile properties. The extra strength was linearly related to the Nb remaining in solution after the hot working. The maximum contribution from Nb was reached for a coiling temperature of 873 K (600 °C).

  4. Myocardial Bridging

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    2016-02-01

    Full Text Available Abstract Myocardial bridging is rare. Myocardial bridges are most commonly localized in the middle segment of the left anterior descending coronary artery. The anatomic features of the bridges vary significantly. Alterations of the endothelial morphology and the vasoactive agents impact on the progression of atherosclerosis of myocardial bridging. Patients may present with chest pain, myocardial infarction, arrhythmia and even sudden death. Patients who respond poorly to the medical treatment with β-blockers warrant a surgical intervention. Myotomy is a preferred surgical procedure for the symptomatic patients. Coronary stent deployment has been in limited use due to the unsatisfactory long-term results.

  5. FRP : Strengthened RC Structures

    Science.gov (United States)

    Teng, J. G.; Chen, J. F.; Smith, S. T.; Lam, L.

    2002-01-01

    The strengthening of reinforced concrete (RC) structures using advanced fibre-reinforced polymer (FRP) composites, and in particular the behaviour of FRP-strengthened RC structures is a topic which has become very popular in recent years. This popularity has arisen due to the need to maintain and upgrade essential infrastructure in all parts of the world, combined with the well-known advantages of FRP composites, such as good corrosion resistance and ease for site handling due to their light weight. The continuous reduction in the material cost of FRP composites has also contributed to their popularity. While a great amount of research now exists in the published literature on this topic, it is scattered in various journals and conference proceedings. This book therefore provides the first ever comprehensive, state-of-the-art summary of the existing research on FRP strengthening of RC structures, with the emphasis being on structural behaviour and strength models. The main topics covered include: Bond behaviour Flexural and shear strengthening of beams Column strengthening Flexural strengthening of slabs. For each area, the methods of strengthening are discussed, followed by a description of behaviour and failure modes and then the presentation of rational design recommendations, for direct use in practical design of FRP strengthening measures. Researchers, practicing engineers, code writers and postgraduate students in structural engineering and construction materials, as well as consulting firms, government departments, professional bodies, contracting firms and FRP material suppliers will find this an invaluable resource.

  6. Evaluation of the strengthening of the conditions of voltage security using sensitivity analysis; Avaliacao do reforco das condicoes da seguranca de tensao utilizando a analise de sensibilidade

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, A.L.S.; Costa, V.M. da; Peres, W. [Universidade Federal de Juiz de Fora (UFJF), MG (Brazil). Faculdade de Engenharia], Emails: arleilucas@gmail.com, vander@lacee.ufjf.br, wesley.peres@yahoo.com.br; Prada, R.B. [Pontificia Universidade Catolica (PUC-Rio), Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Eletrica], Email: prada@ele.puc-rio.br

    2009-07-01

    Voltage stability or voltage security analysis has motivated an expressive attention of power systems researchers. In this work, a simple and fast method evaluates voltage security and proposes conditions to improve the loading margin. System analysis is carried out in terms of active power transmission path. Sensitivity analysis provides the most adequate buses to active and reactive power redispatch. A sequential iterative methodology to reinforce system conditions is presented. (author)

  7. Application of a three-dimensional aeroelastic model to study the wind-induced response of bridge stay cables in unsteady wind conditions

    Science.gov (United States)

    Raeesi, Arash; Cheng, Shaohong; Ting, David S.-K.

    2016-08-01

    The possibility of bridge stay cables experiencing violent dry inclined cable galloping raises great concern in the engineering community. Numerous experimental and analytical studies have been conducted to investigate this phenomenon, most of which were in the context of steady wind past a rigid cylindrical body. Real stay cables however, are generally long and flexible. They are exposed to more "broad" range of atmospheric boundary layer type of wind velocity profile which is also unsteady and turbulent by nature. To better understand the physics underlying this type of wind-induced cable vibration and to elucidate various contributing factors, a more realistic analytical model which is capable of addressing the above elements is imperative. In the current paper, a three-dimensional aeroelastic model is proposed to study the aerodynamic response of an inclined and/or yawed slender flexible cylindrical body subjected to unsteady mean wind, with practical application to wind-induced vibrations of bridge stay cables under no precipitation condition. The non-linear aerodynamic forces derived in the present study are combined with the cable free vibration equations available in literature to obtain the equations of motion for the wind-induced vibration of stay cables, which are solved numerically by an explicit finite difference scheme. The proposed three-dimensional aeroelastic model and numerical solution technique are validated by comparing the predicted cable free vibration responses with existing data in the literature. The mechanism which triggers dry inclined cable galloping and the required conditions for its growth are explored. In addition, the impact of different initial conditions and various unsteady mean wind scenarios on this violent cable motion are investigated. Results show that the occurrence of dry inclined cable galloping is associated with an opposite-phase relation between the relative wind speed and the aerodynamic force along the direction of

  8. Experimental study of distribution on prestressed strand mesh in strengthening concrete bridges%预应力钢绞线网加固混凝土桥梁的索力分布试验研究

    Institute of Scientific and Technical Information of China (English)

    郭琦; 叶全斌; 尹海军; 闫雯

    2014-01-01

    对于采用挤压头连接锚固工艺的高强钢绞线网的桥梁加固技术,为了在预加应力阶段对一次锚固得到的预应力水平与索力分布均匀程度进行便捷和高精度的监测,基于静力平衡原理推导了修正边界的钢绞线索力监测公式,并开展了两组大比例模型梁钢绞线网张拉与索力监控试验研究.试验结果表明:修正后的索力监测值与实际值的相对误差为4.6%,测试精度满足工程要求.基于索力分布统计规律开展了应力松弛试验,提出了无应力索长控制的索力修正模型,以减小钢绞线网索力分布的界限波动率,达到了一致性索力设计状态.该方法解决了狭小空间下预应力钢绞线网索力监测问题,对于后续索力调整研究及保障设计预应力水平均具有重要的意义.%For bridge reinforcement using high-strength prestressed strand mesh with extruded joint anchorage, the corrected boundary formula of stretching force for a single steel strand is derived based on static balance principle in order to monitor the stretching force and its distribution state in convenient and high-precision way once after anchorage,. Experiment on two group of large-scale PC beam models is conducted as well for the purpose of testing the method mentioned before. The test result shows that the relative error for stretching force of a single strand between monitoring value and actual one is less than 4.6 percent. Based on statistical distribution mode of stretching force and stress relaxation test, amending model on stress-free length is promoted to reduce the limited fluctuation ratio of the stretching force distribution of steel wire mesh. This method solves the problem of stretching force monitoring on prestressed strand mesh in small spaces and meets the requirement of engineering accuracy and therefore, has great significance for subsequent research of stretching force adjustment and can guarantee the

  9. 粘钢加固损伤混凝土箱型桥墩的抗震性能Ⅰ:双向拟静力试验%Anti-seismic properties of damaged concrete bridge piers with hollow box-section strengthened with adhering steel plates Ⅰ:bi-directional quasi-static test

    Institute of Scientific and Technical Information of China (English)

    宗周红; 邓江东; 黎雅乐; 刘爱荣

    2013-01-01

    11 scaled models of reinforced concrete bridge piers with hollow box-section were de-signed and fabricated in the lab.Bi-directional quasi-static tests for these scaled pier models strength-ened with adhering steel plates were carried out.Several seismic performance indicators, such as load-displacement hysteretic and skeleton curves, ductility, degradation of rigidity, and energy dissi-pation were investigated.The experimental results show that all the strengthened piers present typical flexural failure modes, and plastic hinge appears in the superior margin of steel plates in stead of in the bottom for piers without strengthening.The improvement of anti-seismic properties exhibits that it was an effective method to change the plastic hinge position by adhering steel plates.The load ca-pacity and the lateral rigid along the strong axis direction are greater, while the energy dissipation a-long the weak axis direction is stronger.The hysteretic curves of the weak axis exhibit notable pinch effects.The initial damage only has small effect on the degradation of rigidity and energy dissipation of the strengthening piers.Meanwhile, the changes of axial compression ratio and slenderness ratio have a great impact on the seismic performance.With the increase of the axial compression ratio, the carrying capacity, the ductility performance and energy dissipation of models increase, but the ulti-mate displacement decreases.With the decrease of the slenderness ratio, the carrying capacity of piers strengthened with adhering steel plates increases;however the ultimate deformation capacity de-creases, while the degradation of rigidity becomes more serious.%设计制作了11个钢筋混凝土箱型截面桥墩缩尺模型,对其进行了粘钢加固后的双向拟静力试验,分析了加固桥墩的荷载位移滞回曲线、骨架曲线、延性能力、刚度退化和耗能能力等。结果表明,加固墩柱均发生以弯曲破坏为主的延性破坏,破坏塑性

  10. Managing concrete bridges: Methods for reducing costs and user inconveniences

    DEFF Research Database (Denmark)

    Goltermann, Per

    2005-01-01

    . These approaches are focused on cost reductions, but must as well lead to a reduction of the user inconveniences (traffic delays, noise, dust) and to a reduction of the environmental impact. These approaches can be based on an assessment of the structures safety, which incorporates the inaccuracies......The paper presents experiences from modern bridge maintenance management, which has been forced to develop new and cost-efficient approaches in order to cope with the increase in overall deterioration of the aging bridge stock, the growing requirements to accessibility and the decreasing budgets...... in the condition assessments, the models and the predictions in the strategies and the cost estimations. This may lead to increased inspection frequencies, detailed simulations, monitoring and testing to be used as alternatives to extensive repairs, rehabilitations or strengthening. The approaches will in other...

  11. Bridge Management Systems

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper bridge management systems are discussed with special emphasis on management systems for reinforced concrete bridges. Management systems for prestressed concrete bridges, steel bridges, or composite bridges can be developed in a similar way.......In this paper bridge management systems are discussed with special emphasis on management systems for reinforced concrete bridges. Management systems for prestressed concrete bridges, steel bridges, or composite bridges can be developed in a similar way....

  12. Programmevaluierung Bridge

    OpenAIRE

    Warta, Katharina; Good, Barbara; Geyer, Anton

    2009-01-01

    BRIDGE is an initiative funded by the Ministry for Transport, Innovation and Technology (BMVIT) that aims to close the “funding gap” between basic and applied research in stand-alone projects with the primary objective of jointly developing the potential of basic and applied research. BRIDGE acts as an  umbrella structure under which the Austrian Science Fund (FWF) and the  Austrian Research Promotion Agency (FFG) coordinate two thematically open funding programmes: The ...

  13. Effects of surface roughness and cross-sectional distortions on the wind-induced response of bridge cables in dry conditions

    DEFF Research Database (Denmark)

    Matteoni, Giulia; Georgakis, Christos T.

    Theoretical and experimental investigations to date assumed that bridge stay cables can be modelled as ideal circular cylinders and that their aerodynamic coefficients are invariant with wind angle-of-attack. These changes are neglected when the potential for bridge cable instability is evaluated...

  14. National Bridge Inventory (NBI) Bridges

    Data.gov (United States)

    Department of Homeland Security — The NBI is a collection of information (database) describing the more than 600,000 of the Nation's bridges located on public roads, including Interstate Highways,...

  15. External Prestressing Bridge Reinforcement Technology Review

    Directory of Open Access Journals (Sweden)

    Zhu Hanbing

    2015-01-01

    Full Text Available Externally prestressed bridge can not only limit and reduce the cracks and deformation of the structure, improve the rigidity and bearing capacity of structure, improve the stress state of structure, but also have less interference for bridge operation when it is operating and have the good economic efficiency. This paper introduces the advantages and disadvantages of external prestressed strengthening technique, its calculation theory and construction technology described in detail, and finally the paper discusses the deficiency of existing research.

  16. An application of Auto-regressive (AR model in predicting Aeroelastic Effectsof Lekki Cable Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Hassan Abba Musa

    2016-06-01

    Full Text Available In current practice, the predictive analysis of stochastic problems encompasses a variety of statistical techniques from modeling, machine, and data mining that analyse current and historical facts to make predictions about future. Therefore, this research uses an AR Model whose codes are incorporated in the MATLAB software to predict possible aero-elastic effects of Lekki Bridge based on its existing parametric data and the conditions around the bridge. It was seen that, the fluctuating components of the wind velocity as displayed by the fluctuant curve will result in the vibration of the structure, even strengthening the resonance effect of the structure. Therefore, it suggested that, the natural frequency of the bridge should be set aside far from system frequency considering direct parametric excitation of pedestrian or vehicular traffic speed.

  17. Building Bridges

    DEFF Research Database (Denmark)

    The report Building Bridges adresses the questions why, how and for whom academic audience research has public value, from the different points of view of the four working groups in the COST Action IS0906 Transforming Audiences, Transforming Societies – “New Media Genres, Media Literacy and Trust...... in the Media”, “Audience Interactivity and Participation”, “The Role of Media and ICT Use for Evolving Social Relationships” and “Audience Transformations and Social Integration”. Building Bridges is the result of an ongoing dialogue between the Action and non-academic stakeholders in the field of audience...

  18. Istanbul Bridge Conference 2014

    CERN Document Server

    Gülkan, Polat; Mahmoud, Khaled

    2016-01-01

      The book includes peer-reviewed contributions selected from presentations given at the Istanbul Bridge Conference 2014, held from August 11 – 13 in Istanbul, Turkey. It reports on the current challenges in bridge engineering faced by professionals around the globe, giving a special emphasis to recently developed techniques, innovations and opportunities. The book covers key topics in the field, including modeling and analysis methods; construction and erection techniques; design for extreme events and condition assessment and structural health monitoring. There is a balanced presentation of theory, research and practice. This book, which provides the readers with a comprehensive and timely reference guide on current practices in bridge engineering, is intended for professionals, academic researchers and students alike.

  19. Path transformations of first passage bridges

    OpenAIRE

    Bertoin, Jean

    2003-01-01

    We define the first passage bridge from 0 to $\\lambda$ as the Brownian motion on the time interval $[0,1]$ conditioned to first hit $\\lambda$ at time 1. We show that this process may be related to the Brownian bridge, the Bessel bridge or the Brownian excursion via some path transformations, the main one being an extension of Vervaat's transformation. We also propose an extension of these results to certain bridges with cyclically exchangeable increments.

  20. Building Bridges

    DEFF Research Database (Denmark)

    The report Building Bridges adresses the questions why, how and for whom academic audience research has public value, from the different points of view of the four working groups in the COST Action IS0906 Transforming Audiences, Transforming Societies – “New Media Genres, Media Literacy and Trust...

  1. Bridged graphite oxide materials

    Science.gov (United States)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

    2010-01-01

    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  2. General design of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Yuan Hong; Pei Minshan; Dai Jie; Xu Lin

    2009-01-01

    The main span of Sutong Bridge is a double-pylon, double-plane cable-stayed bridge with steel box girder, which has the world's longest central span of 1 088 m within cable-stayed bridges. To overcome problems caused by severe meteorological conditions, perplexing hydrological conditions, deep buried bedrock and higher navigation level, many new technics and methods were created. Keys including structural system, steel box girder, stayed cable, tower, pier, tower foundation, collision avoidance system, wind-resistance, seismic-resistance, structural nonlinear response and structural static stability were presented individually in this paper.

  3. Foot muscles strengthener

    Directory of Open Access Journals (Sweden)

    Boris T. Glavač

    2012-04-01

    Full Text Available Previous experience in the correction of flat feet consisted of the use of insoles for shoes and exercises with toys, balls, rollers, inclined planes, etc. A device for strengthening foot muscles is designed for the correction of flat feet in children and, as its name suggests, for strengthening foot muscles in adults. The device is made of wood and metal, with a mechanism and technical solutions, enabling the implementation of specific exercises to activate muscles responsible for the formation of the foot arch. It is suitable for home use with controlled load quantities since it has calibrated springs. The device is patented with the Intellectual Property Office, Republic of Serbia, as a petty patent.

  4. NDT evaluation of long-term bond durability of CFRP-structural systems applied to RC highway bridges

    Science.gov (United States)

    Crawford, Kenneth C.

    2016-06-01

    The long-term durability of CFRP structural systems applied to reinforced-concrete (RC) highway bridges is a function of the system bond behavior over time. The sustained structural load performance of strengthened bridges depends on the carbon fiber-reinforced polymer (CFRP) laminates remaining 100 % bonded to concrete bridge members. Periodic testing of the CFRP-concrete bond condition is necessary to sustain load performance. The objective of this paper is to present a non-destructive testing (NDT) method designed to evaluate the bond condition and long-term durability of CFRP laminate (plate) systems applied to RC highway bridges. Using the impact-echo principle, a mobile mechanical device using light impact hammers moving along the length of a bonded CFRP plate produces unique acoustic frequencies which are a function of existing CFRP plate-concrete bond conditions. The purpose of this method is to test and locate CFRP plates de-bonded from bridge structural members to identify associated deterioration in bridge load performance. Laboratory tests of this NDT device on a CFRP plate bonded to concrete with staged voids (de-laminations) produced different frequencies for bonded and de-bonded areas of the plate. The spectra (bands) of frequencies obtained in these tests show a correlation to the CFRP-concrete bond condition and identify bonded and de-bonded areas of the plate. The results of these tests indicate that this NDT impact machine, with design improvements, can potentially provide bridge engineers a means to rapidly evaluate long lengths of CFRP laminates applied to multiple highway bridges within a national transportation infrastructure.

  5. Characterization of water-quality and bed-sediment conditions in Currituck Sound, North Carolina, prior to the Mid-Currituck Bridge construction, 2011–15

    Science.gov (United States)

    Wagner, Chad R.; Fitzgerald, Sharon; Antolino, Dominick

    2016-01-01

    The North Carolina Turnpike Authority, a division of the North Carolina Department of Transportation, is planning to make transportation improvements in the Currituck Sound area by constructing a two-lane bridge from U.S. Highway 158 just south of Coinjock, North Carolina, to State Highway 12 on the Outer Banks just south of Corolla, North Carolina. The results of the Final Environmental Impact Study associated with the bridge and existing roadway improvements indicated potential water-quality and habitat impacts to Currituck Sound related to stormwater runoff, altered light levels, introduction of piles as hard substrate, and localized turbidity and siltation during construction.

  6. Characterization of water-quality and bed-sediment conditions in Currituck Sound, North Carolina, prior to the Mid-Currituck Bridge construction, 2011–15

    Science.gov (United States)

    Wagner, Chad R.; Fitzgerald, Sharon; Antolino, Dominick

    2015-12-24

    The North Carolina Turnpike Authority, a division of the North Carolina Department of Transportation, is planning to make transportation improvements in the Currituck Sound area by constructing a two-lane bridge from U.S. Highway 158 just south of Coinjock, North Carolina, to State Highway 12 on the Outer Banks just south of Corolla, North Carolina. The results of the Final Environmental Impact Study associated with the bridge and existing roadway improvements indicated potential water-quality and habitat impacts to Currituck Sound related to stormwater runoff, altered light levels, introduction of piles as hard substrate, and localized turbidity and siltation during construction.

  7. Safety Technologies for Bridges of the Highway Bridge Beam Installation under the Conditions of 500kV Ultra-high Voltage Transmission Lines across by Low Altitude%500kV超高压线路低空跨越条件下公路大桥桥梁架设的安全技术

    Institute of Scientific and Technical Information of China (English)

    覃文元

    2012-01-01

    通过对在500kV超高压电线低空跨越条件下公路大桥架梁施工安全技术与组织管理措施的研究并实施,以采用架桥机架梁方案为基础,对500kV超高压电线低空跨越下的架梁工况条件、高压感应电场的强度和电流进行计算与分析,对作业人员和设备的伤害状况作出了分析,并提出了保证作业人员、设备和电力设施安全的防护技术与组织管理措施。%Through researches and construction implementation of safety technology and organizational management measures for highway bridges installation under the conditions of 500 kV ultraigh voltage transmission lines above by low altitude, based on the program of bridges installation with bridge erector, the article introduces the calculation and analysis of bridges installation conditions, electrostatic induction intensity and electric current in high voltage electric field and their harm to operator and equipments under the conditions that 500 kV ultra-high voltage transmission lines above by low altitude. And protection technologies and organization management measures to ensure the safety of the workers, equipments and power facilities are proposed.

  8. Nematic liquid crystal bridges

    Science.gov (United States)

    Doss, Susannah; Ellis, Perry; Vallamkondu, Jayalakshmi; Danemiller, Edward; Vernon, Mark; Fernandez-Nieves, Alberto

    We study the effects of confining a nematic liquid crystal between two parallel glass plates with homeotropic boundary conditions for the director at all bounding surfaces. We find that the free surface of the nematic bridge is a surface of constant mean curvature. In addition, by changing the distance between the plates and the contact angle with the glass plates, we transition between loops and hedgehogs that can be either radial or hyperbolic.

  9. APPLICATION OF PRESTRESSED SHELLS TO STRENGTHEN STRIP FOUNDATIONS

    OpenAIRE

    Ter-Martirosjan Zaven Grigor'evich; Pronozin Jakov Aleksandrovich; Naumkina Julija Vladimirovna

    2012-01-01

    Effective method of strengthening of foundations of existing buildings by pre-stressed shells is considered in the paper. Advantages of the proposed strengthening method, its production technology and pre-conditions of its analysis are also presented. Presently, strengthening of ground foundations and foundations of buildings and structures is a relevant civil engineering challenge. It is driven by high intensity of restructuring and modernization of buildings and alteration of geological eng...

  10. Strengthening nuclear security

    International Nuclear Information System (INIS)

    The international situation after the end of the Cold-War has been quite unstable, due to the occurrence of frequent regional conflicts and domestic wars based on ethnic, religious or racial reasons. Further, threats to the would peace and security by non-state actors, like international terrorist groups, have been recognized after 9.11 terrorist attacks to the World Trade Center buildings and to the Pentagon. Utilization of nuclear energy, which encompasses both peaceful uses and military ones, required an establishment of regulatory system, by which risks associated with the development of nuclear energy can be controlled. Accordingly, nuclear safety control system, and then non-proliferation control system has been developed, both in the international level and notional level. In recognition of the present unstable international situations, it is required to establish, maintain and strengthen a system which control nuclear security aspect, in addition to the present systems. (author)

  11. Strengthening regional safeguards

    International Nuclear Information System (INIS)

    Nuclear cooperation between Argentina and Brazil has been growing since the early 1980's and as it grew, so did cooperation with the US Department of Energy (DOE). The Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) was formed in December 1991 to operate the Common System of Accounting and Control of Nuclear Materials (SCCC). In April 1994, ABACC and the DOE signed an Agreement of Cooperation in nuclear material safeguards. This cooperation has included training safeguards inspectors, exchanging nuclear material measurement and containment and surveillance technology, characterizing reference materials, and studying enrichment plant safeguards. The goal of the collaboration is to exchange technology, evaluate new technology in Latin American nuclear facilities, and strengthen regional safeguards. This paper describes the history of the cooperation, its recent activities, and future projects. The cooperation is strongly supported by all three governments: the Republics of Argentina and Brazil and the United States

  12. Strengthening regional safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Palhares, L.; Almeida, G.; Mafra, O. [Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials, Rio de Janeiro (Brazil)] [and others

    1996-08-01

    Nuclear cooperation between Argentina and Brazil has been growing since the early 1980`s and as it grew, so did cooperation with the US Department of Energy (DOE). The Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) was formed in December 1991 to operate the Common System of Accounting and Control of Nuclear Materials (SCCC). In April 1994, ABACC and the DOE signed an Agreement of Cooperation in nuclear material safeguards. This cooperation has included training safeguards inspectors, exchanging nuclear material measurement and containment and surveillance technology, characterizing reference materials, and studying enrichment plant safeguards. The goal of the collaboration is to exchange technology, evaluate new technology in Latin American nuclear facilities, and strengthen regional safeguards. This paper describes the history of the cooperation, its recent activities, and future projects. The cooperation is strongly supported by all three governments: the Republics of Argentina and Brazil and the United States.

  13. Overview Shear Strengthening of RC Beams with Externally Bonded FRP Composites

    Science.gov (United States)

    Alzoubi, Feras; Zhengliang, Li

    Shear strengthening is required when an RC beam is found deficient in shear, or when its shear capacity falls below its flexural capacity after flexural strengthening. This study presents a state-of-the-art review of existing research on this topic. The research programs conducted to investigate the shear performance and to evaluate the shear capacity of the strengthened beams are reviewed in this paper by details. The research is a good reference for all engineers and researchers in fields of shear strengthening and repair RC beams in building and bridges.

  14. Liquid-Bridge Breaking Limits

    Science.gov (United States)

    Macner, Ashley; Steen, Paul

    2011-11-01

    Wet adhesion by liquid bridges in large arrays shows promise for use in lightweight, controllable on-demand devices. Applications include grab/release of wafer substrates, transport of micron-sized tiles for use in 3D printing and micro-dosing of personalized pharmaceutical drugs. By wetting and spreading, a drop can form a bridge and thereby ``grab'' a nearby solid substrate. By volume decrease or extension, the bridge can break. The breaking limit corresponds to bridge instability which can be predicted, knowing the static mechanical response of the bridge. Mechanical behaviors include force-volume (FV), pressure-volume (pV) and force-length (FL) responses. Instability crucially depends on the mode of failure - failure under constant-force or constant length are typical cases. We study single bridge equilibria for their breaking limits. FV diagrams for the pin-pin equal and pin-pin unequal radii boundary conditions for different bridge heights are measured in the laboratory. The FL response in the case of pin-pin equal radii is also measured. Results are compared to predictions of static theory. Static results are then used to compare to dynamical sequences where volume is driven quasistatically by syringe or an electro-osmotic pump. As the breaking limit is approached, the shape deformation accelerates leading to non-equilibrium shapes not captured by the static analysis.

  15. [Retention of adhesive bridges].

    Science.gov (United States)

    Raes, F; De Boever, J

    1994-04-01

    Since the development of adhesive bridges in the early seventies, the retention and therefore the durability of these bridges has been tremendously improved. Conditioning of the non-precious metal by silanisation, careful acid etching of the enamel and the use of the appropriate composite resin are of prime importance. Furthermore, the meticulous preparation with enough interproximal embrace, occlusal rests, interocclusal clearance and cingulum stops is equally important. Including more teeth in the design does not necessarily lead to an improved retention. Besides the material and technical aspects, the whole clinical procedure needs much attention. The retention does not depend on one single factor, but on the precision of all the necessary clinical steps and on a well-defined selection of the material. In this way a five-year survival rate of close to 80% can be obtained. PMID:11830965

  16. Rehabilitation and Strengthening of a Railway Bridge Pier under Operating Condition%某单线铁路桥墩在线路运营状况下的加固施工

    Institute of Scientific and Technical Information of China (English)

    沈阳云

    2002-01-01

    某单线铁路桥,经检测发现明显质量缺陷,分析质量缺陷产生的原因,介绍桥墩加固施工方法,即原承台外侧增设钻孔桩,桩顶新建承台与原墩身固结,施工采用单壁钢围堰稳固墩位处河床,兼作钻孔桩平台支撑结构.

  17. Applications of overburden conveyor bridges

    Energy Technology Data Exchange (ETDEWEB)

    Schachtschneider, H.

    1987-06-01

    In large scale surface mines of the capacities required today, a cross-pit operation with overburden conveyor bridges is the most economical method of overburden removal and disposal. In order to provide the production capacity required in surface mining equipment by the GDR brown coal industry, VEB Schwermaschinenbau Lauchhammerwerk undertook the design and manufacture of standard overburden conveyor bridges for cut heights of 34 m, 45 m and 60 m. All three base types may be equipped to match the site specific geological and geotechnical conditions, and to meet customer's demands. Specifications of the bridges are given as well as details of conveyor belt speeds, modifications to the standards, and number manufactured. Design problems faced with the 60 m bridge are discussed, together with details of the superstructure, method of operation, transportation rates, structural steel used, assembly and power supply. 5 refs.

  18. Evaluation method research on prestressed concrete bridges

    Institute of Scientific and Technical Information of China (English)

    HUANG Qiao; LIN Yang-zi; REN Yuan

    2008-01-01

    Considering the construction features of prestressed concrete bridge, the comprehensive evaluation method about the bridge damage conditions are studied. Particular attentions are paid on establishing a multi-level evaluation model for damaged prestressed concrete bridge, and the evaluation indices of the model as well as the rating standards are defined in the model. A normal relative function about the evaluation indices of each element is developed to calculate the relative degree, and for each element which is no sub-level elements. When evaluating the elements in sub-item level or index level of the model, the weights of elements that are pertained to one element are adopted, taking account of their deterioration degree. At the same time, the dam-age conditions of bridge are characterized by relative degree, element evaluation scale and structural technology mark of bridge ,so it agrees with Code for Maintenance of Highway Bridges and Culvers.

  19. Seismic Evaluation of Highway Bridges - Phase 1

    OpenAIRE

    Ramirez, J.A.; Pan, Austin D.; Mwakasisi, Frank Thompson

    1996-01-01

    The primary objective of the study was to establish the guidelines for screening, assessing, and ranking Indiana bridges for seismic upgrade. The outcome of the study is a complete strategy for the detailed structural assessment of Indiana highway bridges subjected to seismic forces. The structural evaluation is conducted using a nonlinear time-history analysis of the bridge for simulated or actual records. The specific soil conditions at the site are accounted in terms of the ground motio...

  20. Analysis of liquid bridge between spherical particles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A pair of central moving spherical particles connected by a pendular liquid bridge with interstitial Newtonian fluid is often encountered in pariculate coalescence process. In this paper, by assuming perfect-wet condition, the effects of liquid volume and separation distance on static liquid bridge are analyzed, and the relation between rupture energy and liquid bridge volume is also studied. These points would be of significance in industrial processes related to adhesive particles.

  1. Study on structural system of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Pei Minshan; Yuan Hong; Xu Liping; Zhu Bin

    2009-01-01

    Sutong Bridge, whose layout is [ (100 + 100 + 300) + 1 088 + ( 300 + 100 + 100) ] m, marks the largest span of cable-stayed bridges in the world. The complex natural condition at the bridge site and the strict requirements for resistance of wind and seismic action make it crucial to choose a favorable structural system to assure the function and safety of the bridge. The comparison among several optional structural systems for Sutong Bridge is illustrated. After detailed analysis is carried out for viscous damper and hydraulic buffer, super liquid viscous damper with additional displacement limitation is designed for the first application in bridge engineering. The parameters for the damper is analyzed and studied and the dampers are installed suecessfuUy after quality tests.

  2. On-line tribochemical strengthening of gear surface

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    It has been found that under favorable friction conditions some antiwear elements inlubricating additives can permeate into subsurface of metal which can strengthens the friction sur-faces and improves anti-wear capacity of frication pairs. It is in many ways similar to chemical heattreatment. A new concept, technology of on-line strengthening, was logically put forward. Based oncurrent gear surface treatment technology, the on-line strengthen of gear surface is proposed. Itsdesign method is established. Based on it, the on-line strengthen of gear is achieved on CL-100gear test machine. A new method is put forward for strengthen treatment of gear surface. Andthree kinds of surface film were suggested.

  3. 银川黄河大桥横向拓宽拼接构造使用状况调查研究%Survey of Application Condition of Splicing Structure Used to Transverse Widening of Yinchuan Huanghe River Bridge

    Institute of Scientific and Technical Information of China (English)

    吴文清; 翟建勋; 林晶

    2015-01-01

    银川黄河大桥主桥为(60+5×90+60) m三向预应力混凝土T形刚构桥,桥梁拓宽时,新旧桥上下部结构均不连接,采用纵向伸缩装置连接新旧桥面板。为了解纵向伸缩装置用于既有桥梁横向拓宽中的适用性,在该桥拓宽完并运营7年后对弹塑体无缩缝伸缩装置、JFC减振防滑伸缩装置和EM R树脂弹性混凝土伸缩装置的使用状况进行调查,分析伸缩装置损坏率和损坏原因。结果表明:弹塑体无缩缝伸缩装置损坏率最高,EM R树脂弹性混凝土伸缩装置其次,JFC减振防滑伸缩装置最低(仅为6.7%,远低于其它2种);JFC减振防滑伸缩装置与周边混凝土接触处存在细微缝隙,不存在剥离现象,运营状况较好,其它2种与周边混凝土剥离严重;该桥采用结构横向分离式拓宽时,通过纵向伸缩装置连接拼接缝两侧的桥面铺装层基本可行,建议推广使用JFC减振防滑伸缩装置,并对其做针对性改良,以满足结构受力和变形要求。%The main bridge of Yinchuan Huanghe River Bridge is a three‐directional pres‐tressed concrete T rigid‐frame bridge with span arrangement of (60+5 × 90+ 60) m .During the widening of the bridge ,the superstructures and substructures of the new and the old bridges were not connected ,but the new and old bridge decks were connected using longitudinal expansion de‐vices .To study the feasibility of applying longitudinal expansion devices to the transverse widening of existing bridges ,w hen the Yinchuan Huanghe River Bridge has been operated for more than seven years after the widening construction ,the application conditions of its longitudinal expansion devices were investigated ,including the elato‐plastic expansion devices without contraction joints , JFC expansion devices with vibration mitigation and sliding‐resistant function and the EMR resin e‐lastic concrete expansion devices .The results of

  4. PREDICTION OF FATIGUE LIVES OF RC BEAMS STRENGTHENED WITH CFL UNDER RANDOM LOADING

    Institute of Scientific and Technical Information of China (English)

    Rongwei Lin; Peiyan Huang; Chen Zhao; Xinyan Guo; Xiaohong Zheng

    2008-01-01

    The investigation on fatigue lives of reinforced concrete (RC) structures strength ened with fiber laminate under random loading is important for the repairing or the strengthening of bridges and the safety of the traffic.In this paper,two methods are developed for predicting the fatigue lives of RC structures strengthened with carbon fiber laminate (CFL) under random loading based on a residual life and a residual strength model.To discuss the efficiency of the model,12 RC beams strengthened with CFL are tested under random loading by the MTS810 testing system.The predicted residual strength approximately agrees with test results.

  5. Track-Bridge Longitudinal Interaction of Continuous Welded Rails on Arch Bridge

    Directory of Open Access Journals (Sweden)

    Rong Chen

    2013-01-01

    Full Text Available Taking arch bridges, including deck, half-through, and through arch bridges (short for DAB, HTAB, and TAB as examples, mechanics analysis models of longitudinal interaction between continuously welded rails (short for CWRs and arch bridges are established. Based on the finite element method (FEM, the longitudinal interaction calculation software of CWR on arch bridges has been developed. Focusing on an HTAB, the tension, compression, and deflection conditions are calculated and analyzed. The results show that the mechanics analysis models of three types of arch bridges can truly reflect the real state of the structure; the calculation software can be used for systematic research of the CWR on arch bridge; as for HTAB, temperature difference of arch rib has a small effect on rail tension/compression, and arch bridge can be simplified as a continuous beam for rail tension/compression additional force calculation; in calculation of deflection conditions of HTAB, it is suggested that train loads are arranged on half span and full span and take the direction of load entering bridge into account. Additionally, the deflection additional force variation of CFST basket handle arch bridge is different from that of ordinary bridge.

  6. Strengthening mechanisms and fracture surface characteristics of silicate glass matrix composites with inclusion of alumina particles of different particle sizes

    International Nuclear Information System (INIS)

    Strengthening mechanisms of silicate glass by the inclusion of alumina particles of different volume fractions and different particle sizes are reported. The formulas of three responsible strengthening mechanisms, based on inclusion/crack interactions and interfacial elemental diffusion, were deduced; these include crack deflection, crack bridging and interdiffusion. The strength of the glass/alumina composites increased with inclusion fraction, but followed strengthening mechanisms that varied with alumina particle size. Crack deflection and bridging mechanisms dominated in strengthening for the glass/alumina (at mean particle size of 6 μm) composites while interdiffusion mechanism played a major role in the glass/alumina (at mean particle size of 1 μm) composites. The theoretical deduction of strengthening mechanisms depending on the particle size of alumina inclusions was demonstrated by the experimental strength data and fracture surface characteristics of the glass/alumina composites

  7. Strategy for Strengthening Farmer Groups by Institutional Strengthening

    Directory of Open Access Journals (Sweden)

    Purbayu Budi Santoso

    2015-08-01

    Full Text Available Agriculture sector becomes a spotlight because this sector will be full of potential but the welfare of farmers who become the leading actor is not guaranteed and has a poor tendency. The purpose of this study is to formulate strategies to strengthen farmers' groups in order to create the marketing of the agricultural sector that benefit farmers. The method used to achieve this goal is to use a qualitative approach and Analytical Network Process. In addition to the secondary data obtained from several agencies, this study also uses primary data obtained by in-depth interviews and observations. This research results a priority of aspects of the institutional strengthening of farmer groups as well as priority issues and priorities of the solution of each aspect. In addition, the priority of alternative strategies resulted based on the problems and solutions that have been analyzed in order to solve the problems in the institutional strengthening of farmer groups in Demak.

  8. Performance of damage detection methods in bridges through vibration monitoring

    OpenAIRE

    Cruz, Paulo J. S.; Salgado, R.

    2009-01-01

    The important advances achieved in the modal identification, sensors and structural monitoring of bridges have motivated the bridge engineering community to develop damage detection methods based on vibration monitoring. Some of these methods have already been demonstrated under certain conditions in bridges with deliberate damage (Farrar et al., 1998). However, the performance of these methods for damage detection in bridges has not been fully proven so far and more research n...

  9. Solute strengthening at high temperatures

    Science.gov (United States)

    Leyson, G. P. M.; Curtin, W. A.

    2016-08-01

    The high temperature behavior of solute strengthening has previously been treated approximately using various scaling arguments, resulting in logarithmic and power-law scalings for the stress-dependent energy barrier Δ E(τ ) versus stress τ. Here, a parameter-free solute strengthening model is extended to high temperatures/low stresses without any a priori assumptions on the functional form of Δ E(τ ) . The new model predicts that the well-established low-temperature, with energy barrier Δ {{E}\\text{b}} and zero temperature flow stress {τy0} , transitions to a near-logarithmic form for stresses in the regime 0.2range of stresses. The model is applied to literature data on solution strengthening in Cu alloys and captures the experimental results quantitatively and qualitatively. Most importantly, the model accurately captures the transition in strength from the low-temperature to intermediate-temperature and the associated transition for the activation volume. Overall, the present analysis unifies the different qualitative models in the literature and, when coupled with the previous parameter-free solute strengthening model, provides a single predictive model for solute strengthening as a function of composition, temperature, and strain rate over the full range of practical utility.

  10. Solute strengthening at high temperatures

    Science.gov (United States)

    Leyson, G. P. M.; Curtin, W. A.

    2016-08-01

    The high temperature behavior of solute strengthening has previously been treated approximately using various scaling arguments, resulting in logarithmic and power-law scalings for the stress-dependent energy barrier Δ E(τ ) versus stress τ. Here, a parameter-free solute strengthening model is extended to high temperatures/low stresses without any a priori assumptions on the functional form of Δ E(τ ) . The new model predicts that the well-established low-temperature, with energy barrier Δ {{E}\\text{b}} and zero temperature flow stress {τy0} , transitions to a near-logarithmic form for stresses in the regime 0.2data on solution strengthening in Cu alloys and captures the experimental results quantitatively and qualitatively. Most importantly, the model accurately captures the transition in strength from the low-temperature to intermediate-temperature and the associated transition for the activation volume. Overall, the present analysis unifies the different qualitative models in the literature and, when coupled with the previous parameter-free solute strengthening model, provides a single predictive model for solute strengthening as a function of composition, temperature, and strain rate over the full range of practical utility.

  11. Cable Supported Bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    Cable supported bridges in the form of suspension bridges and cable-stayed bridges are distinguished by their ability to overcome large spans.The book concentrates on the synthesis of cable supported bridges, covering both design and construction aspects. The analytical part covers simple methods...... to quantify the different structural configurations and allows a preliminary optimization of the main structure.Included are the most recent advances in structural design, corrosion protection of cables, aerodynamic safety, and erection procedures....

  12. conditions

    Directory of Open Access Journals (Sweden)

    M. Venkatesulu

    1996-01-01

    Full Text Available Solutions of initial value problems associated with a pair of ordinary differential systems (L1,L2 defined on two adjacent intervals I1 and I2 and satisfying certain interface-spatial conditions at the common end (interface point are studied.

  13. Repair and Strengthening of Reinforced Concrete Structures Using CFRP Plates

    International Nuclear Information System (INIS)

    The infrastructure's increasing decay is frequently combined with the need for upgrading so that structures can meet more stringent design requirements (e.g., increased traffic volumes in bridges exceeding the initial design loads), and hence the aspect of civil engineering infrastructure renewal has received considerable attention over the past few years throughout the world. At the same time, seismic retrofit has become equally important, especially in the areas of high seismic risk. The worldwide acceptance of external plate bonding using CFRP laminates for the repair of under strengthened or damaged reinforced concrete beams is the real incentive for many investigators to devote a great deal of effort to physically understand the response of such beams under externally applied loads. This paper is aimed towards providing a review of the repair and strengthening of the RC concrete structures using CFRP plates along with introducing the basics of the above mentioned technique

  14. Semiempirical Methodology for Estimating the Service Life of Concrete Deck Panels Strengthened with Fiber-Reinforced Polymer

    Directory of Open Access Journals (Sweden)

    Eon-Kyoung Kim

    2014-01-01

    Full Text Available Deterioration of concrete bridge decks affects their durability, safety, and function. It is therefore necessary to conduct structural rehabilitation of damaged concrete decks by strengthening them with fiber-reinforced polymer. Of the recent studies on the strengthened structures, most have focused on static behavior; only a few studies have investigated fatigue behavior. Accurate analysis of fatigue in concrete deck performance requires a more realistic simulated moving load. This study developed a theoretical live-load model to reflect the effect of moving vehicle loads, based on a statistical approach to the measurement of real traffic loads over various time periods in Korea. It assessed the fatigue life and strengthening effect of bridge decks strengthened with either carbon fiber sheets or grid carbon fiber polymer plastic using probabilistic and reliability analyses. It used extrapolations and simulations to derive maximum load effects for time periods ranging from 1 day to 75 years. Limited fatigue tests were conducted and probabilistic and reliability analyses were carried out on the strengthened concrete bridge deck specimens to predict the extended fatigue life. Analysis results indicated that strengthened concrete decks provide sufficient resistance against increasing truck loads during the service life of a bridge.

  15. "As Y'all Know": Blog as Bridge

    Science.gov (United States)

    Gallagher, Jamey

    2010-01-01

    Effective writing happens when the values of a genre and the desires of a writer match. Studying the blog entry as a genre has strengthened the author's assumptions about the possibility of using blogs as examples of emplaced, agency-granting writing and as bridges to academic writing. Because blogs are a relatively new form of communication, the…

  16. Bridging the Micro-Macro Gap in Population Forecasting

    NARCIS (Netherlands)

    NIDI, .

    2011-01-01

    MicMac - Bridging the micro-macro gap in population forecasting: a study funded by the European Commission under the 6th Framework Programme "Integrating and strengthening the European Research Area". In an ageing population, the demand for adequate health care services, pension systems and other so

  17. Taizhou Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Taizhou Bridge lies between Taizhou, Zhenjiang and Changzhou City in Jiangsu Province. The total length of Taizhou Bridge is 62.088 kin. The whole line is designed by freeway codes with six lanes in two directions. The wholeinvestment is 9.37 billion RMB and the planned construction duration is 5.5 years. The main bridge crossing the Yangtze River is a continuous three-pylon two-span suspension bridge with the main span of 1 080 m. The bridge system is realized for the first time and ranks first in the world until now.

  18. Fixation of carbon dioxide by macrocyclic lanthanide(III) complexes under neutral conditions producing self-assembled trimeric carbonato-bridged compounds with μ3-η2:η2:η2 bonding.

    Science.gov (United States)

    Bag, Pradip; Dutta, Supriya; Biswas, Papu; Maji, Swarup Kumar; Flörke, Ulrich; Nag, Kamalaksha

    2012-03-28

    A series of mononuclear lanthanide(III) complexes [Ln(LH(2))(H(2)O)(3)Cl](ClO(4))(2) (Ln = La, Nd, Sm, Eu, Gd, Tb, Lu) of the tetraiminodiphenolate macrocyclic ligand (LH(2)) in 95 : 5 (v/v) methanol-water solution fix atmospheric carbon dioxide to produce the carbonato-bridged trinuclear complexes [{Ln(LH(2))(H(2)O)Cl}(3)(μ(3)-CO(3))](ClO(4))(4)·nH(2)O. Under similar conditions, the mononuclear Y(III) complex forms the dimeric compound [{Y(LH(2))(H(2)O)Cl}(μ(2)-CO(3)){Y(LH(2))(H(2)O)(2)}](ClO(4))(3)·4H(2)O. These complexes have been characterized by their IR and NMR ((1)H, (13)C) spectra. The X-ray crystal structures have been determined for the trinuclear carbonato-bridged compounds of Nd(III), Gd(III) and Tb(III) and the dinuclear compound of Y(III). In all cases, each of the metal centers are 8-coordinate involving two imine nitrogens and two phenolate oxygens of the macrocyclic ligand (LH(2)) whose two other imines are protonated and intramolecularly hydrogen-bonded with the phenolate oxygens. The oxygen atoms of the carbonate anion in the trinuclear complexes are bonded to the metal ions in tris-bidentate μ(3)-η(2):η(2):η(2) fashion, while they are in bis-bidentate μ(2)-η(2):η(2) mode in the Y(III) complex. The magnetic properties of the Gd(III) complex have been studied over the temperature range 2 to 300 K and the magnetic susceptibility data indicate a very weak antiferromagnetic exchange interaction (J = -0.042 cm(-1)) between the Gd(III) centers (S = 7/2) in the metal triangle through the carbonate bridge. The luminescence spectral behaviors of the complexes of Sm(III), Eu(III), and Tb(III) have been studied. The ligand LH(2) acts as a sensitizer for the metal ions in an acetonitrile-toluene glassy matrix (at 77 K) and luminescence intensities of the complexes decrease in the order Eu(3+) > Sm(3+) > Tb(3+).

  19. Strategy for Strengthening Farmer Groups by Institutional Strengthening

    OpenAIRE

    Purbayu Budi Santoso; Darwanto Darwanto

    2015-01-01

    Agriculture sector becomes a spotlight because this sector will be full of potential but the welfare of farmers who become the leading actor is not guaranteed and has a poor tendency. The purpose of this study is to formulate strategies to strengthen farmers' groups in order to create the marketing of the agricultural sector that benefit farmers. The method used to achieve this goal is to use a qualitative approach and Analytical Network Process. In addition to the secondary data obtained fro...

  20. Maxwell Tension Supports the Water Bridge

    OpenAIRE

    Widom, A.; Srivastava, Y. N.; Swain, J.; Sivasubramanian, S.

    2008-01-01

    A cylindrical flexible cable made up of pure fluid water can be experimentally spanned across a spatial gap with cable endpoints fixed to the top edges of two glass beakers. The cable has been called a water bridge in close analogy to iron cables employed to build ordinary span bridges. A necessary condition for the construction of a water bridge is that a large electric field exists parallel to and located within the water cable. Presently, there is no accepted detailed theory which quantita...

  1. Initial Semantics for Strengthened Signatures

    CERN Document Server

    Hirschowitz, André; 10.4204/EPTCS.77.5

    2012-01-01

    We give a new general definition of arity, yielding the companion notions of signature and associated syntax. This setting is modular in the sense requested by Ghani and Uustalu: merging two extensions of syntax corresponds to building an amalgamated sum. These signatures are too general in the sense that we are not able to prove the existence of an associated syntax in this general context. So we have to select arities and signatures for which there exists the desired initial monad. For this, we follow a track opened by Matthes and Uustalu: we introduce a notion of strengthened arity and prove that the corresponding signatures have initial semantics (i.e. associated syntax). Our strengthened arities admit colimits, which allows the treatment of the \\lambda-calculus with explicit substitution.

  2. Initial Semantics for Strengthened Signatures

    Directory of Open Access Journals (Sweden)

    André Hirschowitz

    2012-02-01

    Full Text Available We give a new general definition of arity, yielding the companion notions of signature and associated syntax. This setting is modular in the sense requested by Ghani and Uustalu: merging two extensions of syntax corresponds to building an amalgamated sum. These signatures are too general in the sense that we are not able to prove the existence of an associated syntax in this general context. So we have to select arities and signatures for which there exists the desired initial monad. For this, we follow a track opened by Matthes and Uustalu: we introduce a notion of strengthened arity and prove that the corresponding signatures have initial semantics (i.e. associated syntax. Our strengthened arities admit colimits, which allows the treatment of the λ-calculus with explicit substitution.

  3. Concrete bridge prioritization system

    OpenAIRE

    Kesselring, Debbie Anne

    1995-01-01

    An alternative method of prioritization for concrete bridge maintenance, repair, and rehabilitation activities is required due to the inability of the current system to manage the increasing nmnber of aging concrete bridges. The Concrete Bridge Prioritization System was proposed because of its ability to address the critical technical parameters of safety and cost benefit in prioritization of funding and work allocation. The analysis includes four parts, service life assessment, s...

  4. Bridging the Gap

    DEFF Research Database (Denmark)

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska;

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures.......Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures....

  5. Bridging the Gap

    OpenAIRE

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska; Murdock, Karen; Schmidt, Iben Julie

    2015-01-01

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures. Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ve...

  6. Semiconductor bridge (SCB) detonator

    Science.gov (United States)

    Bickes, Jr., Robert W.; Grubelich, Mark C.

    1999-01-01

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length.

  7. Framework for Bridges Maintenance in Egypt

    Directory of Open Access Journals (Sweden)

    Hesham Abd Elkhalek

    2016-01-01

    Full Text Available The traditional approaches for bridges maintenance is proven to be inefficient as they lead to random way of spending maintenance budget and deteriorating bridge conditions. In many cases, maintenance activities are performed due to user complaints. The objective of this paper is to develop a practical and reliable framework to manage the maintenance and repair activities of Bridges network in Egypt considering performance and budget limits. The model solves an optimization problem that maximizes the average condition of the network given the limited budget using Genetic Algorithm (GA. The main tasks of the system are bridge inventory, condition assessment, deterioration using markov model, and maintenance optimization. The developed model takes into account multiple parameters including serviceability requirements, budget allocation, element importance on structural safety and serviceability, bridge impact on network, and traffic. A questionnaire is conducted to complete the research scope. The proposed model is implemented in software, which provides a friendly user interface. The results of the framework are multi – year maintenance plan for the entire network for up to five years. A case study is presented for validating and testing the model with Data collected from “General Authority for Roads, Bridges and Land Transport” in Egypt.

  8. Sleep On It: How Snoozing Strengthens Memories

    Science.gov (United States)

    ... External link, please review our exit disclaimer . Subscribe Sleep On It How Snoozing Strengthens Memories When you ... the best way to remember it is to sleep on it. That’s because sleeping helps strengthen memories ...

  9. Principles of Bridge Reliability

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Nowak, Andrzej S.

    The paper gives a brief introduction to the basic principles of structural reliability theory and its application to bridge engineering. Fundamental concepts like failure probability and reliability index are introduced. Ultimate as well as serviceability limit states for bridges are formulated...

  10. The floating water bridge

    International Nuclear Information System (INIS)

    When high voltage is applied to distilled water filled in two glass beakers which are in contact, a stable water connection forms spontaneously, giving the impression of a floating water bridge. A detailed experimental analysis reveals static and dynamic structures as well as heat and mass transfer through this bridge

  11. Strengthening Families: Community Strategies That Work

    Science.gov (United States)

    Olson, Maril

    2007-01-01

    Supporting and strengthening families has always been part of the early childhood professional's unique role in the community. NAEYC's Supporting Teachers, Strengthening Families initiative (www.naeyc.org/ece/supporting) is a set of activities designed to provide intentional leadership and education in the family-strengthening approach. The…

  12. Glass strengthening and patterning methods

    Science.gov (United States)

    Harper, David C; Wereszczak, Andrew A; Duty, Chad E

    2015-01-27

    High intensity plasma-arc heat sources, such as a plasma-arc lamp, are used to irradiate glass, glass ceramics and/or ceramic materials to strengthen the glass. The same high intensity plasma-arc heat source may also be used to form a permanent pattern on the glass surface--the pattern being raised above the glass surface and integral with the glass (formed of the same material) by use of, for example, a screen-printed ink composition having been irradiated by the heat source.

  13. Nondestructive evaluation inspection of the Arlington Memorial Bridge using a robotic assisted bridge inspection tool (RABIT)

    Science.gov (United States)

    Gucunski, Nenad; Boone, Shane D.; Zobel, Rob; Ghasemi, Hamid; Parvardeh, Hooman; Kee, Seong-Hoon

    2014-04-01

    The information presented in this report provides a detailed assessment of the condition of the Arlington Memorial Bridge (AMB) deck. The field-data collection was obtained by both the RABIT™ Bridge Inspection Tool and a number of semi-automated non-destructive evaluation (NDE) tools. The deployment of the semi-automated NDE tools was performed to inspect the AMB deck condition and also to validate data obtained by the RABIT™ Bridge Inspection Tool. Data mining and analysis were accomplished through enhanced data interpretation and visualization capabilities using advanced data integration, fusion, and 2D rendering. One of the major challenges that the research team had to overcome in assessing the condition of the AMB deck was the presence of an asphalt overlay on the entire bridge deck.

  14. Design aid for shear strengthening of reinforced concrete T-joints using carbon fiber reinforced plastic composites

    Science.gov (United States)

    Gergely, Ioan

    The research presented in the present work focuses on the shear strengthening of beam column joints using carbon fiber composites, a material considered in seismic retrofit in recent years more than any other new material. These composites, or fiber reinforced polymers, offer huge advantages over structural steel reinforced concrete or timber. A few of these advantages are the superior resistance to corrosion, high stiffness to weight and strength to weight ratios, and the ability to control the material's behavior by selecting the orientation of the fibers. The design and field application research on reinforced concrete cap beam-column joints includes analytical investigations using pushover analysis; design of carbon fiber layout, experimental tests and field applications. Several beam column joints have been tested recently with design variables as the type of composite system, fiber orientation and the width of carbon fiber sheets. The surface preparation has been found to be critical for the bond between concrete and composite material, which is the most important factor in joint shear strengthening. The final goal of this thesis is to develop design aids for retrofitting reinforced concrete beam column joints. Two bridge bents were tested on the Interstate-15 corridor. One bent was tested in the as-is condition. Carbon fiber reinforced plastic composite sheets were used to externally reinforce the second bridge bent. By applying the composite, the displacement ductility has been doubled, and the bent overall lateral load capacity has been increased as well. The finite element model (using DRAIN-2DX) was calibrated to model the actual stiffness of the supports. The results were similar to the experimental findings.

  15. Signal and noise in bridging PCR

    Directory of Open Access Journals (Sweden)

    Thaler David S

    2002-07-01

    Full Text Available Abstract Background In a variant of the standard PCR reaction termed bridging, or jumping, PCR the primer-bound sequences are originally on separate template molecules. Bridging can occur if, and only if, the templates contain a region of sequence similarity. A 3' end of synthesis in one round of synthesis that terminates in this region of similarity can prime on the other. In principle, Bridging PCR (BPCR can detect a subpopulation of one template that terminates synthesis in the region of sequence shared by the other template. This study considers the sensitivity and noise of BPCR as a quantitative assay for backbone interruptions. Bridging synthesis is also important to some methods for computing with DNA. Results In this study, BPCR was tested over a 328 base pair segment of the E. coli lac operon and a signal to noise ratio (S/N of approximately 10 was obtained under normal PCR conditions with Taq polymerase. With special precautions in the case of Taq or by using the Stoffel fragment the S/N was improved to 100, i.e. 1 part of cut input DNA yielded the same output as 100 parts of intact input DNA. Conclusions In the E. coli lac operator region studied here, depending on details of protocol, between 3 and 30% per kilobase of final PCR product resulted from bridging. Other systems are expected to differ in the proportion of product that is bridged consequent to PCR protocol and the sequence analyzed. In many cases physical bridging during PCR will have no informational consequence because the bridged templates are of identical sequence, but in a number of special cases bridging creates, or, destroys, information.

  16. Influence of Icing on Bridge Cable Aerodynamics

    DEFF Research Database (Denmark)

    Koss, Holger; Frej Henningsen, Jesper; Olsen, Idar

    2013-01-01

    In recent years the relevance of ice accretion for wind-induced vibration of structural bridge cables has been recognised and became a subject of research in bridge engineering. Full-scale monitoring and observation indicate that light precipitation at moderate low temperatures between zero and -5......°C may lead to large amplitude vibrations of bridge cables under wind action. For the prediction of aerodynamic instability quasi-steady models have been developed estimating the cable response magnitude based on structural properties and aerodynamic force coefficients for drag, lift and torsion...... forces of different bridge cables types. The experiments were conducted in a wind tunnel facility capable amongst others to simulate incloud icing conditions....

  17. Assessment of the Reliability of Concrete Bridges

    DEFF Research Database (Denmark)

    Middleton, C. R.; Thoft-Christensen, Palle

    in the wake of ever increasing traffic loads and volumes, and an ageing population of bridges subject to various mechanisms of deterioration. The goal is to optimise the allocation of limited resources whilst maintaining their bridges in a safe and serviceable condition. Reliability analysis is one tool being......Although there has been a considerable amount of research into different aspects of concrete bridge reliability, it has still not been widely adopted in professional practice other than in the development and calibration of codes. This situation appears to be changing as there has been...... adopted to assist in achieving this goal. Rather than review the specific research on this subject this paper examines a number of key issues related to the practical application of reliability analysis to the assessment of concrete bridges....

  18. Forecasting for strengthening technological development

    Directory of Open Access Journals (Sweden)

    Aida Mayerly Fúquene Montañez

    2010-05-01

    Full Text Available Producing technological innovation is currently one of the key items in being more competitive. However, production sectors are facing great challenges, including analysing a large amount of available technological and market information regarding the en- vironment for strategic decision-making and being able to launch themselves onto the market with technological developments bringing the desired economic returns. Several tools for analysing information have emerged for reducing the uncertainty of tech- nological and market changes. This article provides conceptual and reflective elements so that forecasting strengthens technolo- gical development (TD. Forecasting is initially proposed as being one of the future methods of analysis having a significant im- pact on decision-making, mainly within the field of economics but which could be extrapolated to making a contribution to TD. The techniques which have been the recent instrument for collecting information for producing forecasting are described, as is work about the concept of surveillance/monitoring and the processes used for coordinating such approaches. It can thus be sta- ted that they provide an excellent basis for strengthening TD by providing platforms for new or improved developments in pro- cesses or products. Reflection about these aspects provides perspectives for implementing technological forecasting (TF in pro- duction systems so that they obtain efficient and concrete results via deterministic methods as input in decision-making in techno- logy regarding its middle- and long-term competitiveness.

  19. 移相控制对称半桥变换器软开关条件%ZVS Condition of Symmetry Half-Bridge Converter with Phase-Shifted Control

    Institute of Scientific and Technical Information of China (English)

    蒋玮; 胡仁杰; 黄慧春

    2011-01-01

    对称半桥变换器移相控制软开关技术利用电路寄生参数产生谐振,实现开关器件的零电压开关状态,主要包括开关器件的寄生电容和变压器漏感。在实际应用中,因寄生参数不够,可通过外加谐振器件的方式帮助软开关。本文简要分析了移相控制对称半桥变换器的工作原理和换流过程。通过对软开关过程中的等效电路分析,获得了谐振器件参数与变换器稳态工作条件之间的条件关系,可作为软开关条件下选择开关器件寄生电容以及外加谐振器件参数的依据。样机实验验证了使用该条件能够作为移相控制对称半桥变换器软开关设计的有效依据。%The symmetry half-bridge bidirectional converter's zero voltage switching(ZVS) is achieved by the resonance between the circuit's parasitic elements,including parasitic capacitors of the switches and the leak inductance of the transformer.In application,the additional resonance elements could help the ZVS operation if the parasitic elements are not enough.The topology and operation principle of symmetry half-bridge bidirectional converter is briefly introduced,which could easily achieve zero voltage switching(ZVS).Based on the analysis of its operation modes,the realization of ZVS is indicated.By analyzing the equivalent circuit of the ZVS operation mode,the relationship between the circuit's resonance elements' parameters and the converter's steady operation requirements is built,which could be used to choose the switch's parasitic capacitors and the additional resonance elements.The experimental results verify the illustrated conditions.

  20. Bridge health assessment system with fatigue analysis algorithm

    Science.gov (United States)

    Wang, Xuan; Wang, M. L.; Zhao, Yang

    2005-05-01

    A modern bridge is such a complicated system that is difficult to analyze by conventional mathematic tools. A rational bridge monitoring requires a good knowledge of the actual condition of various structural components. Fatigue analysis of concrete bridges is one of the most important problems. Concrete bridges are often undergoing a fatigue deterioration, starting with cracking and ending with large holes through the web. There is a need for the development of efficient health assessment system for fatigue evaluation and prediction of the remaining life. This information has clear economical consequences, as deficient bridges must be repaired or closed. The goal of this research is to provide a practical expert system in bridge health evaluation and improve the understanding of bridge behavior during their service. Efforts to develop a functional bridge monitoring system have mainly been concentrated upon successful implementation of experienced-based machine learning. The reliability of the techniques adopted for damage assessment is also important for bridge monitoring systems. By applying the system to an in-service PC bridge, it has been verified that this fuzzy logic expert system is effective and reliable for the bridge health evaluation.

  1. Bridge technology report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. As LANs have proliferated, new technologies and system concepts have come to the fore. One of the key issues is how to interconnect networks. One means of interconnection is to use a 'bridge'. Other competing technologies are repeaters, routers, and gateways. Bridges permit traffic isolation, connect network segments together and operate at the MAC layer. Further, because they operate at the MAC layer, they can handle a variety of protocols such as TCP/IP, SNA, and X.25. This report focuses on the specific technology of bridging two netw

  2. STRENGTHENING BIOTECHNOLOGY RESEARCH IN INDONESIA

    Directory of Open Access Journals (Sweden)

    S. Sastrapradja

    2012-09-01

    Full Text Available The wave of biotechnology promises has struck not only the developed countries but the developing countries as well. The scientific community in Indonesia is aware of the opportunities and is eager to take an active part in this particular endeavour. Meanwhile resources are required to welcoming the biotech­nology era. The need of trained manpower, appropriate infrastructure and equipment, operational and maintenance costs requires serious consideration if a unit or a laboratory is expected to be functional in biotechnology. There is a good opportunity of applying biotechnology in the field of agriculture and industry considering the availability of biological resources in Indonesia. This paper outlines what have been done so far, the difficulties encountered and the efforts made to strengthening biotechnology research in Indonesia.

  3. Multivariate Feature Selection for Predicting Scour-Related Bridge Damage using a Genetic Algorithm

    Science.gov (United States)

    Anderson, I.

    2015-12-01

    Scour and hydraulic damage are the most common cause of bridge failure, reported to be responsible for over 60% of bridge failure nationwide. Scour is a complex process, and is likely an epistatic function of both bridge and stream conditions that are both stationary and in dynamic flux. Bridge inspections, conducted regularly on bridges nationwide, rate bridge health assuming a static stream condition, and typically do not include dynamically changing geomorphological adjustments. The Vermont Agency of Natural Resources stream geomorphic assessment data could add value into the current bridge inspection and scour design. The 2011 bridge damage from Tropical Storm Irene served as a case study for feature selection to improve bridge scour damage prediction in extreme events. The bridge inspection (with over 200 features on more than 300 damaged and 2,000 non-damaged bridges), and the stream geomorphic assessment (with over 300 features on more than 5000 stream reaches) constitute "Big Data", and together have the potential to generate large numbers of combined features ("epistatic relationships") that might better predict scour-related bridge damage. The potential combined features pose significant computational challenges for traditional statistical techniques (e.g., multivariate logistic regression). This study uses a genetic algorithm to perform a search of the multivariate feature space to identify epistatic relationships that are indicative of bridge scour damage. The combined features identified could be used to improve bridge scour design, and to better monitor and rate bridge scour vulnerability.

  4. Bridged Race Population Estimates

    Data.gov (United States)

    U.S. Department of Health & Human Services — Population estimates from "bridging" the 31 race categories used in Census 2000, as specified in the 1997 Office of Management and Budget (OMB) race and ethnicity...

  5. Strengthening Chronic Disease Prevention Programming: the Toward Evidence-Informed Practice (TEIP) Program Assessment Tool

    OpenAIRE

    Albert, Dayna; Fortin, Rebecca; Lessio, Anne; Herrera, Christine; Riley, Barbara; Hanning, Rhona; Rush, Brian

    2013-01-01

    Best practices identified solely on the strength of research evidence may not be entirely relevant or practical for use in community-based public health and the practice of chronic disease prevention. Aiming to bridge the gap between best practices literature and local knowledge and expertise, the Ontario Public Health Association, through the Toward Evidence-Informed Practice initiative, developed a set of resources to strengthen evidence-informed decision making in chronic disease preventio...

  6. Long Span Bridges in Scandinavia

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1998-01-01

    The first Scandinavian bridge with a span of more than 500 m was the Lillebælt Suspension Bridge opened to traffic in 1970.Art the end of the 20th century the longest span of any European bridge is found in the Storebælt East Bridge with a main span of 1624 m. Also the third longest span in Europ...

  7. Identifying hidden sexual bridging communities in Chicago.

    Science.gov (United States)

    Youm, Yoosik; Mackesy-Amiti, Mary Ellen; Williams, Chyvette T; Ouellet, Lawrence J

    2009-07-01

    Bridge populations can play a central role in the spread of human immunodeficiency virus (HIV) by providing transmission links between higher and lower prevalence populations. While social network methods are well suited to the study of bridge populations, analyses tend to focus on dyads (i.e., risk between drug and/or sex partners) and ignore bridges between distinct subpopulations. This study takes initial steps toward moving the analysis of sexual network linkages beyond individual and risk group levels to a community level in which Chicago's 77 community areas are examined as subpopulations for the purpose of identifying potential bridging communities. Of particular interest are "hidden" bridging communities; that is, areas with above-average levels of sexual ties with other areas but whose below-average AIDS prevalence may hide their potential importance for HIV prevention. Data for this analysis came from the first wave of recruiting at the Chicago Sexual Acquisition and Transmission of HIV Cooperative Agreement Program site. Between August 2005 through October 2006, respondent-driven sampling was used to recruit users of heroin, cocaine, or methamphetamine, men who have sex with men regardless of drug use, the sex partners of these two groups, and sex partners of the sex partners. In this cross-sectional study of the sexual transmission of HIV, participants completed a network-focused computer-assisted self-administered interview, which included questions about the geographic locations of sexual contacts with up to six recent partners. Bridging scores for each area were determined using a matrix representing Chicago's 77 community areas and were assessed using two measures: non-redundant ties and flow betweenness. Bridging measures and acquired immunodeficiency syndrome (AIDS) case prevalence rates were plotted for each community area on charts representing four conditions: below-average bridging and AIDS prevalence, below-average bridging and above

  8. Integral Abutment and Jointless Bridges

    OpenAIRE

    Cristian-Claudiu Comisu

    2005-01-01

    Integral bridges, or integral abutment and jointless bridges, as they are more commonly known in the USA, are constructed without any movement joints between spans or between spans and abutments. Typically these bridges have stub-type abutments supported on piles and continuous bridge deck from one embankment to the other. Foundations are usually designed to be small and flexible to facilitate horizontal movement or rocking of the support. Integrally bridges are simple or multiple span ones t...

  9. Efficient strengthening technique for reinforced concrete slabs

    OpenAIRE

    Bonaldo, Everaldo; Barros, Joaquim A. O.; Lourenço, Paulo B.

    2006-01-01

    A promising strengthening strategy, using carbon fiber reinforced polymer (CFRP) materials, consists in applying CFRP laminate strips into pre-cut slits opened in the concrete cover of the elements to strengthen. This strengthening technique is designated by Near Surface Mounted (NSM) and has been successfully used to increase the flexural and the shear resistance of concrete and masonry structures. The present work describes an efficient strategy, using steel fiber reinforced concrete (SFRC)...

  10. Assessment of concrete bridge decks with alkali silica reactions

    DEFF Research Database (Denmark)

    Eriksen, Kirsten; Jansson, Jacob; Geiker, Mette Rica

    2008-01-01

    Based on investigations of concrete from an approximately 40 years old bridge a procedure to support the management of maintenance and repair of alkali silica damaged bridges is proposed. Combined petrography and accelerated expansion testing were undertaken on cores from the Bridge at Skovdiget......, Bagsværd, Denmark to provide information on the damage condition as well as the residual reactivity of the concrete. The Danish Road Directory’s guidelines for inspection and assessment of alkali silica damaged bridges will be briefly presented, and proposed modifications will be describe...

  11. Strengthening Injury Surveillance System in Iran

    Directory of Open Access Journals (Sweden)

    Motevalian Seyed Abbas

    2012-02-01

    Full Text Available 【Abstract】Objective: To strengthen the current Injury Surveillance System (IS System in order to better monitor injury conditions, improve protection ways and promote safety. Methods: At first we carried out a study to evaluate the frameworks of IS System in the developed countries. Then all the available documents from World Health Organization, Eastern Mediterranean Regional Organization, as well as Minister of Health and Medical Education concerning Iran were reviewed. Later a national stakeholder抯 consultation was held to collect opinions and views. A national workshop was also intended for provincial representatives from 41 universities to identify the barriers and limitations of the existing program and further to strengthen injury surveillance. Results: The evaluation of the current IS System revealed many problems, mainly presented as lack of accurate pre- and post-hospital death registry, need of precise injury data registry in outpatient medical centers, incomplete injury data registry in hospitals and lack of accuracy in definition of variables in injury registry. The five main characteristics of current IS System including flexibility, acceptability, simplicity, usefulness and timeliness were evaluated as moderate by experts. Conclusions: Major revisions must be considered in the current IS System in Iran. The following elements should be added to the questionnaire: identifier, manner of arrival to the hospital, situation of the injured patient, consumption of alcohol and opioids, other involved participants in the accident, intention, severity and site of injury, side effects of surgery and medication, as well as one month follow-up results. Data should be collected from 10% of all hospitals in Iran and analyzed every 3 months. Simultaneously data should be online to be retrieved by researches. Key words: Wounds and injuries; Population surveillance; Registries; Iran

  12. Strengthening Injury Surveillance System in Iran

    Institute of Scientific and Technical Information of China (English)

    Seyed Abbas Motevalian; Mashyaneh Haddadi; Hesam Akbari; Reza Khorramirouz; Soheil Saadat; Arash Tehrani; Vafa Rahimi-Movaghar

    2011-01-01

    Objective:To strengthen the current Injury Surveillance System (IS System) in order to better monitor injury conditions,improve protection ways and promote safety.Methods:At first we carried out a study to evaluate the frameworks of IS System in the developed countries.Then all the available documents from World Health OrganizationEastern Mediterranean Regional Organization,as well as Minister of Health and Medical Education concerning Iran were reviewed.Later a national stakeholder's consultation was held to collect opinions and views.A national workshop was also intended for provincial representatives from 41 universities to identify the barriers and limitations of the existing program and further to strengthen injury surveillance.Results:The evaluation of the current IS System revealed many problems,mainly presented as lack of accurate pre- and post-hospital death registry,need of precise injury data registry in outpatient medical centers,incomplete injury data registry in hospitals and lack of accuracy in definition of variables in injury registry.The five main characteristics of current IS System including flexibility,acceptability,simplicity,usefulness and timeliness were evaluated as moderate by experts.Contusions:Major revisions must be considered in the current IS System in Iran.The following elements should be added to the questionnaire:identifier,manner of arrival to the hospital,situation of the injured patient,consumption of alcohol and opioids,other involved participants in the accident,intention,severity and site of injury,side effects of surgery and medication,as well as one month follow-up results.Data should be collected from 10% of all hospitals in Iran and analyzed every 3 months.Simultaneously data should be online to be retrieved by researches.

  13. Dynamic Strengthening During High Velocity Shear Experiments with Siliceous Rocks

    Science.gov (United States)

    Liao, Z.; Chang, J. C.; Boneh, Y.; Chen, X.; Reches, Z.

    2011-12-01

    It is generally accepted that dynamic-weakening is essential for earthquake instability, and many experimental works have documented this weakening. Recent observations revealed also opposite trends of dynamic-strengthening in experiments (Reches & Lockner, 2010). We present here our experimental results of this dynamic-strengthening and discuss possible implications to earthquake behavior. We ran hundreds of experiments on experimental faults made of siliceous rock including granite, syenite, diorite, and quartzite. The experimental fault is comprised of two solid cylindrical blocks with a raised-ring contact of 7 cm diameter and 1 cm width. We recognized general, three regimes of strength-velocity relations: (I) Dynamic weakening (drop of 20-60% of static strength) as slip velocity increased from ~0.0003 m/s (lowest experimental velocity) to a critical velocity, Vc=0.008-0.16 m/s; (II) Abrupt transition to dynamic strengthening regime during which the fault strength almost regains its static strength; and (III) Quasi-constant strength with further possible drops as velocity approaches ~1 m/s. The critical velocity depends on the sample lithology: Vc is ~0.06 m/s for granite, ~0.008 m/s for syenite, ~0.01 m/s for diorite, and ~0.16 m/s for quartzite. The strengthening stage is associated with temperature increase, wear-rate increase, and the occurrence of intense, high frequency stick-slip events (Reches & Lockner, 2010). Sammis et al., (this meeting) attributed this strengthening to dehydration of the thin water layer that covers the gouge particles as the temperature increases. On the other hand, we note that tens of experiments with dolomite samples (non-siliceous), which were deformed under similar conditions, did not exhibit the velocity strengthening (unpublished). Based on the analyses by Andrews (2004, 2005), we speculate that velocity strengthening may bound the slip velocity. The numerical models of Andrews show that the slip velocity along a slip

  14. Structural safety monitoring for Nanjing Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    黄方林; 何旭辉; 陈政清; 曾储惠

    2004-01-01

    In order to evaluate objectively and accurately the integrity, safety and operating conditions in real time for the Nanjing Yangtze River Bridge, a large structural safety monitoring system was described. The monitoring system is composed of three parts: sensor system, signal sampling and processing system, and safety monitoring and assessment system. Combining theoretical analysis with measured data analysis, main monitoring contents and layout of measuring points were determined. The vibration response monitoring was significantly investigated. The main contents of safety monitoring on vibration response monitoring are vibration of the main body of the Nanjing Yangtze river bridge, collision avoidance of the bridge piers, vibration of girders on high piers for the bridge approach and earthquake. As a field laboratory, the safety monitorying system also provides information to investigate the unknown and indeterminate problems on bridge structures and specific environment around bridges.

  15. Fragility curves of concrete bridges retrofitted by column jacketing

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The Northridge earthquake inflicted various levels of damage upon a large number of Caltrans' bridges not retrofitted by column jacketing. In this respect, this study represents results of fragility curve development for two (2) sample bridges typical in southern California, strengthened for seismic retrofit by means of steel jacketing of bridge columns. Monte Carlo simulation is performed to study nonlinear dynamic responses of the bridges before and after column retrofit. Fragility curves in this study are represented by Iognormal distribution functions with two parameters and developed as a function of PGA. The sixty (60) ground acceleration time histories for the Los Angeles area developed for the Federal Emergency Management Agcncy (FEMA) SAC (SEAOC-ATC-CUREe) steel project are used for the dynamic analysis of the bridges.The improvement in the fiagility with steel jacketing is quantified by comparing fragility curves of the bridge before and after column retrofit. In this first attempt to formulate the problem of fragility enhancement, the quantification is made by comparing the median values of the fragility curves before and after the retrofit. Under the hypothesis that this quantification also applies to empirical fragility curves developed on the basis of Northridge earthquake damage, the enhanced version of the empirical curves is developed for the ensuing analysis to determine the enhancement of transportation network performance due to the retrofit.

  16. System design for strengthening simply supported RC beams in flexure by retrofitting external unbonded conventional reinforcement

    International Nuclear Information System (INIS)

    The paper presents the practical design approach and guidelines for the system design of a novel strengthening technique where external unbounded ordinary reinforcement is retrofitted to reinforced concrete beams for enhancement of flexural capacity of simply supported and cantilever beams of buildings and bridges. The design guidelines for the system hardware along with the practical consideration in applications have been elaborately presented. Suitable design examples have been included demonstrating the suitability of the technique in comparison to steel plate bonding. Strengthening with external unbounded reinforcement has been shown to provide an appreciable increase in the ultimate flexural strength of reinforced concrete beams. Additionally the technique offers greater simplicity and ease of installation in comparison to other widely used strengthening techniques, such as shotcrete with additional tension reinforcement, epoxy bonded steel plates and external unbounded prestressing tendors, where less stringent requirements for deflectors, anchorage and end zones are encountered. (author)

  17. APPLICATION OF PRESTRESSED SHELLS TO STRENGTHEN STRIP FOUNDATIONS

    Directory of Open Access Journals (Sweden)

    Ter-Martirosjan Zaven Grigor'evich

    2012-10-01

    Full Text Available Effective method of strengthening of foundations of existing buildings by pre-stressed shells is considered in the paper. Advantages of the proposed strengthening method, its production technology and pre-conditions of its analysis are also presented. Presently, strengthening of ground foundations and foundations of buildings and structures is a relevant civil engineering challenge. It is driven by high intensity of restructuring and modernization of buildings and alteration of geological engineering conditions of the areas that are being built up. One of effective methods of strengthening of foundations of existing buildings represents arrangement of pre-stressed concrete shells with conventional steel or metal-free reinforcement. If compared with injection-based technologies, the proposed reinforcement method reduces the cost of construction work by 1.5 times, on average. Therefore, the per-unit cost of shell-based reinforcement of foundations is under 500 Russian roubles per 1 sq. m. of the building floor area. It is noteworthy that no restrictions are imposed on the operation of the building in the course of the above reconstruction, as the secluded backyard is the sole area that accommodates supplementary construction operations.

  18. Social capital to strengthen health policy and health systems.

    Science.gov (United States)

    Ogden, Jessica; Morrison, Ken; Hardee, Karen

    2014-12-01

    This article recounts the development of a model for social capital building developed over the course of interventions focused on HIV-related stigma and discrimination, safe motherhood and reproductive health. Through further engagement with relevant literature, it explores the nature of social capital and suggests why undertaking such a process can enhance health policy and programmes, advocacy and governance for improved health systems strengthening (HSS) outcomes. The social capital process proposed facilitates the systematic and effective inclusion of community voices in the health policy process-strengthening programme effectiveness as well as health system accountability and governance. Because social capital building facilitates communication and the uptake of new ideas, norms and standards within and between professional communities of practice, it can provide an important mechanism for integration both within and between sectors-a process long considered a 'wicked problem' for health policy-makers. The article argues that the systematic application of social capital building, from bonding through bridging into linking social capital, can greatly enhance the ability of governments and their partners to achieve their HSS goals.

  19. Thermomechanical responses of concrete members strengthened with cfrp sheets

    Science.gov (United States)

    Alqurashi, Abdulaziz

    Strengthening structural members means to be able to carry additional loads. Since, 1990s, a lot of materials and techniques have been established to not only increasing the capacity of member but also facing deterioration. Deterioration has become one of the worst highly maintenance cost. According to The ASCE, 27.1% of all bridges in the United States are not effectual. This is because the high traffic reflects negatively to structural members and cause deterioration of these members. This problem has been cost a lot of money. In addition, FRP has approved that it can increase the capacity of member and overcome some disadvantages such as deterioration. Therefore, CFRP sheet has become widely used. However, high temperatures affect the performance of externally bonded CFRP sheet negatively. Investigation should be carried out on relaxation and flexural performance of members under different temperatures. Therefore, this thesis focus on analyzing and investigating the performance of strengthened members exposed to elevated temperatures (25 to 175 °C). The experimental program was divided to two main parts. First, 144 strengthen concrete blocks 100mm X 150mm X 75mm has been exposed to elevated temperatures. These blocks have two main categories, which are different CFRP sheet width, and different CFRP sheet length. Different CFRP width has three types, which are type 0.25B (25mm x 100mm), type 0.5B (50mm x 100mm) and type 0.75B (75mm x 100mm). Also, Different CFRP length has three types, which are type L e (bonded area of 50 mm by 90mm), 1.25 Le (area of 50mm by 125mm) and type 1.5Le (50mm by 137 mm). Second, studying the performance of RC beams exposed to elevated temperatures.

  20. 金温线横向振幅超限桥梁的列车走行性分析%Analysis of train running performance of bridges on Jinwen line with lateral amplitude exceeding limit value

    Institute of Scientific and Technical Information of China (English)

    周智辉; 曾胜钟; 张军; 曾庆元

    2011-01-01

    The lateral amplitudes of part bridges on Jinwen line exceed the limit value of traffic safety given by code. In order to take proper measures on these bridges, the train running performance of these bridges is needed to be evaluated urgently. The calculation model for train -bridge system vibration was presented, and train running performance of four bridges was analyzed with energy random analysis theory for derailment. The analyzed result shows that the safety, comfort and smoothness of running train on Wuyijiang bridge, Linxia bridge and Haoxi bridge can be guaranteed with existing operation condition, and rate -limiting or reinforcement are not needed. The safety of running train on Hubian bridge can' t be guaranteed, and some reinforcement measures must be taken on this bridge, and the piers are suggested to be strengthened to build up bridge lateral rigidity. Before the bridge is strengthened, the speed of freight train should be controlled under 60 km/h. The research results have been adopted on Jinwen line. Reinforcing measures on three bridges are avoided, and lots of profit has been obtained. By comparison between the lateral amplitudes of four bridges and the limit value of traffic safety given by code, it can be seen that limit value of traffic safety of lateral amplitude given by existing code is too rigorous,with which the transport capacity of existing railway bridges is restricted.%金温线部分桥梁横向振幅超过规定的行车安全限值,运营部门担心存在脱轨危险,急需对这些桥梁列车走行性进行评估,以便采取适当的处理措施.建立列车-桥梁系统振动计算模型,运用列车脱轨能量随机分析理论,分析了金温线4座预应力混凝土梁桥的列车走行性.分析结果表明:在现行行车条件下,武义江桥、岭下桥与好溪桥列车走行安全性、平稳性与舒适性有保障,不必采取限速或加固措施;湖边桥列车走行安全性不能保证,建议采取适当的加

  1. Investigation of Aerodynamic Interference of Double Deck Bridges

    Energy Technology Data Exchange (ETDEWEB)

    Sitek, M. A. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division. Transportation Research and Analysis Computing Center (TRACC); Bojanowski, C. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division. Transportation Research and Analysis Computing Center (TRACC); Lottes, S. A. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division. Transportation Research and Analysis Computing Center (TRACC)

    2016-05-01

    Construction of a twin bridge can be a cost effective and minimally disruptive way to increase capacity when an existing bridge is not near the end of its service life. With ever growing vehicular traffic, when demand approaches the capacity of many existing roads and bridges. Remodeling a structure with an insufficient number of lanes can be a good solution in case of smaller and less busy bridges. Closing down or reducing traffic on crossings of greater importance for the construction period, however, can result in major delays and revenue loss for commerce and transportation as well as increasing the traffic load on alternate route bridges. Multiple-deck bridges may be the answer to this issue. A parallel deck can be built next to the existing one, without reducing the flow. Additionally, a new bridge can be designed as a twin or multi-deck structure. Several such structures have been built throughout the United States, among them: - The New NY Bridge Project - the Tappan Zee Hudson River Crossing, - SR-182 Columbia River Bridge, - The Thaddeus Kosciusko Bridge (I-87), - The Allegheny River Bridge, Pennsylvania, which carries I76, - Fred Hartman Bridge, TX, see Figure 1.2. With a growing number of double deck bridges, additional, more detailed, studies on the interaction of such bridge pairs in windy conditions appears appropriate. Aerodynamic interference effects should be examined to assure the aerodynamic stability of both bridges. There are many studies on aerodynamic response of single deck bridges, but the literature on double-deck structures is not extensive. The experimental results from wind tunnels are still limited in number, as a parametric study is required, they can be very time consuming. Literature review shows that some investigation of the effects of gap-width and angle of wind incidence has been done. Most of the CFD computational studies that have been done were limited to 2D simulations. Therefore, it is desirable to investigate twin decks

  2. Science as a Common Language in a Globalised World - Scientific Collaboration Promoting Progress, Building Bridges

    CERN Document Server

    CERN. Geneva. Audiovisual Unit

    2003-01-01

    International scientific collaboration and co-operation can accelerate the progress of science, help build bridges between diverse societies, and foster the development of science and technology in non-industrialised countries. This is possible because science is a common language (although the progress of science is often influenced by non-scientific factors). I shall describe examples of the role that scientific collaboration can play in bridge building and in conflict resolution. I shall then present a proposal for "Bridge Building Fellowships" which would contribute to strengthening scientific capacity in developing countries by helping to stem the brain drain and providing a basis for collaborations with scientists in industrialised countries.

  3. Running Safety of Trains under Vessel-Bridge Collision

    Directory of Open Access Journals (Sweden)

    Yongle Li

    2015-01-01

    Full Text Available To optimize the sensor placement of the health monitoring system, the dynamic behavior of the train-bridge system subjected to vessel-collision should be studied in detail firstly. This study thus focuses on the characteristics of a train-bridge system under vessel-bridge collision. The process of the vessel-bridge collision is simulated numerically with a reliable finite element model (FEM. The dynamic responses of a single car and a train crossing a cable-stayed bridge are calculated. It is shown that the collision causes significant increase of the train’s lateral acceleration, lateral wheelset force, wheel unloading rate, and derailment coefficient. The effect of the collision on the train’s vertical acceleration is much smaller. In addition, parametric studies with various train’s positions, ship tonnage, and train speed are performed. If the train is closer to the vessel-bridge collision position or the ship tonnage is larger, the train will be more dangerous. There is a relatively high probability of running danger at a low speed, resulting from longer stay of the train on the bridge. The train’s position, the ship tonnage, and the train speed must be considered when determining the most adverse conditions for the trains running on bridges under vessel-bridge collision.

  4. Salt bridge as a gatekeeper against partial unfolding.

    Science.gov (United States)

    Hinzman, Mark W; Essex, Morgan E; Park, Chiwook

    2016-05-01

    Salt bridges are frequently observed in protein structures. Because the energetic contribution of salt bridges is strongly dependent on the environmental context, salt bridges are believed to contribute to the structural specificity rather than the stability. To test the role of salt bridges in enhancing structural specificity, we investigated the contribution of a salt bridge to the energetics of native-state partial unfolding in a cysteine-free version of Escherichia coli ribonuclease H (RNase H*). Thermolysin cleaves a protruding loop of RNase H(*) through transient partial unfolding under native conditions. Lys86 and Asp108 in RNase H(*) form a partially buried salt bridge that tethers the protruding loop. Investigation of the global stability of K86Q/D108N RNase H(*) showed that the salt bridge does not significantly contribute to the global stability. However, K86Q/D108N RNase H(*) is greatly more susceptible to proteolysis by thermolysin than wild-type RNase H(*) is. The free energy for partial unfolding determined by native-state proteolysis indicates that the salt bridge significantly increases the energy for partial unfolding by destabilizing the partially unfolded form. Double mutant cycles with single and double mutations of the salt bridge suggest that the partially unfolded form is destabilized due to a significant decrease in the interaction energy between Lys86 and Asp108 upon partial unfolding. This study demonstrates that, even in the case that a salt bridge does not contribute to the global stability, the salt bridge may function as a gatekeeper against partial unfolding that disturbs the optimal geometry of the salt bridge. PMID:26916981

  5. Analysis and Study of Force Conditions of Group Shear Studs of Long Span Steel and Concrete Composite Girder Bridge%大跨度钢—混组合梁桥剪力群钉受力分析研究

    Institute of Scientific and Technical Information of China (English)

    赵建; 郑舟军

    2013-01-01

    组合梁仿真分析时将多个剪力钉简化成一个等效剪力群钉进行模拟,不能准确得到每个剪力钉的受力情况.为解决此问题,根据实桥集束式剪力钉布置方式制作剪力群钉推出试件,并进行推出试验,得知群钉中最不利的单个剪力钉承担了32%~37%的总剪力(平均值仅为25%);由大跨度组合箱梁整体模型计算得到剪力群钉受力均值、钢-混凝土相对位移及钢梁与混凝土桥面板的受力状况;根据剪力群钉荷载分配比例对组合梁整体计算得到的剪力钉计算结果进行修正.结果表明,将剪力群钉受力均值换算得到剪力钉受力极值的方法,可实现对大跨度组合梁及其剪力钉的精确仿真分析.%When the simulation analysis of a composite girder is made,the way of simplifying the multiple shear studs of the girder into the equivalent group shear studs can not exactly acquire the force condition of each stud.To solve the problem,the push-out specimen of the group shear studs was fabricated according to the clustering layout of the shear studs of the practical bridge,the push out test for the specimen was carried out and it was consequently known that the single stud in the group shear studs under the worst force condition sustained 32%~37% of the total shear force (while the average value was 25% only).From the calculation of the integral model of the long span composite box girder,the force average values of the group shear studs,the relative displacement of the steel and concrete and the force conditions of the steel girder and concrete deck slabs were acquired and with reference to the load distribution ratios of the group shear studs,the calculation results of the shear studs were modified.The results of the calculation and modification demonstrate that by way of converting from the force average values of the group shear studs to the force ultimate values of the shear studs,the accurate simulation analysis of

  6. Risk based bridge data collection and asset management and the role of structural health monitoring

    Science.gov (United States)

    Omenzetter, Piotr; Bush, Simon; Henning, Theunis; McCarten, Peter

    2011-04-01

    Bridges are critical to the operation and functionality of the whole road networks. It is therefore essential that specific data is collected regarding bridge asset condition and performance, as this allows proactive management of the assets and associated risks and more accurate short and long term financial planning. This paper proposes and discusses a strategy for collection of data on bridge condition and performance. Recognizing that risk management is the primary driver of asset management, the proposed strategy prioritizes bridges for levels of data collection including core, intermediate and advanced. Individual bridges are seen as parts of wider networks and bridge risk and criticality assessment emphasizes bridge failure or underperformance risk in the network context. The paper demonstrates how more reliable and detailed data can assist in managing network and bridge risks and provides a rationale for application of higher data collection levels for bridges characterized by higher risk and criticality. As the bridge risk and/or criticality increases planned and proactive integration of structural health monitoring (SHM) data into asset management is outlined. An example of bridge prioritization for data collection using several bridges taken from a national highway network is provided using an existing risk and criticality scoring methodology. The paper concludes with a discussion on the role of SHM in data collection for bridge asset management and where SHM can make the largest impacts.

  7. Effect of material uncertainties on dynamic response of segmental box girder bridge

    OpenAIRE

    Suchart Limkatanyu; Kittisak Kuntiyawichai

    2007-01-01

    The main objective of this paper was to investigate the effect of material uncertainties on dynamic response of segmental box girder bridge subjected to a moving load, in this case a rapid passing trains. Literatures concerned with the design of segmental box girder bridge, the application of finite element analysis to model the segmental box girder bridge, and the minimum requirement for structural conditions of the bridge were described and discussed in detail. A series of finite element a...

  8. HIV communication capacity strengthening: a critical review.

    Science.gov (United States)

    Lettenmaier, Cheryl; Kraft, Joan Marie; Raisanen, Keris; Serlemitsos, Elizabeth

    2014-08-15

    HIV communication is most effective and sustainable when it is designed and implemented locally and tailored to the local context. This requires capacity strengthening at national, subnational, and community levels. Through a review of the published and selected "grey" literature, we examine HIV communication capacity strengthening: definitions, measurements, implementation, and effects. We found limited documentation of HIV communication capacity needs or systematic approaches to address them. Most HIV communication capacity strengthening to date has focused on building individual competencies to design and manage social and behavior change communication programs through training courses, often coupled with networking opportunities for participants, post-training mentoring, and technical assistance. A few of these efforts have been evaluated through pre- and post-training tests and qualitative interviews with participants and have shown potential for improvement in individual skills and knowledge. Health communication capacity assessment tools that measure individual and organizational competencies exist, but they have most often been used to identify capacity building needs, not for evaluating capacity strengthening efforts. A new definition of capacity strengthening, grown out of recent efforts to improve effectiveness of international health and development programs, focuses on improving organizational and societal systems that support performance and individual competencies. We propose a holistic model for HIV communication capacity strengthening and call for rigorous documentation and evaluation to determine and scale-up optimal capacity building interventions for strengthening social and behavior change communication for HIV prevention, care, and treatment in developing countries. PMID:25007200

  9. Quantum Bidding in Bridge

    Science.gov (United States)

    Muhammad, Sadiq; Tavakoli, Armin; Kurant, Maciej; Pawłowski, Marcin; Żukowski, Marek; Bourennane, Mohamed

    2014-04-01

    Quantum methods allow us to reduce communication complexity of some computational tasks, with several separated partners, beyond classical constraints. Nevertheless, experimental demonstrations of this have thus far been limited to some abstract problems, far away from real-life tasks. We show here, and demonstrate experimentally, that the power of reduction of communication complexity can be harnessed to gain an advantage in a famous, immensely popular, card game—bridge. The essence of a winning strategy in bridge is efficient communication between the partners. The rules of the game allow only a specific form of communication, of very low complexity (effectively, one has strong limitations on the number of exchanged bits). Surprisingly, our quantum technique does not violate the existing rules of the game (as there is no increase in information flow). We show that our quantum bridge auction corresponds to a biased nonlocal Clauser-Horne-Shimony-Holt game, which is equivalent to a 2→1 quantum random access code. Thus, our experiment is also a realization of such protocols. However, this correspondence is not complete, which enables the bridge players to have efficient strategies regardless of the quality of their detectors.

  10. Bridge of Light

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Lying gleaming white under a brooding sky,the Lhasa River Railway Bridge forms a gate to Lhasa City.Built as a part of Qinghai-Tibet Railway,on July 1,2011, the highest altitude railway in the world has been in service for five years. Lhasa,Tibet

  11. Bridge over troubled water?

    DEFF Research Database (Denmark)

    Svendsen, Gunnar Lind Haase; Nannestad, Peter; Svendsen, Gert Tinggaard

    2008-01-01

    The problem of integrating non-Western immigrants into Western welfare states is the focus of this paper. To address this issue, we suggest a social capital approach in which we apply the conceptual pair of bridging social capital (BR), which connects an individual to the broader social structure...

  12. Building Bridges to China.

    Science.gov (United States)

    Wasta, Stephanie; Scott, Margaret

    1998-01-01

    Describes a theme cycle called "Building Bridges to China" developed for third grade students that focuses on the similarities between the lives of children and families in China and the United States. Explains that the theme cycle addresses the National Geography Standards and three of the National Council for the Social Studies standards. (CMK)

  13. EMOTIONAL STRENGTHENING IN THE FAMILY: INTERVENTION FROM THE SCHOOL CONTEXT

    OpenAIRE

    Jael Alejandra Vargas Rubilar; Laura Beatriz Oros

    2012-01-01

    The psychological consequences from relational styles characterized by lack of affection and interactional mismanagement between family members can inhibit or block the attempt by members to achieve their full potential for healthy psy -chosocial development. In this context, emotional strengthening families would become a key condition for overcoming these dysfunctional patterns.The aim of this work is to show why psychoeducation and emotional stimula-tion can be particularly useful in the c...

  14. Impact of bridge pier on the stability of ice jam

    Institute of Scientific and Technical Information of China (English)

    王军; 施发义; 陈胖胖

    2015-01-01

    River ice jam is one of the most important issues in rivers in cold regions during winter time. With the extra solid boundary due to the ice cover, the flow condition under ice-covered conditions is completely different from that of a open channel flow. The presence of bridge piers will further change the velocity field around the bridge piers. As a consequence, the formation and the accumulation of ice jams in the vicinity of the bridge pier will be affected. On the other side, the formation of an ice jam around the piers can cause extra turbulence to reduce the stability of a river bridge. The present study focuses on the stress analysis of the ice jam in the vicinity of a bridge pier. By developing a governing equation for describing the equilibrium state of an ice jam, the stability of the ice jam around bridge piers is analyzed and determined. As seen from the field data in literature, the stability estimations of an ice jam around bridge piers determined by the present method agree well with the field observations. Therefore, the proposed approach can be used for the prediction of the formation of ice jams around bridge piers.

  15. Timber Elements: Traditional and Modern Strengthening Techniques

    Directory of Open Access Journals (Sweden)

    Raluca Hohan

    2010-01-01

    Full Text Available The main idea of this paper is to analyse the means for the rehabilitation of our cultural heritage timber structures. Several methods together with their application techniques are described, and also, the reasons for what these strengthening operations become imminent at a point. First of all, the necessity of the timber structural elements strengthening is explained through a short presentation of the factors which are degrading the material. Then, certain precautions and strengthening procedures are presented, all involving the usage of traditional materials like wood, metal, or concrete, and of modern materials like fiber reinforced polymeric composite.

  16. Revised Rules for Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Jensen, F. M.; Middleton, C.;

    This paper is based on research performed for the Highway Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: Concrete Bridges" It contains details of a methodology which can be used to generate Whole Life (WL) reliability profiles....... These WL reliability profiles may be used to establish revised rules for Concrete Bridges....

  17. Dynamic Bridge Response for a Bridge-friendly Truck

    Directory of Open Access Journals (Sweden)

    V. Šmilauer

    2004-01-01

    Full Text Available A truck with controlled semi-active suspensions traversing a bridge is examined for benefits to the bridge structure. The original concept of a road-friendly truck was extended to a bridge-friendly vehicle, using the same optimization tools. A half-car model with two independently driven axles is coupled with simply supported bridges (beam, slab model with the span range from 5 m to 50 m. Surface profile of the bridge deck is either stochastic or in the shape of a bump or a pot in the mid-span. Numerical integration in the MATLAB/SIMULINK environment solves coupled dynamic equations of motion with optimized truck suspensions. The rear axle generates the prevailing load and to a great extent determines the bridge response. A significant decrease in contact road-tire forces is observed and the mid-span bridge deflections are on average smaller, when compared to commercial passive suspensions. 

  18. Performance Assessment of Bridges Using GPS: The Juarez Bridge in Culiacan, Mexico

    Science.gov (United States)

    Vazquez, G. E.; Gaxiola-Camacho, J. R.; Trejo, M.; Echagaray, J.; Guzman, G. M.

    2015-12-01

    Performance assessment of bridges has become very important during recent years. Bridges around the world are aging, leading to the incorporation of efficient, reliable, and economic evaluation procedures. These techniques must assess properly the performance of bridges under several loading conditions in a real manner, representing the physics of the problem. Among several approaches, Global Positioning System (GPS) can be intelligently used for the performance evaluation of bridges. We focused on GPS, since it naturally produces position estimates as compared to seismic instruments that record either velocity or acceleration, and thus require an integration. There are several reasons that make the Juarez Bridge a case of study for evaluation: it is approximately 45 years old, it is a reinforced concrete structure, it connects two significant zones of the city, and its spans is closely to 200 meters long. In addition, thousands of vehicles and pedestrians use the Juarez Bridge every day, which make feasible the GPS performance assessment. Hence, in order to produce optimal position estimates, GPS data were collected during two consecutive hours at three different periods of the day for a whole week (Monday through Sunday), to represent three critical limit states of the bridge (mid-span and end-spans). GPS data were processed using the GAMIT/GLOBK software, considering 1-second sampling rate, 15-degree cutoff angle, ionosphere-free double-differenced (DD) carrier phase method, and precise final orbits disseminated by IGS (International GNSS Service). The displacements obtained from the above discussed procedure are compared with allowable values documented in bridge construction manuals. Reliability theory was used to evaluate the probability of failure of the bridge for the three periods of the day. In addition, a conclusion was made about the most risky day of the week for the use of the Juarez Bridge. It is expected that the results from the proposed research

  19. Strengthening entrepreneurship through coaching and developing competencies

    NARCIS (Netherlands)

    Beldman, A.C.G.

    2011-01-01

    Strengthening entrepreneurship is an important strategy for stimulating the transition to sustainable agriculture. But how is that done? One example is the Interactive Strategic Management method, which supports entrepreneurs in the creation and execution of future-focused strategies.

  20. 78 FR 38053 - Regulatory Systems Strengthening

    Science.gov (United States)

    2013-06-25

    ... supply chain; risk assessment, analysis, and management; and emergency response. WHO helps to strengthen... in the world within increasingly complex supply chains. As national and global health programs work...; laboratory capacity; inspection and surveillance of products throughout the supply chain;...

  1. Mechanisms for slow strengthening in granular materials

    Science.gov (United States)

    Losert; Geminard; Nasuno; Gollub

    2000-04-01

    Several mechanisms cause a granular material to strengthen over time at low applied stress. The strength is determined from the maximum frictional force F(max) experienced by a shearing plate in contact with wet or dry granular material after the layer has been at rest for a waiting time tau. The layer strength increases roughly logarithmically with tau only if a shear stress is applied during the waiting time. The mechanisms of strengthening are investigated by sensitive displacement measurements, and by imaging of particle motion in the shear zone. Granular matter can strengthen due to a slow shift in the particle arrangement under shear stress. Humidity also leads to strengthening, but is found not to be its sole cause. In addition to these time dependent effects, the static friction coefficient can also be increased by compaction of the granular material under some circumstances, and by a cycling of the applied shear stress. PMID:11088198

  2. Experimental behavior of FRP strengthened masonry arches

    OpenAIRE

    Oliveira, Daniel V.; Basílio, Ismael; Lourenço, Paulo B.

    2010-01-01

    This paper deals with the experimental behavior of solid clay brick masonry arches strengthened with glass fiber reinforced polymer composites. Twelve half-scaled segmental masonry arches subjected to a load applied at the quarter span were tested under displacement control up to failure. The arches were built using handmade low strength bricks and a commercial lime-based mortar, trying to mimic ancient structures. Besides reference unreinforced arches, five different strengthening arrangemen...

  3. Eccentric Strengthening for Chronic Lateral Epicondylosis

    OpenAIRE

    Wen, Dennis Y.; Schultz, Brian J.; Schaal, Bob; Graham, Scott T.; Kim, Byung Sung

    2011-01-01

    Background: Effective treatments for chronic lateral epicondylosis have not been studied adequately. Eccentric overload exercises have been used with success for other chronic tendinopathy, mainly Achilles and patellar. Hypothesis/Purpose: To compare a wrist extensor eccentric strengthening exercise program with a wrist extensor stretching/modality program for the treatment of chronic lateral epicondylosis. The authors hypothesized that the eccentric strengthening program would produce more f...

  4. Mechanisms for slow strengthening in granular materials

    OpenAIRE

    Losert, W.; Geminard, J. -C.; Nasuno, S.; Gollub, J. P.

    1999-01-01

    Several mechanisms cause a granular material to strengthen over time at low applied stress. The strength is determined from the maximum frictional force F_max experienced by a shearing plate in contact with wet or dry granular material after the layer has been at rest for a waiting time \\tau. The layer strength increases roughly logarithmically with \\tau -only- if a shear stress is applied during the waiting time. The mechanisms of strengthening are investigated by sensitive displacement meas...

  5. Strengthening health systems by health sector reforms

    OpenAIRE

    Senkubuge, Flavia; Modisenyane, Moeketsi; Bishaw, Tewabech

    2014-01-01

    Background: The rising burden of disease and weak health systems are being compounded by the persistent economic downturn, re-emerging diseases, and violent conflicts. There is a growing recognition that the global health agenda needs to shift from an emphasis on disease-specific approaches to strengthening of health systems, including dealing with social, environmental, and economic determinants through multisectoral responses.Methods: A review and analysis of data on strengthening health se...

  6. Prediction of Fatigue Life of a Continuous Bridge Girder Based on Vehicle Induced Stress History

    Directory of Open Access Journals (Sweden)

    V.G. Rao

    2003-01-01

    Full Text Available The fatigue damage assessment of bridge components by conducting a full scale fatigue testing is often prohibitive. A need, therefore, exists to estimate the fatigue damage in bridge components by a simulation of bridge-vehicle interaction dynamics due to the action of the actual traffic. In the present paper, a systematic method has been outlined to find the fatigue damage in the continuous bridge girder based on stress range frequency histogram and fatigue strength parameters of the bridge materials. Vehicle induced time history of maximum flexural stresses has been obtained by Monte Carlo simulation process and utilized to develop the stress range frequency histogram taking into consideration of the annual traffic volume. The linear damage accumulation theory is then applied to calculate cumulative damage index and fatigue life of the bridge. Effect of the bridge span, pavement condition, increase of vehicle operating speed, weight and suspension characteristics on fatigue life of the bridge have been examined.

  7. BRIDGING SERVICE QUALITY GAPS

    OpenAIRE

    BARKATH UNISSA

    2012-01-01

    Bridging the Service quality gaps is one of the foremost areas of concern for amarketer. Service marketing is inherently different from product or goods marketing.Services are distinctively characterized by their intangible, heterogeneous, inseparableand perishable nature. The importance of the service sector in today's world is a verywidely accepted and renowned idea. “We are already experiencing a service society“services do have some basic characteristics which make them fundamentally diff...

  8. Bridging as Coercive Accommodation

    CERN Document Server

    Bos, J W; Mineur, A M; Bos, Johan; Buitelaar, Paul; Mineur, Anne-Marie

    1995-01-01

    In this paper we discuss the notion of "bridging" in Discourse Representation Theory as a tool to account for discourse referents that have only been established implicitly, through the lexical semantics of other referents. In doing so, we use ideas from Generative Lexicon theory, to introduce antecedents for anaphoric expressions that cannot be "linked" to a proper antecedent, but that do not need to be "accommodated" because they have some connection to the network of discourse referents that is already established.

  9. Environmental life cycle assessment comparison between two bridge types: reinforced concrete bridge and steel composite bridge

    DEFF Research Database (Denmark)

    Du, Guangli; Karoumi, Raid

    2013-01-01

    not been integrated into the decision-making process. This paper presents a systematic LCA method for quantifying the environmental impacts for bridges. The comparison study is performed between a reinforced concrete bridge and a steel bridge as an alternative design, with several key maintenance and EOL......The concept of sustainable construction has attracted an increased attention. Bridge infrastructures and their belonged construction activities consume considerable material and energy, which is responsible for large environmental burdens. However, the environmental assessment of bridges has...

  10. A mechanical model for FRP-strengthened beams in bending

    Directory of Open Access Journals (Sweden)

    P. S. Valvo

    2012-10-01

    Full Text Available We analyse the problem of a simply supported beam, strengthened with a fibre-reinforced polymer (FRP strip bonded to its intrados and subjected to bending couples applied to its end sections. A mechanical model is proposed, whereby the beam and FRP strip are modelled according to classical beam theory, while the adhesive and its neighbouring layers are modelled as an interface having a piecewise linear constitutive law defined over three intervals (elastic response – softening response – debonding. The model is described by a set of differential equations with appropriate boundary conditions. An analytical solution to the problem is determined, including explicit expressions for the internal forces, displacements and interfacial stresses. The model predicts an overall non-linear mechanical response for the strengthened beam, ranging over several stages: from linearly elastic behaviour to damage, until the complete detachment of the FRP reinforcement.

  11. Ambient Vibration Test on Reinforced Concrete Bridges

    Directory of Open Access Journals (Sweden)

    Idris Nurul Shazwin

    2016-01-01

    Full Text Available An investigation was carried out to determine dynamic characteristic of reinforced concrete (RC bridges by using ambient vibration test (AVT. The ambient vibration sources on bridges may come from traffic, wind, wave motion and seismic events. AVT describes the dynamic characteristics of the bridge and ground by measuring the natural frequencies using highly sensitive seismometer sensor. This test is beneficial due to light weight equipment and smaller number of operator required, cheap and easy to be handled. It is able to give a true picture of the bridge dynamic behavior without any artificial force excitation when vibration data is recorded. A three-span reinforced concrete bridge located in Sri Medan, Batu Pahat, Johor was measured by using microtremor equipment consist of three units of 1 Hz eigenfrequency passive sensors used in this test was performed in normal operating condition without excitation required from any active sources or short period noise perturbations. Ten measurements were conducted on the bridge deck and ten measurements on the ground surface in order to identify the natural frequencies of the bridge. Several peak frequencies were identified from three components of Fourier Amplitude Spectra (FAS in transverse (North-South, longitudinal (East-West and vertical (Up-Down direction as well as squared average Horizontal to Vertical Spectral Ratio (HVSR of ground response, computed by using Geopsy software. From the result, it was expected the bridge have five vibration modes frequencies in the range of 1.0 Hz and 7.0 Hz with the first two modes in the transverse and longitudinal direction having a frequency 1.0 Hz, the third mode is 2.2 Hz in transverse direction, fourth and fifth mode is 5.8 Hz and 7.0 Hz. For ground natural frequencies are in range 1.0 Hz to 1.3 Hz for North-South direction and 1.0 Hz to 1.6 Hz for East-West direction. Finally the results are compared with several empirical formulas for simple

  12. Numerical analysis of dynamic response of vehicle–bridge coupled system on long-span continuous girder bridge

    Directory of Open Access Journals (Sweden)

    Lipeng An

    2016-07-01

    Full Text Available To systematically study the vehicle–bridge coupled dynamic response and its change rule with different parameters, a vehicle model with seven degrees of freedom was built and the total potential energy of vehicle space vibration system was deduced. Considering the stimulation of road roughness, the dynamic response equation of vehicle–bridge coupled system was established in accordance with the elastic system principle of total potential energy with stationary value and the “set-in-right-position” rule. On the basis of the self-compiled Fortran program and bridge engineering, the dynamic response of long-span continuous girder bridge under vehicle load was studied. This study also included the calculation of vehicle impact coefficient, evaluation of vibration comfort, and analysis of dynamic response parameters. Results show the impact coefficient changes with lane number and is larger than the value calculated by the “general code for design of highway bridges and culverts (China”. The Dieckmann index of bridge vibration is also related to lane number, and the vibration comfort evaluation is good in normal conditions. The relevant conclusions from parametric analyses have practical significance to dynamic design and daily operation of long-span continuous girder bridges in expressways. Safety and comfort are expected to improve significantly with further control of the vibration of vehicle–bridge system.

  13. Strengthening of Deteriorating Decks of Highway Bridges in Indiana Using FRPC

    OpenAIRE

    Sotelino, Elisa D.; Teng, Ming-Hung

    2002-01-01

    Many industries, such as the aerospace and the automotive industries have successfully used Fiber Reinforced Polymer Composites (FRPC). These types of composite materials offer significant advantages over conventional civil engineering materials, such as concrete and steel. This is due to their chemical and corrosion resistance, lightweight, and high strength, which make them attractive for the rehabilitation of civil infrastructures. The objective of this research project is to study the fea...

  14. Seismic response of skewed RC box-girder bridges

    Institute of Scientific and Technical Information of China (English)

    Ahmed Abdel-Mohti; Gokhan Pekcan

    2008-01-01

    It is critical to ensure the functionality of highway bridges after earthquakes to provide access to important facilities.Since the 1971 San Fernando earthquake,there has been a better understanding of the seismic performance of bridges.Nonetheless,there are no detailed guidelines addressing the performance of skewed highway bridges.Several parameters affect the response of skewed highway bridges under both service and seismic loads which makes their behavior complex.Therefore,there is a need for more research to study the effect of skew angle and other related factors on the performance of highway bridges.This paper examines the seismic performance of a three-span continuous concrete box girder bridge with skew angles from 0 to 60 degrees,analytically.Finite element (FE) and simplified beam-stick (BS) models of the bridge were developed using SAP2000.Different types of analysis were considered on both models such as:nonlinear static pushover,and linear and nonlinear time history analyses.A comparison was conducted between FE and BS,different skew angles,abutment support conditions,and time history and pushover analysis.It is shown that the BS model has the capability to capture the coupling due to skew and the significant modes for moderate skew angles.Boundary conditions and pushover load profile are determined to have a major effect on pushover analysis.Pushover analysis may be used to predict the maximum deformation and hinge formation adequately.

  15. The basis for the strengthening of safeguards

    International Nuclear Information System (INIS)

    For the past 30 years, the International Atomic Energy Agency's safeguards system has contributed to the international non-proliferation regime, by providing, inter alia, assurances regarding the peaceful uses of declared nuclear material. However, the discovery of a clandestine nuclear weapons programme in Iraq in 1991 drew world-wide attention to the need to strengthen the system to address the absence of undeclared nuclear material and activities. Efforts to strengthen the IAEA's safeguards system began in 1991 and culminated in 1997 when the IAEA's Board of Governors approved a Model Protocol Additional to IAEA Safeguards Agreements which greatly expands the legal basis and scope of IAEA safeguards. Within this strengthened system it is expected that the IAEA be able to provide assurance not only of the absence of diversion of declared nuclear material but also on the absence of undeclared nuclear material and activities. This is to be done within a safeguards system that uses an optimal combination of all safeguards measures available, thereby achieving maximum effectiveness and efficiency within the available resources. This paper will summarize the evolution of the safeguards system, describe strengthened safeguards, report on the status of implementing the strengthening measures, and outline plans for integrating all available safeguards measures. (author)

  16. RECENT DEVELOPMENTS IN FRP STRENGTHENING TECHNIQUES

    Institute of Scientific and Technical Information of China (English)

    Zhishen WU(吴智深); Hedong Niu

    2004-01-01

    This paper mainly gives a State-of-the-Art report of recent development in FRP strengthening techniques for structural rehabilitation by starting with a brief review on some achievements in clarifying bonding/debonding mechanisms and developing evaluation/design methodology for predicting debonding failure caused by intermedioate flexural cracks of con crete.Due to some drawbacks of current FRP bonding technique,two effective FRP strengthening methods,i.e.FRP prestressing and hybrid strengthening techniques,are investigated in detail to make full advantage of FRP composite materials.Combining with the newly develiped PBO fiber sheets,a more effective prestressing method is established as compared with carbon fiber sheets,a more effective prestressing method is established as compared with carbon fiber sheets,where several anchorage treatments are also established to prevent anchorage bond failure due to high shear stress concentration after release of prestressed FRP ends.In addition,the fatigue performance of RC beams externally strenghened with prestressed PBO fiber sheets is experimentally studied.For the developments of hybrid composites and their strengthening methods,both experimental and analytical studies are performed to clarify the hybrid strengthening behavior in structures.

  17. Circuit bridging of components by smoke

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T.J.; Nowlen, S.P.; Anderson, D.J. [Sandia National Labs., Albuquerque, NM (United States)

    1996-10-01

    Smoke can adversely affect digital electronics; in the short term, it can lead to circuit bridging and in the long term to corrosion of metal parts. This report is a summary of the work to date and component-level tests by Sandia National Laboratories for the Nuclear Regulatory Commission to determine the impact of smoke on digital instrumentation and control equipment. The component tests focused on short-term effects such as circuit bridging in typical components and the factors that can influence how much the smoke will affect them. These factors include the component technology and packaging, physical board protection, and environmental conditions such as the amount of smoke, temperature of burn, and humidity level. The likelihood of circuit bridging was tested by measuring leakage currents and converting those currents to resistance in ohms. Hermetically sealed ceramic packages were more resistant to smoke than plastic packages. Coating the boards with an acrylic spray provided some protection against circuit bridging. The smoke generation factors that affect the resistance the most are humidity, fuel level, and burn temperature. The use of CO{sub 2} as a fire suppressant, the presence of galvanic metal, and the presence of PVC did not significantly affect the outcome of these results.

  18. Experimental Investigation of Aerodynamic Instability of Iced Bridge Cable Sections

    DEFF Research Database (Denmark)

    Koss, Holger; Lund, Mia Schou Møller

    2013-01-01

    The accretion of ice on structural bridge cables changes the aerodynamic conditions of the surface and influences hence the acting wind load process. Full-scale monitoring indicates that light precipitation at moderate low temperatures between zero and -5°C may lead to large amplitude vibrations...... of bridge cables under wind action. This paper describes the experimental simulation of ice accretion on a real bridge cable sheet HDPE tube segment (diameter 160mm) and its effect on the aerodynamic load. Furthermore, aerodynamic instability will be estimated with quasi-steady theory using the determined...

  19. Vulnerability of bridges to fire

    DEFF Research Database (Denmark)

    Giuliani, Luisa; Crosti, C.; Gentili, F.

    2012-01-01

    Even if recent effort in developing methodology and measures for design structures against fire and explosions has been mostly focused on buildings, bridges can also be very sensitive to those actions, as witnesses by some recent bridge accidents, which caused major economic losses and also...... endangered people safety in few cases. Purpose of this paper is making a focus on the state of the art of the research and current regulations concerning the response of bridges to fire. Several cases of bridge fires are reported and a focus is made on the occurrence and consequence of bridge fires......, considering both the costs deriving by structural damages and by limited serviceability and other indirect societal aspects. Few cases of recent bridge fire are reviewed in detail and structural consequences are highlighted, distinguishing between damages directly induced by fire and damages induced by local...

  20. Effects of ice accretion on the aerodynamics of bridge cables

    DEFF Research Database (Denmark)

    Demartino, C.; Koss, Holger; Georgakis, Christos T.;

    2015-01-01

    Undesirable wind induced vibrations of bridge cables can occur when atmospheric conditions are such to generate ice accretion. This paper contains the results of an extensive investigation of the effects of ice accretion due to in-cloud icing, on the aerodynamic characteristics of bridge hangers...... of temperature, wind speed and yaw angle of accretion, were reproduced in a climatic wind tunnel, giving rise to different types of accretion. These were chosen such to generate the most common natural ice formations expected to produce bridge cable vibrations. A description of the geometric characteristics...... and stay cables. The aim of this paper is twofold; first, it was investigated the ice accretion process and the final shape of the ice accreted; then the aerodynamics of the ice accreted bridge cables was characterized, and related to the ice shape. Different climatic conditions, i.e. combinations...

  1. Strengthening of Calcium Microalloying in Pure Gold

    Institute of Scientific and Technical Information of China (English)

    JIN Mingjiang; GENG Yonghong; JIN Xuejun

    2012-01-01

    The mechanical properties of calcium (Ca) microalloyed 24 carat gold (Au99.9Ca0.1) were measured and the corresponding microstructure was observed by TEM in order to investigate the strengthening mechanism.It was observed that the microalloying of 0.1wt% Ca improved the tensile strength (by 79% and 57% for the rolling and annealing states,respectively),hardness and E-Modulus as well as reduced the ductility of the 24 carat Au.Dispersed nano-sized precipitates and high density deformation twins were found in the rolled Au99.9Ca0.1,which are attributed to be the major strengthening factors.The twins subsided after annealing and the strengthening of the annealed Au99.9Ca0.1 is mainly contributed by the coarsened semi-coherent precipitates.

  2. Theory of bridge aerodynamics

    CERN Document Server

    Strømmen, Einar

    2006-01-01

    This text book is intended for studies in wind engineering, with focus on the stochastic theory of wind induced dynamic response calculations for slender bridges or other line ?like civil engineering type of structures. It contains the background assumptions and hypothesis as well as the development of the computational theory that is necessary for the prediction of wind induced fluctuating displacements and cross sectional forces. The simple cases of static and quasi-static structural response calculations are for the sake of completeness also included. The text is at an advanced level in the

  3. Strengthening of Aluminum Alloy 2219 by Thermo-mechanical Treatment

    Science.gov (United States)

    Li, Xifeng; Lei, Kun; Song, Peng; Liu, Xinqin; Zhang, Fei; Li, Jianfei; Chen, Jun

    2015-10-01

    Strengthening of aluminum alloy 2219 by thermo-mechanical treatment has been compared with artificial aging. Three simple deformation modes including pre-stretching, compression, and rolling have been used in thermo-mechanical treatment. The tensile strength, elongation, fracture feature, and precipitated phase have been investigated. The results show that the strengthening effect of thermo-mechanical treatment is better than the one of artificial aging. Especially, the yield strength significantly increases with a small decrease of elongation. When the specimen is pre-stretched to 8.0%, the yield strength reaches 385.0 MPa and increases by 22.2% in comparison to the one obtained in aging condition. The maximum tensile strength of 472.4 MPa is achieved with 4.0% thickness reduction by compression. The fracture morphology reveals locally ductile and brittle failure mechanism, while the coarse second-phase particles distribute on the fracture surface. The intermediate phases θ″ or θ' orthogonally precipitate in the matrix after thermo-mechanical treatment. As compared to artificial aging, the cold plastic deformation increases distribution homogeneity and the volume fraction of θ'' or θ' precipitates. These result in a better strengthening effect.

  4. Bond and flexural behavior of concrete elements strengthened with NSM CFRP laminate strips under fatigue loading

    OpenAIRE

    Fernandes, Pedro Miguel Gomes; Silva, Patrícia; Sena-Cruz, José

    2015-01-01

    This paper presents the results of an experimental research on bond and flexural behavior of concrete elements strengthened with carbon fiber reinforced polymer (CFRP) laminate strips under fatigue loading conditions, applied according to the near-surface mounted (NSM) strengthening technique. Long-term performance of the NSM system could be compromised by fatigue loading, which may result in deterioration and weakening of individual components (steel, FRP, concrete), or loss of b...

  5. Strengthening Nordic-Baltic Defense Capabilities

    DEFF Research Database (Denmark)

    Breitenbauch, Henrik Ø.

    2014-01-01

    troubling challenge to the way international security has been structured in Europe since the end of the Cold War. While most of the existing defense cooperation with a view of strengthening defense capabilities has been carried out within the internationally renowned framework of NORDEFCO, there is no...... reason why this framework could not be extended to the Baltic states.36 A NORBALDEFCO would not only cement the prominent role of Sweden and Finland within NATO as premier partners, it would also formally continue the work begun with Baltic independ- ence after the Cold War, and furthermore strengthen...

  6. Modelling railway bridge asset management

    OpenAIRE

    Le, Bryant Linh Hai

    2014-01-01

    The UK has a long history in the railway industry with a large number of railway assets. Railway bridges form one of the major asset groups with more than 35,000 bridges. The majority of the bridge population are old being constructed over 100 years ago. Many of the bridges were not designed to meet the current network demand. With an expected increasing rate of deterioration due to the increasing traffic loads and intensities, the management authorities are faced with the difficult task of k...

  7. Self-monitoring fiber reinforced polymer strengthening system for civil engineering infrastructures

    Science.gov (United States)

    Jiang, Guoliang; Dawood, Mina; Peters, Kara; Rizkalla, Sami

    2008-03-01

    Fiber reinforced polymer (FRP) materials are currently used for strengthening civil engineering infrastructures. The strengthening system is dependant on the bond characteristics of the FRP to the external surface of the structure to be effective in resisting the applied loads. This paper presents an innovative self-monitoring FRP strengthening system. The system consists of two components which can be embedded in FRP materials to monitor the global and local behavior of the strengthened structure respectively. The first component of the system is designed to evaluate the applied load acting on a structure based on elongation of the FRP layer along the entire span of the structure. Success of the global system has been demonstrated using a full-scale prestressed concrete bridge girder which was loaded up to failure. The test results indicate that this type of sensor can be used to accurately determine the load prior to failure within 15 percent of the measured value. The second sensor component consists of fiber Bragg grating sensors. The sensors were used to monitor the behavior of steel double-lap shear splices tested under tensile loading up to failure. The measurements were used to identify abnormal structural behavior such as epoxy cracking and FRP debonding. Test results were also compared to numerical values obtained from a three dimensional shear-lag model which was developed to predict the sensor response.

  8. Assessment of Infrared Thermography for NDE of FRP Bridge Decks

    OpenAIRE

    Miceli, Marybeth

    2000-01-01

    Statistics released in the fall 1989 showed that 238,357 (41%) of the nation's 577,710 bridges are either structurally deficient or functionally obsolete. New materials, such as fiber reinforced polymeric composites (FRP), are being suggested for use in bridge systems to solve some of the current problems. These materials are thought to be less affected by corrosive environmental conditions than conventional civil engineering materials. Therefore they may require less maintenance and provi...

  9. Multidisciplinarity, Interdisciplinarity, and Bridging Disciplines: A Matter of Process

    Directory of Open Access Journals (Sweden)

    Dawn Youngblood

    2007-01-01

    Full Text Available Bridging disciplines have much to teach regarding how to combine analytical tools to tackle problems and questions that cross traditional disciplinary boundaries. This article explores interdisciplinary aspects of two long established bridging disciplines--geography and anthropology--in order to consider what the relatively young undertaking labeled “interdisciplinary studies” can learn from their long existence. It considers the fallacy of nomothetic claim as well as the fruitful production of solutions by viewing process (methodology, not domain (academic turf, as the key to interdisciplinary success. Staking claim to interdisciplinarity is shown to be unproductive while finding the need for interdisciplinary approaches and following the mandates of that need strengthens both the disciplines and interdisciplinary studies.

  10. Nanoscale strengthening mechanisms in metallic thin film systems

    Science.gov (United States)

    Schoeppner, Rachel Lynn

    Nano-scale strengthening mechanisms for thin films were investigated for systems governed by two different strengthening techniques: nano-laminate strengthening and oxide dispersion strengthening. Films were tested under elevated temperature conditions to investigate changes in deformation mechanisms at different operating temperatures, and the structural stability. Both systems exhibit remarkable stability after annealing and thus long-term reliability. Nano-scale metallic multilayers with smaller layer thicknesses show a greater relative resistance to decreasing strength at higher temperature testing conditions than those with larger layer thicknesses. This is seen in both Cu/Ni/Nb multilayers as well as a similar tri-component bi-layer system (Cu-Ni/Nb), which removed the coherent interface from the film. Both nanoindentation and micro-pillar compression tests investigated the strain-hardening ability of these two systems to determine what role the coherent interface plays in this mechanism. Tri-layer films showed a higher strain-hardening ability as the layer thickness decreased and a higher strain-hardening exponent than the bi-layer system: verifying the presence of a coherent interface increases the strain-hardening ability of these multilayer systems. Both systems exhibited hardening of the room temperature strength after annealing, suggesting a change in microstructure has occurred, unlike that seen in other multilayer systems. Oxide dispersion strengthened Au films showed a marked increase in hardness and wear resistance with the addition of ZnO particles. The threshold for stress-induced grain-refinement as opposed to grain growth is seen at concentrations of at least 0.5 vol%. These systems exhibited stable microstructures during thermal cycling in films containing at least 1.0%ZnO. Nanoindentation experiments show the drop in hardness following annealing is almost completely attributed to the resulting grain growth. Four-point probe resistivity

  11. Eccentric Strengthening for Chronic Lateral Epicondylosis

    Science.gov (United States)

    Wen, Dennis Y.; Schultz, Brian J.; Schaal, Bob; Graham, Scott T.; Kim, Byung Sung

    2011-01-01

    Background: Effective treatments for chronic lateral epicondylosis have not been studied adequately. Eccentric overload exercises have been used with success for other chronic tendinopathy, mainly Achilles and patellar. Hypothesis/Purpose: To compare a wrist extensor eccentric strengthening exercise program with a wrist extensor stretching/modality program for the treatment of chronic lateral epicondylosis. The authors hypothesized that the eccentric strengthening program would produce more favorable results than a stretching/modality program. Study Design: Prospective randomized controlled trial. Methods: Twenty-eight adults with lateral epicondylosis of greater than 4 weeks’ duration were randomized to an eccentric strengthening group or a stretching group. Exercises were taught by a physical therapist, and participants performed most of the exercises on their own at home. Pain scores with visual analog scale from 0 to 100 were obtained at baseline and then at 4, 8, 12, 16, and 20 weeks after the start of the exercise program. Results: Both groups improved their pain scores from baseline to the 4-week time point, followed by nonsignificant further decreases in pain scores thereafter. No statistically significant differences were found between the eccentric strengthening group and stretching groups at any follow-up time point. Conclusions: Despite previous reports documenting favorable results with eccentric exercises for other tendinopathy, the authors were unable to show any statistical advantage to eccentric exercises for lateral epicondylosis during these periods compared with local modalities and stretching exercises. PMID:23016049

  12. Strengthened Chernoff-type variance bounds

    OpenAIRE

    Afendras, G.; Papadatos, N.

    2014-01-01

    Let $X$ be an absolutely continuous random variable from the integrated Pearson family and assume that $X$ has finite moments of any order. Using some properties of the associated orthonormal polynomial system, we provide a class of strengthened Chernoff-type variance bounds.

  13. Strengthening Family Practices for Latino Families

    Science.gov (United States)

    Chartier, Karen G.; Negroni, Lirio K.; Hesselbrock, Michie N.

    2010-01-01

    This study examined the effectiveness of a culturally adapted Strengthening Families Program (SFP) for Latinos to reduce risks for alcohol and drug use in children. Latino families, predominantly Puerto Rican, with a 9- to 12-year-old child and a parent(s) with a substance abuse problem participated in the study. Pre- and post-tests were conducted…

  14. Strengthening 4-H by Analyzing Enrollment Data

    Science.gov (United States)

    Hamilton, Stephen F.; Northern, Angela; Neff, Robert

    2014-01-01

    The study reported here used data from the ACCESS 4-H Enrollment System to gain insight into strengthening New York State's 4-H programming. Member enrollment lists from 2009 to 2012 were analyzed using Microsoft Excel to determine trends and dropout rates. The descriptive data indicate declining 4-H enrollment in recent years and peak…

  15. Institutional strengthening in Egyptian development aid projects

    NARCIS (Netherlands)

    Walbeek, M.M.; Vlotman, W.F.

    2003-01-01

    In recent years Dutch aid projects have focused more on institutional strengthening. The overall impact of this type of aid has been limited. This paper explores possible reasons for this. In Egypt, it appeared to be difficult to make significant changes in the institutional setting. Main constraint

  16. Additive strengthening mechanisms in dispersion hardened polycrystals

    DEFF Research Database (Denmark)

    Hansen, Niels; Ralph, B.

    1986-01-01

    Tensile data from polycrystalline samples of copper dispersion strengthened by alumina are analysed. The basis of this analysis is to look at the strain range from 0.05 to 0.20 where the stress-strain curves show a parabolic hardening behaviour and are parallel to one another. The means by which...

  17. STRengthening analytical thinking for observational studies

    DEFF Research Database (Denmark)

    Altman, Douglas G.; le Cessie, Saskia; Abrahamowicz, Michal;

    2014-01-01

    on their results and conclusions. An efficient way to help researchers to keep up with recent methodological developments is to develop guidance documents that are spread to the research community at large. These observations led to the initiation of the strengthening analytical thinking for observational studies...

  18. Microstructural change on electron irradiated oxide dispersion strengthened ferritic steels

    Science.gov (United States)

    Kinoshita, H.; Akasaka, N.; Takahashi, H.; Shibahara, I.; Onose, S.

    1992-09-01

    Oxide dispersion strengthened (ODS) ferritic steels were irradiated in a high voltage electron microscope (HVEM) to study their response to irradiation. Fe-13Cr with 0.25 wt% Y2O3 as dispersed particles and containing additions of either 0.45% Nb, 0.45% V and 0.67% Zr were irradiated at 673 and 723 K up to 15 dpa. The Y2O3 particles in all specimens were stable under these irradiation conditions. During irradiation, two types of dislocations were formed but observable voids were not formed. Furthermore, plate-like and granular-like precipitates formed in both the irradiated and nonirradiated regions.

  19. Aerodynamic coefficient of vehicle-bridge system by wind tunnel test

    Institute of Scientific and Technical Information of China (English)

    ZHOU Li; GE Yao-jun

    2008-01-01

    The changes of three components of aerodynamic force were discussed with the attack angle conver-sion for three kinds of section models. Based on the project of Shanghai Yangtze River Bridge, the wind tunnel test was conducted to obtain its three components of aerodynamic force including 75 conditions of the construc-tion stage, the bridge without vehicles and the bridge with vehicles from - 12 degrees to + 12 degrees. For the bridge with vehicles, the drag force coefficient and the absolute value of both lift coefficient and moment coeffi-cient were decreased by the vehicles. The test result shows that the bridge railing and vehicles have much influ-ence on the three components of aerodynamic force of the vehicle-bridge system for Shanghai Yangtze River Bridge.

  20. Liquid bridge force between two unequal-sized spheres or a sphere and a plane

    Institute of Scientific and Technical Information of China (English)

    You chuan Chen; Yong zhi Zhao; Hong li Gao; Jin yang Zheng

    2011-01-01

    Liquid bridge force acting between wet particles is an important property in particle characterization.This paper deals with liquid bridge force between either two unequal-sized spherical particles or a sphere and a flat plate under conditions where gravitational effect arising from bridge distortion is negligible.In order to calculate the force of the liquid bridge efficiently and accurately,expressions of liquid configuration and liquid bridge force were derived by building a mechanical model,which assumes the liquid bridge to be circular in shape between either two unequal-sized spheres or a sphere and a plane.To assess the accuracy of the numerical results of the calculated liquid bridge forces,they were compared to the published experimental data.

  1. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Straalen, IJ.J. van

    2005-01-01

    Traffic bridges are subjected to variable loads and should therefore be checked on fatigue. Especially low weight materials, like aluminium, are sensitive to fatigue, because the variable load is a substantial part of the total load. This paper shows the structural design of an aluminium bridge load

  2. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Straalen, IJ.J. van

    2004-01-01

    Traffic bridges are subjected to variable loads and should therefore be checked on fatigue. Especially low weight materials, like aluminium, are sensitive to fatigue, because the variable load is a substantial part of the total load. This paper shows the structural design of an aluminium bridge load

  3. Bridge concrete deteriorating diagnosis by infrared thermography

    Science.gov (United States)

    Shibata, Hiroki; Fukuyama, Nobuhiro; Sakuma, Joji; Mochizuki, Jun; Kimura, Yukinori

    2006-04-01

    Bridge is indispensable as social overhead capital. In the past, concrete construction was believed to be semi-permanent. Actually, however, concrete is deteriorated by various factors including seawater damage, annual temperature change, etc. Therefore, it is now obvious that maintenance and management are essential to keep performance of the bridge. In Japan, we had many reports of using infrared thermography for diagnosis of building, mainly for delamination of tile and mortar used for surface of the building for more than 10 years. In recent years, infrared thermogrephy is more actively used for delamination of surface of the bridge. Passive method is usually used for open-air concrete structure diagnosis, which utilizes intraday environmental temperature change and/or radiation energy emitted from the sun which create delta-T of delamination portion of the concrete structure. It is very important to take thermal image at right conditions. Otherwise, you may easily fall onto false diagnosis. In our presentation, many case examples and study of thermal data will be shown, which are taken at the right condition.

  4. Development of cooperative system bridges

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhe; WAN Qi-bai; SHI Lei

    2008-01-01

    Cooperative system bridges comprise several basic structures that act jointly to improve structural characteristics. We delved into the historical development of cooperative system bridges. Cooperative systems are classified as different-load cooperative systems and same-load cooperative systems by distinguishing the modes of load distribution. For different-load cooperation, individual basic structures are at different positions in the direction along bridge axis and carry the loads separately. While for same-load cooperation, all basic structures overlap in geometrical locations and support the entire loads conjointly. The choosing of span ratios between basic structures, the design of connections of different-load cooperative systems were discussed as well as optimizations of relative rigidity for same-load cooperative systems which greatly influence structural characteristics. The general situation and several structural measurements of several cooperative bridges were demonstrated. This information can assist engineers in developing their concepts in cooperative systems and can lead to more efficient and economical cooperative bridges.

  5. Online Bridge Crack Monitoring with Smart Film

    Directory of Open Access Journals (Sweden)

    Benniu Zhang

    2013-01-01

    Full Text Available Smart film crack monitoring method, which can be used for detecting initiation, length, width, shape, location, and propagation of cracks on real bridges, is proposed. Firstly, the fabrication of the smart film is developed. Then the feasibility of the method is analyzed and verified by the mechanical sensing character of the smart film under the two conditions of normal strain and crack initiation. Meanwhile, the coupling interference between parallel enameled wires of the smart film is discussed, and then low-frequency detecting signal and the custom communication protocol are used to decrease interference. On this basis, crack monitoring system with smart film is designed, where the collected crack data is sent to the remote monitoring center and the cracks are simulated and recurred. Finally, the monitoring system is applied to six bridges, and the effects are discussed.

  6. A simplified fragility analysis of fan type cable stayed bridges

    Institute of Scientific and Technical Information of China (English)

    R. A. Khan; T. K. Datta; S. Ahmad

    2005-01-01

    A simplified fragility analysis of fan type cable stayed bridges using Probabilistic Risk Analysis (PRA)procedure is presented for determining their failure probability under random ground motion. Seismic input to the bridge support is considered to be a risk consistent response spectrum which is obtained from a separate analysis. For the response analysis, the bridge deck is modeled as a beam supported on springs at different points. The stiffnesses of the springs are determined by a separate 2D static analysis of cable-tower-deck system. The analysis provides a coupled stiffness matrix for the spring system. A continuum method of analysis using dynamic stiffness is used to determine the dynamic properties of the bridges .The response of the bridge deck is obtained by the response spectrum method of analysis as applied to multidegree of freedom system which duly takes into account the quasi - static component of bridge deck vibration. The fragility analysis includes uncertainties arising due to the variation in ground motion, material property, modeling, method of analysis,ductility factor and damage concentration effect. Probability of failure of the bridge deck is determined by the First Order Second Moment (FOSM) method of reliability. A three span double plane symmetrical fan type cable stayed bridge of total span 689 m, is used as an illustrative example. The fragility curves for the bridge deck failure are obtained under a number of parametric variations. Some of the important conclusions of the study indicate that (i) not only vertical component but also the horizontal component of ground motion has considerable effect on the probability of failure; (ii) ground motion with no time lag between support excitations provides a smaller probability of failure as compared to ground motion with very large time lag between support excitation; and (iii) probability of failure may considerably increase for soft soil condition.

  7. Cascaded resonant bridge converters

    Science.gov (United States)

    Stuart, Thomas A. (Inventor)

    1989-01-01

    A converter for converting a low voltage direct current power source to a higher voltage, high frequency alternating current output for use in an electrical system where it is desired to use low weight cables and other circuit elements. The converter has a first stage series resonant (Schwarz) converter which converts the direct current power source to an alternating current by means of switching elements that are operated by a variable frequency voltage regulator, a transformer to step up the voltage of the alternating current, and a rectifier bridge to convert the alternating current to a direct current first stage output. The converter further has a second stage series resonant (Schwarz) converter which is connected in series to the first stage converter to receive its direct current output and convert it to a second stage high frequency alternating current output by means of switching elements that are operated by a fixed frequency oscillator. The voltage of the second stage output is controlled at a relatively constant value by controlling the first stage output voltage, which is accomplished by controlling the frequency of the first stage variable frequency voltage controller in response to second stage voltage. Fault tolerance in the event of a load short circuit is provided by making the operation of the first stage variable frequency voltage controller responsive to first and second stage current limiting devices. The second stage output is connected to a rectifier bridge whose output is connected to the input of the second stage to provide good regulation of output voltage wave form at low system loads.

  8. Identification of the operational frequencies of 300+ bridges using smartphones

    Science.gov (United States)

    Castellanos, Sebastián.; Marulanda, Johannio; Preciado, Mónica; Cruz, Alejandro; Thomson, Peter

    2016-04-01

    A country's economic development depends heavily on transportation networks and hence, as a vital aspect, bridge structures must function safely at all times. Structural Health Monitoring (SHM) and Damage Prognosis (DP) of bridges should be a priority in order to prevent deterioration, avoid collapse and ensure user's safety. One objective of SHM for civil structures is the behavior assessment due to ambient, operational and seismic excitations, for which acceptable ranges are established for the variation of dynamic properties. Through Operational Modal Analysis (OMA) it is possible to estimate operational frequencies of a bridge and provide a measure of its current dynamic behavior. These frequencies can then be used for future comparisons to revise if the structure has been damaged or has experienced changes due to environmental conditions. In this paper, vertical and horizontal operational frequencies of more than 300 vehicular and pedestrian bridges of the transportation network of Santiago de Cali, Colombia, were estimated using ambient vibration tests. Data were obtained using smartphones and processed using frequency domain analyses. Correlations of these frequencies with the structural characteristics of the bridges are presented. The results of this study represent the current state of each bridge and provide a baseline for future evaluations of changes due to environmental conditions or damage.

  9. Noise Reduction of Fractional Source in Cryogenic Current Comparator Bridge

    Directory of Open Access Journals (Sweden)

    C. Jassadajin

    2013-10-01

    Full Text Available In this work, a resistance measurement is done at both high accuracy and precision using Cryogenic Current Comparator (CCC bridge system [1]. A CCC bridge circuit consists of three parts: coil, current source and detector parts. There are electronic components in the current source of the system. They generate thermal noise in the measurement system. This paper shows the noise reduction in a fractional source of CCC Bridge which is a ramp generator. The bridge receives the voltage signal, which is supplied to a CCC coil to achieve the magnetic flux balance condition inside the superconductorshield, from a null detector. By analysing the noise of the circuit in the fractional part and improving the circuit, it can minimize the noise to obtain a better output of the fractional source for improved accurate and more stability. Finally, the noise can be reduced for a designed bandwidth, a unity noise gain and minimized input resistance in the circuit.

  10. Conditioned Reinforcement and Response Strength

    Science.gov (United States)

    Shahan, Timothy A.

    2010-01-01

    Stimuli associated with primary reinforcers appear themselves to acquire the capacity to strengthen behavior. This paper reviews research on the strengthening effects of conditioned reinforcers within the context of contemporary quantitative choice theories and behavioral momentum theory. Based partially on the finding that variations in…

  11. Writing Strengthens Orthography and Alphabetic-Coding Strengthens Phonology in Learning to Read Chinese

    NARCIS (Netherlands)

    Guan, C.Q.; Liu, Y.; Chan, D.H.L.; Ye, F.F.; Perfetti, C.A.

    2011-01-01

    Learning to write words may strengthen orthographic representations and thus support word-specific recognition processes. This hypothesis applies especially to Chinese because its writing system encourages character-specific recognition that depends on accurate representation of orthographic form. W

  12. Grain boundary strengthening in austenitic nitrogen steels

    International Nuclear Information System (INIS)

    The effect of nitrogen and carbon on the strengthening of the austenitic steel Cr18Ni16Mn10 by grain boundaries is studied. It is established in accordance with previous results that contrary to carbon nitrogen increases the coefficient k in the Hall-Petch equation markedly. Because of a pronounced planar slip induced by nitrogen and the absence of any noticeable segregation of nitrogen atoms at the grain boundaries, nitrogen austenite presents an excellent object for testing different existing models of grain boundary strengthening (pile-up, grain boundary dislocation sources, work hardening theories). Based on the analysis of available data and measurements of interaction between nitrogen (carbon) atoms and dislocations it is shown that the nitrogen effect can be attributed to a strong blocking of dislocation sources in grains adjacent to those where the slip started. (orig.)

  13. Finite Element and Experimental Analysis and Evaluation of Static and Dynamic Responses of Oblique Pre-stressed Concrete Box Girder Bridge

    Directory of Open Access Journals (Sweden)

    Ali Fadhil Naser

    2013-10-01

    Full Text Available Hashuang bridge is type of prestressed concrete box girder oblique bridge and it is located in Harbin City within Heilongjiang province in the east north of China. The objectives of this study are to investigate the appearance of the bridge structure and identify all the damages in the bridge structural members and to evaluate the structural performance of the bridge structure under dead and live loads. Finite element analysis is used to analyze the static designed internal forces and dynamic responses by adopting SAP200 software Ver. 14.2.0. Static and dynamic load test are adopted to evaluate the structural performance of the bridge structure. The results of field investigation process of the bridge appearance show that the bridge suffers from serious damages. The web of box girder of the second span near pier No.2 (in the quarter of middle span at 39m on the bridge length suffers from serious shear cracks. The state of abutments, piers and sidewalks is good, but the bearing, drainage holes, steel rail and expansion joints are not good and they suffer from much damage. The steel rail is corroded and the expansion joint loses the material which fills the joint. There are many dusts and debris is collected on the bridge deck in the location near sidewalk. The analysis results of finite element and load tests show that there are high tensile stresses in the quarter of middle span at distance 39 m of the bridge length and the state of the bridge structure is not good and the main problem of the bridge structure in the original design of prestressed tendons. Therefore, this study recommends for repairing and strengthening the bridge structure to increase the stiffness and strength and to improve the bearing capacity of the bridge structural members to increase the service live of the bridge structure.

  14. Collection of "strengthening sets" of aerobics lesson.\\\\

    OpenAIRE

    CAKL, Vojtěch

    2011-01-01

    The aim of this bachelor study was to create a strengthening sets for aerobic lessons including showing these possisions in practice on selective aerobic lessons . Based on special literature the author had chosen suitable muscle development exercises to increase the body strenth. These exercises were there practised for six weeks continuously. Before and after the research were selected individuals who were compared by 4 exact same tests to detect static and dynamic body strength. The result...

  15. Strengthening of structure using advanced composites

    OpenAIRE

    Recuero, A.; Miravete, A.

    1997-01-01

    [EN] Restoration, strengthening and rehabilitation of buildings becomes one of the more interesting aspects of the use of composites. Construction industry has not yet accepted the wide structural use of these new materials because it does not know the advantages of composites in comparison with traditional materials, such as concrete or steel. Proffesionals involved in design and construction are conservative and resist to changes. They require codes and specifications, ...

  16. Understanding backward design to strengthen curricular models.

    Science.gov (United States)

    Emory, Jan

    2014-01-01

    Nurse educators have responded to the call for transformation in education. Challenges remain in planning curricular implementation to facilitate understanding of essential content for student success on licensure examinations and in professional practice. The conceptual framework Backward Design (BD) can support and guide curriculum decisions. Using BD principles in conjunction with educational models can strengthen and improve curricula. This article defines and describes the BD process, and identifies reported benefits for nursing education. PMID:24743175

  17. Strengthening behavior of carbon/metal nanocomposites

    OpenAIRE

    Shin, S. E.; Choi, H. J.; Hwang, J. Y.; Bae, D. H.

    2015-01-01

    Nanocomposites reinforced with nano-scale reinforcements exhibit excellent mechanical properties with low volume fraction of the reinforcement. For instance, only an addition of 0.7 vol.% few-layer graphene (FLG) into the pure titanium shows strength of ~1.5 GPa, obviously much superior to that of the monolithic titanium. The strengthening efficiency of composites is determined by several factors such as reinforcement geometrical/spatial characteristics and interfacial features between the ma...

  18. Strengthening of HSLA steels by cool deformation

    OpenAIRE

    a Fatehi; Calvo Muñoz, Jessica; Elwazri, A. M.; Yue, S

    2010-01-01

    In microalloyed steels, the refinement of ferrite grains together with a controlled amount of precipitation has key roles in the mechanical properties improvement. Applying small amounts of deformation, at very low hot working temperatures (i.e. coiling temperature), in the ferrite region (i.e. cool deformation) has an appreciable strengthening effect via controlling the final microstructure of the steel. One of the microstructural effects is thought to be the much finer and more uniformly...

  19. Bridge Creek IMW database - Bridge Creek Restoration and Monitoring Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The incised and degraded habitat of Bridge Creek is thought to be limiting a population of ESA-listed steelhead (Oncorhynchus mykiss). A logical restoration...

  20. National Bridge Inventory - National Geospatial Data Asset (NGDA) Bridges

    Data.gov (United States)

    Department of Transportation — The NBI (NTAD 2015) is a collection of information (database) describing the more than 610,000 of the Nation's bridges located on public roads, including Interstate...

  1. Complex Testing of the Bridges

    Directory of Open Access Journals (Sweden)

    Savić Adrijana

    2016-01-01

    Full Text Available This article describes the process of examining bridges. AB road bridge, founded on the columns by the Karpoš system and damaged due to erosive action of the river, is given as an example. The first tests of the bridge are conducted on the impact load of V 300, because of the appearance of longitudinal cracks. The results of the columns testing are presented in this paper, as well as the rehabilitation measures thus increasing the load capacity of the column.

  2. Thermal bridges of modern windows

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Møller, Eva B.; Nielsen, Anker;

    2013-01-01

    With its focus on reduced energy consumption, contemporary housing construction requires a highly insulated and airtight building envelope with as few thermal bridges as possible.Windows must be carefully designed, as thermal bridges can lead to surface condensation or mold growth, even...... if the window has an U-factor of 1 W/(m2·K) or lower. This paper describes the development of modern, energy efficient Danish windows with reduced thermal bridges. It focuses on materials, geometry, and sealing of window panes based on a literature review. Examples of modern windows are presented. Experience...

  3. Reliability Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Middleton, C. R.

    This paper is partly based on research performed for the Highways Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: concrete bridges". It contains the details of a methodology which can be used to generate Whole Life (WL) reliability...... profiles. These WL reliability profiles may be used to establish revised rules for concrete bridges. This paper is to some extend based on Thoft-Christensen et. al. [1996], Thoft-Christensen [1996] et. al. and Thoft-Christensen [1996]....

  4. 热老化条件下公路桥梁板式氯丁橡胶支座受压试验%Compression Tests of Plain Chloroprene Rubber Bearings of l Highway Bridge Under Thermal Aging Condition

    Institute of Scientific and Technical Information of China (English)

    张延年; 单春红; 郑怡; 沈小俊; 高飞; 熊卫士

    2012-01-01

    The impact of climate is more serious to highway bridge rubber bearings than to building rubber bearings. In order to investi- gate the changes of the mechanical properties of plain chloroprene rubber bearings of highway bridge in high temperature of summer, the plain chloroprene rubber bearings were processed in 20, 40, 60, 80 days by high-temperature chamber, and then the axial compression tests were carried by pressure testing machine. The impact of thermal aging in carrying capacity, ultimate compressive strength, vertical stiffness, and elastic modulus of compression was analyzed. The results showed that, under thermal aging, the plain chloroprene rubber bearings was easier to brittle failure, the elastic stage was shorten, and the phenomenon which plate exposure, cracks and layered damage was more serious. With deepening of degree in thermal aging, the carrying capacities, ultimate compressive strength, vertical stiffness, and elastic modulus of compression were decreased. The dates of compressive strength and elastic modulus of compression in 50 years were analyzed using the least square method, and the results showed that the decay function and decay curve were basically in line with variation of power function.%公路桥梁橡胶支座比建筑橡胶支座更容易受到气候的影响。为了研究公路桥梁板式氯丁橡胶支座在热老化条件下的各项力学性能指标变化,将氯丁橡胶支座在高温试验箱中进行热老化处理20、40、60、80d,并采用压力试验机对其进行轴心受压试验。研究热老化对氯丁橡胶支座的承载力、极限抗压强度、竖向刚度、抗压弹性模量的影响。试验结果表明,在热老化条件下,氯丁橡胶支座更易发生脆性破坏,弹性阶段缩短,发生钢板外露、裂缝、层状破坏等现象更严重;承载力、极限抗压强度、竖向刚度、抗压弹性模量随热老化程度的加深而逐渐降低;采用最小二乘法对50年抗

  5. The Higgs Bridge

    CERN Document Server

    Allen, Roland E

    2013-01-01

    The particle recently discovered at the Large Hadron Collider near Geneva is almost certainly a Higgs boson, the long-sought completion of the Standard Model of particle physics. But this discovery, an achievement by more than six thousand scientists (including students), is actually much more than a mere capstone of the Standard Model. It instead represents a bridge from the Standard Model to exciting discoveries of the future, at higher energies or in other experiments, and to the properties of matter at very low temperatures. The mere existence of a particle with zero spin implies a need for new physics, with the most likely candidate being supersymmetry, which requires that every known particle has a superpartner yet to be discovered. And phenomena similar to the Higgs are seen in superconducting metals and superfluid gases at low temperatures, which extend down to a millionth or even a billionth of a degree Kelvin. So the discovery of a Higgs boson has a central place in our attempts both to achieve a tr...

  6. Mineral bridges in nacre revisited

    CERN Document Server

    Checa, Antonio G; Willinger, Marc-Georg

    2012-01-01

    We confirm with high-resolution techniques the existence of mineral bridges between superposed nacre tablets. In the towered nacre of both gastropods and the cephalopod Nautilus there are large bridges aligned along the tower axes, corresponding to gaps (150-200 nm) in the interlamellar membranes. Gaps are produced by the interaction of the nascent tablets with a surface membrane that covers the nacre compartment. In the terraced nacre of bivalves bridges associated with elongated gaps in the interlamellar membrane (> 100 nm) have mainly been found at or close to the edges of superposed parental tablets. To explain this placement, we hypothesize that the interlamellar membrane breaks due to differences in osmotic pressure across it when the interlamellar space below becomes reduced at an advanced stage of calcification. In no cases are the minor connections between superimposed tablets (< 60 nm), earlier reported to be mineral bridges, found to be such.

  7. Simulation of multivariate diffusion bridges

    DEFF Research Database (Denmark)

    Bladt, Mogens; Finch, Samuel; Sørensen, Michael

    We propose simple methods for multivariate diffusion bridge simulation, which plays a fundamental role in simulation-based likelihood and Bayesian inference for stochastic differential equations. By a novel application of classical coupling methods, the new approach generalizes a previously...

  8. Bridge Culture of Langde Village

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Langde, a village in Leishan County ofsouthwestern Guizhou province, is known for itslarge number of unique bridges bearing the distinctdesign style of the Miao ethnic group. Animpressive variety of well-preserved ancient

  9. ANGIOGRAPHIC ASPECTS OF MYOCARDIAL BRIDGES

    Directory of Open Access Journals (Sweden)

    Sujatha. M

    2015-12-01

    Full Text Available Introduction: The segment of epicardial coronary artery that traverses intramurally through the myocardium and bridged by a bunch of cardiac muscle fibers is called tunneled artery or intramural artery. The band of cardiac muscle fibers passing over the tunneled artery segment is named as myocardial bridge. During angiography milking effect is observed during systole due to the external pressure of muscle fibers on the tunneled artery that leads to narrowing of vessel lumen and further ischemia. Materials & Methods: It is a prospective study performed from 2012- 2015 in cardiac centers available around Tirupati, Andhra Pradesh, South India. A total number of 2015 adult patients who underwent diagnostic coronary angiography were evaluated to detect myocardial bridges. With the informed consent the relevant data was collected from the patients and analyzed. Results: The prevalence of myocardial bridges was 3.17%. Among the 2015 patients 70.7% are males and 29.2% are females. Among 64 myocardial bridge positive cases 62.5% were male and 37.5% were female patients. Regarding coronary dominance 84% were right dominant and 14.4% were left dominant and 1.6% are balanced. The percentage incidence of myocardial bridging according to dominance was 3.01% for right dominant patients, 4.12% for left dominant patients and 3.1% for balanced dominant patients. In all the myocardial bridge positive cases they were located on the left anterior descending artery (LAD. According to diagnosis the patients with normal coronaries were 22.6%, patients with MILD CAD were 17.9%, patients with single vessel disease were 23.4%, patients with two vessel disease were 14.7% and the patients with triple vessel disease were 21.3%. The 64 myocardial bridging cases were grouped in to three groups according to their age. Incidence of double bridges was observed in 3 cases of which 66.7% males & 33.3% in females. Conclusion: These results show that Andhra Pradesh population are

  10. The stories of two bridges in Ghana

    DEFF Research Database (Denmark)

    Andreasen, Jørgen

    2004-01-01

    Public participation in bridge building was promoted by un habitat in the village of Mankrong. The neighbouring village did not participate in the construction of their bridge. The first flooding washed the second bridge down while the "participative bridge" stood up....

  11. An Expert System for Concrete Bridge Management

    DEFF Research Database (Denmark)

    Brito, J. de; Branco, F. A.; Thoft-Christensen, Palle;

    1997-01-01

    The importance of bridge repair versus new bridge construction has risen in recent decades due to high deterioration rates that have been observed in these structures. Budgets both for building new bridges and keeping the existing ones are always limited. To help rational decision-making, bridge...

  12. Stability of liquid crystalline bridges

    Science.gov (United States)

    Mahajan, Milind P.; Tsige, Mesfin; Taylor, P. L.; Rosenblatt, Charles

    1999-02-01

    The stability of cylindrical bridges of the liquid crystal octylcyanobiphenyl in an immiscible liquid bath was investigated in the nematic and smectic A phases. In the nematic phase the bridge was found to destabilize at a length-to-diameter (slenderness) ratio R similar to that of ordinary Newtonian fluids. On the other hand, the Bingham behavior of the smectic A phase, i.e., an apparent yield stress, enabled the formation of stable columns with R well in excess of π.

  13. The Impact of the HMCFRP Ratio on the Strengthening of Steel Composite I-Beams

    Directory of Open Access Journals (Sweden)

    E. Agcakoca

    2012-01-01

    Full Text Available Carbon fiber-reinforced polymer materials have become popular in the construction industry during the last decade for their ability to strengthen and retrofit concrete structures. The recent availability of high-modulus carbon fiber-reinforced polymer strips (HMCFRP has opened up the possibility of using this material in strengthening steel structures as well. The strips can be used in steel bridge girders and structures that are at risk of corrosion-induced cross-sectional losses, structural deterioration from aging, or changes in function. In this study, a set of bending experiments was performed on three types of steel beams reinforced with HMCFRP. The results were used to enhance a nonlinear finite element model built with ABAQUS software. The accuracy of the mathematical models for HMCFRP, epoxy, and steel profiles was compared with the experimental results, and the ability of HMCFRP to continue carrying load from the steel beams during rupture and postrupture scenarios was observed using numerical analysis. Using these verified finite element models, a parametric analysis was performed on the HMCFRP failure modes and the quantity to be used with IPE profile steel beams. The maximum amount of HMCFRP needed for strengthening was determined, and an upper limit for its use was calculated to avoid any debonding failure of the fiber material.

  14. Behavior of Reinforced Concrete Box Beam Strengthened with CFRP U-Wrap Strips Under Torsion

    Directory of Open Access Journals (Sweden)

    Ma Shengqiang

    2016-01-01

    Full Text Available The present study focuses on the torsional strengthening behavior of reinforced concrete (RC box section beams that are widely used in bridges. Four RC box beams were fabricated, and three of them were wrapped by carbon fiber-reinforced polymer (CFRP U-wrap strips with or without longitudinal strips. The different wrapping configuration, cracking angle, failure pattern, and tensile strain of fibers were investigated and discussed accordingly. The experimental results addressed that U-wrap strips strengthening also can upgrade the ultimate torque of beams moderately. In particular, using U-wrap and longitudinal strips to bond the box beams increased the torsional stiffness slightly. The same equation from different codes for calculating RC specimens can accurately predict the ultimate strength of the control beam, but the calculation of the fib model overestimated the torsional strengthening improvement of the wrapped specimens. However, Ghobarah et al. assumed approximately 3000με of the average ultimate fiber strain in calculating the ultimate strength of the wrapped box beams which shows in relatively appropriate agreement with testing results.

  15. 高负载铁路桥梁体外预应力的受力情况分析研究%Study on Stress Analysis of External Prestressing of High Load Railway Bridge

    Institute of Scientific and Technical Information of China (English)

    贾巧燕; 邹晓琴

    2016-01-01

    Under the condition of high load, the model of external prestressing is analyzed, and the loading analysis and mathematical simulation are carried out to overcome the problems such as stress and strain lag, and to improve the life span of railway bridge. The mechanical anchoring of the high load railway bridge load, analysis of the load under the elastic modulus of the bridge, yield strength and external prestressing constitutive relation model, a prestressed force test of strengthened specimens and contrast test, through the experiment analysis of the high load railway bridge load displacement curve, the railroad bridge in external prestressing stress nephogram.%在高负载条件下分析路桥梁体外预应力模型,对受力情况进行试验加载分析和数学模拟,克服应力、应变滞后等问题,提高铁路桥梁的寿命。采用机械锚固的方式进行高负载铁路桥梁体的负荷加载,分析了负荷加载下桥梁体的弹性模量、屈服强度与体外预应力的本构关系模型,对加固试件及对比试件进行预应力的受力情况测试,采用界面粘结强度响应法进行动态曲率修正,得到高负载铁路桥梁体外预应力受力状态增量。通过试验分析了高负载铁路桥梁荷载位移曲线,得到铁路桥梁在外预应力的受力云图。

  16. Gold's monetary roll will be strengthened - Plumbridge

    International Nuclear Information System (INIS)

    Delivering his Presidential address at the Chamber's annual general meeting, Mr Plumbridge said the gold market would enter a new phase and listed seven reasons why gold's monetary role would be strengthened. There was a dramatic increase in the demand for gold jewellery. He also forecasted that South African uranium production would again attain its former peak annual production of about 6000t. There is an essential need for a sustained growth in nuclear power and the prospects for uranium mining industry remain encouraging

  17. Buffeting Response of Suspension Bridge Girder with Separate Control Flaps

    DEFF Research Database (Denmark)

    Huynh, Truc; Thoft-Christensen, Palle

    This paper presents the calculation of the root mean square (RMS) response of a suspension bridge using separate control flaps (SCF) in turbulence conditions. It is assumed that the mean wind velocity is not large enough to cause coupled vibrations and that single mode buffeting response is of in......This paper presents the calculation of the root mean square (RMS) response of a suspension bridge using separate control flaps (SCF) in turbulence conditions. It is assumed that the mean wind velocity is not large enough to cause coupled vibrations and that single mode buffeting response...... on the basis of independent flutter derivatives and independent aeroelastic coefficients from the girder and from the flaps. The theory is demonstrated by a numerical example based on a long-span suspension bridge model with the Great Belt girder....

  18. The formation of liquid bridge in different operating modes of AFM

    Science.gov (United States)

    Wei, Zheng; Sun, Yan; Ding, WenXuan; Wang, ZaiRan

    2016-09-01

    The liquid bridge is one of the principal factors that cause artifacts in ambient-pressure atomic force microscope (AFM) images. Additionally, it is the main component of the adhesion force in ambient conditions. To understand the AFM imaging mechanism and the sample characteristics, it is essential to study the liquid bridge. This study interprets the physical mechanism involved in liquid bridge formation, which is composed of three different physical processes: the squeezing process, capillary condensation, and liquid film flow. We discuss the contributions of these three mechanisms to the volume and the capillary force of the liquid bridge in different AFM operation modes.

  19. Nondestructive Evaluation of Railway Bridge by System Identification Using Field Vibration Measurement

    International Nuclear Information System (INIS)

    This paper presents a nondestructive evaluation approach for system identification (SID) of real railway bridges using field vibration test results. First, a multi-phase SID scheme designed on the basis of eigenvalue sensitivity concept is presented. Next, the proposed multi-phase approach is evaluated from field vibration tests on a real railway bridge (Wondongcheon bridge) located in Yangsan, Korea. On the steel girder bridge, a few natural frequencies and mode shapes are experimentally measured under the ambient vibration condition. The corresponding modal parameters are numerically calculated from a three-dimensional finite element (FE) model established for the target bridge. Eigenvalue sensitivities are analyzed for potential model-updating parameters of the FE model. Then, structural subsystems are identified phase-by-phase using the proposed model-updating procedure. Based on model-updating results, a baseline model and a nondestructive evaluation of test bridge are identified

  20. GPS Dynamic Monitoring Experiment and Result Analysis of Long-Span Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    For the sake of timely appraising the working condition of the bridge, measuring the dynamic characteristics of the bridge structure is very important and necessary. A GPS dynamic monitoring test was carried out in the Wuhan Baishazhou Bridge, which is one of the longest span cable-stayed bridges having been built in China. This paper introduces the experimental implementing scheme and data processing method. The vibration characteristics of the middle span of cable-stayed bridge are availably obtained by use of the spectral analytic approach. The measuring results are very identical to the theoretical designed values. The research demonstrates that, with GPS receiver of the high sampling rate and suitable data processing method, the vibration characteristics of the bridge structure can be determined with high accuracy.

  1. Assessment of seismic performance of skew reinforced concrete box girder bridges

    Science.gov (United States)

    Abdel-Mohti, Ahmed; Pekcan, Gokhan

    2013-12-01

    The seismic vulnerability of highway bridges remains an important problem and has received increased attention as a consequence of unprecedented damage observed during several major earthquakes. A significant number of research studies have examined the performance of skew bridges under service and seismic loads. The results of these studies are particularly sensitive to modeling assumptions in view of the interacting parameters. In the present study, three-dimensional improved beam-stick models of two-span highway bridges with skew angles varying from 0° to 60° are developed to investigate the seismic response characteristics of skew box girder bridges. The relative accuracy of beam-stick models is verified against counterpart finite element models. The effect of various parameters and conditions on the overall seismic response was examined such as skew angle, ground motion intensity, soil condition, abutment support conditions, bridge aspect ratio, and foundation-base conditions. The study shows that the improved beam-stick models can be used to conduct accurate nonlinear time history analysis of skew bridges. Skew angle and interacting parameters were found to have significant effect on the behavior of skewed highway bridges. Furthermore, the performance of shear keys may have a predominant effect on the overall seismic response of the skew bridges.

  2. 公路与桥梁连接处的施工管理探讨%Discussion on Construction Management of the Joint of Road and Bridge

    Institute of Scientific and Technical Information of China (English)

    邹金龙

    2011-01-01

    公路与桥连接处的施工管理是整个公路施工管理的重点.因此,加强公路与桥梁连接处的施工管理十分有必要.%The construction management of the joint of road and bridge is the emphasis of the entire road construction management. So, it is very necessary to strengthen construction management of the joint of road and bridge.

  3. The mechanical response of multi-tower continuous-span suspension bridge deck pavement based on whole bridge analysis

    Institute of Scientific and Technical Information of China (English)

    Li Hongtao; Zhang Chenchen; Hu Jing; Qian Zhendong

    2011-01-01

    The effect of multiple span suspension structure on the mechanical response of bridge deck pavement was studied, and finite element analysis (FEM) of stress and strain of pavement according to the bridge floor system features of super-long and high flexibility was made. Meanwhile, the FEM results were compared with those of the single span suspension structure. Three-stage analytic hierarchy process (AHP) is developed to analyze the mechanical response including whole bridge analysis, partial beams section analysis and orthotropic plate analysis. The most unfavorable load position was determined by the numerical solutions acquired from each stage to study the main mechanical index of multiple span suspension structure. The FEM results showed that the mechanical response numerical solutions by using the three-stage AHP are greater than those by simplified boundary condition, and the force condition of multiple span suspension structure is worse than that of the single span suspension structure.

  4. Strengthening the Canadian alcohol advertising regulatory system.

    Science.gov (United States)

    Heung, Carly M; Rempel, Benjamin; Krank, Marvin

    2012-01-01

    Research evidence points to harmful effects from alcohol advertising among children and youth. In particular, exposure to alcohol advertising has been associated with adolescents drinking both earlier and heavier. Although current federal and provincial guidelines have addressed advertising practices to prevent underage drinking, practice has not been supported by existing policy. While protective measures such as social marketing campaigns have the potential for counteracting the effects from alcohol advertising, the effectiveness of such measures can be easily drowned out with increasing advertising activities from the alcohol industry, especially without effective regulation. Research reviewed by the European Focus on Alcohol Safe Environment (FASE) Project has identified a set of key elements that are necessary to make alcohol advertising policy measures effective at protecting children and youth from the harmful effects of alcohol marketing. Using these key elements as an evaluation framework, there are critical components in the Canadian alcohol advertising regulatory system that clearly require strengthening. To protect impressionable children and youth against the harmful effects of alcohol advertising, 13 recommendations to strengthen current alcohol advertising regulations in Canada are provided for Canadian policy-makers, advertising standard agencies, and public health groups. PMID:23618638

  5. Strengthening the foundations of proliferation assessment tools.

    Energy Technology Data Exchange (ETDEWEB)

    Rexroth, Paul E.; Saltiel, David H.; Rochau, Gary Eugene; Cleary, Virginia D.; Ng, Selena (AREVA NC, Paris, France); Greneche, Dominique (AREVA NC, Paris, France); Giannangeli, Don (Texas A& M University, College Station, TX); Charlton, William S. (Texas A& M University, College Station, TX); Ford, David (Texas A& M University, College Station, TX)

    2007-09-01

    Robust and reliable quantitative proliferation assessment tools have the potential to contribute significantly to a strengthened nonproliferation regime and to the future deployment of nuclear fuel cycle technologies. Efforts to quantify proliferation resistance have thus far met with limited success due to the inherent subjectivity of the problem and interdependencies between attributes that lead to proliferation resistance. We suggest that these limitations flow substantially from weaknesses in the foundations of existing methodologies--the initial data inputs. In most existing methodologies, little consideration has been given to the utilization of varying types of inputs--particularly the mixing of subjective and objective data--or to identifying, understanding, and untangling relationships and dependencies between inputs. To address these concerns, a model set of inputs is suggested that could potentially be employed in multiple approaches. We present an input classification scheme and the initial results of testing for relationships between these inputs. We will discuss how classifying and testing the relationship between these inputs can help strengthen tools to assess the proliferation risk of nuclear fuel cycle processes, systems, and facilities.

  6. Near-fault directivity pulse-like ground motion effect on high-speed railway bridge

    Institute of Scientific and Technical Information of China (English)

    陈令坤; 张楠; 蒋丽忠; 曾志平; 陈格威; 国巍

    2014-01-01

    The vehicle-track-bridge (VTB) element was used to investigate how a high-speed railway bridge reacted when it was subjected to near-fault directivity pulse-like ground motions. Based on the PEER NAG Strong Ground Motion Database, the spatial analysis model of a vehicle-bridge system was developed, the VTB element was derived to simulate the interaction of train and bridge, and the elasto-plastic seismic responses of the bridge were calculated. The calculation results show that girder and pier top displacement, and bending moment of the pier base increase subjected to near-fault directivity pulse-like ground motion compared to far-field earthquakes, and the greater deformation responses in near-fault shaking are associated with fewer reversed cycles of loading. The hysteretic characteristics of the pier subjected to a near-fault directivity pulse-like earthquake should be explicitly expressed as the bending moment-rotation relationship of the pier base, which is characterized by the centrally strengthened hysteretic cycles at some point of the loading time-history curve. The results show that there is an amplification of the vertical deflection in the girder’s mid-span owing to the high vertical ground motion. In light of these findings, the effect of the vertical ground motion should be used to adjust the unconservative amplification constant 2/3 of the vertical-to-horizontal peak ground motion ratio in the seismic design of bridge.

  7. Substructural strengthening in molybdenum and Mo-33Re

    International Nuclear Information System (INIS)

    Strengthening from defect substructures has been studied in Mo-33Re deformed in tension and by cold rolling, and in shock-loaded molybdenum and Mo-33Re. In cold-rolled and tensile-deformed Mo-33Re, strengthening arises from dislocation-dislocation interactions for smaller strains (less than 0.3), while at larger strains by rolling there is additional strengthening from dislocation cell formation and texture development. In shock-loaded molybdenum, dislocation-dislocation interactions are the primary source of strengthening, while in shock-loaded Mo-33Re dislocations and twin boundaries both contribute to strengthening. The coefficients for dislocation strengthening in both shock-loaded molybdenum and shock-loaded Mo-33Re are consistent with the values for the cold-rolled Mo-33Re and with published values for a wide range of other materials, indicating that the strengthening mechanism is similar for conventional and shock deformation. (Auth.)

  8. Floating liquid bridge charge dynamics

    Science.gov (United States)

    Teschke, Omar; Soares, David Mendez; Gomes, Whyllerson Evaristo; Valente Filho, Juracyr Ferraz

    2016-01-01

    The interaction of liquid with electric fields is investigated in a configuration where up to 13 kV are applied between electrodes resulting in a 106 V/m electric field in the capillaries and where there is the formation of a free-standing fluid bridge in the interelectrode gap. The Mott-Gurney equation was fitted to the measured ionization current vs applied voltage curve which indicates that the ionization rate at the high-voltage anode electrode dimethylsulfoxide (DMSO) interface and space charging in the interelectrode gap determine the floating liquid bridge current for a given cathode-to-anode voltage. Space charge effects were measured in the cathode becker and also at the liquid bridge since the ionized charges at the anode migrate to the bridge outer surface and decrease the interfacial tension from 43 mJ/m2 to 29 mJ/m2. Two distinct structural regions then form the bridge, a charged plastic (bulk modulus ˜100 MPa) conducting outer layer with a surface conductivity of ˜10-9 Ω-1, which shapes and supports the floating fluid structure, and an inner liquid cylinder, where DMSO molecules flow.

  9. A strange bridge by Leonardo

    CERN Document Server

    Huylebrouck, Dirk

    2013-01-01

    On folio 855 recto of the Codex Atlanticus, Leonardo da Vinci drew three 'easily movable' bridges, but one of them is enigmatic: all 'replicas' in Leonardo museums and exhibitions come as a surprise, to say the least, to any engineer or architect whose attention is drawn to it. This is the case for models in Amboise (France), Chicago and Portland (USA), Florence (Italy) and for the one of the traveling exhibition by the Australian company 'Grande Exhibitions' that already visited 40 major cities in the world. All 'replicas' of the bridge model attributed to Leonardo have pillars standing on the deck of the bridge, while the deck is suspended by cables attached on these pillars. At first sight this problem does not catch the attention of the observer, as the bridge seems to be a mixed form of a beam and a suspension bridge, but it was not overlooked by my colleague architect-engineer Dr. Laurens Luyten (Gent, Belgium). Yet, after a TV-interview in Brussels so much pressure was exerted by some of the museum col...

  10. Sustainable Bridges – A European Integrated Research Project – Background Overview and Results

    DEFF Research Database (Denmark)

    Täljsten, Björn; Elfgren, Lennart

    2008-01-01

    of energy and release of greenhouse gases. To help our society to be more sustainable, it is important to retain and use what we already have where possible, rather than investing in new structures. Instead of tearing down old, often beautiful, railway bridges and replacing them with new ones, we need...... to preserve and upgrade them by using better assessment, monitoring and strengthening methods. This was also the aim of the European Integrated Research Project “Sustainable Bridges – Assessment for Future Traffic Demands and Longer Lives” when it was accepted for funding by the European Commission in 2003....... The project established the following three specific goals: 1. increase the transport capacity of existing railway bridges by allowing higher axle loads (up to 33 tons) for freight traffic at moderate speeds or by allowing higher speeds (up to 350 km/hour) for passenger traffic with low axle loads 2. extend...

  11. Dynamics of modular expansion joints: The Martinus Nijhoff Bridge

    NARCIS (Netherlands)

    Zuada Coelho, B.A.; Vervuurt, A.H.J.M.; Peelen, W.H.A.; Leendertz, J.S.

    2013-01-01

    Modular expansion joints are structures that are submitted to severe fatigue load conditions. This may lead to unexpected premature damage of the structure which, besides the economic cost of repair, may limit the regular service of the bridge. To better understand the dynamic behaviour of modular e

  12. Evacuation of mixed populations from trains on bridges

    DEFF Research Database (Denmark)

    Kindler, C.; Sørensen, J.G.; Dederichs, A.S.

    2012-01-01

    An understanding of human evacuation dynamics and performance are important when designing complex buildings such as bridges and when applying performance-based codes in order to reduce the risk of exposing occupants to critical conditions in case of fire. The majority of previous studies deal wi...

  13. Bridging history and social psychology

    DEFF Research Database (Denmark)

    Glaveanu, Vlad Petre; Yamamoto, Koji

    2012-01-01

    This special issue aims to bridge history and social psychology by bringing together historians and social psychologists in an exercise of reading and learning from each other’s work. This interdisciplinary exercise is not only timely but of great importance for both disciplines. Social...... hand historians can enhance their analysis of historical sources by drawing upon the conceptual tools developed in social psychology. They can “test” these tools and contribute to their validation and enrichment from completely different perspectives. Most important, as contributions to this special......-traditionalized societies—a distinction that lies at the heart of many social psychology accounts of the world we live in. The present editorial will introduce and consider this act of bridging history and social psychology by focusing on three main questions: What is the bridge made of? How can the two disciplines...

  14. Austenitic Oxide Dispersion Strengthened Steels : A Review

    Directory of Open Access Journals (Sweden)

    Lavanya Raman

    2016-06-01

    Full Text Available Materials play an important role in the fast breeder reactors.  Materials used in cladding tube and fuel pins should have better creep and void swelling resistance. To overcome these difficulties, a new class of material known as oxide dispersion strengthened (ODS steels are used. There are two groups of ODS steels, the ferritic and the austenitic ODS steels based on the matrix. The present paper reviews the current status of research in austenitic ODS steels. The interaction of dislocations with finely dispersed incoherent, hard particles that governs the strength and high temperature properties of ODS materials is briefly reviewed. The synthesis route adopted for these ODS steels, which is mostly through powder metallurgy route is also discussed. The role of various oxides such as Y2O3, ZrO2and TiO2and the clusters formed in these ODS steels on the mechanical properties and void swelling characteristics is also discussed.

  15. Study on WC dispersion-strengthened copper

    Institute of Scientific and Technical Information of China (English)

    WANG Mengjun; ZHANG Liyong; LIU Xinyu

    2004-01-01

    Dispersion-strengthened copper (DSC) with WC as dispersoid was prepared by means of mechanical alloying (MA) following the traditional powder metallurgy (P/M) route. Influence of WC content on the properties of material was discussed in detail, and result shows that when the volume fraction of WC is 1.6%, the material achieves the best overall property, and a little more particle addition led to a less superior property owing to occurrence of particle agglomeration The as-sintered composite was designed to undergo a deformation of 75%. It is proved that appropriate deformation is helpful to attain a higher density and consequently better properties. Deformed material was then exposed to elevated temperature to test its effect on material. Annealing for 1 h at 1173K caused material to recover quite completely, but no obvious recrystallization was observed. It's supposed the particles handicaps motion of dislocations and material demonstrates good retention of strength with substantial improvement in elongation.

  16. Irradiation creep of dispersion strengthened copper alloy

    Energy Technology Data Exchange (ETDEWEB)

    Pokrovsky, A.S.; Barabash, V.R.; Fabritsiev, S.A. [and others

    1997-04-01

    Dispersion strengthened copper alloys are under consideration as reference materials for the ITER plasma facing components. Irradiation creep is one of the parameters which must be assessed because of its importance for the lifetime prediction of these components. In this study the irradiation creep of a dispersion strengthened copper (DS) alloy has been investigated. The alloy selected for evaluation, MAGT-0.2, which contains 0.2 wt.% Al{sub 2}O{sub 3}, is very similar to the GlidCop{trademark} alloy referred to as Al20. Irradiation creep was investigated using HE pressurized tubes. The tubes were machined from rod stock, then stainless steel caps were brazed onto the end of each tube. The creep specimens were pressurized by use of ultra-pure He and the stainless steel caps subsequently sealed by laser welding. These specimens were irradiated in reactor water in the core position of the SM-2 reactors to a fluence level of 4.5-7.1 x 10{sup 21} n/cm{sup 2} (E>0.1 MeV), which corresponds to {approx}3-5 dpa. The irradiation temperature ranged from 60-90{degrees}C, which yielded calculated hoop stresses from 39-117 MPa. A mechanical micrometer system was used to measure the outer diameter of the specimens before and after irradiation, with an accuracy of {+-}0.001 mm. The irradiation creep was calculated based on the change in the diameter. Comparison of pre- and post-irradiation diameter measurements indicates that irradiation induced creep is indeed observed in this alloy at low temperatures, with a creep rate as high as {approx}2 x 10{sup {minus}9}s{sup {minus}1}. These results are compared with available data for irradiation creep for stainless steels, pure copper, and for thermal creep of copper alloys.

  17. Strengthening of HSLA steels by cool deformation

    Energy Technology Data Exchange (ETDEWEB)

    Fatehi, A., E-mail: arya.fatehi@gmail.com [Department of Mining, Metals and Materials Engineering, McGill University, 3610 University Street, Montreal, QC, H3A 2B2 (Canada); Calvo, J.; Elwazri, A.M.; Yue, S. [Department of Mining, Metals and Materials Engineering, McGill University, 3610 University Street, Montreal, QC, H3A 2B2 (Canada)

    2010-06-25

    In microalloyed steels, the refinement of ferrite grains together with a controlled amount of precipitation has key roles in the mechanical properties improvement. Applying small amounts of deformation, at very low hot working temperatures (i.e. coiling temperature), in the ferrite region (i.e. cool deformation) has an appreciable strengthening effect via controlling the final microstructure of the steel. One of the microstructural effects is thought to be the much finer and more uniformly dispersed precipitates in the steel matrix. In the present study, the effects of Nb and Cu on mechanical properties and corresponding microstructures in steels with different levels of cool deformation are investigated. The mechanical properties of the samples were determined using the shear punch test and the microstructure was examined by scanning and transmission electron microscopy. Thermodynamic simulations with FactSage were done to further analyze the precipitation possibility of different elements. It has been found that these alloying elements respond very well to cool deformation, with the strength being highest in steels containing both Nb and Cu. However, a cool deformation effect in the non-Nb and Cu bearing steel is also observed. In all cases, it was confirmed that precipitation plays a key role in the effect of cool deformation, with much of the precipitation taking place dynamically. Nevertheless, static processes also seem to have a measurable effect on room temperature properties. Even low amounts of copper (e.g. {approx}0.4 wt%) can contribute to strengthening of the steel. The Cu addition is found to affect the mechanical properties by affecting the precipitation and growth of Nb compounds.

  18. Strengthening of HSLA steels by cool deformation

    International Nuclear Information System (INIS)

    In microalloyed steels, the refinement of ferrite grains together with a controlled amount of precipitation has key roles in the mechanical properties improvement. Applying small amounts of deformation, at very low hot working temperatures (i.e. coiling temperature), in the ferrite region (i.e. cool deformation) has an appreciable strengthening effect via controlling the final microstructure of the steel. One of the microstructural effects is thought to be the much finer and more uniformly dispersed precipitates in the steel matrix. In the present study, the effects of Nb and Cu on mechanical properties and corresponding microstructures in steels with different levels of cool deformation are investigated. The mechanical properties of the samples were determined using the shear punch test and the microstructure was examined by scanning and transmission electron microscopy. Thermodynamic simulations with FactSage were done to further analyze the precipitation possibility of different elements. It has been found that these alloying elements respond very well to cool deformation, with the strength being highest in steels containing both Nb and Cu. However, a cool deformation effect in the non-Nb and Cu bearing steel is also observed. In all cases, it was confirmed that precipitation plays a key role in the effect of cool deformation, with much of the precipitation taking place dynamically. Nevertheless, static processes also seem to have a measurable effect on room temperature properties. Even low amounts of copper (e.g. ∼0.4 wt%) can contribute to strengthening of the steel. The Cu addition is found to affect the mechanical properties by affecting the precipitation and growth of Nb compounds.

  19. Myocardial bridge: The cause of angina in a young man

    International Nuclear Information System (INIS)

    Myocardial bridging is basically the systolic narrowing of epicardial coronary arteries, secondary to their tunneled course in myocardium. Though it is a benign condition it can have the symptoms like acute coronary syndrome, arrhythmias and sudden cardiac death. We report a 32-year-old male, who presented with typical exertional angina, had positive exercise treadmill and thallium-201 test. Coronary angiography revealed myocardial bridge of distal left anterior descending coronary artery. He was put on β-blockers and was doing well at 8 years of follow-up

  20. A cellular automaton model for a bridge traffic bottleneck

    Institute of Scientific and Technical Information of China (English)

    Shifa Xiao; Lingjiang Kong; Muren Liu

    2005-01-01

    A cellular automaton (CA) model is proposed in this paper to analyze a bridge traffic bottleneck. The simulation results with this model show that there are several phase transitions in the traffic average density, velocity and flow for each lane under a periodic boundary condition. An unstable phase in the traffic average density and velocity for the upstream and downstream lanes of the bridge is shown in a range of initial traffic densities. The critical points of the phase transitions and the phenomenon of the unstable phase found in the simulation are also explained with the mean-field theory.

  1. Dynamic test and finite element model updating of bridge structures based on ambient vibration

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The dynamic characteristics of bridge structures are the basis of structural dynamic response and seismic analysis,and are also an important target of health condition monitoring.In this paper,a three-dimensional finite-element model is first established for a highway bridge over a railroad on No.312 National Highway.Based on design drawings,the dynamic characteristics of the bridge are studied using finite element analysis and ambient vibration measurements.Thus,a set of data is selected based on sensitivity analysis and optimization theory;the finite element model of the bridge is updated.The numerical and experimental results show that the updated method is more simple and effective,the updated finite element model can reflect the dynamic characteristics of the bridge better,and it can be used to predict the dynamic response under complex external forces.It is also helpful for further damage identification and health condition monitoring.

  2. Excitation Methods for Bridge Structures

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, C.R.; Duffy, T.A.; Cornwell, P.J.; Doebling, S.W.

    1999-02-08

    This paper summarizes the various methods that have been used to excited bridge structures during dynamic testing. The excitation methods fall into the general categories of ambient excitation methods and measured-input excitation methods. During ambient excitation the input to the bridge is not directly measured. In contrast, as the category label implies, measured-input excitations are usually applied at a single location where the force input to the structure can be monitored. Issues associated with using these various types of measurements are discussed along with a general description of the various excitation methods.

  3. Bridge Number and Conway Products

    OpenAIRE

    Blair, Ryan C.

    2007-01-01

    Schubert proved that, given a composite link $K$ with summands $K_{1}$ and $K_{2}$, the bridge number of $K$ satisfies the following equation: $$\\beta(K)=\\beta(K_{1})+\\beta(K_{2})-1.$$ In ``Conway Produts and Links with Multiple Bridge Surfaces", Scharlemann and Tomova proved that, given links $K_{1}$ and $K_{2}$, there is a Conway product $K_{1}\\times_{c}K_{2}$ such that $$\\beta(K_{1}\\times_{c} K_{2}) \\leq \\beta(K_{1}) + \\beta(K_{2}) - 1$$ In this paper, we define the generalized Conway prod...

  4. Optimum selection on bridge erection with floating crane in East China Sea Bridge and Hangzhou Bay Bridge

    Institute of Scientific and Technical Information of China (English)

    Shunquan Qin; Pu Zhou; Youheng Hua

    2004-01-01

    @@ Introduction With the rapid development of China′s economy, many bridges will be built over the Chinese coastal waters of Pacific Ocean. Among them, construction of East China Sea Bridge has been commenced in June 2001, and will be completed at the end of 2005, Hangzhou Bay Bridge was also started to construct in June 2003(Fig. 1). These two ultralong bridges are designed as twin expressway bridges standing side by side each carries a 3-lane one-way carriageway. The total width is 31.5m and 33.0m respectively. East China Sea Bridge starts from Nanhui District, Shanghai and extends to the Yangshan Deep Water Port Area, which is located at one of the Qiqu Islands. The total length of the bridge is about 31.0 km, in which 25 km are on the sea, and 22 km is in the unnavigable region. Hangzhou Bay Bridge across the mouth of Qiantang River.

  5. Is myocardial bridging a bridge connecting to cardiovascular events?

    Institute of Scientific and Technical Information of China (English)

    LI Jian-jun

    2010-01-01

    @@ Coronary arteries and their major branches usually course on the surface of the heart in the subepicardial tissue. However, a muscle hber overlying the intramyocardial segment of an epicardial coronary artery was defined as myocardial bridging (MB), and subsequently the artery coursing within the myocardium is called a tunneled artery.

  6. Integrated Approach to Repair and Seismic Strengthening of Mustafa Pasha Mosque in Skopje

    Science.gov (United States)

    Sendova, Veronika; Gavrilovic, Predrag; Stojanoski, Blagojce

    2008-07-01

    Mustafa Pasha's Mosque is one of the biggest and the best preserved monuments of the Ottoman sacral architecture in Skopje and the Balkan. As a cultural historic monument of an extraordinary importance for the city of Skopje and Republic of Macedonia, it is under protection of the Law on Protection of Cultural Heritage. IZIIS is currently elaborating a project on repair and strengthening of Mustafa Pasha's mosque. Respecting the modern requirements in protection of historical monuments, as is the main principles of seismic strengthening are: application of new technologies and materials, reversibility and invisibility of the applied technique. The concept of structural strengthening and repair aimed at reaching the designed level of earthquake protection has been selected based on: (i) investigations of the soil conditions, (ii) investigations of the characteristics of the built-in materials, (iii) investigation of the main dynamic characteristics, as well as (iv) previous experimental investigation of the mosque model.

  7. Integrated Approach to Repair and Seismic Strengthening of Mustafa Pasha Mosque in Skopje

    International Nuclear Information System (INIS)

    Mustafa Pasha's Mosque is one of the biggest and the best preserved monuments of the Ottoman sacral architecture in Skopje and the Balkan. As a cultural historic monument of an extraordinary importance for the city of Skopje and Republic of Macedonia, it is under protection of the Law on Protection of Cultural Heritage. IZIIS is currently elaborating a project on repair and strengthening of Mustafa Pasha's mosque. Respecting the modern requirements in protection of historical monuments, as is the main principles of seismic strengthening are: application of new technologies and materials, reversibility and invisibility of the applied technique. The concept of structural strengthening and repair aimed at reaching the designed level of earthquake protection has been selected based on: (i) investigations of the soil conditions, (ii) investigations of the characteristics of the built-in materials, (iii) investigation of the main dynamic characteristics, as well as (iv) previous experimental investigation of the mosque model

  8. Evacuation of mixed populations from trains on bridges

    DEFF Research Database (Denmark)

    Kindler, C.; Sørensen, J.G.; Dederichs, A.S.

    2012-01-01

    An understanding of human evacuation dynamics and performance are important when designing complex buildings such as bridges and when applying performance-based codes in order to reduce the risk of exposing occupants to critical conditions in case of fire. The majority of previous studies deal...... with the evacuation behavior of abled bodied homogeneous groups. Hence, a significant part of the population is poorly described such as are people with impairments which are about 10%-21% of the world's population, furthermore elderly people, giving an additional 10% and 20% of the population are aged below 15 years....... The discussion of "equal access" is only followed slowly by the demand on "equal egress". However, the passengers on trains on bridges are rarely homogeneous mixture. At the same time equal egress is far from assured today. In this paper the evacuation of mixed populations from trains on bridges are considered...

  9. Analysis of the strengthening mechanisms in pipeline steels as a function of the hot rolling parameters

    Energy Technology Data Exchange (ETDEWEB)

    Carretero Olalla, V., E-mail: Victor.carretero@ugent.be [Ghent University, Department of Materials Science and Engineering, Technologiepark 903, Zwijnaarde, B-9052 Gent (Belgium); Bliznuk, V., E-mail: vitaliy.bliznuk@ugent.be [Ghent University, Department of Materials Science and Engineering, Technologiepark 903, Zwijnaarde, B-9052 Gent (Belgium); Sanchez, N., E-mail: nuria.sanchezmourino@arcelormittal.com [ArcelorMittal Global R and D Gent, OCAS NV Pres. J.F. Kennedylaan 3, BE-9060 Zelzate (Belgium); Thibaux, P., E-mail: philippe.thibaux@arcelormittal.com [ArcelorMittal Global R and D Gent, OCAS NV Pres. J.F. Kennedylaan 3, BE-9060 Zelzate (Belgium); Kestens, L.A.I., E-mail: leo.kestens@ugent.be [Ghent University, Department of Materials Science and Engineering, Technologiepark 903, Zwijnaarde, B-9052 Gent (Belgium); Delft University of Technology, Department of Materials Science and Engineering, Mekelweg 2, 2628 CD Delft (Netherlands); Petrov, R.H., E-mail: Roumen.Petrov@ugent.be [Ghent University, Department of Materials Science and Engineering, Technologiepark 903, Zwijnaarde, B-9052 Gent (Belgium); Delft University of Technology, Department of Materials Science and Engineering, Mekelweg 2, 2628 CD Delft (Netherlands)

    2014-05-01

    The yield strength of different pipeline steel grades, rolled under four different conditions, was correlated with calculated strengthening contributions. Slabs with the same composition were rolled under identical roughing conditions but varied finish rolling temperature (FRT). Two cooling routes, consisting of accelerated water cooling condition (ACC) followed by slow cooling in an oven to simulate coiling and air cooling were applied after the last rolling pass. The microstructures obtained after each thermo mechanical controlled process (TMCP) schedule, were characterized using Transmission Electron Microscopy (TEM), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Electron backscatter diffraction (EBSD). The mechanical properties of the plates were determined by means of tensile tests and Charpy V-notch impact test. It was confirmed that a combination of fast cooling rate and low finish rolling temperature produces higher strength than the slow cooling rate and high finish rolling temperature. Contributions to the strengthening arising from the various microstructural features like solid solution strengthening, grain size, dislocation density and precipitation hardening, were analyzed using Taylor, Hall–Petch and Ashby–Orowan approaches. The root of the sum of the squares method was applied to link the experimental with the model-predicted strength. It is believed that this approach provides a better understanding of the effect of TMCP parameters on the microstructure and strengthening mechanisms in pipeline steels.

  10. Analysis of the strengthening mechanisms in pipeline steels as a function of the hot rolling parameters

    International Nuclear Information System (INIS)

    The yield strength of different pipeline steel grades, rolled under four different conditions, was correlated with calculated strengthening contributions. Slabs with the same composition were rolled under identical roughing conditions but varied finish rolling temperature (FRT). Two cooling routes, consisting of accelerated water cooling condition (ACC) followed by slow cooling in an oven to simulate coiling and air cooling were applied after the last rolling pass. The microstructures obtained after each thermo mechanical controlled process (TMCP) schedule, were characterized using Transmission Electron Microscopy (TEM), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Electron backscatter diffraction (EBSD). The mechanical properties of the plates were determined by means of tensile tests and Charpy V-notch impact test. It was confirmed that a combination of fast cooling rate and low finish rolling temperature produces higher strength than the slow cooling rate and high finish rolling temperature. Contributions to the strengthening arising from the various microstructural features like solid solution strengthening, grain size, dislocation density and precipitation hardening, were analyzed using Taylor, Hall–Petch and Ashby–Orowan approaches. The root of the sum of the squares method was applied to link the experimental with the model-predicted strength. It is believed that this approach provides a better understanding of the effect of TMCP parameters on the microstructure and strengthening mechanisms in pipeline steels

  11. Characterisation of a Selection of AC and DC Resistance Bridges for Standard Platinum Resistance Thermometry

    Science.gov (United States)

    Pearce, J. V.; Gray, J.; Veltcheva, R. I.

    2016-11-01

    Accurate resistance bridges are used to measure the ratio between the resistance of standard platinum resistance thermometers and a reference (standard) resistor at the level of microkelvin in temperature terms and as such play a critical role in the realisation and dissemination of the ITS-90. For AC bridges, the ratio test unit has been available for some time, and for both AC and DC bridges, the increasing availability of resistance bridge calibrators based on combinatorial calibration has increased the ease with which the accuracy and linearity of resistance bridges may be determined, under conditions which provide a realistic representation of the actual measurement set-up. In this study, the performance of 14 resistance bridges, which were available for testing at NPL, consisting of a range of manufacturers and types, has been evaluated and expressed in terms of the standard deviation of the bridge errors over a given range of ratios, namely s. In general, the bridges are found to comply with the manufacturers' specifications. The uncertainty of s has also been determined using Monte Carlo techniques and is found to be of the order of 10 % of s for most bridge types.

  12. Aesthetic design of bridges; Kyoryo ni okeru keikan sekkei no rekishi

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, H. [Kyushu Institute of Technology, Kitakyushu (Japan)

    1995-01-01

    The present paper outlines the bridge design in harmony with both ambient and natural environments. The condition which the bridge must clear has its two phases, i.e., `rational phase` focused on the practical utility to be managed by the engineering and `sensible phase` for the aesthetic achievement. The profile and scenery of bridge are based on the perfect teleology to engineer and process them by taking the influence into consideration on the mental phase. The beauty of bridge belongs to a category of technical beauty converting the technical product into an aesthetic object. The technical beauty is composed of `formal beauty` (The composition of all different members forms the beauty of harmony.), `functional beauty` (All different members under tension generate the dynamic beauty.) and `harmony with the environment`. For the harmony with the environment, what is taken into consideration is the steel, concrete and other material feeling, type of bridge adaptable to the environment, and color good for the environment. The following three methods are applied to the combination of bridge and environment: elimination method to vaguely immerse the bridge in the environment. Accentuation method to select the bridge as a main element of scenery. Harmonization method to harmonize the bridge with the environment. 21 refs., 14 figs.

  13. Effect of surfactant on kinetics of thinning of capillary bridges

    Science.gov (United States)

    Nowak, Emilia; Kovalchuk, Nina; Simmons, Mark

    2015-11-01

    Kinetics of thinning of capillary bridges is of great scientific and industrial interest being of vital importance for example in various emulsification and microfluidic processes. It is well known that the rate of bridge thinning is proportional to the interfacial tension. Therefore it is expected that the process should slow down by addition of surfactant. The kinetics of capillary bridges in the presence of surfactant was studied by the dripping of liquid from a capillary tip under conditions of nearly zero flow rate (We personal care products. The viscosity, surfactant activity and adsorption kinetics have been controlled by addition of glycerol and sodium chloride. The study has shown that the kinetics of capillary bridges are determined by dynamic surface tension rather than by its equilibrium value. In particular, the kinetics of the bridge thinning for the 0.1 g L-1 aqueous SLES solution is practically the same as that of pure water despite twice lower equilibrium surface tension. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  14. Technique for Determining Bridge Displacement Response Using MEMS Accelerometers.

    Science.gov (United States)

    Sekiya, Hidehiko; Kimura, Kentaro; Miki, Chitoshi

    2016-02-19

    In bridge maintenance, particularly with regard to fatigue damage in steel bridges, it is important to determine the displacement response of the entire bridge under a live load as well as that of each member. Knowing the displacement response enables the identification of dynamic deformations that can cause stresses and ultimately lead to damage and thus also allows the undertaking of appropriate countermeasures. In theory, the displacement response can be calculated from the double integration of the measured acceleration. However, data measured by an accelerometer include measurement errors caused by the limitations of the analog-to-digital conversion process and sensor noise. These errors distort the double integration results. Furthermore, as bridges in service are constantly vibrating because of passing vehicles, estimating the boundary conditions for the numerical integration is difficult. To address these problems, this paper proposes a method for determining the displacement of a bridge in service from its acceleration based on its free vibration. To verify the effectiveness of the proposed method, field measurements were conducted using nine different accelerometers. Based on the results of these measurements, the proposed method was found to be highly accurate in comparison with the reference displacement obtained using a contact displacement gauge.

  15. Technique for Determining Bridge Displacement Response Using MEMS Accelerometers

    Directory of Open Access Journals (Sweden)

    Hidehiko Sekiya

    2016-02-01

    Full Text Available In bridge maintenance, particularly with regard to fatigue damage in steel bridges, it is important to determine the displacement response of the entire bridge under a live load as well as that of each member. Knowing the displacement response enables the identification of dynamic deformations that can cause stresses and ultimately lead to damage and thus also allows the undertaking of appropriate countermeasures. In theory, the displacement response can be calculated from the double integration of the measured acceleration. However, data measured by an accelerometer include measurement errors caused by the limitations of the analog-to-digital conversion process and sensor noise. These errors distort the double integration results. Furthermore, as bridges in service are constantly vibrating because of passing vehicles, estimating the boundary conditions for the numerical integration is difficult. To address these problems, this paper proposes a method for determining the displacement of a bridge in service from its acceleration based on its free vibration. To verify the effectiveness of the proposed method, field measurements were conducted using nine different accelerometers. Based on the results of these measurements, the proposed method was found to be highly accurate in comparison with the reference displacement obtained using a contact displacement gauge.

  16. Numerical simulation of tests for the evaluation of the performance of the reinforced concrete slabs strengthening by FRCM

    Directory of Open Access Journals (Sweden)

    Anania Laura

    2016-01-01

    Full Text Available In this work the attention is focused to the numerical simulation of the experimental bending tests carried out on a total of six reinforced concrete r.c. plates the latter aimed to provide a basic understanding of the its performance when strengthened by Fiber Reinforced Cementitius Matrix (FRCM Composites. Three of those were used as control specimens. The numerical simulation was carried out by LUSAS software. A good correlation between the FE results and data obtained from the test, both in the load–deformation behavior and the failure load was highlighted. This permits to prove that applied strengthening system gives back an enhancement 2.5 times greater in respect of the unreinforced case. A greater energy dissipation ability and a residual load-bearing capacity makes the proposed system very useful in the retrofitting as well as in the case of strengthening of bridge structures. Based on the validation of the FE results in bending, the numerical analysis was also extended to characterize the behavior of this strengthening system in tensile.

  17. Analysis of Seismic Response of Main Bridge of Yili River Bridge%新疆伊犁河大桥主桥地震响应分析

    Institute of Scientific and Technical Information of China (English)

    刘坤

    2012-01-01

    研究目的:新疆伊犁河大桥是连接218国道和313省道的重点控制工程,主桥为(66+5×120+66)m 双肢薄壁连续刚构桥,该桥被称为新疆第一大桥.桥址位于7度地震区内,目前对这类大跨度连续刚构桥的地震反应研究很少.为保证该桥的抗震安全,研究该桥的地震响应规律,为同类桥梁设计提供参考依据.研究结论:通过分析得出:(1)对于连续刚构桥而言,塑性铰的位置出现在刚构墩的墩顶及墩底,抗震设计时需要加强此处的设计;(2)该大桥在地震反应下,虽然出现塑性铰,但与破坏位移还有一定的距离;(3)该桥具有一定的延性能力,满足大震不倒的要求.%Research purposes: The Yili River Bridge is an important project to connect the 218 National Highway with 313 Provincial Highway and is the largest bridge in Xingjiang with main bridge of coupled thin wall continuous rigid frame bridge(66 +5×120 +66) m. It is located in 7 degree earthquake region. As there is a little research on the seismic response of long span continuous rigid frame bridge is very rare , it is necessary to research the seismic response regulations of this bridge to make sure the bridge safety and provide the reference to the similar works. Research conclusions:From the analysis it is concluded (1) For the continuous rigid frame bridge, the plastic hinges region is on the top or bottom of frame pier and where need to be strengthened. (2) Under the seismic reaction, the plastic hinges happen to this bridge, but they keep certain away from the damaged displacement. (3) The Yili River Bridge has enough ductility and it can not fall under the serious earthquake.

  18. 建立并创新适应新形势的企业技术标准工作模式%Build Enterprise Technical Standards Work Pattern to Adapt to New Condition

    Institute of Scientific and Technical Information of China (English)

    陈晓红

    2013-01-01

    With new requirements proposed for technical standards work under the new circumstances, the article combining with the practice of Wuhan Iron and Steel Company Limited (WISCO) points out that enterprises must improve the work pattern of standards development and revision, and strengthen the standards implementation management and product quality supervision, so that technical standards can serve as a bridge between technologies and industrialization, support the industrial upgrading and structural optimization, create conditions for promoting trade and unify the market and provides means for global competition, helping enterprises to better cope with the increasing market competition.

  19. Luster Polish Strengthening Treatment for Raceway Surface of Aeroengine Bearings

    Institute of Scientific and Technical Information of China (English)

    DENG Si-er; TENG Hong-fei; MA Fu-jian; HAO Jian-jun; CHEN Tao

    2007-01-01

    A new surface strengthening technology, luster polish strengthening treatnent, was proposed to treat the raceway surface of aeroengine bearings (9Cr18Mo) with the centrifugal strengthening machine exclusively designed for luster polish strengthening treatment. The experimental results showed that luster polish strengthening treatment produced a compressive residual stress layer with a depth of over 80 μm below the surface of the bearing raceway, and thus effectively removed the metamorphic layer in the raceway surface. After luster polish strengthening treatment, the average surface hardness of the aeroengine bearing raceway was increased from 61.02 HRC to 63.01 HRC, the surface roughness was reduced from 0.06 μm to 0.03 μm, and the contact fatigue life of the aeroengine bearings was improved by about 90%, with the dispersion of fatigue life being reduced remarkably.Theoretical calculation result agrees with that obtained by experiment.

  20. Behavior of preloaded RC beams strengthened with CFRP laminates

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Eighteen reinforced concrete beams, including 16 beams strengthened with CFRP laminate at different levels of preload and 2 control beams, were tested to investigate the influence ofpreload level on flexural behavior of CFRP-strengthened RC beam. The experimental parameters include rebar ratios, number of plies of CFRP laminates and preload level at the time of strengthening. Theoretical analysis was also carried out to explain the experimental phenomena and results. The experimental and theoretical results indicated that the preload level has more influence on the stiffness and deflection of the strengthened beam, bothat post-cracking and post-yielding stage, than that on the yielding and ultimate flexural strength of the strengthened beam. The main failure mode of CFRP-strengthened beam is the intermediate crack-induced debonding of CFRP laminates, provided that the development length of CFRP laminates and shear capacity of the beam are sufficient.

  1. Architectural engineering of FRP bridges

    OpenAIRE

    Smits, J.E.P.

    2014-01-01

    This paper deals with the use of Fibre Reinforced Polymers (FRP's) in architectural and structural bridge design. The challenges and opportunities that come with this relatively new material are discussed. An inventory is made of recent engineers' solutions in FRP, followed by a discussion on architectural application of FRP's derived from the authors architectural practice.

  2. Instability of the capillary bridge

    Science.gov (United States)

    Pare, Gounseti; Hoepffner, Jerome

    2014-11-01

    Capillary adhesion is a physical mechanism that maintains two bodies in contact by capillarity through a liquid ligament. The capillary bridge is an idealization of this capillary adhesion. In this study we first focus on the classical case of the stability of the capillary bridge. Secondly we study a slightly more complex configuration, imagining a flow in the capillary bridge as in the case of the dynamics of the neck of a liquid ligament, in its withdrawal under the effect of capillarity. Inspired by the experiments on soap films of Plateau, the configuration analyzed consists of an initially axisymmetric, mass of fluid held by surface tension forces between two parallel, coaxial, solid pipes of the same diameter. The results presented are obtained by numerical simulations using the free software, Gerris Flow Solver. We first focus on the capillary Venturi. In the static configuration the stability diagram of the capillary bridge obtained is in perfect agreement with the results of Lev A. Slobozhanin. In the dynamic case we develop a matlab code based on the one dimensional equations of Eggers and Dupont. The comparison of the bifurcation diagram obtained and the numerical simulations shows a good agreement.

  3. Bridge Aesthetics and Structural Honesty

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    In bridges the overall form must be chosen with due respect to the transmission of forces if efficient structures shall be created, The design must therefore be governed by experienced structural engineers - in some cases assisted by aesthetic advisers on specific issues. Some basic requirements...

  4. The Wien Bridge Oscillator Family

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2006-01-01

    A tutorial in which the Wien bridge family of oscillators is defined and investigated. Oscillators which do not fit into the Barkhausen criterion topology may be designed. A design procedure based on initial complex pole quality factor is reported. The dynamic transfer characteristic...

  5. Architectural engineering of FRP bridges

    NARCIS (Netherlands)

    Smits, J.E.P.

    2014-01-01

    This paper deals with the use of Fibre Reinforced Polymers (FRP's) in architectural and structural bridge design. The challenges and opportunities that come with this relatively new material are discussed. An inventory is made of recent engineers' solutions in FRP, followed by a discussion on archit

  6. Intercellular bridges in vertebrate gastrulation.

    Directory of Open Access Journals (Sweden)

    Luca Caneparo

    Full Text Available The developing zebrafish embryo has been the subject of many studies of regional patterning, stereotypical cell movements and changes in cell shape. To better study the morphological features of cells during gastrulation, we generated mosaic embryos expressing membrane attached Dendra2 to highlight cellular boundaries. We find that intercellular bridges join a significant fraction of epiblast cells in the zebrafish embryo, reaching several cell diameters in length and spanning across different regions of the developing embryos. These intercellular bridges are distinct from the cellular protrusions previously reported as extending from hypoblast cells (1-2 cellular diameters in length or epiblast cells (which were shorter. Most of the intercellular bridges were formed at pre-gastrula stages by the daughters of a dividing cell maintaining a membrane tether as they move apart after mitosis. These intercellular bridges persist during gastrulation and can mediate the transfer of proteins between distant cells. These findings reveal a surprising feature of the cellular landscape in zebrafish embryos and open new possibilities for cell-cell communication during gastrulation, with implications for modeling, cellular mechanics, and morphogenetic signaling.

  7. Dynamic identification of paradela historic railway bridge

    OpenAIRE

    Ramos, Luís F.; Valente, Isabel; Guimarães, Paulo; Vazquez, Kevin; Lourenço, Paulo B.

    2013-01-01

    Paradela Bridge is a metallic bridge located along the bank of the Tua River in northern Portugal. While the bridge is not currently in service, its structure is representative of many metallic truss structures built across the country between the 19th and the 20th century. The construction of the Paradela Bridge was completed in 1886 and served for about 120 years connecting northern Portugal. Tua Line belongs to the Douro area that UNESCO recently declared as world heritage. This work acqui...

  8. Transition Slabs of Integral Abutment Bridges

    OpenAIRE

    Dreier, Damien; Muttoni, Aurelio; BURDET, Olivier

    2011-01-01

    Over the past decades, an increasing number of bridges with integral abutment have been built in Switzerland. This type of bridge offers various advantages over standard bridges with abutments, equipped with expansion joints and bearings that require regular inspection and maintenance. One main concern of integral abutment bridges is related to the soil-structure interaction, in particular between the transition slab and the embankment. To avoid any expansion joints, transition slabs are dire...

  9. SHM-Based Probabilistic Fatigue Life Prediction for Bridges Based on FE Model Updating.

    Science.gov (United States)

    Lee, Young-Joo; Cho, Soojin

    2016-03-02

    Fatigue life prediction for a bridge should be based on the current condition of the bridge, and various sources of uncertainty, such as material properties, anticipated vehicle loads and environmental conditions, make the prediction very challenging. This paper presents a new approach for probabilistic fatigue life prediction for bridges using finite element (FE) model updating based on structural health monitoring (SHM) data. Recently, various types of SHM systems have been used to monitor and evaluate the long-term structural performance of bridges. For example, SHM data can be used to estimate the degradation of an in-service bridge, which makes it possible to update the initial FE model. The proposed method consists of three steps: (1) identifying the modal properties of a bridge, such as mode shapes and natural frequencies, based on the ambient vibration under passing vehicles; (2) updating the structural parameters of an initial FE model using the identified modal properties; and (3) predicting the probabilistic fatigue life using the updated FE model. The proposed method is demonstrated by application to a numerical model of a bridge, and the impact of FE model updating on the bridge fatigue life is discussed.

  10. Use of Woven Fabrics for Strengthening of Reinforced Concrete Beams

    OpenAIRE

    Parthraj R. Puranik; Deval A. Vasavada

    2014-01-01

    Worldwide, a great deal of research is currently being conducted concerning the use of fiber reinforced plastic wraps, laminates and sheets in the repair and strengthening of reinforced concrete (RC) members. Fibre-reinforced polymer (FRP) application is a very effective way to repair and strengthen structures that have become structurally weak over their life span. But the use of woven fabrics for strengthening RC members has not been much investigated. Woven fabrics though cannot provide co...

  11. Behaviour of RC beams shear strengthening with NSM CFRP laminates

    OpenAIRE

    Dias, Salvador J. E.; Barros, Joaquim A. O.

    2008-01-01

    The effectiveness of the Near Surface Mounted (NSM) technique with Carbon Fiber Reinforced Polymer (CFRP) laminates for the shear strengthening of T cross section reinforced concrete (RC) beams is assessed by experimental research. The influence of the percentage and inclination of CFRP laminates on the shear strengthening contribution was evaluated. The experimental program also includes beams strengthened according to the externally bonded reinforcement (EBR) technique in ord...

  12. Study of the Tensile Properties of CFRP Strengthened Steel Plates

    OpenAIRE

    Yiyan Lu; Weijie Li; Shan Li; Xiaojin Li; Tao Zhu

    2015-01-01

    This paper presents the experimental results of steel plates strengthened with carbon fiber reinforced polymer (CFRP) sheets under tensile load. The number of CFRP layers (ranging from one to four), strengthening schemes (single-sided and double-sided bonding), and temperatures (ranging from 25 to 120 °C) were investigated. Results showed that the number of CFRP layers and strengthening schemes had insignificant effects on failure modes of specimens. The failure modes were dominated by the de...

  13. How to Strengthen Child Learners’Self-confidence

    Institute of Scientific and Technical Information of China (English)

    李文敬

    2013-01-01

    Self-confidence is closely related to L2 learning. In order to make their learners enjoy English learning, English teach-ers need to strengthen the learners’English learning confidence. This article is to find out English teachers’role to strengthening learners’self-confidence in ELL by means of class observation. The writer concludes improving speaking ability; giving praise and offering gentle error correcting can help to strengthen the learners’confidence.

  14. Shear Strengthening of Corbels with Carbon Fibre Reinforced Polymers (CFRP

    Directory of Open Access Journals (Sweden)

    Nawaz, A.

    2010-09-01

    Full Text Available Corbels constitute what are known as “disturbed” regions in concrete structures, where typical shear failure may be anticipated on the grounds of small shear span-to-depth ratios. The concentration of stress induced by the weight of girders on the very small loadbearing areas in corbels often causes cracking in bridges and other structures. Little experimental research can be found in the literature on the shear strengthening of corbels. In the present study, nine such members were tested. Two had no carbon fibre reinforced polymers attached, while CFRP laminates were externally bonded to the other seven, in a number of different spatial arrangements. Ultimate shear strength was found and compared for all specimens. The results showed that CFRP configuration and geometry directly affected corbel shear strength, which was higher in all the CFRPstrengthened corbels than in the controls. The highest strength values were recorded for specimens whose shear-critical area was wrapped in CFRP.

    Las ménsulas constituyen lo que conocemos como regiones de “distorsión” en las estructuras de hormigón, zonas en que pueden preverse roturas por cortante debido a las bajas relaciones luz de cortante-canto presentes en ellas. La concentración de solicitaciones producida por el peso de las vigas sobre superficies de carga muy reducidas en las ménsulas a menudo provoca el agrietamiento de puentes y otras estructuras de obra civil. En la literatura especializada sobre el refuerzo a cortante de las ménsulas existen escasos ejemplos de estudios experimentales. Para la presente investigación se han realizado ensayos con nueve elementos de este tipo. Dos de ellos no incluían polímeros reforzados con fibra de carbono (CFRP, mientras que los siete restantes llevaban láminas externas de CFRP, dispuestas siguiendo distintas configuraciones espaciales. Los resultados indican que la configuración y la disposición geométrica de los CFRP repercuten

  15. Technology of Strengthening Steel Details by Surfacing Composite Coatings

    Science.gov (United States)

    Burov, V. G.; Bataev, A. A.; Rakhimyanov, Kh M.; Mul, D. O.

    2016-04-01

    The article considers the problem of forming wear resistant meal ceramic coatings on steel surfaces using the results of our own investigations and the analysis of achievements made in the country and abroad. Increasing the wear resistance of surface layers of steel details is achieved by surfacing composite coatings with carbides or borides of metals as disperse particles in the strengthening phase. The use of surfacing on wearing machine details and mechanisms has a history of more than 100 years. But still engineering investigations in this field are being conducted up to now. The use of heating sources which provide a high density of power allows ensuring temperature and time conditions of surfacing under which composites with peculiar service and functional properties are formed. High concentration of energy in the zone of melt, which is created from powder mixtures and the hardened surface layer, allows producing the transition zone between the main material and surfaced coating. Surfacing by the electron beam directed from vacuum to the atmosphere is of considerable technological advantages. They give the possibility of strengthening surface layers of large-sized details by surfacing powder mixtures without their preliminary compacting. A modified layer of the main metal with ceramic particles distributed in it is created as a result of heating surfaced powders and the detail surface layer by the electron beam. Technology of surfacing allows using powders of refractory metals and graphite in the composition of powder mixtures. They interact with one another and form the particles of the hardening phase of the composition coating. The chemical composition of the main and surfaced materials is considered to be the main factor which determines the character of metallurgical processes in local zones of melt as well as the structure and properties of surfaced composition.

  16. 47 CFR 80.331 - Bridge-to-bridge communication procedure.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge communication procedure. 80..., Alarm, Urgency and Safety Procedures § 80.331 Bridge-to-bridge communication procedure. (a) Vessels... position). I plan to (give proposed course of action). Over. (3) (Coast station), this is (vessel's...

  17. Design and construction of scour protection for deep-water group pile foundation structures of two pylons in the Sutong Bridge project

    Institute of Scientific and Technical Information of China (English)

    He Ping; Guan Yijun; Zhang Xiongwen; Zhang Qun; Zhou Jianhua

    2009-01-01

    Sutong Bridge, as a world-record cable-stayed bridge with its main span exceeding 1 000 m constructed in Yangtze River estuary region in China, is located at a site with complicated hydrologic conditions and poor geotechnical conditions and therefore, scour protection will be a decisive factor for ensuring smooth and successful construction of this bridge. This paper, starting from structural description of deep-water group pile foundation, analyzes impact to the bridge safety introduced by scour and its protection and further presents different solutions of scour protection for foundation structures of this bridge.

  18. Removal of failed crown and bridge.

    Science.gov (United States)

    Sharma, Ashu; Rahul, G R; Poduval, Soorya T; Shetty, Karunakar

    2012-07-01

    Crown and bridge have life span of many years but they fail for a number of reasons. Over the years, many devices have been designed to remove crowns and bridges from abutment teeth. While the removal of temporary crowns and bridges is usually very straightforward, the removal of a definitive cast crown with unknown cement is more challenging. Removal is often by destructive means. There are a number of circumstances, however, in which conservative disassembly would aid the practitioner in completing restorative/endodontic procedures. There are different mechanisms available to remove a failed crown or bridge. But there is no information published about the classification of available systems for crown and bridge removal. So it is logical to classify these systems into different groups which can help a clinician in choosing a particular type of system depending upon the clinical situation. The aim of this article is to provide a classification for various crown and bridge removal systems; describe how a number of systems work; and when and why they might be used. A PubMed search of English literature was conducted up to January 2010 using the terms: Crown and bridge removal, Crown and bridge disassembly, Crown and bridge failure. Additionally, the bibliographies of 3 previous reviews, their cross references as well as articles published in various journals like International Endodontic Journal, Journal of Endodontics and were manually searched. Key words:Crown and bridge removal, Crown and bridge disassembly, Crown and bridge failure. PMID:24558549

  19. Remediation: Higher Education's Bridge to Nowhere

    Science.gov (United States)

    Complete College America, 2012

    2012-01-01

    The intentions were noble. It was hoped that remediation programs would be an academic bridge from poor high school preparation to college readiness. Sadly, remediation has become instead higher education's "Bridge to Nowhere." This broken remedial bridge is travelled by some 1.7 million beginning students each year, most of whom will…

  20. Fatigue test of RC beams strengthened with prestressed CFLs

    Science.gov (United States)

    Guo, Xinyan; Huang, Peiyan; Liu, Guangwan; Xie, Jianhe

    2008-11-01

    Applying prestress to fiber reinforced polymer (FRP) can be used more efficiently since a greater portion energy of its tensile capacity is engaged. Based on carbon fiber laminate (CFL), fatigue tests are made to find out the fatigue behavior of reinforced concrete (RC) beams strengthened with prestressed CFL. The interfacial debonding is a main failure mode for RC beams strengthened with prestressed CFLs under the cyclic loading. Furthermore, it has been found that the stress value of CFLs decide whether the additional prestressing has a negative or positive effect on the fatigue behavior of the strengthened beam, and the excessive prestressing would reduce the fatigue life of the strengthened beam.

  1. China and ROK to Strengthen Cooperation in Environmental Issues

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The environment ministers of China and the Republic of Korea have agreed to strengthen bilateral cooperation in tackling regional environmental problems while promoting the development ofrelevant industries.

  2. Monolithic Approach to Oxide Dispersion Strengthened Aluminum Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Nassau Stern Company is investigating an approach for manufacturing oxide dispersion strengthened (ODS) aluminum in bulk rather than powder form. The approach...

  3. China Strengthens Macro-management in Petrochemical Branches

    Institute of Scientific and Technical Information of China (English)

    Xu Hui

    1997-01-01

    @@ China will strengthen macro-management in petrochemical branches in order to reasonably utilize the national petroleum resources and improve its competitive capacity in international refinery industrial market.

  4. Comparison between Modern Violin Bridge and Baroque Violin Bridge by Photoelastic Observation and Frequency Analysis

    Science.gov (United States)

    Matsutani, Akihiro

    2004-05-01

    A comparison between the modern bridge and the baroque bridge of the violin by photoelastic observation was carried out. The relationship between the stress part and the hole is symmetric in the modern and baroque bridges. The measured spectral envelopes of baroque bridges are similar to those of modern bridges in D- or G-strings, and have peaks at a frequency higher than those of modern bridges in E-string. The visualization method as used in this study may provide hints for the design of violin bridges.

  5. Mechanical Tests of Tetrafluoride Skateboard Plain Chloroprene Rubber Bearings of Highway Bridge under Freeze-Thaw Cycle Condition%冻融条件下公路桥梁四氟滑板氯丁橡胶支座力学性能试验

    Institute of Scientific and Technical Information of China (English)

    张延年; 单春红; 郑怡; 熊卫士; 沈小俊; 高飞

    2013-01-01

    目的 研究公路桥梁四氟滑板氯丁橡胶支座经过冻融循环后的承载力变化情况,为各项公路桥梁的施工提供依据.方法 将四氟滑板氯丁橡胶支座放入标准冻融试验箱中进行100次的冻融循环处理,而后进行轴心受压及抗剪试验.与标准试件进行对比分析,研究承载力、极限抗压和抗剪强度、竖向刚度、水平等效刚度、弹性模量等各项性能指标的变化.结果 四氟滑板氯丁橡胶支座经过冻融循环处理,更易发生脆性破坏,且钢板外露、裂缝等破坏现象较标准试件更为严重.经处理的四氟滑板氯丁橡胶支座的承载力、极限抗压及抗剪强度、抗压及抗剪弹性模量小于标准试件.结论 经冻融循环处理,公路桥梁四氟滑板氯丁橡胶支座的各项力学性能指标均明显降低,建议提高四氟滑板氯丁橡胶支座的最低使用温度,严格控制其温度适用范围,在寒冷地区尽量采用天然橡胶支座.%In order to provide the basis for the construction of the highway bridge,we study the changes of capacity of the tetrafluoride skateboard plain chloroprene rubber bearings of highway bridge under freeze-thaw cycle condition. The tetrafluoride skateboard plain chloroprene rubber bearings were processed 100 times by freeze-thaw cycle in the standard freeze-thaw chamber,and then the axial compression and shear tests were carried. Compared with the standard test pieces, studied the changes of the performance indicators in the bearing capacity,the ultimate compressive strength and shear strength,vertical stiffness,horizontal e-quivalent stiffness, and elastic modulus. The results show that the tetrafluoride skateboard plain chloroprene rubber bearings which after the freeze-thaw cycle were more prone to brittle failure,the steel plate exposed, cracks and other damage phenomenon were more serious than the standard test pieces. The bearing capacity, ultimate compressive strength and shear

  6. Strengthening Self-efficacy through Supportive Mentoring

    Science.gov (United States)

    Haacker, R.

    2015-12-01

    The geosciences have had a chronic problem of underrepresentation of students from diverse ethnic, cultural, gender and socio-economic backgrounds. As a community we need to strengthen our support of young scientists from all backgrounds to sustain their enthusiasm and ensure their success in our field. Investing in mentoring programs that empower students and young professionals is one of the best ways to do so. The Significant Opportunities in Atmospheric Research and Science (SOARS) program, now entering its 20th year, has successfully developed and tested several mentoring models. The personalized, caring and consistent support is one of the key elements of the program's success; since its inception, 90% of SOARS participants have entered graduate school, research or science related careers after graduation. Many of our alumni who are now faculty apply the same mentoring strategies to build self-esteem and perseverance in their students. This presentation will cover the design and implementation of our four mentoring strategies, and provide insights on potential challenges, training aspects and impact assessment. The mentoring strategies include: 1) Multi-faceted, long-term mentoring of undergraduate and graduate students from diverse backgrounds. 2) Empowering advanced students to serve as peer mentors and role models. 3) Training faculty and professional scientists from all backgrounds to become mentors who are aware of diversity issues. 4) Providing mentor training for partner programs and laboratories. All four strategies have contributed to the creation of a mentoring culture in the geosciences.

  7. Strengthening CERN’s international relations

    CERN Multimedia

    2010-01-01

    Council’s decision in June to open membership of CERN to the world in a clear and well-defined way means that it’s time to strengthen our international relations. Non-Member State interest, and participation, in CERN has been rising for many years, and with the LHC running smoothly that trend is continuing.   Furthermore, the long-term future of particle physics may well see Europe contributing to facilities in other regions of the world, with European participation coordinated through CERN. It was with these developments in mind that I established the External Relations Office under Felicitas Pauss at the start of my mandate last year. Council’s decision underlines the need for that office, and clarifies its liaison role of with Member and non-Member States. Clarity of function demands clarity of name, so from now on, the Office will be known as the Office for International Relations. It will continue to be headed by Felicitas Pauss. The Office’s main r...

  8. Ion implantations of oxide dispersion strengthened steels

    Science.gov (United States)

    Sojak, S.; Simeg Veternikova, J.; Slugen, V.; Petriska, M.; Stacho, M.

    2015-12-01

    This paper is focused on a study of radiation damage and thermal stability of high chromium oxide dispersion strengthened steel MA 956 (20% Cr), which belongs to the most perspective structural materials for the newest generation of nuclear reactors - Generation IV. The radiation damage was simulated by the implantation of hydrogen ions up to the depth of about 5 μm, which was performed at a linear accelerator owned by Slovak University of Technology. The ODS steel MA 956 was available for study in as-received state after different thermal treatments as well as in ions implanted state. Energy of the hydrogen ions chosen for the implantation was 800 keV and the implantation fluence of 6.24 × 1017 ions/cm2. The investigated specimens were measured by non-destructive technique Positron Annihilation Lifetime Spectroscopy in order to study the defect behavior after different thermal treatments in the as-received state and after the hydrogen ions implantation. Although, different resistance to defect production was observed in individual specimens of MA 956 during the irradiation, all implanted specimens contain larger defects than the ones in as-received state.

  9. Achievements to date in strengthened safeguards

    International Nuclear Information System (INIS)

    There is substantial progress in developing and implementing measures to strengthen the effectiveness and improve the efficiency of the Safeguards System. The measures comprise those to be implemented pursuant to the Agency's legal authority conferred by existing safeguards agreements as well as those to be implemented under the complementary legal authority conferred by Additional Protocols concluded on the basis of Document INFCIRC/540(Corrected). Activities on implementing measures under existing legal authority, particularly with respect to the evaluation of States' nuclear programmes, environmental sampling and the use of remote monitoring for safeguards purposes had been carried continuously ion the recent post. In 1998, additional protocols entered into force with four States (the Holy See, Jordan, New Zealand and Uzbekistan). Additional protocols with a further 27 States were approved by the Board and were awaiting ratification by the respective States. The additional protocol with Australia, which entered into force in December 1997, was being implemented following receipt of its Article 2 declaration. Agency consultations on concluding additional protocols take place with a number of States on a regular basis. As of 1 October 1999, Additional Protocols had been concluded and approved by the Board of Governors with a total of 45 States. Of these, Additional Protocols with 44 States had been signed and five had entered into force. (author)

  10. Nanotwinned fcc metals: Strengthening versus softening mechanisms

    Science.gov (United States)

    Stukowski, A.; Albe, K.; Farkas, D.

    2010-12-01

    The strengthening effect of twins in nanocrystalline metals has been reported both in experiment and simulation. While twins are mostly considered as effective barriers to dislocation slip transfer, they can also provide nucleation sites for dislocations or migrate during the deformation process, thereby contributing to plasticity. By comparing twinned and nontwinned samples, we study the effect of twins on the deformation behavior of nanocrystalline Cu and Pd using atomistic simulations. While Cu shows hardening due to the presence of twins, Pd shows the opposite effect. A quantitative dislocation analysis method is applied, which allows to analyze dislocation interactions with twin planes and grain boundaries and to measure dislocation, stacking fault, and twin-boundary densities as functions of strain. A statistical analysis of the occurring dislocation types provides direct evidence for the role of twin boundaries as effective sources for twinning dislocations, which are the reason for the observed softening in some fcc materials. In addition, we discuss how the orientation of the loading direction with respect to the twin planes affects the response of nanotwinned Cu and Pd.

  11. Micropolar crystal plasticity simulation of particle strengthening

    Science.gov (United States)

    Mayeur, J. R.; McDowell, D. L.

    2015-09-01

    The yield and work hardening behavior of a small-scale initial-boundary value problem involving dislocation plasticity in an idealized particle strengthened system is investigated using micropolar single crystal plasticity and is compared with results for the same problem from dislocation dynamics simulations. A micropolar single crystal is a work-conjugate higher-order continuum that treats the lattice rotations as generalized displacements, and supports couple stresses that are work-conjugate to the lattice torsion-curvature, leading to a non-symmetric Cauchy stress. The resolved skew-symmetric component of the Cauchy stress tensor results in slip system level kinematic hardening during heterogeneous deformation that depends on gradients of lattice torsion-curvature. The scale-dependent mechanical response of the micropolar single crystal is dictated both by energetic (higher-order elastic constants) and dissipative (plastic torsion-curvature) intrinsic material length scales. We show that the micropolar model captures essential details of the average stress-strain behavior predicted by discrete dislocation dynamics and of the cumulative slip and dislocation density fields predicted by statistical dislocation dynamics.

  12. Strengthened enforcement enhances marine sanctuary performance

    Directory of Open Access Journals (Sweden)

    Brendan P. Kelaher

    2015-01-01

    Full Text Available Marine sanctuaries are areas where the extraction of biota is not permitted. Although most marine sanctuaries have a positive influence on biotic communities, not all sanctuaries are meeting their conservation objectives. Amidst possible explanations (e.g., size, age and isolation, insufficient enforcement is often speculated to be a key driver of marine sanctuary underperformance. Despite this, there are few studies directly linking quantitative enforcement data to changes in biotic communities within marine sanctuaries. Here, we used an asymmetrical-BACI experimental design from 2006–2012 to test whether new enforcement initiatives enhanced abundances of target fishes and threatened species in an existing large sub-tropical marine sanctuary relative to areas open to fishing. Implementation of the new enforcement initiatives in 2010 was associated with a 201% increase in annual fine rate and a significant increase in target fish and elasmobranch abundance, as well as sightings of a critically-endangered shark, in the marine sanctuary relative to areas open to fishing. Overall, these results demonstrate that strengthening enforcement can have a rapid positive influence on target fish and perhaps threatened species in a subtropical marine sanctuary. From this, we contend that increased enforcement guided by risk-based compliance planning and operations may be a useful first step for improving underperforming marine sanctuaries.

  13. Accelarated urban landscape: from the Imperator bridge to the Constructor bridge

    OpenAIRE

    Nogueira, Adriana Dantas; Silva, Eder Donizeti da; Giacomet, Maria Clara

    2010-01-01

    This paper approaches the transformation of the urban landscape of Aracaju, a Brazilian Northeast city, located in the coast line, which has, in only 155 years, changed from the condition of village to a city-metropolis. The main case study involves the occurred transformations in a bordering landscape which can be seen from the main river of the city, in where two bridges are located. One of them has been inaugurated at the end of the 19 century and the other one at the beginning of the 2...

  14. Indian practice on estimation of scour around bridge piers—A comment

    Indian Academy of Sciences (India)

    Umesh C Kothyari

    2007-06-01

    Well-laid foundation is mostly provided in road and railway bridges in India over large and medium-sized rivers. The age-old Lacey–Inglis method is used for estimation of the design scour depth around bridge elements such as pier, abutment, guide bank, spur and groyene. Codal provisions are seen to produce too large a scour depth around bridge elements resulting in bridge sub-structures that lead to increased construction costs. Limitations that exist in the codes of practice are illustrated in this paper using examples. The methods recently developed for estimation of the scour are described. New railway and road bridges are required to be built in large numbers in the near future across several rivers to strengthen such infrastructure in the country. It is strongly felt that provisions in the existing codes of practice for determination of design scour depth require immediate review. The present paper provides a critical note on the practices followed in India for estimating the design scour depth.

  15. Comprehensive Real-Time Bridge Health Monitoring System of Tongtai Bridge

    OpenAIRE

    Lei Su-su; Gao Yong-tao; Pan Dan-guang

    2015-01-01

    Tongtai Bridge is the world’s largest suspension curve-girder-skew-arch bridge, which is located in Zhangjiakou, China. The understanding of mechanics characteristics is limited to such complex bridges, so it is necessary to establish reliable health monitoring system to investigate the static and dynamic responses and monitor the safety of the bridge. A comprehensive real-time bridge health monitoring system is establish, which includes four aspects: sensor system, data acquisition and trans...

  16. Design and behavior of reinforced concrete beams strengthened with fiber-reinforced plastics (FRP)

    Science.gov (United States)

    El-Mihilmy, Mahmoud Tharwat

    A comprehensive investigation of the design and behavior of reinforced concrete beams strengthened with externally bonded FRP laminates has been conducted. The study has confirmed the applicability of the strain compatibility method for calculating the increased ultimate moment capacity of the repaired beams. An upper limit to the amount of FRP that can be added to a specific structure was recommended to ensure ductile behavior. Design charts to facilitate calculations of the ultimate moment capacity for reinforced concrete beams strengthened with FRP laminates were developed. The results of a subsequent parametric investigation indicate that strengthening reinforced concrete beams with FRP laminates can enhance their ultimate capacity by as much as three times the original strength, especially for beams with a low steel ratio. It was also determined that, increasing the concrete compressive strength and the FRP modulus of elasticity increases the beam ultimate flexural capacity significantly; however, the repaired beams are less ductile than the pre-repaired concrete beams. During the course of the study, it had been noticed that the current ACI recommended method for calculating deflections for ordinary reinforced concrete beams does not render an accurate estimate for reinforced concrete beams strengthened with FRP laminates. A simplified equation for predicting the deflection of reinforced concrete beams repaired with FRP was developed and verified with comparisons to experimental results. The effectiveness of strengthening an existing bridge with externally bonded FRP laminates was investigated through comprehensive static and dynamic finite element analyses. The results of these analyses correlate well with field load test results. The repaired girders exhibited an average reduction in reinforcing steel stresses of 11 percent and an average reduction in midspan girder deflections of 9 percent. The results of the study also indicated that existing methods for

  17. Risk assessment study on bridge foundation in deep overlying stratum

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiangqun; Wang Jingguo; Liu Manhong

    2012-01-01

    Based on the analysis about the hydrogeological conditions and engineering geological conditions, this paper makes analysis on the possible risks of the deep overlying stratum foundation and establishes the risk evaluation index system during the foundation operating period. Such methods as analytic hierarchy process (AHP) , Delphi method and fuzzy comprehensive evaluation method are adopted to make the quantitative analysis on the risk factors and establish the risk judgment model. According to the actual engineering of Taizhou Bridge, the paper evaluates the risk of the foundation during the operating period at the condition of deep overlying stratum. The evaluation results can provide the reference for the risk management of the bridge foundation durin~ the ooerating period.

  18. New Concept for Durable Concrete Bridges

    OpenAIRE

    Damek, Marek

    2015-01-01

    This master’s thesis covers the design of a post-tensioned concrete bridge in Trondheim municipality in Norway, in collaboration with Statens vegvesen (SVV). The concept of the bridge is inspired by Egg-Graben-Brücke in Austria, which was designed and built without steel reinforcement in the bridge deck. The idea is to eliminate steel reinforcement which can corrode in the bridge deck. The total length of the bridge is 73 meters and it is divided into 3 spans. The crosssection ...

  19. Numerical simulation of wind effects on the temperature analysis of bridges

    Science.gov (United States)

    Chen, Lan; Li, Fengwu; Zhou, Linren; Ji, Jing

    2016-04-01

    Structural temperatures and their uneven distributions have significantly negative effects on bridges. It is very important to accurately calculate the structural temperatures. Structural temperatures are deeply affected by the surrounding weather conditions, and the environmental wind is a critical factor. In this study, the wind effects on the thermal analysis of bridges are investigated using numerical simulation. Frist, the traditional theory and method are briefly introduced to show the important effects of wind on structural heat transfer analysis. Then, a new approach is proposed to take account of the wind effects for temperature analysis of bridges. At last, numerical study based on the finite element transient heat transfer analysis of a box-girder bridge is carried out and discussed to verify the proposed method. The results indicate that the proposed method is more reasonable than the traditional methods. This method can be easily implemented in practice for temperature analysis of bridges.

  20. Computational design of donor-bridge-acceptor systems exhibiting pronounced quantum interference effects.

    Science.gov (United States)

    Gorczak, Natalie; Renaud, Nicolas; Galan, Elena; Eelkema, Rienk; Siebbeles, Laurens D A; Grozema, Ferdinand C

    2016-03-01

    Quantum interference is a well-known phenomenon that dictates charge transport properties of single molecule junctions. However, reports on quantum interference in donor-bridge-acceptor molecules are scarce. This might be due to the difficulties in meeting the conditions for the presence of quantum interference in a donor-bridge-acceptor system. The electronic coupling between the donor, bridge, and acceptor moieties must be weak in order to ensure localised initial and final states for charge transfer. Yet, it must be strong enough to allow all bridge orbitals to mediate charge transfer. We present the computational route to the design of a donor-bridge-acceptor molecule that features the right balance between these contradicting requirements and exhibits pronounced interference effects.

  1. Catastrophic model for stability analysis of high pile-column bridge pier

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    According to the engineering features of higher pile-column bridge pier in mountainous area, a clamped beam mechanical model was set up by synthetically analyzing the higher pile-column bridge pier buckling mechanism. Based on the catastrophe theory, the cusp catastrophe model of higher pile-column bridge pier was established by the determination of its potential function and bifurcation set equation, the necessary instability conditions of high pile-column bridge pier were deduced, and the determination method for column-buckling and lateral displacement of high pile-column bridge pier was derived. The comparison between the experimental and calculated results show that the calculated curves agree with testing curves and the method is reasonable and effective.

  2. Structural health monitoring of long-span suspension bridges using wavelet packet analysis

    Institute of Scientific and Technical Information of China (English)

    Ding Youliang; Li Aiqun

    2007-01-01

    During the service life of civil engineering structures such as long-span bridges, local damage at key positions may continually accumulate, and may finally result in their sudden failure. One core issue of global vibration-based health monitoring methods is to seek some damage indices that are sensitive to structural damage. This paper proposes an online structural health monitoring method for long-span suspension bridges using wavelet packet transform (WPT). The WPTbased method is based on the energy variations of structural ambient vibration responses decomposed using wavelet packet analysis. The main feature of this method is that the proposed wavelet packet energy spectrum (WPES) has the ability to detect structural damage from ambient vibration tests of a long-span suspension bridge. As an example application, the WPES-based health monitoring system is used on the Runyang Suspension Bridge under daily environmental conditions. The analysis reveals that changes in environmental temperature have a long-term influence on the WPES, while the effect of traffic loadings on the measured WPES of the bridge presents instantaneous changes because of the nonstationary properties of the loadings. The condition indication indices VD reflect the influences of environmental temperature on the dynamic properties of the Runyang Suspension Bridge. The field tests demonstrate that the proposed WPES-based condition indication index VD is a good candidate index for health monitoring of long-span suspension bridges under ambient excitations.

  3. Discrete fiber-reinforced polyurea systems for infrastructure strengthening and blast mitigation

    Science.gov (United States)

    Carey, Natalia L.

    available experimental results. A parametric analysis was conducted on four aged bridges in Missouri using an internal force equilibrium approach and material characterization results of the various DFRP systems to evaluate an increase in flexural capacity due to strengthening systems.

  4. Strengthening IAEA Safeguards for Research Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Reid, Bruce D.; Anzelon, George A.; Budlong-Sylvester, Kory

    2016-09-28

    During their December 10-11, 2013, workshop in Grenoble France, which focused on the history and future of safeguarding research reactors, the United States, France and the United Kingdom (UK) agreed to conduct a joint study exploring ways to strengthen the IAEA’s safeguards approach for declared research reactors. This decision was prompted by concerns about: 1) historical cases of non-compliance involving misuse (including the use of non-nuclear materials for production of neutron generators for weapons) and diversion that were discovered, in many cases, long after the violations took place and as part of broader pattern of undeclared activities in half a dozen countries; 2) the fact that, under the Safeguards Criteria, the IAEA inspects some reactors (e.g., those with power levels under 25 MWt) less than once per year; 3) the long-standing precedent of States using heavy water research reactors (HWRR) to produce plutonium for weapons programs; 4) the use of HEU fuel in some research reactors; and 5) various technical characteristics common to some types of research reactors that could provide an opportunity for potential proliferators to misuse the facility or divert material with low probability of detection by the IAEA. In some research reactors, for example, such characteristics include rapid on-line refueling, and a core design with room for such a large number of assemblies or targets that it is difficult to detect diversion or undeclared irradiation. In addition, infrastructure associated with research reactors, such as hot cells, where plutonium could be separated, could pose a safeguards challenge because, in some cases, they are not declared (because they are not located in the facility or because nuclear materials are not foreseen to be processed inside) and may not be accessible to inspectors in States without an Additional Protocol in force.

  5. Strengthening IAEA Safeguards for Research Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Reid, Bruce D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Anzelon, George A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Budlong-Sylvester, Kory [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-01

    During their December 10-11, 2013, workshop in Grenoble France, which focused on the history and future of safeguarding research reactors, the United States, France and the United Kingdom (UK) agreed to conduct a joint study exploring ways to strengthen the IAEA’s safeguards approach for declared research reactors. This decision was prompted by concerns about: 1) historical cases of non-compliance involving misuse (including the use of non-nuclear materials for production of neutron generators for weapons) and diversion that were discovered, in many cases, long after the violations took place and as part of broader pattern of undeclared activities in half a dozen countries; 2) the fact that, under the Safeguards Criteria, the IAEA inspects some reactors (e.g., those with power levels under 25 MWt) less than once per year; 3) the long-standing precedent of States using heavy water research reactors (HWRR) to produce plutonium for weapons programs; 4) the use of HEU fuel in some research reactors; and 5) various technical characteristics common to some types of research reactors that could provide an opportunity for potential proliferators to misuse the facility or divert material with low probability of detection by the IAEA. In some research reactors, for example, such characteristics include rapid on-line refueling, and a core design with room for such a large number of assemblies or targets that it is difficult to detect diversion or undeclared irradiation. In addition, infrastructure associated with research reactors, such as hot cells, where plutonium could be separated, could pose a safeguards challenge because, in some cases, they are not declared (because they are not located in the facility or because nuclear materials are not foreseen to be processed inside) and may not be accessible to inspectors in States without an Additional Protocol in force.

  6. Full Model Wind Tunnel Study on the Xia-Zhang Bridge Under Operation Stage

    Directory of Open Access Journals (Sweden)

    Ayad T. Saeed

    2010-01-01

    Full Text Available Problem statement: Long-span cable-stayed bridges under service and particular construction conditions are very susceptible to wind action due to their great flexibility, so the aerodynamic stability is becoming a major concern in the design and construction phrases. Cable-stayed bridges may exhibit wind-induced vibration phenomena such as flutter, buffeting and vortex oscillation under wind excitation. The study concentrated on the issues concerning the aerodynamic response of Xia-Zhang cable-stayed Bridge to make it safe and stable under wind action. Although there have been accumulating experience in the building of cable-stayed bridges and research on wind-resistant stability in Chinese Mainland, most of the research focuses on inland cable-stayed bridges or littoral ones of mid-length, but not on littoral ones whose main span is over 600 m. Therefore, wind-resistant performance research of north branch bridge of Xia-Zhang cross-sea Bridges is very necessary and important for its wind-resistant stability, safety and applicability in the operation condition. Approach: This study mainly presented the wind tunnel test program of the Xia-Zhang Bridge aeroelastic full model, including test method, test contents, test results and so on. Results: The test results contained Root Mean Square (RMS of accelerations and displacements as well as average values of displacements. Conclusion: The conclusions were as follows: (a In the uniform flow field, under the condition of entire bridge without rail may vibration divergence occur when α = 3°, V>122 m sec-1. (b No vortex-induced vibration with extreme amplitudes or static collapsing was detected in all the testing conditions. (c In the turbulent flow field, there were very obvious buffeting phenomena. Responses to turbulence are quite intense.

  7. Health Systems Analysis for Better Health System Strengthening

    OpenAIRE

    Berman, Peter; Bitran, Ricardo

    2011-01-01

    Health system strengthening and reform are often necessary actions to achieve better outcomes. The World Bank's 2007 strategy for health, nutrition, and population emphasizes the importance of health system strengthening for results. This paper proposes 'health systems analysis' as a distinct methodology that should be developed and practiced in the design of policies and programs for heal...

  8. Supporting Teachers, Strengthening Families: A Model Child Abuse Prevention Approach

    Science.gov (United States)

    Olson, Maril

    2007-01-01

    This article talks about a model child abuse prevention approach called, "Supporting Teachers, Strengthening Families." It is NAEYC's professional development initiative to help early childhood educators play leading roles in preventing child abuse and neglect through family strengthening efforts. It focuses on six strategies that high-quality…

  9. Strengthening of Concrete Structures with cement based bonded composites

    DEFF Research Database (Denmark)

    Täljsten, Björn; Blanksvärd, Thomas

    2008-01-01

    Due to demands on higher loads, degradation, re-construction etc. there is a constant need for repair or strengthening of existing concrete structures. Many varying methods exist to strengthen concrete structures, one such commonly used technique utilizes surface epoxy bonded FRPs (Fibre Reinforc...

  10. Full-bridge capacitive extensometer

    Science.gov (United States)

    Peters, Randall D.

    1993-08-01

    Capacitive transducers have proven to be very effective sensors of small displacements, because of inherent stability and noninvasive high resolution. The most versatile ones have been those of a differential type, in which two elements are altered in opposite directions in response to change of the system parameter being monitored. Oftentimes, this differential pair has been incorporated into a bridge circuit, which is a useful means for employing synchronous detection to improve signal to noise ratios. Unlike previous differential capacitive dilatometers which used only two active capacitors, the present sensor is a full-bridge type, which is well suited to measuring low-level thermal expansions. This analog sensor is capable of 0.1 μm resolution anywhere within a range of several centimeters, with a linearity of 0.1%. Its user friendly output can be put on a strip chart recorder or directed to a computer for sophisticated data analysis.

  11. Noise Considerations in Resistance Bridges

    DEFF Research Database (Denmark)

    Diamond, Joseph M.

    1963-01-01

    thermometry, where the noise in the unknown resistor will predominate strongly. An impedance step-up device (transformer or tuned circuit) is valuable in raising the bridge signal and noise level above the noise of the first amplifier tube. However, as the step-up ratio is increased, two counterfactors appear......, namely, noise in the loss resistance of the step-up device, and grid current noise. There is therefore an optimum step-up ratio, which has been found. The step-up device is permitted to have a different temperature from the unknown and standard resistors, to evaluate the advantage of cooling it....... With certain assumptions about the noise and grid current of the first tube it is found that the equivalent temperature of a unity ratio (Mueller) bridge used for liquid helium measurements may be 400°K....

  12. Stability of Axisymmetric Liquid Bridges

    CERN Document Server

    Rubinstein, Boris

    2016-01-01

    We study stability of axisymmetric liquid bridges between two axisymmetric solid bodies in the absence of gravity under arbitrary asymmetric perturbations which are expanded into a set of angular Fourier modes. We determine the stability region boundary for every angular mode in case of both fixed and free contact lines. Application of this approach allows us to demonstrate existence of stable convex nodoid menisci between two spheres.

  13. 2015 Bridge Inspection ERC Training

    OpenAIRE

    Dougherty, Merril

    2015-01-01

    This presentation will discuss recent changes to the County Bridge Inspection Program from the perspective of both the FHWA and INDOT. We will also discuss the responsibilities of the local public agency’s (LPA’s) employee in responsible charge (ERC) with respect to managing this program. As this course is a yearly requirement, all county ERCs are encouraged to attend. Pre-registering is strongly encouraged by e-mailing your contact information to .

  14. The Bridge Program - Participant Perspectives

    OpenAIRE

    Rönnqvist, Riitta; Hakonen, Anu; Vartiainen, Matti

    2015-01-01

    The Nokia Bridge Program was established in summer 2011 in order to "make the best of the restructuring: create meaningful opportunities for individuals and local economies impacted by workforce reductions" and to "assist individuals in re-employment". This document reports whether and how the program helped individuals avoid the known negative effects of job loss and find meaningful re-employment. The document also reports how affected employees formed perceptions about Nokia´s fairness and ...

  15. Inspection Strategies for Concrete Bridges

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1989-01-01

    In this paper an optimal inspection strategy for concrete bridges based on periodic routine and detailed inspections is presented. The failure mode considered is corrosion of the reinforcement due to chlorides. A simple modelling of the corrosion and of the inspection strategy is presented....... The optimal inspection strategy is determined from an optimization problem, where the design variables are time intervals between detailed inspections and the concrete cover. The strategy is illustrated on a simple structure, namely a reinforced concrete beam....

  16. Parabolic metamaterials and Dirac bridges

    Science.gov (United States)

    Colquitt, D. J.; Movchan, N. V.; Movchan, A. B.

    2016-10-01

    A new class of multi-scale structures, referred to as `parabolic metamaterials' is introduced and studied in this paper. For an elastic two-dimensional triangular lattice, we identify dynamic regimes, which corresponds to so-called `Dirac Bridges' on the dispersion surfaces. Such regimes lead to a highly localised and focussed unidirectional beam when the lattice is excited. We also show that the flexural rigidities of elastic ligaments are essential in establishing the `parabolic metamaterial' regimes.

  17. Severe ASR damaged concrete bridges

    DEFF Research Database (Denmark)

    Antonio Barbosa, Ricardo; Gustenhoff Hansen, Søren

    2015-01-01

    Technical University of Denmark (DTU) and University of Southern Denmark (SDU) have conducted several full-scale experiments with severe ASR deteriorated bridges. This paper presents few and preliminary results from both the shear tests and the measuring of the material properties. The shear test...... show that the shear capacity is almost unaffected of ASR despite significant reduction in compressive concrete strength. Furthermore, measurements show a significant tensile reinforcement strain developed due to ASR expansion....

  18. Use of Woven Fabrics for Strengthening of Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    Parthraj R. Puranik

    2014-03-01

    Full Text Available Worldwide, a great deal of research is currently being conducted concerning the use of fiber reinforced plastic wraps, laminates and sheets in the repair and strengthening of reinforced concrete (RC members. Fibre-reinforced polymer (FRP application is a very effective way to repair and strengthen structures that have become structurally weak over their life span. But the use of woven fabrics for strengthening RC members has not been much investigated. Woven fabrics though cannot provide compressive strength, but have a great potential to provide bending or tensile strength to RC beams. In the present investigation, three different woven fabrics were used to strengthen RC beams. The aim is to study the effectiveness of woven fabric in strengthening of RC beams and the effect of number of fabric layers on load carrying capacity of RC beams.

  19. Joining of Oxide Dispersion Strengthened Steels for Advanced Reactors

    Science.gov (United States)

    Baker, B. W.; Brewer, L. N.

    2014-12-01

    The design, manufacture, and experimental analysis of structural materials capable of operation in the high temperatures, corrosive environments, and radiation damage spectra of future reactor designs remain one of the key pacing items for advanced reactor designs. The most promising candidate structural materials are vanadium-based refractory alloys, silicon carbide composites and oxide dispersion strengthened steels. Of these, oxide dispersion strengthened steels are a likely near-term candidate to meet required demands. This paper reviews different variants of oxide dispersion strengthened steels and discusses their capability with regard to high-temperature strength, corrosion resistance, and radiation damage resistance. Additionally, joining of oxide dispersion strengthened steels, which has been cited as a limiting factor preventing their use, is addressed and reviewed. Specifically, friction stir welding of these steels is reviewed as a promising joining method for oxide dispersion strengthened steels.

  20. Halliburton Composite Bridge Plug Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Starbuck, J.M.; Luttrell, C.R.; Aramayo, G.

    2005-01-15

    The overall objectives of this CRADA were to assist Halliburton in analyzing a composite bridge plug and to determine why their original design was failing in the field. In Phase 1, finite element analyses were done on the original composite slip design and several alternative designs. The composite slip was the component in the bridge plug that was failing. The finite element code ABAQUS was used for these calculations and I-DEAS was used as the pre- and post-processor in the analyses. Several different designs and materials were analyzed and recommendations were made towards improving the design. In Phase 2, the objective was to develop finite element models that would accurately represent the deformations in the entire all-composite 4-1/2' diameter bridge plug assembly. The finite element code LS-DYNA was used and the results from this effort were intended to expand Halliburton's composite design and analysis capabilities with regard to developing future composite components for downhole tools. In addition to the finite element modeling, this effort involved the utilization of micromechanics to determine the necessary composite material properties that were needed as input for finite element codes.

  1. 乌溪江大桥方案设计%Scheme Design of Wuxijiang Bridge

    Institute of Scientific and Technical Information of China (English)

    张红星; 刘德宝; 余茂峰

    2011-01-01

    乌溪江大桥为浙江省遂昌县西南部跨越乌溪江水库的一座特大型桥梁.根据桥梁建设条件、景观、造价等因素,拟定了钢管混凝土拱桥、劲性骨架混凝土拱桥、连续刚构三种桥型方案.通过综合比较,确定钢管混凝土拱桥作为推荐桥型方案.%Wuxijiang Bridge is a long span bridge across Wuxijiang Reservoir in the southwest of Suichang County, Zhejiang Province. On the basis of the conditions of bridge construction, landscape, cost and other factors, three shemes of concrete-filled steel pipe arch bridge, concrete arch bridge with stiff skeleton, continuous rigid frame bridge are put forward. Through comprehensive comparison, concrete-filled steel pipe arch bridge is determined as recommended bridge type.

  2. Human-simulated intelligent control of train braking response of bridge with MRB

    Science.gov (United States)

    Li, Rui; Zhou, Hongli; Wu, Yueyuan; Wang, Xiaojie

    2016-04-01

    The urgent train braking could bring structural response menace to the bridge under passive control. Based on the analysis of breaking dynamics of a train-bridge vibration system, a magnetorheological elastomeric bearing (MRB) whose mechanical parameters are adjustable is designed, tested and modeled. A finite element method (FEM) is carried out to model and optimize a full scale vibration isolation system for railway bridge based on MRB. According to the model above, we also consider the effect of different braking stop positions on the vibration isolation system and classify the bridge longitudinal vibration characteristics into several cases. Because the train-bridge vibration isolation system has multiple vibration states and strongly coupling with nonlinear characteristics, a human-simulated intelligent control (HSIC) algorithm for isolating the bridge vibration under the impact of train braking is proposed, in which the peak shear force of pier top, the displacement of beam and the acceleration of beam are chosen as control goals. The simulation of longitudinal vibration control system under the condition of train braking is achieved by MATLAB. The results indicate that different braking stop positions significantly affect the vibration isolation system and the structural response is the most drastic when the train stops at the third cross-span. With the proposed HSIC smart isolation system, the displacement of bridge beam and peak shear force of pier top is reduced by 53.8% and 34.4%, respectively. Moreover, the acceleration of bridge beam is effectively controlled within limited range.

  3. 高性能桥梁钢A709M-HPS485wf动态再结晶临界条件的预测%Prediction on critical conditions of dynamic recrystallization for advanced bridge steel A709M-HPS485wf

    Institute of Scientific and Technical Information of China (English)

    禹宝军; 关小军; 赵健; 周兰聚; 王丽君; 刘千千

    2011-01-01

    Based on the stress-strain data collected from the single-pass isothermal compression tests, the critical conditions of dynamic recrystallization for advanced bridge steel A709M-HPS485wf at temperature ranging from 1273 K to 1423 K with strain rate from 0. 1 s-1 to 3 s-1 were investigated by using both Najafizadeh-Jonas work hardening rate-stress model and Cingara-McQueen flow stress model. The ratios of critical stress to peak stress ( σc/σp) and critical strain to peak strain ( εc/εp ) were determined. Furthermore, the quantitative relationships between critical conditions and deformation parameters were analyzed by linear regression.%通过单道次等温热压缩实验,分别采用Najafizadeh-Jonas加工硬化率模型和Cingara-McQueen流变应力模型研究了高性能桥梁钢A709 M-HPS485wf在温度为1273~1423K,应变速率为0.1~3s-1)变形条件下的奥氏体动态再结晶临界条件,获得了动态再结晶的临界应力与峰值应力比(σc/σp)及临界应变与峰值应变比(εc/εp),且由线性回归方法建立了该钢动态再结晶临界应力(σc)及临界应变(εc)与变形参数之间的定量关系.

  4. Nondestructive evaluation techniques for enhanced bridge inspection

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, G.; Benson, S.; Durbin, P.; Del Grande, N.; Haskins, J.; Brown, A.; Schneberk, D.

    1993-10-01

    Nondestructive evaluation of bridges is a critical aspect in the US aging infrastructure problem. For example in California there are 26,000 bridges, 3000 are made of steel, and of the steel bridges, 1000 are fracture critical. California Department of Transportation (Caltrans), Federal Highway Administration, and Lawrence Livermore National Laboratory (LLNL) are collaborating to develop and field NDE techniques to improve bridge inspections. We have demonstrated our NDE technologies on several bridge inspection applications. An early collaboration was to ultrasonically evaluate the steel pins in the E-9 pier on the San Francisco Bay Bridge. Following the Loma-Prieta earthquake in 1989 and the road way collapse at the E-9 pier, a complete nondestructive evaluation was conducted by Caltrans inspectors and several ultrasonic indications were noted. LLNL worked with Caltrans to help identify the source of these reflections. Another project was to digitally enhance high energy radiographs of bridge components such as cable end caps. We demonstrated our ability to improve the detection of corrosion and fiber breakage inside the end cap. An extension of this technology is limited view computer tomography (CT). We implemented our limited view CT software and produced cross-sectional views of bridge cables from digitized radiographic films. Most recently, we are developing dual band infrared imaging techniques to assess bridge decks for delaminations. We have demonstrated the potential of our NDE technology for enhancing the inspection of the country`s aging bridges.

  5. Strengthening Cost-Effectiveness Analysis for Public Health Policy.

    Science.gov (United States)

    Russell, Louise B; Sinha, Anushua

    2016-05-01

    Although the U.S. spends more on medical care than any country in the world, Americans live shorter lives than the citizens of other high-income countries. Many important opportunities to improve this record lie outside the health sector and involve improving the conditions in which Americans live and work: safe design and maintenance of roads, bridges, train tracks, and airports; control of environmental pollutants; occupational safety; healthy buildings; a safe and healthy food supply; safe manufacture of consumer products; a healthy social environment; and others. Faced with the overwhelming array of possibilities, U.S. decision makers need help identifying those that can contribute the most to health. Cost-effectiveness analysis is designed to serve that purpose, but has mainly been used to assess interventions within the health sector. This paper briefly reviews the objective of cost-effectiveness analysis and its methodologic evolution and discusses the issues that arise when it is used to evaluate interventions that fall outside the health sector under three headings: structuring the analysis, quantifying/measuring benefits and costs, and valuing benefits and costs.

  6. Experimental Study on Shear Lag Effect of Partial Cable-Stayed Bridge and Elasto-Plastic Seismic Analysis

    Institute of Scientific and Technical Information of China (English)

    WU Gao-feng; XU Hong; CHEN Xing-chong

    2005-01-01

    The project of Xiaoxihu Yellow River Bridge in Lanzhou is chosen as partial cable-stayed bridge. To get the shear lag effect and anti-earthquake performance of the actual bridge under various loading conditions, organic glass scaled model was adopted to have an experiment and a theory research at one time. The experiment result is the basically same as the theory calculation which proves the FEA method can well calculate shear lag effect and dynamical performance. As a result, because the bridge is located in a seismic area of 8 degree, an elasto-plastic seismic checking is performed by customized FEA program in this paper.

  7. Strengthening of defected beam–column joints using CFRP

    Directory of Open Access Journals (Sweden)

    Mohamed H. Mahmoud

    2014-01-01

    Full Text Available This paper presents an experimental study for the structural performance of reinforced concrete (RC exterior beam–column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP. The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam–column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity.

  8. Strengthening of defected beam-column joints using CFRP.

    Science.gov (United States)

    Mahmoud, Mohamed H; Afefy, Hamdy M; Kassem, Nesreen M; Fawzy, Tarek M

    2014-01-01

    This paper presents an experimental study for the structural performance of reinforced concrete (RC) exterior beam-column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP). The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam-column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM) CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity. PMID:25685473

  9. Strengthening of defected beam–column joints using CFRP

    Science.gov (United States)

    Mahmoud, Mohamed H.; Afefy, Hamdy M.; Kassem, Nesreen M.; Fawzy, Tarek M.

    2013-01-01

    This paper presents an experimental study for the structural performance of reinforced concrete (RC) exterior beam–column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP). The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam–column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM) CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity. PMID:25685473

  10. Design of unballasted track bridges on Beijing--Tianjin intercity railway%Design of unballasted track bridges on Beijing--Tianjin intercity railway

    Institute of Scientific and Technical Information of China (English)

    Sun Shuli; Zhang Wenjian; Wang Zhaohu; Su Wei; Wu Cailan; Bu Qinghao

    2011-01-01

    Beijing--Tianjin intercity railway is the first newly-built passenger dedicated line with operating speed of 350 km/h in our country. During design, new ideas of bridge construction were carried out to ensure the requirements of safety, comfort and stability of the train under high-speed condition. At the same time, concepts of environmental adaptability, service to transportation and comprehensive benefits were observed. On the whole line, long-bridge schemes were adopted and the most advanced technologies of unballasted track were utilized on bridges, the length of which accounts for 87.7 % of the total line. The success of design and construction of the bridges on this rail has accu- mulated valuable experience for high-speed railway construction on a large scale in the future, and made it a marking, demonstrating, and model project to follow.

  11. Zinc Oxide Nanorod Based Ultraviolet Detectors with Wheatstone Bridge Design

    Science.gov (United States)

    Vasudevan, Arun

    This research work, for the first time, investigated metal semiconductor-metal (MSM) zine oxide (ZnO) nanorod based ultra-violet (UV) detectors having a Wheatstone bridge design with a high responsivity at room temperature and above, as well as a responsivity that was largely independent of the change in ambient conditions. The ZnO nanorods which acted as the sensing element of the detector were grown by a chemical growth technique. Studies were conducted to determine the effects on ZnO nanorod properties by varying the concentration of the chemicals used for the rod growth. These studies showed how the rod diameter and the deposition of ZnO nanorods from the solution was controlled by varying the concentration of the chemicals used for the rod growth. Conventional MSM UV detectors were fabricated with ZnO nanorods grown under optimized conditions to determine the dependence of UV response on electrode dimension and rod dimension. These studies gave insights into the dependence of UV response on the width of the electrode, spacing between the electrodes, density of the rod growth, and length and diameter of the rods. The UV responsivity was affected by varying the number of times the seed layer was spin coated, by varying the spin speed of seed layer coating and by varying the annealing temperature of the seed and rod. Based on these studies, optimum conditions for the fabrication of Wheatstone bridge UV ZnO nanorod detectors were determined. The Wheatstone bridge ZnO nanorod UV detectors were fabricated in three different configurations, namely, symmetric, asymmetric, and quasi-symmetric. The transient responses of the symmetric, asymmetric and quasi-symmetric configurations at room temperature and above showed how the response stability differed. At high temperature the responsivity of quasi-symmetric Wheatstone bridge detector configuration did not drop after saturation and the responsivity drifted by 17% to 25% from the room temperature response

  12. Rejection of Power Supply Noise in Wheatstone Bridges : Application to Piezoresistive MEMS

    CERN Document Server

    Boujamaa, El Mehdi; Mailly, Frédérick; Latorre, Laurent; Nouet, Pascal

    2008-01-01

    This paper deals with the design of MEMS using piezoresistivity as transduction principle. It is demonstrated that when the sensor topology doesn't allow a perfect matching of strain gauges, the resolution is limited by the ability of the conditioning circuit (typically a Wheatstone bridge) to reject power supply noise. As this ability is strongly reduced when an offset voltage is present at the output of the bridge, the proposed architecture implements a feedback loop to control MOS transistors inserted in the Wheatstone bridge to compensate resistor mismatches. This feedback exhibits a very good offset cancellation and therefore a better resolution is achieved.

  13. An Evaluation of the Durability of Polymer Concrete Bonds to Aluminum Bridge Decks

    OpenAIRE

    Zhang, Huiying

    1999-01-01

    The objective of this study is to evaluate the bond durability of an epoxy-based polymer concrete wearing surface bonded to aluminum bridge decks. In the bridge design, an aluminum alloy bridge deck is used with a polymer concrete wearing surface. A modified mixed mode flexure fracture test was developed to assess the bond durability of specimens aged in the following environmental conditionings: 30°C [86°F], 98% RH; 45°C [113°F], 98% RH; 60°C [140°F], 98% RH; freezing and thawing; sal...

  14. Research and application of non-clay low damage temporary bridging drilling/completion fluids system

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Following the basic theory of protecting gas-reservoirs from damage with the temporary bridging technology,inert calcium carbonate (CaCO3) particles,whose diameter is consistent with the size of pores or apertures in the reservoir,were selected as the bridging agent,and modified resolvable starch was selected as filtration loss reducing particles to form the non-clay low damage temporary bridging drilling/completion fluids system (NLTDFS). Under the simulated condition of the well bottom during real drillin...

  15. An evaluation of iced bridge hanger vibrations through wind tunnel testing and quasi-steady theory

    DEFF Research Database (Denmark)

    Gjelstrup, Henrik; Georgakis, Christos T.; Larsen, A.

    2012-01-01

    Bridge hanger vibrations have been reported under icy conditions. In this paper, the results from a series of static and dynamic wind tunnel tests on a circular cylinder representing a bridge hanger with simulated thin ice accretions are presented. The experiments focus on ice accretions produced...... roughness is also examined. The static force coefficients are used to predict parameter regions where aerodynamic instability of the iced bridge hanger might be expected to occur, through use of an adapted theoretical 3- DOF quasi-steady galloping instability model, which accounts for sectional axial......-indicating the possible inability of quasi-steady theory to fully predict these vibrational instabilities....

  16. Slender reinforced concrete columns strengthened with fibre reinforced polymers

    Science.gov (United States)

    Gajdošová, K.; Bilčík, J.

    2011-06-01

    The requirement for a long life with relatively low maintenance costs relates to the use of building structures. Even though the structure is correctly designed, constructed and maintained, the need for extensions of its lifetime can appear. The preservation of the original structure with a higher level of resistance or reliability is enabled by strengthening. Conventional materials are replaced by progressive composites - mainly carbon fibre reinforced polymers (CFRP). They are used for strengthening reinforced concrete columns in two ways: added reinforcement in the form of CFRP strips in grooves or CFRP sheet confinement and eventually their combination. This paper presents the effect of the mentioned strengthening methods on slender reinforced concrete columns.

  17. FIRE PROTECTION OF TIMBER STRUCTURES STRENGTHENED WITH FRP MATERIALS

    Directory of Open Access Journals (Sweden)

    Radek Zigler

    2015-12-01

    Full Text Available Modern, progressive methods of structures’ strengthening based on the use of composite materials composed of high strength fibers (carbon, glass, aramid or basalt and matrices based on epoxy resins brings, among many indisputable advantages (low weight, high effectiveness, easy application etc. also some disadvantages. One of the major disadvantages is a low fire resistance of these materials due to the low glass transition temperature Tg of the resin used. Based on an extensive research of strengthening of historic structures with FRP materials [1], the article outlines possible approaches to this problem, especially while strengthening timber load- bearing structures of historic buildings.

  18. Ukraine : Soil Fertility to Strengthen Climate Resilience

    OpenAIRE

    Fileccia, Turi; Guadagni, Maurizio; Hovhera, Vasyl; Bernoux, MARTIAL,

    2014-01-01

    Ukraine is renowned as the breadbasket of Europe thanks to its black soils ( Chernozem black because of the high organic matter content) which offer exceptional agronomic conditions. One-third of the worldwide stock of the fertile black soils, which cover more than half of Ukraine s arable land, a large variety of climatic zones, and favourable temperature and moisture regimes, offers att...

  19. Using Songs to Strengthen Reading Fluency

    Science.gov (United States)

    Patel, Pooja; Laud, Leslie E.

    2007-01-01

    This study evaluated the use of songs with lyrics to increase the reading fluency rates of three middle school students. In the first condition, students heard fluent reading modeled, read regular passages repeatedly and then received feedback on accuracy, phrasing and expression. After that, students received the same intervention, except that…

  20. A State-of-the-Art Review on Fatigue Life Assessment of Steel Bridges

    Directory of Open Access Journals (Sweden)

    X. W. Ye

    2014-01-01

    Full Text Available Fatigue is among the most critical forms of damage potentially occurring in steel bridges, while accurate assessment or prediction of the fatigue damage status as well as the remaining fatigue life of steel bridges is still a challenging and unsolved issue. There have been numerous investigations on the fatigue damage evaluation and life prediction of steel bridges by use of deterministic or probabilistic methods. The purpose of this review is devoted to presenting a summary on the development history and current status of fatigue condition assessment of steel bridges, containing basic aspects of fatigue, classical fatigue analysis methods, data-driven fatigue life assessment, and reliability-based fatigue condition assessment.

  1. Integrating Real-time Bridge Scouring Monitoring System with Mobile Location-Based Services

    Directory of Open Access Journals (Sweden)

    Yung-Bin Lin

    2011-12-01

    Full Text Available Typhoons and torrential rains not only erode river beds and coasts and damage river-crossing structures, but also affect the geomorphology and topography of rivers and coasts. Additionally, typhoons and torrential rains cause debris flows and flooding in metropolitan areas and threaten the safety of people’s lives and properties. Disaster prevention and reduction of damage caused by typhoons and torrential rains have always been a crucial task of government agencies. Bridges in Taiwan are generally old and have insufficient shock resistance; some bridge foundations are also severely eroded and exposed. Because of global climate changes in recent years, rainfall has become comparatively heavy and rapid. Furthermore, the soil in mountain areas has softened because of factors such as earthquakes or human developments. Debris rushes down with rain every time a torrential rain strikes, significantly impacting the safety of bridges downstream. Although government bridge management units have made budget plans to progressively renovate dangerous old bridges, these bridges are still being use for traffic and transportation. These dangerous old bridges pose a serious threat to the safety of people when an earthquake, typhoon, or flood occurs. During typhoons and floods, increased water levels and changes of the scouring depths have dramatic effects on the safety of bridges. The bridge maintenance unit currently uses the water level and water flow conditions as references when determining whether to close a bridge; however, this is not a good permanent solution. A bridge scour monitoring and warning system that is stable, reliable, and operates normally under flood attacks is required for on-site installation and verification. In recent years, the applied technologies of smart phones have expanded beyond entertainment and communication. Mobile communications are used to transmit relevant information to bridge maintenance and management units and road

  2. Spitzer view of massive star formation in the tidally stripped Magellanic Bridge

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.-H. Rosie; Indebetouw, Remy [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Muller, Erik; Kawamura, Akiko [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Gordon, Karl D.; Meixner, Margaret; Seale, Jonathan P.; Shiao, Bernie [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Sewiło, Marta [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Whitney, Barbara A.; Meade, Marilyn R. [Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States); Fukui, Yasuo [Department of Astrophysics, Nagoya University, Furocho, Chikusaku, Nagoya 464-8602 (Japan); Madden, Suzanne C. [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Oliveira, Joana M.; Van Loon, Jacco Th. [Astrophysics Group, Lennard-Jones Laboratories, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom); Robitaille, Thomas P., E-mail: rchen@mpifr-bonn.mpg.de [Max Planck Institute for Astronomy, D-69117 Heidelberg (Germany)

    2014-04-20

    The Magellanic Bridge is the nearest low-metallicity, tidally stripped environment, offering a unique high-resolution view of physical conditions in merging and forming galaxies. In this paper, we present an analysis of candidate massive young stellar objects (YSOs), i.e., in situ, current massive star formation (MSF) in the Bridge using Spitzer mid-IR and complementary optical and near-IR photometry. While we definitely find YSOs in the Bridge, the most massive are ∼10 M {sub ☉}, <<45 M {sub ☉} found in the LMC. The intensity of MSF in the Bridge also appears to be decreasing, as the most massive YSOs are less massive than those formed in the past. To investigate environmental effects on MSF, we have compared properties of massive YSOs in the Bridge to those in the LMC. First, YSOs in the Bridge are apparently less embedded than in the LMC: 81% of Bridge YSOs show optical counterparts, compared to only 56% of LMC sources with the same range of mass, circumstellar dust mass, and line-of-sight extinction. Circumstellar envelopes are evidently more porous or clumpy in the Bridge's low-metallicity environment. Second, we have used whole samples of YSOs in the LMC and the Bridge to estimate the probability of finding YSOs at a given H I column density, N(H I). We found that the LMC has ∼3 × higher probability than the Bridge for N(H I) >12 × 10{sup 20} cm{sup –2}, but the trend reverses at lower N(H I). Investigating whether this lower efficiency relative to H I is due to less efficient molecular cloud formation or to less efficient cloud collapse, or to both, will require sensitive molecular gas observations.

  3. REPORT: BioMedBridges standards workshop

    OpenAIRE

    Conte, Nathalie; Hancocks, Tom; Suhr, Stephanie

    2014-01-01

    This workshop, co-organized by BioMedBridges WP3 and 12, was held on 24-25 June and hosted by BioMedBridges partners at VUMC in Amsterdam. Attendees included BioMedBridges personnel, members from the ESFRI BMS research infrastructures and invited external experts from existing standards organisations. The following aspects of data standardisation were explored: Defining entity identifiers and identifiers best practice Development of a Meta models and Mappings Registry for bio...

  4. Bridge engineering handbook construction and maintenance

    CERN Document Server

    Chen, Wai-Fah

    2014-01-01

    Over 140 experts, 14 countries, and 89 chapters are represented in the second edition of the Bridge Engineering Handbook. This extensive collection highlights bridge engineering specimens from around the world, contains detailed information on bridge engineering, and thoroughly explains the concepts and practical applications surrounding the subject.Published in five books: Fundamentals, Superstructure Design, Substructure Design, Seismic Design, and Construction and Maintenance, this new edition provides numerous worked-out examples that give readers step-by-step design procedures, includes c

  5. Markovian Bridges: Weak continuity and pathwise constructions

    OpenAIRE

    Chaumont, Loïc; Uribe Bravo, Gerónimo

    2009-01-01

    A Markovian bridge is a probability measure taken from a disintegration of the law of an initial part of the path of a Markov process given its terminal value. As such, Markovian bridges admit a natural parameterization in terms of the state space of the process. In the context of Feller processes with continuous transition densities, we construct by weak convergence considerations the only versions of Markovian bridges which are weakly continuous with respect to their parameter. We use this ...

  6. Life Cycle Assessment of a Norwegian Bridge

    OpenAIRE

    Dequidt, Thomas Charles Edouard

    2012-01-01

    Life cycle assessment (LCA) methodology aims at evaluating the environmental impacts of a product or system from a holistic approach. In this methodology, all life cycle phases of the product are identified and assessed, from the raw material acquisition to the end-of-life phase. This master thesis is dealing with the LCA of a Norwegian bridge. First, a literature review is realized by going through 14 bridge LCA references. Then, a detailed description of bridge LCA methodology ...

  7. Bridge Engineering-Oriented Parametric Model

    Institute of Scientific and Technical Information of China (English)

    周凌远; 李乔

    2004-01-01

    A new model is proposed to improve the efficiency of structural modeling. In this model, the bridge structural components are expressed with component description, parametric description and geometric description in a software system. This model provides both convenience and flexibility for users in structural modeling process. The object-oriented method is applied in the model implementation. A bridge analysis preprocessor is developed on the basis of this model. It provides an effective way for bridge modeling.

  8. Dynamics and Statics of Nonaxisymmetric Liquid Bridges

    Science.gov (United States)

    Alexander, J. Iwan D.; Resnick, Andrew H.; Slobozhanin, L. A.

    1996-01-01

    Theoretical and experimental investigation of the stability of nonaxisymmetric and nonaxisymmetric bridges contained between equal and unequal radii disks as a function of Bond and Weber number with emphasis on the transition from unstable axisymmetric to stable nonaxisymmetric shapes, are conducted. Numerical analysis of the stability of nonaxisymmetric bridges between unequal disks for various orientations of the gravity vector is performed. Experimental and theoretical investigation of large (nonaxisymmetric) oscillations and breaking of liquid bridges are also conducted.

  9. Maximal liquid bridges between horizontal cylinders

    OpenAIRE

    Cooray, Himantha; Huppert, Herbert E.; Neufeld, Jerome A

    2016-01-01

    We investigate two-dimensional liquid bridges trapped between pairs of identical horizontal cylinders. The cylinders support forces due to surface tension and hydrostatic pressure which balance the weight of the liquid. The shape of the liquid bridge is determined by analytically solving the nonlinear Laplace-Young equation. Parameters that maximize the trapping capacity (defined as the cross-sectional area of the liquid bridge) are then determined. The results show that these parameters can ...

  10. Axisymmetric long liquid bridges stability and resonances

    OpenAIRE

    Meseguer Ruiz, José; Sanz Andres, Angel Pedro; Perales Perales, José Manuel

    1990-01-01

    In this paper mathematical expressions for minimum-volume stability limits and resonance frequencies of axisymmetric long liquid bridges are presented. These expressions are valid for a wide range of liquid bridge configurations, accounting for ef-fects like unequal disks and axial microgravity in the case of minimum-volume stability limits,and unequal disks, axial microgravity,non-zero viscosity and liquid bridge volume different from the cylindrical one in the case of resonance frequenc...

  11. Analysis of the strengthening and toughening of a biomaterial interface

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the transmission electron micrographs of nacre, the existence of mineral bridges in the organic matrix interface is confirmed. It is proposed that the microarchitecture of nacre should be considered as a “brick-bridge-mortar” (BBM) arrangement rather than traditional “brick and mortar” (BM) one. Experiments and analyses indicate that the mineral bridges effectively affect the strength and toughness of the interfaces in nacre. Comparison with a laminated composite with BM structure, SiC/BN, shows that the pattern of the crack extension and the toughening mechanism of the two materials are different. This reveals that the mineral bridges play a key role in the toughening mechanisms of nacre, which gives a conceptual guidance in material synthesis.

  12. Crystal growth under bridge foundation

    OpenAIRE

    Ramon Tarragona, Anna; Alonso Pérez de Agreda, Eduardo

    2012-01-01

    W(H)YDOC PhD Prize 2012, durant el 4th International Workshop of Young Doctors in Geomechanics W(H)YDOC 2012. A high-speed railway viaduct experienced a sustained heave at high rates after its construction. The pillars of the bridge are founded on an Eocene hard anhydritic-gypsiferous claystone by means of massive foundations. Field investigations identified an active layer below the piles’ tips where expansions occur as a result of gypsum crystal growth in discontinuities from supersatura...

  13. Nanoclusters a bridge across disciplines

    CERN Document Server

    Jena, Purusottam

    2010-01-01

    This comprehensive book on Nanoclusters comprises sixteen authoritative chapters written by leading researchers in the field. It provides insight into topics that are currently at the cutting edge of cluster science, with the main focus on metal and metal compound systems that are of particular interest in materials science, and also on aspects related to biology and medicine. While there are numerous books on clusters, the focus on clusters as a bridge across disciplines sets this book apart from others. Delivers cutting edge coverage of cluster science Covers a broad range of topics in

  14. Family Medicine: Bridge to Life.

    Science.gov (United States)

    Luz, Clare

    2016-01-01

    Reflecting on the suicide of a close friend, this essay explores what comprises, and inspires a will to live, and how those in Family Medicine can address suicide risk even in the face of debilitating or terminal illness. Research indicates that the will to live is a measurable indicator of general well-being, distinct from depression, and an important predictor of a person's motivation to "hold on to life". As such, understanding what is at the heart of a desire to live should alter clinical practice. This essay offers ideas for ways in which to create bridges for patients that could help sustain life.

  15. A bridge to advanced mathematics

    CERN Document Server

    Sentilles, Dennis

    2011-01-01

    This helpful workbook-style ""bridge"" book introduces students to the foundations of advanced mathematics, spanning the gap between a practically oriented calculus sequence and subsequent courses in algebra and analysis with a more theoretical slant. Part 1 focuses on logic and number systems, providing the most basic tools, examples, and motivation for the manner, method, and concerns of higher mathematics. Part 2 covers sets, relations, functions, infinite sets, and mathematical proofs and reasoning. Author Dennis Sentilles also discusses the history and development of mathematics as well a

  16. Myocardial bridges: morphological and functional aspects.

    OpenAIRE

    A.G. Ferreira; Trotter, S E; König, B; Décourt, L V; Fox, K; Olsen, E G

    1991-01-01

    OBJECTIVE--To assess the arrangement of myocardial bridges. DESIGN--A necropsy study of 90 consecutive hearts (56 male, 34 female). RESULTS--Myocardial bridges, either single or multiple, were seen in 50 (55.6%) of the 90 hearts. The left anterior descending artery was the most commonly affected artery. Thirty five of the 50 hearts which contained in total 41 muscle bridges were dissected further with a magnifying glass. Two different types of muscle bridges could be identified. Thirty one of...

  17. A data management infrastructure for bridge monitoring

    Science.gov (United States)

    Jeong, Seongwoon; Byun, Jaewook; Kim, Daeyoung; Sohn, Hoon; Bae, In Hwan; Law, Kincho H.

    2015-04-01

    This paper discusses a data management infrastructure framework for bridge monitoring applications. As sensor technologies mature and become economically affordable, their deployment for bridge monitoring will continue to grow. Data management becomes a critical issue not only for storing the sensor data but also for integrating with the bridge model to support other functions, such as management, maintenance and inspection. The focus of this study is on the effective data management of bridge information and sensor data, which is crucial to structural health monitoring and life cycle management of bridge structures. We review the state-of-the-art of bridge information modeling and sensor data management, and propose a data management framework for bridge monitoring based on NoSQL database technologies that have been shown useful in handling high volume, time-series data and to flexibly deal with unstructured data schema. Specifically, Apache Cassandra and Mongo DB are deployed for the prototype implementation of the framework. This paper describes the database design for an XML-based Bridge Information Modeling (BrIM) schema, and the representation of sensor data using Sensor Model Language (SensorML). The proposed prototype data management framework is validated using data collected from the Yeongjong Bridge in Incheon, Korea.

  18. Review of Energy Harvesters Utilizing Bridge Vibrations

    Directory of Open Access Journals (Sweden)

    Farid Ullah Khan

    2016-01-01

    Full Text Available For health monitoring of bridges, wireless acceleration sensor nodes (WASNs are normally used. In bridge environment, several forms of energy are available for operating WASNs that include wind, solar, acoustic, and vibration energy. However, only bridge vibration has the tendency to be utilized for embedded WASNs application in bridge structures. This paper reports on the recent advancements in the area of vibration energy harvesters (VEHs utilizing bridge oscillations. The bridge vibration is narrowband (1 to 40 Hz with low acceleration levels (0.01 to 3.8 g. For utilization of bridge vibration, electromagnetic based vibration energy harvesters (EM-VEHs and piezoelectric based vibration energy harvesters (PE-VEHs have been developed. The power generation of the reported EM-VEHs is in the range from 0.7 to 1450000 μW. However, the power production by the developed PE-VEHs ranges from 0.6 to 7700 μW. The overall size of most of the bridge VEHs is quite comparable and is in mesoscale. The resonant frequencies of EM-VEHs are on the lower side (0.13 to 27 Hz in comparison to PE-VEHs (1 to 120 Hz. The power densities reported for these bridge VEHs range from 0.01 to 9539.5 μW/cm3 and are quite enough to operate most of the commercial WASNs.

  19. Gust loading on streamlined bridge decks

    DEFF Research Database (Denmark)

    Larose, Guy; Mann, Jakob

    1998-01-01

    The current analytical description of the buffeting action of wind on long-span bridges is based on the strip assumption. However, recent experiments on closed-box girder bridge decks have shown that this assumption is not valid and is the source of an important part of the error margin of the an......The current analytical description of the buffeting action of wind on long-span bridges is based on the strip assumption. However, recent experiments on closed-box girder bridge decks have shown that this assumption is not valid and is the source of an important part of the error margin...

  20. Vital stability of territory: the contents and ways of strengthening

    Directory of Open Access Journals (Sweden)

    Vladimir Stepanovich Bochko

    2013-09-01

    Full Text Available The paper shows that the traditional outlook on development of territories as the process of alignment of their socio-economic development with the help of external influences should be advanced and replaced by a new vision. The purpose of the work is the definition of the basic rules of the concept of vital stability of territories. The creation by the local population of the riches and well being by expansion of manufacturing industry on the basis of the use of intelligence — technological and moral — ethical factors are shown as the basic contents of the offered concept. A consequence of such approach is the growing feedback of made expenses, as technologically completed production will be realized but not raw material or semi-finished item. Only the differentiation industrial development of the territory is capable to deduce it from a condition of poverty and depression. The understanding of development of the territory as creation of conditions for growth of people’s wellbeing and formation of a man as a person is opened. The accent of the attention on the promotion of a man not only as the purpose of transformation of territory, but also as the factor of its safe development through an increase of his or her intellectual and spiritual levels is made. The measures and instruction on innovation to the strengthening of vital stability of territories are offered. The separate results of research were used at the prolongation of the Plan for strategic development of Yekaterinburg up to 2020. Authorities of territories at the formation of their development strategy can apply the new offered rules.

  1. Chemically modified heparins inhibit fibrinogen-bridged indirect adhesion between tumor cells and platelets

    OpenAIRE

    Zheng, Sheng; Liu, Yan; Jiao, Yang; Min WEI; ZENG, XIANLU

    2011-01-01

    The interaction between platelets and tumor cells is critical for the hematogenous metastasis of tumor cells. We recently reported that fibrinogen was capable of bridging and enhancing the interaction of platelets and tumor cells under conditions of physical shear force. In the present study, we aimed to detect the effects of 8 chemically modified heparins on the binding of fibrinogen to platelets or tumor cells using flow cytometry assays, as well as the fibrinogen-bridged adhesion of platel...

  2. Increasing the Capacity of Existing Bridges by Using Unbonded Prestressing Technology: A Case Study

    OpenAIRE

    Antonino Recupero; Nino Spinella; Piero Colajanni; Cosimo D. Scilipoti

    2014-01-01

    External posttensioning or unbonded prestressing was found to be a powerful tool for retrofitting and for increasing the life extension of existing structures. Since the 1950s, this technique of reinforcement was applied with success to bridge structures in many countries, and was found to provide an efficient and economic solution for a wide range of bridge types and conditions. Unbonded prestressing is defined as a system in which the post-tensioning tendons or bars are located outside the ...

  3. An application of Auto-regressive (AR) model in predicting Aeroelastic Effectsof Lekki Cable Stayed Bridge

    OpenAIRE

    Hassan Abba Musa; Dr. A. Mohammed

    2016-01-01

    In current practice, the predictive analysis of stochastic problems encompasses a variety of statistical techniques from modeling, machine, and data mining that analyse current and historical facts to make predictions about future. Therefore, this research uses an AR Model whose codes are incorporated in the MATLAB software to predict possible aero-elastic effects of Lekki Bridge based on its existing parametric data and the conditions around the bridge. It was seen that, the fluc...

  4. Strengthen Credit Risk Management of SMEs

    Institute of Scientific and Technical Information of China (English)

    Bin Qiang

    2009-01-01

    @@ Definition What kind of enterprises can be called SMEs - small and medium enterprises? What is the standard? According to the standards written in the Law of Small and Medium Enterprises, in industry, small and medium enterprises must accord with the following conditions: the number of employees is under 2,000, or the amount of total sale is under 0.3 billion yuan, or the total assets are under 0.4billion yuan. In addition, medium enterprises must in the meantime satisfy the following conditions: the number of employees is above 300, the number of total sale is above 30 million yuan, and the total assets are above 40 million yuan. And the rest enterprises are small enterprises.

  5. Creep modelling of particle strengthened steels

    OpenAIRE

    Magnusson, Hans

    2007-01-01

    Materials used in thermal power plants have to resist creep deformation for time periods up to 30 years. Material evaluation is typically based on creep testing with a maximum duration of a few years. This information is used as input when empirically deriving models for creep. These kinds of models are of limited use when considering service conditions or compositions different from those in the experiments. In order to provide a more general model for creep, the mechanisms that give creep s...

  6. Bipedal tool use strengthens chimpanzee hand preferences

    OpenAIRE

    Braccini, Stephanie; Lambeth, Susan; Schapiro, Steve; Fitch, W. Tecumseh

    2010-01-01

    The degree to which non-human primate behavior is lateralized, at either individual or population levels, remains controversial. We investigated the relationship between hand preference and posture during tool use in chimpanzees (Pan troglodytes) during bipedal tool use. We experimentally induced tool use in a supported bipedal posture, an unsupported bipedal posture, and a seated posture. Neither bipedal tool use nor these supported conditions have been previously evaluated in apes. The hypo...

  7. Monte Carlo simulation of liquid bridge rupture: Application to lung physiology

    Science.gov (United States)

    Alencar, Adriano M.; Wolfe, Elie; Buldyrev, Sergey V.

    2006-08-01

    In the course of certain lung diseases, the surface properties and the amount of fluids coating the airways changes and liquid bridges may form in the small airways blocking the flow of air, impairing gas exchange. During inhalation, these liquid bridges may rupture due to mechanical instability and emit a discrete sound event called pulmonary crackle, which can be heard using a simple stethoscope. We hypothesize that this sound is a result of the acoustical release of energy that had been stored in the surface of liquid bridges prior to its rupture. We develop a lattice gas model capable of describing these phenomena. As a step toward modeling this process, we address a simpler but related problem, that of a liquid bridge between two planar surfaces. This problem has been analytically solved and we use this solution as a validation of the lattice gas model of the liquid bridge rupture. Specifically, we determine the surface free energy and critical stability conditions in a system containing a liquid bridge of volume Ω formed between two parallel planes, separated by a distance 2h , with a contact angle Θ using both Monte Carlo simulation of a lattice gas model and variational calculus based on minimization of the surface area with the volume and the contact angle constraints. In order to simulate systems with different contact angles, we vary the parameters between the constitutive elements of the lattice gas. We numerically and analytically determine the phase diagram of the system as a function of the dimensionless parameters hΩ-1/3 and Θ . The regions of this phase diagram correspond to the mechanical stability and thermodynamical stability of the liquid bridge. We also determine the conditions for the symmetrical versus asymmetrical rupture of the bridge. We numerically and analytically compute the release of free energy during rupture. The simulation results are in agreement with the analytical solution. Furthermore, we discuss the results in connection

  8. The Effects of Knee Joint and Hip Abduction Angles on the Activation of Cervical and Abdominal Muscles during Bridging Exercises.

    Science.gov (United States)

    Lee, Su-Kyoung; Park, Du-Jin

    2013-07-01

    [Purpose] The purpose of this study was to examine the effects of the flexion angle of the knee joint and the abduction angle of the hip joint on the activation of the cervical region and abdominal muscles. [Subjects] A total of 42 subjects were enrolled 9 males and 33 females. [Methods] The bridging exercise in this study was one form of exercise with a knee joint flexion angle of 90°. Based on this, a bridging exercise was conducted at the postures of abduction of the lower extremities at 0, 5, 10, and 15°. [Result] The changes in the knee joint angle and the hip abduction angle exhibited statistically significant effects on the cervical erector spinae, adductor magnus, and gluteus medius muscles. The abduction angles did not result in statistically significant effects on the upper trapezium, erector spinae, external oblique, and rectus abdominis muscles. However, in relation to the knee joint angles, during the bridging exercise, statistically significant results were exhibited. [Conclusion] When patients with both cervical and back pain do a bridging exercise, widening the knee joint angle would reduce cervical and shoulder muscle activity through minimal levels of abduction, permitting trunk muscle strengthening with reduced cervical muscle activity. This method would be helpful for strengthening trunk muscles in a selective manner. PMID:24259870

  9. Strengthening of metallic alloys with nanometer-size oxide dispersions

    Science.gov (United States)

    Flinn, J.E.; Kelly, T.F.

    1999-06-01

    Austenitic stainless steels and nickel-base alloys containing, by wt. %, 0.1 to 3.0% V, 0.01 to 0.08% C, 0.01 to 0.5% N, 0.05% max. each of Al and Ti, and 0.005 to 0.10% O, are strengthened and ductility retained by atomization of a metal melt under cover of an inert gas with added oxygen to form approximately 8 nanometer-size hollow oxides within the alloy grains and, when the alloy is aged, strengthened by precipitation of carbides and nitrides nucleated by the hollow oxides. Added strengthening is achieved by nitrogen solid solution strengthening and by the effect of solid oxides precipitated along and pinning grain boundaries to provide temperature-stabilization and refinement of the alloy grains. 20 figs.

  10. Predicting sales performance: Strengthening the personality – job performance linkage

    NARCIS (Netherlands)

    T.B. Sitser (Thomas)

    2014-01-01

    markdownabstract__Abstract__ Many organizations worldwide use personality measures to select applicants for sales jobs or to assess incumbent sales employees. In the present dissertation, consisting of four independent studies, five approaches to strengthen the personality-sales performance linkage

  11. On the velocity-strengthening behavior of dry friction

    CERN Document Server

    Bar-Sinai, Yohai; Brener, Efim A; Bouchbinder, Eran

    2013-01-01

    The onset of frictional instabilities, e.g. earthquakes nucleation, is intimately related to velocity-weakening friction, in which the frictional resistance of interfaces decreases with increasing slip velocity. While this frictional response has been studied extensively, much less attention has been given to steady-state velocity-strengthening friction, in spite of its importance for various aspects of frictional phenomena such as the propagation speed of interfacial rupture fronts and the amount of stored energy released by them. In this note we suggest that a crossover from steady-state velocity-weakening friction at small slip velocities to steady-state velocity-strengthening friction at higher velocities might be a generic feature of dry friction. We further argue that while thermally activated rheology naturally gives rise to logarithmic steady-state velocity-strengthening friction, a crossover to stronger-than-logarithmic strengthening might take place at higher slip velocities, possibly accompanied by...

  12. Shear Strengthening of Reinforced Concrete Beams Using GFRP Wraps

    Directory of Open Access Journals (Sweden)

    M. A. A. Saafan

    2006-01-01

    Full Text Available The objective of the experimental work described in this paper was to investigate the efficiency of GFRP composites in strengthening simply supported reinforced concrete beams designed with insufficient shear capacity. Using the hand lay-up technique, successive layers of a woven fiberglass fabric were bonded along the shear span to increase the shear capacity and to avoid catastrophic premature failure modes. The strengthened beams were fabricated with no web reinforcement to explore the efficiency of the proposed strengthening technique using the results of control beams with closed stirrups as a  web reinforcement. The test results of 18 beams are reported, addressing the influence of different shear strengthening schemes and variable longitudinal reinforcement ratios on the structural behavior. The results indicated that significant increases in the shear strength and improvements in the overall structural behavior of beams with insufficient shear capacity could be achieved by proper application of GFRP wraps.

  13. Shear capacity of reinforced concrete columns strengthened with CFRP sheet

    Institute of Scientific and Technical Information of China (English)

    XIE Jian; LIU Xue-mei; ZHAO Tong

    2005-01-01

    This paper discusses the results of tests on the shear capacity of reinforced concrete columns strengthened with carbon fiber reinforced plastic (CFRP) sheet. The shear transfer mechanism of the specimens reinforced with CFRP sheet was studied. The factors affecting the shear capacity of reinforced concrete columns strengthened with CFRP sheet were analyzed. Several suggestions such as the number of layers, width and tensile strength of the CFRP sheet are proposed for this new strengthening technique. Finally, a simple and practical design method is presented in the paper. The calculated results of the suggested method are shown to be in good agreement with the test results. The suggested design method can be used in evaluating the shear capacity of reinforced concrete columns strengthened with CFRP sheet.

  14. 49 CFR 237.101 - Scheduling of bridge inspections.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Scheduling of bridge inspections. 237.101 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.101 Scheduling of bridge inspections. (a) Each bridge management program shall include a provision for scheduling...

  15. Finite element of multilayer surfacing systems on orthotropic steel bridges

    NARCIS (Netherlands)

    Li, J.; Liu, X.; Scarpas, A.; Tzimiris, G.

    2013-01-01

    Light weight orthotropic steel bridge decks have been widely utilized for bridges in seismic zones, movable bridges and long span bridges. In the last three decades, severe problems were reported in relation to asphaltic surfacing materials on orthotropic steel deck bridges. Earlier investigations h

  16. Limit analysis on FRP-strengthened RC members

    OpenAIRE

    D. De Domenico; A.A.Pisano; P. Fuschi

    2014-01-01

    Reinforced concrete (RC) members strengthened with externally bonded fiber-reinforced-polymer (FRP) plates are numerically investigated by a plasticity-based limit analysis approach. The key-concept of the present approach is to adopt proper constitutive models for concrete, steel reinforcement bars (re-bars) and FRP strengthening plates according to a multi-yield-criteria formulation. This allows the prediction of concrete crushing, steel bars yielding and FRP rupture that may oc...

  17. Coefficient strengthening : a tool for formulating mixed integer programs

    OpenAIRE

    Andersen, Kent; Pochet, Yves

    2007-01-01

    Providing a good formulation is an important part of solving a mixed integer program. We suggest to measure the quality of a formulation by whether it is possible to strengthen the coefficients of the formulation. Sequentially strengthening coefficients can then be used as a tool for improving formulations. We believe this method could be useful for analyzing and producing tight formulations of problems that arise in practice. We illustrate the use of the approach on a problem in production s...

  18. Post-compressed plates for strengthening preloaded reinforced concretecolumns

    OpenAIRE

    Wang, Lu; 王璐

    2013-01-01

    Reinforced concrete (RC) columns are the primary load-bearing structural components in buildings. Over time these columns may need to be repaired or strengthened either due to defective construction, having higher loads than those foreseen in the initial design of the structure, or as a result of material deterioration or accidental damage. Three external strengthening methods, namely steel jacketing, concrete jacketing and composite jacketing, are commonly adopted for upgrading the ultimate...

  19. Modeling and characterization of strengthened concrete tension members

    DEFF Research Database (Denmark)

    Hansen, Christian Skodborg; Stang, Henrik

    2011-01-01

    The structural potential for cracking of externally strengthened concrete tension members, can be predicted with three parameters, describing the structural cracking potential based on fracture mechanical properties of the of concrete and interface between concrete and strengthening medium....... With these parameters, it is possible to design reinforcement and obtain a required cracking behavior of a given structure. Design recommendations for single and multiple cracking of the tension specimen are given in terms of fracture mechanical parameters, and a structural stiffness parameter....

  20. The Strengthening of Cu-15Ni-8Sn Alloy

    Institute of Scientific and Technical Information of China (English)

    WANG Yan-hui; WANG Ming-pu; HONG Bin

    2004-01-01

    The microstructure, property and relation between them of Cu-15Ni-8Sn alloy are studied by means of TEM and the measurement of hardness. The results show that γ ' metastable phase strengthens alloy because of its ordering structure.The ordering structure includes two types of DO22 and L12 ordering. Their strengthening for the alloy is much stronger than that of spinodal decomposition.

  1. Strengthening masonry infill panels using engineered cementitious composites

    DEFF Research Database (Denmark)

    Dehghani, Ayoub; Fischer, Gregor; Nateghi Alahi, Fariborz

    2015-01-01

    This comprehensive experimental study aims at investigating the behavior of masonry infill panels strengthened by fiber reinforced engineered cementitious composites (ECC). The experimental program included testing of materials, masonry elements and panels. Material tests were carried out first...... on masonry elements. Finally, a total of 10 brick panels including two control specimens and eight specimens with different ECC-strengthening configuration were selected. The specimens were subjected to diagonal compression loading under displacement control to evaluate their in-plane deformation...

  2. Bridging evidence, policy, and practice to strengthen health systems for improved maternal and newborn health in Pakistan.

    Science.gov (United States)

    Hirose, Atsumi; Hall, Sarah; Memon, Zahid; Hussein, Julia

    2015-01-01

    Policy and decision making should be based on evidence, but translating evidence into policy and practice is often sporadic and slow. It is recognised that the relationship between research and policy uptake is complex and that dissemination of research findings is necessary, but insufficient, for policy uptake. Political, social, and economic context, use of (credible) data and dialogues between and across networks of researchers and policymakers play important roles in evidence uptake. Advocacy is the process of mobilising political and public opinions to achieve specific aims and its role is crucial in mobilising key actors to push for policy uptake. Advocacy and research groups (i.e. those who would like to see research evidence used by policymakers) may use different approaches and tools to stimulate the diffusion of research findings. The use of mass- and social media, communication with study participants, and the involvement of stakeholders at the early stages of research development are examples of the approaches that can be employed to stimulate diffusion of evidence and increase evidence uptake. The Research and Advocacy Fund (RAF) for Maternal and Newborn Health (MNH) worked within the health system context in Pakistan with the aim of espousing the principles of evidence, advocacy, and dissemination to improve MNH outcomes. The articles included in this special issue are outputs of RAF and highlight where RAF's approaches contributed to MNH policy reforms. The papers discuss critical health system issues facing Pakistan, including service delivery components, demand creation, equitable access, transportation interventions for improved referrals, availability of medicines and equipment, and health workforce needs. In addition to these tangible elements, the health system 'software', i.e. the power and the political and social contexts, is also represented in the collection. These articles highlight three considerations for the future: the growing importance of implementation research, the crucial need for participation and ownership, and the recognition that policymaking can be 'informed' by rather than 'based-on' evidence. The future challenge will be to continue the momentum RAF has created and to welcome a new era of health, wealth, and growth for Pakistan. PMID:26791789

  3. The Bridge of Mandolin County

    Science.gov (United States)

    Lantz, Juliette M.; Feindt, Jenny E.; Lewellyn, Eric P. B.; Walczak, Mary M.

    1999-12-01

    The Bridge of Mandolin County is a case designed to teach the general chemistry principles of molar mass, ions and aqueous reactions, solubility rules, and inorganic nomenclature. Through the instructor-facilitated class discussion, students consider the options before the Mandolin Town Council regarding deicing the newly constructed bridge connecting Mandolin with a large nearby city. The students must decipher contradictory claims made on behalf of sodium chloride, the traditional deicer, and calcium magnesium acetate, a new environmentally friendly deicer, to arrive at the most cost-effective and environmentally appropriate deicing product. As they work through the analysis they raise questions that can be addressed in a laboratory setting. Four optional role-playing experiments are included, which can be used by the students to gather information helpful to resolution of the case. The case is intended to be used over two class periods, with a laboratory period in between, though suggestions for other models are provided. Laboratory procedures include an EDTA titration for Ca2+ and Mg2+, a gravimetric analysis, a qualitative examination of ions and solubility, an introduction to freezing point depression and measurement, and an experimental design activity. This case can also successfully be used without alteration in non-majors chemistry or environmental chemistry courses, or upper-level analytical or environmental chemistry courses.

  4. Study of the Tensile Properties of CFRP Strengthened Steel Plates

    Directory of Open Access Journals (Sweden)

    Yiyan Lu

    2015-12-01

    Full Text Available This paper presents the experimental results of steel plates strengthened with carbon fiber reinforced polymer (CFRP sheets under tensile load. The number of CFRP layers (ranging from one to four, strengthening schemes (single-sided and double-sided bonding, and temperatures (ranging from 25 to 120 °C were investigated. Results showed that the number of CFRP layers and strengthening schemes had insignificant effects on failure modes of specimens. The failure modes were dominated by the degradation of resin matrix at temperatures lower than Tg + 10 or 20 °C, where Tg is the glass transition temperature, and were dominated by the volume decrease of resin matrix at temperatures above that. Through bonding CFRP sheets, the ultimate load and post-elastic stiffness of specimens were significantly increased. However, the increase in the number of CFRP layers also led to the decrease in strengthening and stiffening efficiency. The double-sided strengthened specimens showed more preferable mechanical properties than the single-sided strengthened specimens. As temperature increased, significant decreases in ultimate load and post-elastic stiffness were observed. Analytical modeling to predict the mechanical properties at ambient and elevated temperatures were conducted, respectively. The modeling results were verified by the test data.

  5. A novel bridge scour monitoring and prediction system

    Science.gov (United States)

    Valyrakis, Manousos; Michalis, Panagiotis; Zhang, Hanqing

    2015-04-01

    Earth's surface is continuously shaped due to the action of geophysical flows. Erosion due to the flow of water in river systems has been identified as a key problem in preserving ecological health but also a threat to our built environment and critical infrastructure, worldwide. As an example, it has been estimated that a major reason for bridge failure is due to scour. Even though the flow past bridge piers has been investigated both experimentally and numerically, and the mechanisms of scouring are relatively understood, there still lacks a tool that can offer fast and reliable predictions. Most of the existing formulas for prediction of bridge pier scour depth are empirical in nature, based on a limited range of data or for piers of specific shape. In this work, the use of a novel methodology is proposed for the prediction of bridge scour. Specifically, the use of an Adaptive Neuro-Fuzzy Inference System (ANFIS) is proposed to estimate the scour depth around bridge piers. In particular, various complexity architectures are sequentially built, in order to identify the optimal for scour depth predictions, using appropriate training and validation subsets obtained from the USGS database (and pre-processed to remove incomplete records). The model has five variables, namely the effective pier width (b), the approach velocity (v), the approach depth (y), the mean grain diameter (D50) and the skew to flow. Simulations are conducted with data groups (bed material type, pier type and shape) and different number of input variables, to produce reduced complexity and easily interpretable models. Analysis and comparison of the results indicate that the developed ANFIS model has high accuracy and outstanding generalization ability for prediction of scour parameters. The effective pier width (as opposed to skew to flow) is amongst the most relevant input parameters for the estimation. Training of the system to new bridge geometries and flow conditions can be achieved by

  6. Flexural Capacity of Reinforced Concrete Beams Strengthened Using GFRP Sheet after Fatigue Loading

    OpenAIRE

    Djamaluddin, Rudy

    2015-01-01

    Fiber reinforced polymer (FRP) has been applied not only for the simple structures but also for the advanced structures such as bridges or highway bridges. In case of bridges or highway bridges, the structures experience not only static loadings but also fatigue loadings that may limited the serviceability of the bridge structures. In order to extend of the application of FRP on the such bridge structures, the flexural capacity due to fatigue loading should be clarified. Glass composed FRP sh...

  7. Inspection and Numerical Analysis of an Ottoman Railway Bridge in Jordan

    Directory of Open Access Journals (Sweden)

    Amin H. Almasri

    2016-01-01

    Full Text Available The construction of bridges represents a big challenge, since they require enormous economic effort and specialized technical skills. Bridges were historically important as they help connecting people and thus diffusing cultures, sharing ideas, and providing the backbone of transportation networks. This study focuses on the inspection and structural analysis of a 20th-century Ottoman railway stone arched bridge located on the Hejaz railway network in Jordan. The bridge has a very important cultural heritage value which stems from its history. The bridge stone material was cut and tested to determine its strength, in order to be used in the analysis. The structural analysis was carried out to assess the structural condition of the bridge and its suitability for reuse. The study includes static analysis under gravity loads and seismic analysis under earthquake loads. Despite the existence of deterioration in the bridge body construction materials due to a combination of human and natural factors, the analysis results proved enough structural capability to sustain the imposed gravity loads, but not a strong earthquake.

  8. Dynamic behaviors of historical wrought iron truss bridges: a field testing case study

    Science.gov (United States)

    Dai, Kaoshan; Wang, Ying; Hedric, Andrew; Huang, Zhenhua

    2016-04-01

    The U.S. transportation infrastructure has many wrought iron truss bridges that are more than a century old and still remain in use. Understanding the structural properties and identifying the health conditions of these historical bridges are essential to deciding the maintenance or rebuild plan of the bridges. This research involved an on-site full-scale system identification test case study on the historical Old Alton Bridge (a wrought iron truss bridge built in 1884 in Denton, Texas) using a wireless sensor network. The study results demonstrate a practical and convenient experimental system identification method for historical bridge structures. The method includes the basic steps of the in-situ experiment and in-house data analysis. Various excitation methods are studied for field testing, including ambient vibration by wind load, forced vibration by human jumping load, and forced vibration by human pulling load. Structural responses of the bridge under these different excitation approaches were analyzed and compared with numerical analysis results.

  9. Influence of central buckle on suspension bridge dynamic characteristics and driving comfort

    Institute of Scientific and Technical Information of China (English)

    王达; 邓扬; 刘扬

    2015-01-01

    The central buckle, which is often used in a suspension bridge, can improve bridges’ performance in the actual operation condition. The influence of the central buckle on natural vibration characteristics and bridge-deck driving comfort of a long-span suspension bridge is studied by using a case study of Siduhe Suspension Bridge in China. Based on the finite element software ANSYS and independently complied program, the influence of the central buckle on the structure force-applied characteristics of a long-span suspension bridge has been explored. The results show that the huge increases of natural frequencies can result in the presence of central buckles because of the increases of bending and torsional rigidities. The central buckle basically makes the stiffening girders and cables within the triangular area covered as a relatively approximate rigid area. Hence, the central buckle can reduce the torsional displacement of the main girder. However, the increases of bending and torsional rigidities have little influence on the impact factor, which is obtained by using vehicle-bridge coupled vibration analysis. This means that the central buckle has little effect on the comfort indices. In addition, it is found that the central buckle can enhance the bridge deck’s driving stability due to the decrease of the torsional displacements of the main girder.

  10. Effect of vehicle weight on natural frequencies of bridges measured from traffic-induced vibration

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Recently, ambient vibration test (AVT) is widely used to estimate dynamic characteristics of large civil structures. Dynamic characteristics can be affected by various environmental factors such as humidity, intensity of wind, and temperature. Besides these environmental conditions, the mass of vehicles may change the measured values when traffic-induced vibration is used as a source of AVT for bridges. The effect of vehicle mass on dynamic characteristics is investigated through traffic-induced vibration tests on three bridges; (1) three-span suspension bridge (128m+404m+128m), (2) five-span continuous steel box girder bridge (59m+3@95m+59m), (3) simply supported plate girder bridge (46m). Acceleration histories of each measurement location under normal traffic are recorded for 30 minutes at field. These recorded histories are divided into individual vibrations and are combined into two groups according to the level of vibration; one by heavy vehicles such as trucks and buses and the other by light vehicles such as passenger cars. Separate processing of the two groups of signals shows that, for the middle and long-span bridges, the difference can be hardly detected, but, for the short span bridges whose mass is relatively small, the measured natural frequencies can change up to 5.4%.

  11. Bridge recognition based on Gabor filter in forward-looking infrared images

    Science.gov (United States)

    Liu, Songlin; Sun, Gang; Niu, Zhaodong; Chen, Zengping

    2013-10-01

    Conventional methods often assume that water region is homogeneous and bridge is brighter than background. They usually recognize target by parallel lines detection. But grayscale of bridge has bipolar problem in FLIR images due to interference of complex background and constraints of imaging conditions, which means that it can be greater or lower than river. Furthermore, water is not a homogeneous area as a whole because of the interference of water clutter and shoals. This paper proposes a novel algorithm of bridge recognition based on Gabor filter. Firstly, we obtain target ROI by extracting the horizontal line. And then ROI sub-images are enhanced by Gabor filter and target polarity is determined by bridge body detection. Finally, bridge recognition can be achieved by pier detection according to the target polarity and location of bridge body. Experimental results of nearly 3000 frames show that the proposed algorithm can effectively overcome problems such as bipolar target and low image contrast. It offers a good practicability and accuracy in bridge recognition in FLIR images.

  12. Development and simulation of microfluidic Wheatstone bridge for high-precision sensor

    Science.gov (United States)

    Shipulya, N. D.; Konakov, S. A.; VKrzhizhanovskaya, V.

    2016-08-01

    In this work we present the results of analytical modeling and 3D computer simulation of microfluidic Wheatstone bridge, which is used for high-accuracy measurements and precision instruments. We propose and simulate a new method of a bridge balancing process by changing the microchannel geometry. This process is based on the “etching in microchannel” technology we developed earlier (doi:10.1088/1742-6596/681/1/012035). Our method ensures a precise control of the flow rate and flow direction in the bridge microchannel. The advantage of our approach is the ability to work without any control valves and other active electronic systems, which are usually used for bridge balancing. The geometrical configuration of microchannels was selected based on the analytical estimations. A detailed 3D numerical model was based on Navier-Stokes equations for a laminar fluid flow at low Reynolds numbers. We investigated the behavior of the Wheatstone bridge under different process conditions; found a relation between the channel resistance and flow rate through the bridge; and calculated the pressure drop across the system under different total flow rates and viscosities. Finally, we describe a high-precision microfluidic pressure sensor that employs the Wheatstone bridge and discuss other applications in complex precision microfluidic systems.

  13. Oxide dispersion strengthened ferritic steels: a basic research joint program in France

    Science.gov (United States)

    Boutard, J.-L.; Badjeck, V.; Barguet, L.; Barouh, C.; Bhattacharya, A.; Colignon, Y.; Hatzoglou, C.; Loyer-Prost, M.; Rouffié, A. L.; Sallez, N.; Salmon-Legagneur, H.; Schuler, T.

    2014-12-01

    AREVA, CEA, CNRS, EDF and Mécachrome are funding a joint program of basic research on Oxide Dispersion Strengthened Steels (ODISSEE), in support to the development of oxide dispersion strengthened 9-14% Cr ferritic-martensitic steels for the fuel element cladding of future Sodium-cooled fast neutron reactors. The selected objectives and the results obtained so far will be presented concerning (i) physical-chemical characterisation of the nano-clusters as a function of ball-milling process, metallurgical conditions and irradiation, (ii) meso-scale understanding of failure mechanisms under dynamic loading and creep, and, (iii) kinetic modelling of nano-clusters nucleation and α/α‧ unmixing.

  14. Electric Contact Strengthening to Improve the Bonding Between WC-Co Coating and 45# Steel Substrate

    Science.gov (United States)

    Wang, Yalin; Zhu, Shigen; Gu, Weisheng; Qi, Xiaoben

    2010-09-01

    Adhesion between thermally sprayed coating and the substrate is a type of mechanical bonding. In many cases, the adhesion strength is relatively low. In this study, an electric contact surface strengthening method was used to improve the bonding between thermally sprayed WC/Co coating and 45# steel substrate. Electric contact strengthening equipment was made for this research. Localization of resistive heating was obtained by passing 12-18 kA current through the contact between the electrode and the workpiece, the small size of the contact imposed a severe constriction on the current causing intense resistive heating the contact. In this way, the bonding way between the WC/Co coating and the 45# steel substrate would be changed from mechanical bonding to metallurgical bonding. Orthogonal array design was applied to select the optimum conditions. The effects of different factors and levels have been studied using a statistic method.

  15. Pounding Effects on the Earthquake Response of Adjacent Reinforced Concrete Structures Strengthened by Cable Elements

    Directory of Open Access Journals (Sweden)

    Liolios Angelos

    2014-06-01

    Full Text Available A numerical approach for estimating the effects of pounding (seismic interaction on the response of adjacent Civil Engineering structures is presented. Emphasis is given to reinforced concrete (RC frames of existing buildings which are seismically strengthened by cable-elements. A double discretization, in space by the Finite Element Method and in time by a direct incremental approach is used. The unilateral behaviours of both, the cable-elements and the interfaces contact-constraints, are taken strictly into account and result to inequality constitutive conditions. So, in each time-step, a non-convex linear complementarity problem is solved. It is found that pounding and cable strengthening have significant effects on the earthquake response and, hence, on the seismic upgrading of existing adjacent RC structures.

  16. Methods for Measurement and Statistical Analysis of the Frangibility of Strengthened Glass

    Directory of Open Access Journals (Sweden)

    Zhongzhi eTang

    2015-06-01

    Full Text Available Chemically strengthened glass features a surface compression and a balancing central tension (CT in the interior of the glass. A greater CT is usually associated with a higher level of stored elastic energy in the glass. During a fracture event, release of a greater amount of stored energy can lead to frangibility, i.e., shorter crack branching distances, smaller fragment size, and ejection of small fragments from the glass. In this paper, the frangibility and fragmentation behaviors of a series of chemically strengthened glass samples are studied using two different manual testing methods and an automated tester. Both immediate and delayed fracture events were observed. A statistical method is proposed to determine the probability of frangible fracture for glasses ion exchanged under a specific set of conditions, and analysis is performed to understand the dependence of frangibility probability on sample thickness, CT, and testing method. We also propose a more rigorous set of criteria for qualifying frangibility.

  17. Oxide dispersion strengthened ferritic steels: a basic research joint program in France

    International Nuclear Information System (INIS)

    AREVA, CEA, CNRS, EDF and Mécachrome are funding a joint program of basic research on Oxide Dispersion Strengthened Steels (ODISSEE), in support to the development of oxide dispersion strengthened 9–14% Cr ferritic–martensitic steels for the fuel element cladding of future Sodium-cooled fast neutron reactors. The selected objectives and the results obtained so far will be presented concerning (i) physical–chemical characterisation of the nano-clusters as a function of ball-milling process, metallurgical conditions and irradiation, (ii) meso-scale understanding of failure mechanisms under dynamic loading and creep, and, (iii) kinetic modelling of nano-clusters nucleation and α/α′ unmixing

  18. Bipedal tool use strengthens chimpanzee hand preferences

    DEFF Research Database (Denmark)

    Braccini, Stephanie; Lambeth, Susan; Schapiro, Steve;

    2010-01-01

    The degree to which non-human primate behavior is lateralized, at either individual or population levels, remains controversial. We investigated the relationship between hand preference and posture during tool use in chimpanzees (Pan troglodytes) during bipedal tool use. We experimentally induced...... tool use in a supported bipedal posture, an unsupported bipedal posture, and a seated posture. Neither bipedal tool use nor these supported conditions have been previously evaluated in apes. The hypotheses tested were 1) bipedal posture will increase the strength of hand preference, and 2) a bipedal...... stance, without the use of one hand for support, will elicit a right hand preference. Results supported the first, but not the second hypothesis: bipedalism induced the subjects to become more lateralized, but not in any particular direction. Instead, it appears that subtle pre-existing lateral biases...

  19. Bridge Lock-up Device System

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    The Colebrand Lock-up Device (LUD) provides additional substructure strength to resist seismic forces as a structural shock transmission unit for highway bridges. This system can provide a temporary rigid link between bridge structural members under seismic, braking, or other fast-acting type loads, while permitting slow thermal movements.

  20. Paul Dirac:. Building Bridges of the Mind

    Science.gov (United States)

    Brown, Laurie M.

    2003-12-01

    Paul Dirac was a brilliant and original thinker. He used his physical intuition and his ideal of mathematical beauty to construct bridges between major areas of physics. This article discusses several such important works, including the bridge between quantum mechanics and relativity that led to his prediction of the existence of antimatter.

  1. History of cable-stayed bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    The principle of supporting a bridge deck by inclined tension members leading to towers on either side of the span has been known for centuries. However, the real development of cable-stayed bridges did not begin before the 1950s. Since then the free span has been increased from 183 m in the Strö...

  2. COUPLING VIBRATION OF VEHICLE-BRIDGE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    陈炎; 黄小清; 马友发

    2004-01-01

    By applying the sinusoidal wave mode to simulate the rugged surface of bridge deck,accounting for vehicle-bridge interaction and using Euler-Bernoulli beam theory, a coupling vibration model of vehicle-bridge system was developed. The model was solved by mode analyzing method and Runge-Kutta method, and the dynamic response and the resonance curve of the bridge were obtained. It is found that there are two resonance regions, one represents the main resonance while the other the minor resonance, in the resonance curve. The influence due to the rugged surface, the vibration mode of bridge, and the interaction between vehicle and bridge on vibration of the system were discussed. Numerical results show that the influence due to these parameters is so significant that the effect of roughness of the bridge deck and the mode shape of the bridge can't be ignored and the vehicle velocity should be kept away from the critical speed of the vehicle.

  3. A STUDY OF BARRIERS IN BRIDGING COMMUNICATION

    OpenAIRE

    Niteen V. Dandekar

    2014-01-01

    The main objective of this paper is to make a thought provoking discussion on the role barriers in bridging communication. It focuses on the concept of communication, process and the role of language related barriers in bridging communication. It studies the significance of communication in modern human life.

  4. General framework for bridge life cycle design

    Institute of Scientific and Technical Information of China (English)

    Junhai MA; Airong CHEN; Jun HE

    2009-01-01

    Based on a detailed illustration for bridge life cycle design which comprises the processes of service life design, aesthetics design, performance design, environ-mental and ecological design, inspection, maintenance and repair design as well as cost analysis, this paper presented a general framework for bridge life cycle design comprising three design phases and six design processes.

  5. Active aerodynamic stabilisation of long suspension bridges

    DEFF Research Database (Denmark)

    Nissen, Henrik Ditlev; Sørensen, Paul Haase; Jannerup, Ole Erik

    2004-01-01

    The paper describes the addition of actively controlled appendages (flaps) attached along the length of the bridge deck to dampen wind-induced oscillations in long suppension bridges. A novel approach using control systems methods for the analysis of dynamic stability is presented. In order to ma...

  6. Lifetime Reliability Assessment of Concrete Slab Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    A procedure for lifetime assesment of the reliability of short concrete slab bridges is presented in the paper. Corrosion of the reinforcement is the deterioration mechanism used for estimating the reliability profiles for such bridges. The importance of using sensitivity measures is stressed...

  7. Re-Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper two aspects of re-assessment of the reliability of concrete bridges are discussed namely modelling of the corrosion of reinforcement and updating of uncertain variables. The main reason for deterioration of concrete bridges is corrosion of the reinforcement. Therefore, modelling...

  8. Optimum Maintenance Strategies for Highway Bridges

    DEFF Research Database (Denmark)

    Frangopol, Dan M.; Thoft-Christensen, Palle; Das, Parag C.;

    As bridges become older and maintenance costs become higher, transportation agencies are facing challenges related to implementation of optimal bridge management programs based on life cycle cost considerations. A reliability-based approach is necessary to find optimal solutions based on minimum ...... is described. The end result of this investigation will be a general reliability-based framework to be used by the UK Highways Agency in order to plan optimal strategies for the maintenance of its bridge network so as to optimize whole-life costs....... expected life-cycle costs or maximum life-cycle benefits. This is because many maintenance activities can be associated with significant costs, but their effects on bridge safety can be minor. In this paper, the program of an investigation on optimum maintenance strategies for different bridge types...

  9. The I-35W bridge Project Website

    DEFF Research Database (Denmark)

    Kampf, Constance

    How can websites be used to rebuild trust?  In August 2007, the Interstate Highway 35-W bridge in Minneapolis, MN collapsed during rush hour.  Although many people were rescued and casualties were as limited as could be expected due to quick and effective intervention, the image of a major bridge...... collapsing during rush hour damaged the Minnesota Department of Transportation's reputation and resulted in the loss of public trust for the organization.  The ensuing bridge reconstruction project included a project website intended to rebuild this trust through transparency, community involvement......, and the use of multimodal features.  This paper looks at the I35-W bridge reconstruction project in Minneapolis through web-based communication by the Minnesota Department of Transportation (MnDOT) about the project. The MnDOT bridge reconstruction website will be examined using a combination of 1). Weick...

  10. Multiple Liquid Bridges with Non-Smooth Interfaces

    CERN Document Server

    Fel, Leonid; Ratner, Vadim

    2015-01-01

    We consider a coexistence of two axisymmetric liquid bridges LB_i and LB_m of two immiscible liquids i and m which are immersed in a third liquid (or gas) e and trapped between two smooth solid bodies with axisymmetric surfaces S_1,S_2 and free contact lines. Evolution of liquid bridges allows two different configurations of LB_i and LB_m with multiple (five or three) interfaces of non-smooth shape. We formulate a variational problem with volume constraints and present its governing equations supplemented by boundary conditions. We find a universal relationship between curvature of the interfaces and discuss the Young relation at the singular curve where all liquids meet together.

  11. Assistant pullback technique for main span closure of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Chen Ming; Luo Chengbin; Wu Qihe; Zhang Yongtao; You Xinpeng

    2009-01-01

    Sutong Bridge is a cable-stayed steel box girder bridge with a main span of 1 088 m. The erection of upper structure adopts geometry control method and requires no change to the unit's size and the structure's none-stress geometry. Before main span closure, the cantilever of girder reaches 540.8 m, the structure state is noticeably influenced by external circumstances, the main span closure face great difficulty. By abstracting the advantage of the pullback method abroad and the domestic temperature-cutting method, a new assistant pullback method have put forward and bring into practice actually. In this paper, the analysis key point of practice conditions, key parameter of practice, main measures of the method and the performance is introduced.

  12. Stress and noises of steel box girders in Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Xue Tao; Chen Zhijian; Dong Xuewu

    2008-01-01

    Sutong Bridge is a cable-stayed bridge with a main span of 1 088 m.370 high-precision stress monitoring measured data show that in the process of hoisting the steel box girders,the stress of the main girders is in the fluctuant and complex state and many meteorological factors,such as sunshine radiation,temperature and wind,have important influence on the change of stress of the steel box girders.According to the real-time weather data,the stress data after the process of wavelet denoising from representative measuring points in different weather conditions is picked to estab-lish the stress response brought by meteorological factors with Layered Separation method,thereby basically eliminating the influence of meteorological factors on the stress of main girders,so that accurate and reliable stress data can be got for steel box girders adjustment and cable-tensioned construction control.

  13. Nanoparticles as strengthening agents in polymer systems

    Science.gov (United States)

    Shahid, Naureen

    2005-11-01

    Carboxylate-substituted alumina nanoparticles are produced solvent free using mechanical shear. The general nature of this method has been demonstrated for L-lysine-, stearate, and p-hydroxybenzoate-derived materials. The reaction rate and particle size is controlled by a combination of temperature and shear rate. The nanoparticles are spectroscopically equivalent to those reported from aqueous syntheses, however, the average particle size can be decreased and the particle size distribution narrowed depending on the reaction conditions. Lysine and p-hydroxybenzoato alumoxanes have been introduced in carbon fiber reinforced epoxide resin composites. Different preparation conditions have been studied to obtain composite with enhanced performances that are ideal for the motor sports and aerospace industries. A new composite material has been fabricated utilizing surface-modified carboxylate alumoxane nanoparticles and the biodegradable polymer poly(propylene fumarate)/poly(propylene fumarate)-diacrylate (PPF/PPF-DA). For this study, composites were prepared using various functional groups including: a surfactant alumoxane to enhance nanoparticle dispersion into the polymer; an activated-alumoxane to enhance nanoparticle interaction with the polymer matrix; a mixed alumoxane containing both activated and surfactant groups. Nanocomposites prepared with all types of alumoxane, as well as blank polymer resin and unmodified boehmite, underwent mechanical testing and were characterized by SEM and microprobe analysis. A nanocomposite composed of mixed alumoxane nanoparticles dispersed in PPF/PPF-DA exhibited increased flexural modulus compared to polymer resin alone, and a significant enhancement over both the activated and surfacted alumoxanes. Boric acid is used as the cross-linking agent in oil well drilling industry even though the efficacy of the borate ion, [B(OH)4]- , as a cross-linking agent is poor. The reaction product of boric acid and the polysaccharide guaran

  14. Modified Geometry of Transition Slabs for Integral Bridges

    OpenAIRE

    Dreier, Damien

    2010-01-01

    Over the past decades, an increasing number of integral bridges have been built. This type of bridge offers various advantages in comparison with standard bridges equipped with expansion joints and bearings. In particular, integral bridges require less maintenance since they require less mechanical elements. Transition slabs, which are used in integral bridges, are directly connected to the bridge deck and therefore they are subjected to large displacements caused by creep, shrinkage and temp...

  15. Building bridges … and accelerators

    CERN Multimedia

    2009-01-01

    Lyn Evans, the LHC project leader, was awarded an honorary doctorate from the University of Geneva (UNIGE) to celebrate his role not just in building accelerators, but also in building bridges between nations. He was one of four notables honoured at the event on Friday 5 June, coinciding with the University’s 450th Anniversary. Lyn Evans arriving at the ceremony with Archbishop Desmond Tutu. "It was a big surprise when I found out I’d been nominated," recounts Evans, "but it was an even bigger surprise to find out with whom I’d been nominated". At the ceremony Evans was awarded the honorary doctorate along with three others: Archbishop Desmond Tutu, who was acclaimed for his fight against apartheid in South Africa, Mary Robinson, first woman president of Ireland and former United Nations’ high commissioner of human rights, and Pascal Lamy, Director-General of the World Trade Organization. The award ceremony, known as the �...

  16. Root coverage with bridge flap

    Directory of Open Access Journals (Sweden)

    Pushpendra Kumar Verma

    2013-01-01

    Full Text Available Gingival recession in anterior teeth is a common concern due to esthetic reasons or root sensitivity. Gingival recession, especially in multiple anterior teeth, is of huge concern due to esthetic reasons. Various mucogingival surgeries are available for root coverage. This case report presents a new bridge flap technique, which allows the dentist not only to cover the previously denuded root surfaces but also to increase the zone of attached gingiva at a single step. In this case, a coronally advanced flap along with vestibular deepening technique was used as root coverage procedure for the treatment of multiple recession-type defect. Here, vestibular deepening technique is used to increase the width of the attached gingiva. The predictability of this procedure results in an esthetically healthy periodontium, along with gain in keratinized tissue and good patient′s acceptance.

  17. The effects of performing a one-legged bridge with hip abduction and use of a sling on trunk and lower extremity muscle activation in healthy adults

    Science.gov (United States)

    Choi, Kyuju; Bak, Jongwoo; Cho, Minkwon; Chung, Yijung

    2016-01-01

    [Purpose] This study investigated the changes in the muscle activities of the trunk and lower limbs of healthy adults during a one-legged bridge exercise using a sling, and with the addition of hip abduction. [Subjects and Methods] Twenty-seven healthy individuals participated in this study (14 males and 13 females). The participants were instructed to perform the bridge exercises under five different conditions. Trunk and lower limb muscle activation of the erector spinae (ES), external oblique (EO), gluteus maximus (GM), and biceps femoris (BF) was measured using surface electromyography. Data analysis was performed using the mean scores of three trials performed under each condition. [Results] There was a significant increase in bilateral EO and contralateral GM with the one-legged bridge compared with the one-legged bridge with sling exercise. Muscle activation of the ipsilateral GM and BF was significantly less during the one-legged bridge exercise compared to the one-legged bridge with sling exercise, and was significantly greater during the one-legged bridge with hip abduction compared to the one-legged bridge exercise. The muscle activation of the contralateral GM and BF was significantly greater with the one-legged bridge with hip abduction compared to the general bridge exercise. [Conclusion] With the one-legged bridge with hip abduction, the ipsilateral EO, GM and BF muscle activities were significantly greater than those of the one-legged bridge exercise. The muscle activation of all trunk and contralateral lower extremity muscles increased with the bridge with sling exercises compared with general bridge exercises. PMID:27799708

  18. Structural health monitoring of bridges using accelerometers – a case study at Apollo Bridge in Bratislava

    Directory of Open Access Journals (Sweden)

    Alojz Kopáčik

    2015-04-01

    Full Text Available Building structures are extremely sensitive at influence of outdoor conditions. Most often these are the influence of wind, sunshine, temperature changes of the surrounding and at least the influence of the own or other loading. According to resonance of the structure with the surrounding is coming to vibration and oscillation in relative high frequency interval (0.1 Hz - 100.0 Hz. These phenomena significantly affect the static and dynamic characteristics of structures, their safety and functionality. The paper brings example of monitoring these phenomena. The object of monitoring is the Danube Bridge Apollo in Bratislava, which main steel structure was measured by acceleration sensors with frequency up to10 Hz. The main topic of the paper is the analysis of dynamic behaviour of structure using spectral analysis method. The usage of Fourier Transform is described, own frequencies and amplitudes of structure oscillation are calculated.

  19. Warming strengthens an herbivore-plant interaction.

    Science.gov (United States)

    O'Connor, Mary I

    2009-02-01

    Temperature has strong, predictable effects on metabolism. Through this mechanism, environmental temperature affects individuals and populations of poikilotherms by determining rates of resource use, growth, reproduction, and mortality. Predictable variation in metabolic processes such as growth and reproduction could affect the strength of species interactions, but the community-level consequences of metabolic temperature dependence are virtually unexplored. I experimentally tested the hypothesis that plant-herbivore interaction strength increases with temperature using a common species of marine macroalga (Sargassum filipendula) and the grazing amphipod Ampithoe longimana. Increasing temperature increased per capita interaction strength in two independent experiments and reversed a positive effect of temperature on plant growth. Temperature did not alter palatability of plant tissue to herbivores or average herbivore feeding rate. A predictable effect of temperature on herbivore-plant interaction strength could provide key information toward understanding local food web responses to changing temperatures at different spatial and temporal scales. Efforts to extend the effects of physiological mechanisms to larger scale patterns, including projections of the ecological effects of climate change, must be expanded to include the effects of changing conditions on trophic interactions. PMID:19323223

  20. Free vibrations of multi-girder and multi-cell box bridges with transverse deformations effects

    Science.gov (United States)

    Hamed, E.; Frostig, Y.

    2005-01-01

    A general mathematical approach is developed for the free vibration behaviour analysis of multi-girder and multi-cell box bridges with a single or multi span, including the effects of the transverse deformations of the bridge cross-section. The governing equations of motion and the corresponding boundary and continuity conditions are derived via the variational principle of virtual work following Hamilton's principle. The model is general and valid for any boundary and continuity conditions, and is applicable for multi-girder bridges with longitudinal and cross beams and for multi-cell box bridges. The warping and the distortion of the bridge cross-section effects are included in the proposed model. Closed-form solutions of the governing equations are derived and the Newton-Raphson method is used to determine the eigenfrequencies. Numerical examples are presented to validate the proposed model, and are also used to examine the accuracy of other approximate models used in the analysis of bridges. The results of the proposed model are validated through comparison with three-dimensional finite element models. The results reveal that the transverse deformations decrease the magnitudes of the eigenfrequencies of the torsional mode shapes, as well as the high flexural modes.

  1. Environmental variability study on the measured responses of Runyang Cablestayed Bridge using wavelet packet analysis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The structural damage alarming method based on wavelet packet energy spectrum (WPES) for long-span cable-stayed bridges is presented through combination of ambient vibration test and wavelet packet analysis. The environmental variability in the measured WPES and damage alarming indices ERVD of the Runyang Cable-stayed Bridge are discussed in detail using the wavelet packet analysis of the measured acceleration responses of the bridge under daily environmental conditions. The analysis results reveal that the actual environmental conditions including traffic loadings, environmental temperature and typhoon loadings have remarkable correlations with the measured WPES. The changes of environmental temperature have a long-term trend influence on the WPES, while the influences of traffic and typhoon loadings on the measured WPES of the bridge present instantaneous changes because of the nonstationary properties of the loadings. The analysis results of the measured responses further reveal that the damage alarming indices ERVD can sensitively reflect the influences of environmental temperature and typhoon loadings on the dynamic properties of Runyang Cable-stayed Bridge. Therefore, the proposed structural damage alarming indices ERVD under ambient vibrations are suitable for real-time damage alarming for long-span cable-stayed bridges.

  2. Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure

    Directory of Open Access Journals (Sweden)

    You-Liang Ding

    2015-01-01

    Full Text Available Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge’s abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature.

  3. Aerodynamics of bridge hangers in smooth and turbulent flow and implications on aeroelastic stability

    DEFF Research Database (Denmark)

    Demartino, Cristoforo; Ricciardelli, Francesco; Georgakis, Christos T.

    2015-01-01

    The aerodynamics of circular cylinders featuring geometric imperfections, such as bridge cables, has received much attention in recent years due to the recognition that such imperfections can be the cause of large amplitude vibrations. Bridge cables are usually made of strands or wires protected...... by an extruded High Density PolyEthylene (HDPE) circular sheath [1]. In the last 20 years, several bridge cable manufacturers have introduced surface modifications on HDPE sheath in order to reduce the drag and to ensure the aerodynamic stability in all climatic conditions. In the case of plain HDPE sheaths......, of mechanical damage occurring during transport and installation, as well as of the ageing process due to the exposure to environmental factors. Few experimental works are already available dealing with the effects of imperfections on the aerodynamics of bridge cables. For example, Matteoni and Georgakis...

  4. Effects of surface design on aerodynamic forces of iced bridge cables

    DEFF Research Database (Denmark)

    Koss, Holger

    2014-01-01

    In recent years the relevance of ice accretion for wind-induced vibration of structural bridge cables has been recognised and became a subject of research in bridge engineering. Full-scale monitoring and observation indicate that light precipitation at moderate low temperatures between zero and -5......°C may lead to large amplitude vibrations of bridge cables under wind action. For the prediction of aerodynamic instability quasi-steady models have been developed estimating the cable response magnitude based on structural properties and aerodynamic force coefficients for drag, lift and torsion....... The determination of these force coefficients require a proper simulation of the ice layer occurring under the specific climatic conditions, favouring real ice accretion over simplified artificial reproduction. The work presented in this paper was performed to study whether the design of bridge cable surface...

  5. Dynamic finite element model updating of prestressed concrete continuous box-girder bridge

    Institute of Scientific and Technical Information of China (English)

    Lin Xiankun; Zhang Lingmi; Guo Qintao; Zhang Yufeng

    2009-01-01

    The dynamic finite element model (FEM) of a prestressed concrete continuous box-girder bridge, called the Tongyang Canal Bridge, is built and updated based on the results of ambient vibration testing (AVT) using a real-coded accelerating genetic algorithm (RAGA). The objective functions are defined based on natural frequency and modal assurance criterion (MAC) metrics to evaluate the updated FEM. Two objective functions are defined to fully account for the relative errors and standard deviations of the natural frequencies and MAC between the AVT results and the updated FEM predictions. The dynamically updated FEM of the bridge can better represent its structural dynamics and serve as a baseline in long-term health monitoring, condition assessment and damage identification over the service life of the bridge.

  6. Performance evaluation of corrosion-affected reinforced concrete bridge girders using Markov chains with fuzzy states

    Indian Academy of Sciences (India)

    M B ANOOP; K BALAJI RAO

    2016-08-01

    A methodology for performance evaluation of reinforced concrete bridge girders in corrosive environments is proposed. The methodology uses the concept of performability and considers both serviceability- and ultimate-limit states. The serviceability limit states are defined based on the degree of cracking (characterized by crack width) in the girder due to chloride induced corrosion of reinforcement, and the ultimate limit states are defined based on the flexural load carrying capacity of the girder (characterized in terms of rating factor using the load and resistance factor rating method). The condition of the bridge girder is specified by the assignment of a condition state from a set of predefined condition states. Generally, the classification of condition states is linguistic, while the condition states are considered to be mutually exclusive and collectivelyexhaustive. In the present study, the condition states of the bridge girder are also represented by fuzzy sets to consider the ambiguities arising due to the linguistic classification of condition states. A non-homogeneous Markov chain (MC) model is used for modeling the condition state evolution of the bridge girder with time. The usefulness of the proposed methodology is demonstrated through a case study of a severely distressed beam of the Rocky Point Viaduct. The results obtained using the proposed approach are compared with those obtained using conventional MC model. It is noted that the use of MC with fuzzy states leads to conservative decision making for the problem considered in the case study.

  7. The role of the cold Okhotsk Sea in the strengthening the Pacific subtropical high and Baiu precipitation

    Science.gov (United States)

    Kawasaki, Kenta; Tachibana, Yoshihiro; Nakamura, Tetsu; Yamazaki, Koji; Kodera, Kunihiko

    2016-04-01

    It is commonly known that the formation of a stationery precipitation zone in association with the Baiu front is influenced by the existence of the warm Tibetan Plateau. Some GCM studies in which the Tibetan Plateau is removed pointed out that without the Tibetan Plateau, the Baiu front wound not appear. The cold Okhotsk Sea, which is located to the north of Japan, is also important in forming cold air for the Bai front. This study focused on the role of the Okhotsk Sea in the formation of the Baiu front by using an atmospheric GCM. One GCM is executed without the Okhotsk Sea, in which was changed to an eastern part of the Eurasian continent as if the Okhotsk Sea was totally landfilled (land run). The other (sea run) is a control run under the boundary condition of climatic seasonal changes of the SST over the globe. The comparison of the land run with the sea run showed that precipitation over Japan would weaken in the Baiu season without the Okhotsk Sea, indicating that the existence of the Okhotsk Sea has an impact on the increase in precipitation. The precipitation increase in the sea run is directly accounted by the strengthening of southeast wind in association with the strengthening of the subtropical high located over the Pacific Ocean. The westerly jet, which is located at the northern part of the subtropical high, was also accelerated in the sea run. The subtropical high in association with the accelerated jet was strengthened by meridional atmospheric thermal gradient caused by underlying cold Okhotsk Sea and the warm Pacific Ocean. The strengthened thermal gradient also activated the storm track that extends zonally over the Okhotsk Sea, and the activated storm track further strengthened the jet and subtropical high by wave-mean flow feedback. This feedback loop could further strengthen the Baiu precipitation. In consequence, the Okhotsk plays a significant role in the strengthening the subtropical high and its associated Baiu precipitation.

  8. Strut deformation in CFRP-strengthened reinforced concrete deep beams.

    Science.gov (United States)

    Panjehpour, Mohammad; Chai, Hwa Kian; Voo, Yen Lei

    2014-01-01

    Strut-and-tie model (STM) method evolved as one of the most useful designs for shear critical structures and discontinuity regions (D-regions). It provides widespread applications in the design of deep beams as recommended by many codes. The estimation of bottle-shaped strut dimensions, as a main constituent of STM, is essential in design calculations. The application of carbon fibre reinforced polymer (CFRP) as lightweight material with high tensile strength for strengthening D-regions is currently on the increase. However, the CFRP-strengthening of deep beam complicates the dimensions estimation of bottle-shaped strut. Therefore, this research aimed to investigate the effect of CFRP-strengthening on the deformation of RC strut in the design of deep beams. Two groups of specimens comprising six unstrengthened and six CFRP-strengthened RC deep beams with the shear span to the effective depth ratios (a/d) of 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00 were constructed in this research. These beams were tested under four-point bending configuration. The deformation of struts was experimentally evaluated using the values of strain along and perpendicular to the strut centreline. The evaluation was made by the comparisons between unstrengthened and CFRP-strengthened struts regarding the widening and shortening. The key variables were a/d ratio and applied load level. PMID:25197698

  9. Strut Deformation in CFRP-Strengthened Reinforced Concrete Deep Beams

    Directory of Open Access Journals (Sweden)

    Mohammad Panjehpour

    2014-01-01

    Full Text Available Strut-and-tie model (STM method evolved as one of the most useful designs for shear critical structures and discontinuity regions (D-regions. It provides widespread applications in the design of deep beams as recommended by many codes. The estimation of bottle-shaped strut dimensions, as a main constituent of STM, is essential in design calculations. The application of carbon fibre reinforced polymer (CFRP as lightweight material with high tensile strength for strengthening D-regions is currently on the increase. However, the CFRP-strengthening of deep beam complicates the dimensions estimation of bottle-shaped strut. Therefore, this research aimed to investigate the effect of CFRP-strengthening on the deformation of RC strut in the design of deep beams. Two groups of specimens comprising six unstrengthened and six CFRP-strengthened RC deep beams with the shear span to the effective depth ratios (a/d of 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00 were constructed in this research. These beams were tested under four-point bending configuration. The deformation of struts was experimentally evaluated using the values of strain along and perpendicular to the strut centreline. The evaluation was made by the comparisons between unstrengthened and CFRP-strengthened struts regarding the widening and shortening. The key variables were a/d ratio and applied load level.

  10. Seismic strengthening of RC structures with exterior shear walls

    Indian Academy of Sciences (India)

    Hasan Kaplan; Salih Yilmaz; Nihat Cetinkaya; Ergin Atimtay

    2011-02-01

    Vulnerable buildings and their rehabilitation are important problems for earthquake regions. In recent decades the goal of building rehabilitation and strengthening has gained research attention and numerous techniques have been developed to achieve this. However, most of these strengthening techniques disturb the occupants, who must vacate the building during renovation. In this study, a new strengthening alternative for RC structures, namely exterior shear walls, has been experimentally investigated under reversed cyclic loading. Using the proposed technique, it is possible to strengthen structures without disturbing their users or vacating the building during renovation. In this technique, shear walls are installed in parallel to the building’s exterior sides. It has been observed that the usage of exterior shear walls considerably improve the capacity and sway stiffness of RC structures. The experimental results have also been compared and found to be in agreement with the numerical solutions. Post attached exterior shear walls behaved as a monolithic member of the structure. Design considerations for the exterior shear wall-strengthened buildings have also been discussed in the paper.

  11. Strut Deformation in CFRP-Strengthened Reinforced Concrete Deep Beams

    Science.gov (United States)

    Panjehpour, Mohammad; Chai, Hwa Kian; Voo, Yen Lei

    2014-01-01

    Strut-and-tie model (STM) method evolved as one of the most useful designs for shear critical structures and discontinuity regions (D-regions). It provides widespread applications in the design of deep beams as recommended by many codes. The estimation of bottle-shaped strut dimensions, as a main constituent of STM, is essential in design calculations. The application of carbon fibre reinforced polymer (CFRP) as lightweight material with high tensile strength for strengthening D-regions is currently on the increase. However, the CFRP-strengthening of deep beam complicates the dimensions estimation of bottle-shaped strut. Therefore, this research aimed to investigate the effect of CFRP-strengthening on the deformation of RC strut in the design of deep beams. Two groups of specimens comprising six unstrengthened and six CFRP-strengthened RC deep beams with the shear span to the effective depth ratios (a/d) of 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00 were constructed in this research. These beams were tested under four-point bending configuration. The deformation of struts was experimentally evaluated using the values of strain along and perpendicular to the strut centreline. The evaluation was made by the comparisons between unstrengthened and CFRP-strengthened struts regarding the widening and shortening. The key variables were a/d ratio and applied load level. PMID:25197698

  12. CFRP Mechanical Anchorage for Externally Strengthened RC Beams under Flexure

    Science.gov (United States)

    Ali, Alnadher; Abdalla, Jamal; Hawileh, Rami; Galal, Khaled

    De-bonding of carbon fiber reinforced polymers (CFRP) sheets and plates from the concrete substrate is one of the major reasons behind premature failures of beams that are externally strengthened with such CFRP materials. To delay or prevent de-bonding and therefore enhancing the load carrying capacity of strengthened beams, several anchorage systems were developed and used. This paper investigates the use of CFRP mechanical anchorage of CFRP sheets and plates used to externally strengthen reinforced concrete beams under flexure. The pin-and-fan shape CFRP anchor, which is custom-made from typical rolled fiber sheets and bundles of loose fiber is used. Several reinforced concrete beams were casted and tested in standard four-point bending scheme to study the effectiveness of this anchorage system. The beams were externally strengthened in flexure with bonded CFRP sheets and plates and then fastened to the soffit of the beams' using various patterns of CFRP anchors. It is observed that the CFRP plates begins to separate from the beams as soon as de-bonding occurs in specimens without CFRP anchors, while in beams with CFRP anchors de-bonding was delayed leading to increase in the load carrying capacity over the un-anchored strengthened beams.

  13. Development of the strengthened safeguards system and the Additional Protocol

    International Nuclear Information System (INIS)

    For the past 30 years, the IAEA's safeguards system has contributed to the international non-proliferation regime by providing, inter alia, assurances regarding the peaceful uses of declared nuclear material. However, the discovery of a clandestine nuclear weapons program in Iraq in 1991 drew world-wide attention to the need to strengthen the system to address the absence of undeclared nuclear material and activities. Efforts to strengthen the IAEA's safeguards system began in 1991 and culminated in 1997 when the IAEA's Board of Governors approved a Model Protocol Additional to IAEA Safeguards Agreements which greatly expands the legal basis and scope of IAEA safeguards. Within this strengthened system it is expected that the IAEA be able to provide assurance not only of the absence of diversion of declared nuclear material but also on the absence of undeclared nuclear material and activities. This is to be done within a safeguards system that uses an optimal combination of all safeguards measures available, thereby achieving maximum effectiveness and efficiency within the available resources. The paper summarizes the evolution of the safeguards system, describes strengthened safeguards, reports on the status of implementing the strengthening measures, and outlines plans for integrating all available safeguards measures. (author)

  14. Integration of computer imaging and sensor data for structural health monitoring of bridges

    International Nuclear Information System (INIS)

    The condition of civil infrastructure systems (CIS) changes over their life cycle for different reasons such as damage, overloading, severe environmental inputs, and ageing due normal continued use. The structural performance often decreases as a result of the change in condition. Objective condition assessment and performance evaluation are challenging activities since they require some type of monitoring to track the response over a period of time. In this paper, integrated use of video images and sensor data in the context of structural health monitoring is demonstrated as promising technologies for the safety of civil structures in general and bridges in particular. First, the challenges and possible solutions to using video images and computer vision techniques for structural health monitoring are presented. Then, the synchronized image and sensing data are analyzed to obtain unit influence line (UIL) as an index for monitoring bridge behavior under identified loading conditions. Subsequently, the UCF 4-span bridge model is used to demonstrate the integration and implementation of imaging devices and traditional sensing technology with UIL for evaluating and tracking the bridge behavior. It is shown that video images and computer vision techniques can be used to detect, classify and track different vehicles with synchronized sensor measurements to establish an input–output relationship to determine the normalized response of the bridge

  15. Oscillations in a sunspot with light bridges

    CERN Document Server

    Yuan, Ding; Huang, Zhenghua; Li, Bo; Su, Jiangtao; Yan, Yihua; Tan, Baolin

    2014-01-01

    Solar Optical Telescope onboard Hinode observed a sunspot (AR 11836) with two light bridges (LBs) on 31 Aug 2013. We analysed a 2-hour \\ion{Ca}{2} H emission intensity data set and detected strong 5-min oscillation power on both LBs and in the inner penumbra. The time-distance plot reveals that 5-min oscillation phase does not vary significantly along the thin bridge, indicating that the oscillations are likely to originate from the underneath. The slit taken along the central axis of the wide light bridge exhibits a standing wave feature. However, at the centre of the wide bridge, the 5-min oscillation power is found to be stronger than at its sides. Moreover, the time-distance plot across the wide bridge exhibits a herringbone pattern that indicates a counter-stream of two running waves originated at the bridge sides. Thus, the 5-min oscillations on the wide bridge also resemble the properties of running penumbral waves. The 5-min oscillations are suppressed in the umbra, while the 3-min oscillations occupy...

  16. Finite Element Analysis for Fatigue Damage Reduction in Metallic Riveted Bridges Using Pre-Stressed CFRP Plates

    Directory of Open Access Journals (Sweden)

    Elyas Ghafoori

    2014-04-01

    Full Text Available Many old riveted steel bridges remain operational and require retrofit to accommodate ever increasing demands. Complicating retrofit efforts, riveted steel bridges are often considered historical structures where structural modifications that affect the original construction are to be avoided. The presence of rivets along with preservation requirements often prevent the use of traditional retrofit methods, such as bonding of fiber reinforced composites, or the addition of supplementary steel elements. In this paper, an un-bonded post-tensioning retrofit method is numerically investigated using existing railway riveted bridge geometry in Switzerland. The finite element (FE model consists of a global dynamic model for the whole bridge and a more refined sub-model for a riveted joint. The FE model results include dynamic effects from axle loads and are compared with field measurements. Pre-stressed un-bonded carbon fiber reinforced plastic (CFRP plates will be considered for the strengthening elements. Fatigue critical regions of the bridge are identified, and the effects of the un-bonded post-tensioning method with different pre-stress levels on fatigue susceptibility are explored. With an applied 40% CFRP pre-stress, fatigue damage reductions of more than 87% and 85% are achieved at the longitudinal-to-cross beam connections and cross-beam bottom flanges, respectively.

  17. Strengthening of building structures using carbon composite materials

    Directory of Open Access Journals (Sweden)

    N.V. Paranicheva

    2010-03-01

    Full Text Available Currently, the question of ensuring the reliability of various building structures both at the stage of their construction and during operation is very urgent. There are a lot of different ways and constructive methods of structures strengthening. Аt the same time, traditional ways of concrete structures strengthening with steel reinforcement are such expensive, time consuming and in some cases require to interrupt the building operation. As an alternative, it is proposed to use composite materials based on high-strength carbon fibers.The authors consider the properties, advantages, disadvantages and the methods of application of these materials. This article presents results of a technical survey carried out in a public building in 2009. In this building the CFRP was used to strengthen concrete slabs, resting on the crossbar consoles. The calculation of the strength is adduced and the section selection is made. The authors demonstrate their conclusions about the feasibility of using carbon composite materials.

  18. RC Columns Strengthened with Novel CFRP Systems: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Annalisa Napoli

    2015-10-01

    Full Text Available This paper presents an experimental study undertaken to investigate the seismic behavior of full scale square (300 mm × 300 mm reinforced concrete (RC columns strengthened with novel systems employing carbon fiber-reinforced polymers (CFRP wraps. Experimental tests were carried out by subjecting specimens to a constant axial load and a cyclically reversed horizontal force applied in displacement control. Results have allowed for investigating the influence of the used strengthening systems on the specimens’ performance in terms of flexural strength and ductility as well as on the exhibited failure modes. The effectiveness of the studied techniques is also evaluated by comparing the performance of tested specimens with that of companion columns strengthened with alternative CFRP systems investigated in a previous experimental campaign.

  19. Experimental Study on CFRP Strengthened Cold Formed Channel Columns

    Directory of Open Access Journals (Sweden)

    Sreedhar Kalavagunta

    2013-09-01

    Full Text Available Cold-formed steel members usually display local-global buckling interaction which strongly effects the structural strength of columns. Through strengthening web of the members this buckling can be controlled to some extent. In this investigation, Carbon Fibre Reinforced Polymers (CFRP is used for strengthening cold formed steel channel member. This paper presents compression tests of cold-formed plain and CFRP strengthened steel channel section columns. This paper also proposes a design method based on Direct Strength Method provisions specified in American Iron and Steel Institute (AISI, for determining the axial compression strength. Results obtained from the proposed design method are compared with experimental test data and are found to be in good agreement.

  20. Interfacial stresses in strengthened beam with shear cohesive zone model

    Indian Academy of Sciences (India)

    Zergua Abdesselam

    2015-02-01

    The failure of strengthened beams with fibre-reinforced polymer (FRP) materials is due to high stress concentration of FRP–concrete interface. Understanding the cause and mechanism of the debonding of the FRP plate and the prediction of the stress distribution at the concrete–FRP interface are important for more effective strengthening technique. This paper presents an analytical solution, based on Smith and Teng’s equations, for interfacial shear and normal stresses in reinforced concrete (RC) beams strengthened with a fibre reinforced polymer (FRP) plate. However, the shear stress–strain relationship is considered to be bilinear curve. The effects of the shear deformations are calculated in an RC beam, an adhesive layer, and an FRP plate. The results of parametric study are compared with those of Smith and Teng. They confirm the accuracy of the proposed approach in predicting both interfacial shear and normal stresses.