A Comparative Assessment of Aerodynamic Models for Buffeting and Flutter of Long-Span Bridges

Directory of Open Access Journals (Sweden)

Igor Kavrakov

2017-12-01

Full Text Available Wind-induced vibrations commonly represent the leading criterion in the design of long-span bridges. The aerodynamic forces in bridge aerodynamics are mainly based on the quasi-steady and linear unsteady theory. This paper aims to investigate different formulations of self-excited and buffeting forces in the time domain by comparing the dynamic response of a multi-span cable-stayed bridge during the critical erection condition. The bridge is selected to represent a typical reference object with a bluff concrete box girder for large river crossings. The models are viewed from a perspective of model complexity, comparing the influence of the aerodynamic properties implied in the aerodynamic models, such as aerodynamic damping and stiffness, fluid memory in the buffeting and self-excited forces, aerodynamic nonlinearity, and aerodynamic coupling on the bridge response. The selected models are studied for a wind-speed range that is typical for the construction stage for two levels of turbulence intensity. Furthermore, a simplified method for the computation of buffeting forces including the aerodynamic admittance is presented, in which rational approximation is avoided. The critical flutter velocities are also compared for the selected models under laminar flow. Keywords: Buffeting, Flutter, Long-span bridges, Bridge aerodynamics, Bridge aeroelasticity, Erection stage

DYNAMIC BEHAVIOR OF TWO-SPAN CONTINUOUS CONCRETE BRIDGES UNDER MOVING OF HIGH-SPEED TRAINS

Directory of Open Access Journals (Sweden)

O. H. Marinichenko

2017-10-01

Full Text Available Purpose. The scientific work provides a comparison of the results of the movement of a high-speed passenger train across the bridge, obtained as a result of finite element modeling in the SAP2000 software package, and real tests of a double-span concrete railway bridge. Analysis of the rigid characteristics of flying structures. Methodology.The numerical method presented in this study shows valid results concerning the dynamic analysis of the behavior of bridges in conditions of high-speed train traffic. The factors influencing the dynamic behavior of bridges under moving loads, the influence of design parameters and rolling stock, as well as the interaction of the train and spans are determined. The system was used in the form of moving concentrated forces simulating the axes of the train. Findings. Maximum movements and accelerations were obtained as a result of the dynamic calculation for different speeds of the train and compared with practical tests. The correctness of the model of a span structure with regard to continuous ferroconcrete spans was verified. Originality. Within the framework of the work, the latest test results were used, including those with speeds calculated on the prospect of rail passenger traffic. For these tests, a model of a span structure was developed. Practical value. The results of the research can be used to plan the introduction of high-speed train traffic on existing and planned flying structures of reinforced concrete bridges. An approach to the design of span structures that will be effective when passing high-speed passenger trains is implemented.

Comparative Research of Extra-large-span Cable-stayed Bridge with Steel Truss Girder and Steel Box Girder

Directory of Open Access Journals (Sweden)

Tan Manjiang

2015-01-01

Full Text Available To research structural performance of extra-large-span cable-stayed bridge under different section forms, with the engineering background of a 800m main-span cable-stayed bridge with steel truss girder, the cable-stayed bridge with steel box girder is designed according to the current bridge regulations when two bridges are designed in an ultimate state of the carrying capacity, so the maximum stress and minimum stress of the stress envelope diagram are substantially the same. A comprehensive comparison is given to two types of bridge on the aspect of static force, natural vibration frequency, stability, economic performance and so on. Analysis results provide future reference for the large-span cable-stayed bridge to select between the steel truss girder and the steel box girder.

Progressive collapse susceptibility of a long span suspension bridge

DEFF Research Database (Denmark)

Olmati, Pierluigi; Giuliani, Luisa

2013-01-01

Long span bridges are complex structural systems, often having strategic roles in the network infrastructures; consequently their susceptibility to a disproportionate response in case of local failures needs to be assessed. In particular, current regulations prescribe that the structural robustness...... should be maintained in case of an accidental hanger detachment. Local damages in bridges, which are characterized by an horizontal load transfer system, may progress along the deck or along the suspension system, as the dynamic overloading of the structural elements immediately adjacent to the failed...

A Summary Review of Correlations between Temperatures and Vibration Properties of Long-Span Bridges

Directory of Open Access Journals (Sweden)

Guang-Dong Zhou

2014-01-01

Full Text Available The shift of modal parameters induced by temperature fluctuation may mask the changes of vibration properties caused by structural damage and result in false structural condition identification. Thoroughly understanding the temperature effects on vibration properties of long-span bridges becomes an especially important issue before vibration-based damage detection methodologies are applied in real bridges. This paper presents an overview of current research activities and developments in the field of correlations between temperatures and vibration properties of long-span bridges. The theoretical derivation methods using classical structural dynamics and closed-form formulations are first briefly introduced. Then the trend analysis methods that are intended to extract the degree of variability in vibration property under temperature variation for different bridges by numerical analysis, laboratory test, or field monitoring are reviewed in detail. Following that, the development of quantitative models to quantify the temperature influence on vibration properties is discussed including the linear model, nonlinear model, and learning model. Finally, some promising research efforts for promoting the study of correlations between temperatures and vibration properties of long-span bridges are suggested.

Simple Evaluation of Load-Carrying Capacity of Multi-Span Folding Bridges based on Floating Supports

Directory of Open Access Journals (Sweden)

Jan Marszałek

2014-12-01

Full Text Available [b]Abstract[/b]. The papers covers simple evaluation of load-carrying capacity of multi-span folding bridges based on floating supports. Combined bridges built in this approach, could be used as a temporary crossing. The methodology of this evaluation is shown graphically on the basis of designed nomograms for two existing bridge structures i.e. MS-54 and DMS-65, mounted on rigid and floating supports. These nomograms facilitate the simple and fast determination of the impact of changing fixed support into floating support with different bridge length spans on the carrying capacity of the bridge. The paper also presents the influence of long-term use (enlarging the mounting backlash in the joints of these structures on the carrying capacity of the bridge.[b]Keywords[/b]: building, folding bridges, nomograms, assembly clearances

Seismic Responses of Shot Span Bridge under Three Different Patterns of Earthquake Excitations

International Nuclear Information System (INIS)

Zhou Daochuan; Chen Guorong; Lu Yan

2010-01-01

This paper presents a study of the influence of three different types of seismic input methods on the longitudinal seismic response of a short, three-span, variable cross-section, reinforced concrete bridge. Research progress of the seismic model is introduced briefly. Finite element model is created for the bridge and time history analysis conducted. Three different types of illustrative excitations are considered: 1) the EI-Centro seismic wave is used as uniform excitations at all bridge supports; 2) fixed apparent wave velocity is used for response analysis of traveling wave excitations on the bridge; 3) conforming to a selected coherency model, the multiple seismic excitation time histories considering spatially variable effects are generated. The contrast study of the response analysis result under the three different seismic excitations is conducted and the influence of different seismic input methods is studied. The comparative analysis of the bridge model shows that the uniform ground motion input can not provide conservative seismic demands-in a number of cases it results in lower response than that predicted by multiple seismic excitations. The result of uniform excitation and traveling wave excitation shows very small difference. Consequently, multiple seismic excitations needs to be applied at the bridge supports for response analysis of short span bridge.

Nondestructive assessment of single-span timber bridges using a vibration- based method

Science.gov (United States)

Xiping Wang; James P. Wacker; Angus M. Morison; John W. Forsman; John R. Erickson; Robert J. Ross

2005-01-01

This paper describes an effort to develop a global dynamic testing technique for evaluating the overall stiffness of timber bridge superstructures. A forced vibration method was used to measure the natural frequency of single-span timber bridges in the laboratory and field. An analytical model based on simple beam theory was proposed to represent the relationship...

Increased of the capacity integral bridge with reinforced concrete beams for single span

Science.gov (United States)

Setiati, N. Retno

2017-11-01

Sinapeul Bridge that was built in 2012 in Sumedang is a bridge type using a full integral system. The prototype of integral bridge with reinforced concrete girder and single span 20 meters until this year had decreased capacity. The bridge was conducted monitoring of strain that occurs in the abutment in 2014. Monitoring results show that based on the data recorded, the maximum strain occurs at the abutment on the location of the integration of the girder of 10.59 x 10-6 tensile stress of 0.25 MPa (smaller than 150 x 10-6) with 3 MPa tensile stress as limit the occurrence of cracks in concrete. Sinapeul bridge abutment with integral system is still in the intact condition. Deflection of the bridge at the time of load test is 1.31 mm. But this time the bridge has decreased exceeded permission deflection (deflection occurred by 40 mm). Besides that, the slab also suffered destruction. One cause of the destruction of the bridge slab is the load factor. It is necessary for required effort to increase the capacity of the integral bridge with retrofitting. Retrofitting method also aims to restore the capacity of the bridge structure due to deterioration. Retrofitting can be done by shortening of the span or using Fibre Reinforced Polymer (FRC). Based on the results obtained by analysis of that method of retrofitting with Fibre Reinforced Polymer (FRC) is more simple and effective. Retrofitting with FRP can increase the capacity of the shear and bending moment becomes 41% of the existing bridge. Retrofitting with FRP method does not change the integral system on the bridge Sinapeul become conventional bridges.

Static and Dynamic Characteristics of a Long-Span Cable-Stayed Bridge with CFRP Cables

Directory of Open Access Journals (Sweden)

Xu Xie

2014-06-01

Full Text Available In this study, the scope of CFRP cables in cable-stayed bridges is studied by establishing a numerical model of a 1400-m span of the same. The mechanical properties and characteristics of CFRP stay cables and of a cable-stayed bridge with CFRP cables are here subjected to comprehensive analysis. The anomalies in the damping properties of free vibration, nonlinear parametric vibration and wind fluctuating vibration between steel cables and CFRP cables are determined. The structural stiffness, wind resistance and traffic vibration of the cable-stayed bridge with CFRP cables are also analyzed. It was found that the static performances of a cable-stayed bridge with CFRP cables and steel cables are basically the same. The natural frequencies of CFRP cables do not coincide with the major natural frequencies of the cable-stayed bridge, so the likelihood of CFRP cable-bridge coupling vibration is minuscule. For CFRP cables, the response amplitudes of both parametric vibration and wind fluctuating vibration are smaller than those of steel cables. It can be concluded from the research that the use of CFRP cables does not change the dynamic characteristics of the vehicle-bridge coupling vibration. Therefore, they can be used in long-span cable-stayed bridges with an excellent mechanical performance.

Static and Dynamic Characteristics of a Long-Span Cable-Stayed Bridge with CFRP Cables.

Science.gov (United States)

Xie, Xu; Li, Xiaozhang; Shen, Yonggang

2014-06-23

In this study, the scope of CFRP cables in cable-stayed bridges is studied by establishing a numerical model of a 1400-m span of the same. The mechanical properties and characteristics of CFRP stay cables and of a cable-stayed bridge with CFRP cables are here subjected to comprehensive analysis. The anomalies in the damping properties of free vibration, nonlinear parametric vibration and wind fluctuating vibration between steel cables and CFRP cables are determined. The structural stiffness, wind resistance and traffic vibration of the cable-stayed bridge with CFRP cables are also analyzed. It was found that the static performances of a cable-stayed bridge with CFRP cables and steel cables are basically the same. The natural frequencies of CFRP cables do not coincide with the major natural frequencies of the cable-stayed bridge, so the likelihood of CFRP cable-bridge coupling vibration is minuscule. For CFRP cables, the response amplitudes of both parametric vibration and wind fluctuating vibration are smaller than those of steel cables. It can be concluded from the research that the use of CFRP cables does not change the dynamic characteristics of the vehicle-bridge coupling vibration. Therefore, they can be used in long-span cable-stayed bridges with an excellent mechanical performance.

Ultimate strength analysis of long-span cable-stayed bridges; Chodai chachokyo no shukyoku kyodo kaiseki to kyodo ni kansuru ichikosatsu

Energy Technology Data Exchange (ETDEWEB)

Xie, X.; Yamaguchi, H. [Saitama Univ., Urawa (Japan)] Nagai, M. [Nagaoka Technical Coll., Niigata (Japan)

1998-07-21

Recently, span of cable-stayed bridges has been getting loner and longer, present situation is that cable-stayed bridges with span 600 to 800m class have been built inside and outside the country, and accurate determination of its ultimate strength has been an important problem statistically. However, concrete design method for evaluating load bearing stress of long-span cable-stayed bridge. Particularly of the main beam whose axial stress is dominating, has not been established so far. As for cable-stayed bridge, even for long-span, effect of plasticization of cross section on ultimate strength is severe because there is little effect of geometric nonlinearity and it is thought that accurate evaluation of ultimate strength only by elastic finite potential analysis is difficult. Accordingly, it is necessary to study the behavior by using combined nonlinear analysis considering the nonlinearity of the material in order to evaluate the safety and economy to long-span cable-stayed bridge. In this report, 3 dimensional analysis method was formularized taking into account the combine nonlinearity of multi-box girder and analysis program of ultimate strength behavior of long-span cable-stayed bridge was developed. 19 refs., 17 figs., 2 tabs.

Seismic Vulnerability Evaluation of a Three-Span Continuous Beam Railway Bridge

Directory of Open Access Journals (Sweden)

Chongwen Jiang

2017-01-01

Full Text Available In order to evaluate the seismic vulnerability of a railway bridge, a nonlinear finite element model of typical three-span continuous beam bridge on the Sichuan-Tibet railway in China was built. It further aimed at performing a probabilistic seismic demand analysis based on the seismic performance of the above-mentioned bridge. Firstly, the uncertainties of bridge parameters were analyzed while a set of finite element model samples were formulated with Latin hypercube sampling method. Secondly, under Wenchuan earthquake ground motions, an incremental dynamic method (IDA analysis was performed, and the seismic peak responses of bridge components were recorded. Thirdly, the probabilistic seismic demand model for the bridge principal components under the prerequisite of two different kinds of bearing, with and without seismic isolation, was generated. Finally, comparison was drawn to further ascertain the effect of two different kinds of bearings on the fragility components. Based on the reliability theory, results were presented concerning the seismic fragility curves.

Dynamic analysis of a long span, cable-stayed freeway bridge using NASTRAN

Science.gov (United States)

Salus, W. L.; Jones, R. E.; Ice, M. W.

1973-01-01

The dynamic analysis for earthquake- and wind-induced response of a long span, cable-stayed freeway bridge by NASTRAN in conjunction with post-processors is described. Details of the structural modeling, the input data generation, and numerical results are given. The influence of the dynamic analysis on the bridge design is traced from the project initiation to the development of a successful earthquake and wind resistant configuration.

Strand Tension Control in Anchor Span for Suspension Bridge Using Dynamic Balance Theory

Directory of Open Access Journals (Sweden)

Da Wang

Full Text Available Abstract Strand tension control is essential in suspension bridge safety. However, few quantitative studies have examined the bending rigidity and boundary condition behavior of strands in the anchor span of suspension bridges because of their special structure and complex configuration. In this paper, a new calculation method for strand tension is explored by using dynamic balance theory to determine the effect of bending rigidity and boundary conditions. The accuracy and effectiveness of the proposed method are tested and confirmed with verification examples and application on Nanxi Yangtze Suspension Bridge in China. The results indicated that only low-order frequency calculation could be used to calculate the strand tension without considering the effect of bending rigidity to ensure control accuracy. The influence of bending rigidity on the control precision is related to the tension and the length of the strands, which is significantly determined by the specific value between the stress rigidity and the bending rigidity. The uncertain boundary conditions of the anchor span cable, which are fixed between consolidated and hinged, also have a major effect on the control accuracy. To improve the accuracy of strand tension control, the least squares method is proposed during the tension construction control of the anchor span. This approach can significantly improve the accuracy of the tension control of the main cable strand. Some recommendations for future bridge analysis are provided based on the results of this study.

Life-Cycle Monitoring of Long-Span PSC Box Girder Bridges through Distributed Sensor Network: Strategies, Methods, and Applications

Directory of Open Access Journals (Sweden)

Zheheng Chen

2015-01-01

Full Text Available Structural health monitoring (SHM has attracted much attention in recent years, which enables early warnings of structural failure, condition assessments, and rational maintenance/repair strategies. In the context of bridges, many long-span steel bridges in China have been installed with the SHM systems; however, the applications of the SHM in prestressed concrete (PSC bridges are still rather limited. On the other hand, the PSC box girder bridges are extensively used in highway and railway systems and premature damage of these bridges is often reported, resulting in considerable maintenance and/or replacement costs. First, this paper presents a state-of-art review on the SHM of long-span PSC bridges. Monitoring strategies, methods, and previous applications for these bridges are summarized and discussed. In order to well capture the behavior of the bridge during its whole life and to maximize the use of sensors, a life-cycle monitoring strategy is proposed, in which the sensor layout is determined according to requirements for construction monitoring, completion test, and in-service monitoring. A case study is made on a three-span PSC box girder bridge in China. The system configuration, sensor layout, and data communications, and so forth, are presented. The up-to-date monitored structural responses are analyzed and compared with the design values.

Seismic performance evaluation of multi-span existing masonry arch bridge

Science.gov (United States)

Laterza, Michelangelo; D'Amato, Michele; Casamassima, Vito Michele

2017-07-01

Existing old masonry arch bridges represent an architectural and cultural heritage of inestimable value, assuming nowadays an important strategic role since most of them are still in service and link roads of primary importance for vehicular traffic. They were mostly built in the last century without considering any horizontal action, and nowadays are serving roads characterized by a transit loads certainly heavier and more frequent than the ones of past. Moreover, very often due to absence of maintenance and to weathering conditions, the elements deteriorate more and more with a consequent loss of integrity and reduction of their carrying capacity. In this paper the seismic assessment of an old multi span masonry arch bridge still in service is illustrated. Pushover analyses are performed with the aim to investigate the numerical model sensitivity and the influence on the global nonlinear response of the bridge components.

Stochastic finite element analysis of long-span bridges with CFRP ...

Indian Academy of Sciences (India)

Stochastic seismic analysis of long-span bridges with Carbon fibre reinforced polymer (CFRP) cables are presented in this study through combination of the advantages ... Gümüşhane University, Department of Civil Engineering, 29000, Gümüşhane, Turkey; Karadeniz Technical University, Department of Civil Engineering, ...

Construction Simulation Analysis of 60m-span Concrete Filled Steel Tube arch bridge

Science.gov (United States)

Shi, Jing Xian; Ding, Qing Hua

2018-06-01

The construction process of the CFST arch bridge is complicated. The construction process not only affects the structural stress in the installation, but also determines the form a bridge and internal force of the bridge. In this paper, a 60m span concrete filled steel tube tied arch bridge is taken as the background, and a three-dimensional finite element simulation model is established by using the MIDAS/Civil bridge structure analysis software. The elevation of the main arch ring, the beam stress, the forces in hanger rods and the modal frequency of the main arch during the construction stage are calculated, and the construction process is simulated and analyzed. Effectively and reasonably guide the construction and ensure that the line and force conditions of the completed bridge meet the design requirements and provides a reliable technical guarantee for the safe construction of the bridge.

The Development of a Proper Laser Displacement Monitoring System for Medium and Short Span Bridges

Directory of Open Access Journals (Sweden)

Hao Tian

2014-09-01

Full Text Available The Health Monitoring System (HMS for a Medium and Short Span (MSS bridge is different to one for a long span bridge, because of factors such assize, scale and importance. Therefore a proper HMS needs to be developed to meet the economic and applicability requirements of the large number of MSS bridges. Approximately 90 % of existing bridges in China are categorized as MSS bridges and most are beginning to deteriorate. Furthermore, there is not a suitable HMS that can assess the condition of the bridge in accordance with a growth market where traffic volumes are likely to increase. Indeed, the artificial patrolling system currently in use is unable to monitor bridges in the long-term and highlight problems within a sufficient time scale. Having discussed the necessity of a HMS for MSS bridges, this paper proposes a suitable system that uses displacement monitoring in addition to the necessary precision. Displacement was chosen as the main monitoring indicator for intuitive, convenient and direct viewing, as its critical characteristic is that it is both economical and straightforward to use. Specific details regarding the laser displacement sensor and the development of a wireless data acquisition and transmission system are also provided. The reliability of the displacement monitoring sensor and data processing system is confirmed through different stages of an installation test.

Some studies on structural planning of long-span cable stayed bridge; Choshikan shachokyo no kozo keikaku ni kansuru 2,3 no kosatsu

Energy Technology Data Exchange (ETDEWEB)

Endo, T. [NKK Corp., Tokyo (Japan)

1997-06-20

Feasibility of cabled-stayed bridges with 1000m-grade spans is discussed while re-examining the plan for constructing a Great Tatara Bridge to connect Honshu and Shikoku, Japan, and in this process various tasks and questions are isolated. Some which will be problems in designing the new bridge structure are taken up, including the load-bearing capability of the bridge as a whole, vibration of long cables, resistance to long-period earthquakes, and accuracy management during the construction work. Findings are stated below. A cable-stayed bridge is not significantly different from a suspension bridge and is sufficiently feasible until the span exceeds 1500m. When the span is longer, however, the bridge beam cross section needs be designed very prudently in view of the great axial force and wind load to be imposed on it. Effective for the assurance of load-bearing capability for a long-span cabled-stayed bridge is a structure in which load is elastically confined in the direction of the bridge axis. In connection with vibration damping for very long cables, it is verified that a new dimpled cable suits the purpose of suppressing wind load from increasing without reduction in damping effect. 28 refs., 23 figs., 7 tabs.

Design and evaluation of a single-span bridge using ultra-high performance concrete.

Science.gov (United States)

2009-09-01

"Research presented herein describes an application of a newly developed material called Ultra-High Performance Concrete (UHPC) to a : single-span bridge. The two primary objectives of this research were to develop a shear design procedure for possib...

Influence of apparent wave velocity on seismic performance of a super-long-span triple-tower suspension bridge

Directory of Open Access Journals (Sweden)

Hao Wang

2015-06-01

Full Text Available As one of the main characteristics of seismic waves, apparent wave velocity has great influence on seismic responses of long-span suspension bridges. Understanding these influences is important for seismic design. In this article, the critical issues concerning the traveling wave effect analysis are first reviewed. Taizhou Bridge, the longest triple-tower suspension bridge in the world, is then taken as an example for this investigation. A three-dimensional finite element model of the bridge is established in ABAQUS, and the LANCZOS eigenvalue solver is employed to calculate the structural dynamic characteristics. Traveling wave effect on seismic responses of these long-span triple-tower suspension bridges is investigated. Envelopes of seismic shear force and moment in the longitudinal direction along the three towers, relative displacements between the towers and the girder, and reaction forces at the bottoms of the three towers under different apparent wave velocities are calculated and presented in detail. The results show that the effect of apparent wave velocity on the seismic responses of triple-tower suspension bridge fluctuates when the velocity is lower than 2000 m/s, and the effects turn stable when the velocity becomes larger. In addition, the effects of traveling wave are closely related to spectral characteristics and propagation direction of the seismic wave, and seismic responses of components closer to the source are relatively larger. Therefore, reliable estimation of the seismic input and apparent wave velocity according to the characteristics of the bridge site are significant for accurate prediction of seismic responses. This study provides critical reference for seismic analysis and design of long-span triple-tower suspension bridges.

Static behaviors of long-span cable-stayed bridge; Chodai shachokyo no seiteki kyodo ni kansuru kosatsu

Energy Technology Data Exchange (ETDEWEB)

Xie, Xu [Saitama Univ., Saitama (Japan). Graduate School; Yamaguchi, H.; Ito, M. [Saitama Univ., Urawa (Japan). Faculty of Engineering

1996-04-21

In this study, incremental equation of cable-stayed bridge is formulated by finite element method taking the geometrical nonlinear analysis into account. Then, as an example of designing a bridge with 1500m span, setting up the initial tension, analysis of in-plane behavior caused by live loads as well as analysis of the behavior against wind caused by out-of-plane wind load that are necessary for designing a bridge with 1500m span are carried out. The main results obtained through the study are as follows. As for the cable stayed bridge with 1500m center super long-span having supplementary supporting points between the side arms, the geometrical non-linearity caused by the in-plane design live loads is not remarkable. The effects of wind which acts on girders on analysis of the behaviors against wind are different depending on the aerodynamic performance of the girder and in the case of high wind speed, strong effects on the behavior against wind of the in-plane and screws generate. As the changing of tension of the cable makes influences on the force of in-plane cross section and on displacement of the girder, if the wind speed is very high, the analysis results of the behaviors against wind of in-plane and screws of the cable-stayed bridge may be different depending on in what manner the wind load on the cable to be treated. 16 refs., 16 figs., 1 tab.

Arch-Axis Coefficient Optimization of Long-Span Deck-Type Concrete-Filled Steel Tubular Arch Bridge

Science.gov (United States)

Liu, Q. J.; Wan, S.; Liu, H. C.

2017-11-01

This paper is based on Nanpuxi super major bridge which is under construction and starts from Wencheng Zhejiang province to Taishun highway. A finite element model of the whole bridge is constructed using Midas Civil finite element software. The most adverse load combination in the specification is taken into consideration to determine the method of calculating the arch-axis coefficient of long-span deck-type concrete-filled steel tubular arch bridge. By doing this, this paper aims at providing references for similar engineering projects.

Proposal and study of a long-span composite cable-stayed bridge with new hybrid girder; Atarashii gosei kozo shuketa wo mochiita chodai fukugo shachokyo no kenkyu

Energy Technology Data Exchange (ETDEWEB)

Yoshida, K.; Hishiki, Y.; Furuichi, K. [Kajima Corp., Tokyo (Japan)

1999-09-30

A hybrid or mixed structure (composite structures) are a matter of increasing concern which takes in each advantage of steel and concrete. A field of bridges is no exception, with the plan and construction carried out for the new type of composite bridge, such as a composite cable-stayed bridge and a composite extra dose bridge as a long span bridge, and a composite truss bridge and a corrugated steel plate web bridge as a medium-span bridge, with technological development becoming active in this field. In such a technological trend, a hybrid two-girder structure was devised, a structure consisting of a concrete filled steel pipe for a girder and a precast (PC) floor plate for a floor board, as the girder structure of a long-span cable-stayed bridge in the subject research; also, applicability was examined using, as an example, the composite cable-stayed bridge with hybrid girders employed for the span. This paper reports the result of the analysis of the entire system, the analysis made for the purpose of examining the characteristic and the feasibility of this hybrid girder. The analysis revealed the structural feasibility of the long-span composite cable-stayed bridge using two hybrid girders of concrete-filled steel pipes thus devised. (NEDO)

Application of an automated wireless structural monitoring system for long-span suspension bridges

International Nuclear Information System (INIS)

Kurata, M.; Lynch, J. P.; Linden, G. W. van der; Hipley, P.; Sheng, L.-H.

2011-01-01

This paper describes an automated wireless structural monitoring system installed at the New Carquinez Bridge (NCB). The designed system utilizes a dense network of wireless sensors installed in the bridge but remotely controlled by a hierarchically designed cyber-environment. The early efforts have included performance verification of a dense network of wireless sensors installed on the bridge and the establishment of a cellular gateway to the system for remote access from the internet. Acceleration of the main bridge span was the primary focus of the initial field deployment of the wireless monitoring system. An additional focus of the study is on ensuring wireless sensors can survive for long periods without human intervention. Toward this end, the life-expectancy of the wireless sensors has been enhanced by embedding efficient power management schemes in the sensors while integrating solar panels for power harvesting. The dynamic characteristics of the NCB under daily traffic and wind loads were extracted from the vibration response of the bridge deck and towers. These results have been compared to a high-fidelity finite element model of the bridge.

Application of AN Automated Wireless Structural Monitoring System for Long-Span Suspension Bridges

Science.gov (United States)

Kurata, M.; Lynch, J. P.; van der Linden, G. W.; Hipley, P.; Sheng, L.-H.

2011-06-01

This paper describes an automated wireless structural monitoring system installed at the New Carquinez Bridge (NCB). The designed system utilizes a dense network of wireless sensors installed in the bridge but remotely controlled by a hierarchically designed cyber-environment. The early efforts have included performance verification of a dense network of wireless sensors installed on the bridge and the establishment of a cellular gateway to the system for remote access from the internet. Acceleration of the main bridge span was the primary focus of the initial field deployment of the wireless monitoring system. An additional focus of the study is on ensuring wireless sensors can survive for long periods without human intervention. Toward this end, the life-expectancy of the wireless sensors has been enhanced by embedding efficient power management schemes in the sensors while integrating solar panels for power harvesting. The dynamic characteristics of the NCB under daily traffic and wind loads were extracted from the vibration response of the bridge deck and towers. These results have been compared to a high-fidelity finite element model of the bridge.

Lifetime fatigue reliability evaluation of short to medium span bridges under site-specific stochastic truck loading

OpenAIRE

Yan, Donghuang; Luo, Yuan; Yuan, Ming; Lu, Naiwei

2017-01-01

Bridges are vulnerable to the fatigue damage accumulation caused by traffic loading over the service period. A continuous growth in both the vehicle weight and the traffic volume may cause a safety hazard to existing bridges. This study presented a computational framework for probabilistic modeling of the fatigue damage accumulation of short to medium span bridges under actual traffic loading. Stochastic truck-load models were simulated based on site-specific weigh-in-motion measurements. A r...

Seismic assessment of a multi-span steel railway bridge in Turkey based on nonlinear time history

Science.gov (United States)

Yılmaz, Mehmet F.; Çağlayan, Barlas Ö.

2018-01-01

Many research studies have shown that bridges are vulnerable to earthquakes, graphically confirmed by incidents such as the San Fernando (1971 USA), Northridge (1994 USA), Great Hanshin (1995 Japan), and Chi-Chi (1999 Taiwan) earthquakes, amongst many others. The studies show that fragility curves are useful tools for bridge seismic risk assessments, which can be generated empirically or analytically. Empirical fragility curves can be generated where damage reports from past earthquakes are available, but otherwise, analytical fragility curves can be generated from structural seismic response analysis. Earthquake damage data in Turkey are very limited, hence this study employed an analytical method to generate fragility curves for the Alasehir bridge. The Alasehir bridge is part of the Manisa-Uşak-Dumlupınar-Afyon railway line, which is very important for human and freight transportation, and since most of the country is seismically active, it is essential to assess the bridge's vulnerability. The bridge consists of six 30 m truss spans with a total span 189 m supported by 2 abutments and 5 truss piers, 12.5, 19, 26, 33, and 40 m. Sap2000 software was used to model the Alasehir bridge, which was refined using field measurements, and the effect of 60 selected real earthquake data analyzed using the refined model, considering material and geometry nonlinearity. Thus, the seismic behavior of Alasehir railway bridge was determined and truss pier reaction and displacements were used to determine its seismic performance. Different intensity measures were compared for efficiency, practicality, and sufficiency and their component and system fragility curves derived.

Life-Cycle Monitoring of Long-Span PSC Box Girder Bridges through Distributed Sensor Network: Strategies, Methods, and Applications

OpenAIRE

Chen, Zheheng; Guo, Tong; Yan, Shengyou

2015-01-01

Structural health monitoring (SHM) has attracted much attention in recent years, which enables early warnings of structural failure, condition assessments, and rational maintenance/repair strategies. In the context of bridges, many long-span steel bridges in China have been installed with the SHM systems; however, the applications of the SHM in prestressed concrete (PSC) bridges are still rather limited. On the other hand, the PSC box girder bridges are extensively used in highway and railway...

Static and Dynamic Mechanical Properties of Long-Span Cable-Stayed Bridges Using CFRP Cables

Directory of Open Access Journals (Sweden)

Mei Kuihua

2017-01-01

Full Text Available The elastic modulus and deadweight of carbon fiber-reinforced polymer (CFRP cables are different from those of steel cables. Thus, the static and dynamic behaviors of cable-stayed bridges using CFRP cables are different from those of cable-stayed bridges using steel cables. The static and dynamic performances of the two kinds of bridges with a span of 1000 m were studied using the numerical method. The effects of geometric nonlinear factors on static performance of the two kinds of cable-stayed bridges were analyzed. The live load effects and temperature effects of the two cable-stayed bridges were also analyzed. The influences of design parameters, including different structural systems, the numbers of auxiliary piers, and the space arrangement types of cable, on the dynamic performance of the cable-stayed bridge using CFRP cables were also studied. Results demonstrate that sag effect of the CFRP cable is much smaller than that of steel cable. The temperature effects of CFRP cable-stayed bridge are less than those of steel cable-stayed bridge. The vertical bending natural vibration frequency of the CFRP cable-stayed bridge is generally lower than that of steel cable-stayed bridge, whereas the torsional natural vibration frequency of the former is higher than that of the latter.

a Method for the Extraction of Long-Term Deformation Characteristics of Long-Span High-Speed Railway Bridges Using High-Resolution SAR Images

Science.gov (United States)

Jia, H. G.; Liu, L. Y.

2016-06-01

Natural causes and high-speed train load will result in the structural deformation of long-span bridges, which greatly influence the safety operation of high-speed railway. Hence it is necessary to conduct the deformation monitoring and regular status assessment for long-span bridges. However for some traditional surveying technique, e.g. control-point-based surveying techniques, a lot of human and material resources are needed to perform the long-term monitoring for the whole bridge. In this study we detected the long-term bridge deformation time-series by persistent scatterer interferometric synthetic aperture radar (PSInSAR) technique using the high-resolution SAR images and external digital elevation model. A test area in Nanjing city in China is chosen and TerraSAR-X images and Tandem-X for this area have been used. There is the Dashengguan bridge in high speed railway in this area as study object to evaluate this method. Experiment results indicate that the proposed method can effectively extract the long-term deformation of long-span high-speed railway bridge with higher accuracy.

A METHOD FOR THE EXTRACTION OF LONG-TERM DEFORMATION CHARACTERISTICS OF LONG-SPAN HIGH-SPEED RAILWAY BRIDGES USING HIGH-RESOLUTION SAR IMAGES

Directory of Open Access Journals (Sweden)

H. G. Jia

2016-06-01

Full Text Available Natural causes and high-speed train load will result in the structural deformation of long-span bridges, which greatly influence the safety operation of high-speed railway. Hence it is necessary to conduct the deformation monitoring and regular status assessment for long-span bridges. However for some traditional surveying technique, e.g. control-point-based surveying techniques, a lot of human and material resources are needed to perform the long-term monitoring for the whole bridge. In this study we detected the long-term bridge deformation time-series by persistent scatterer interferometric synthetic aperture radar (PSInSAR technique using the high-resolution SAR images and external digital elevation model. A test area in Nanjing city in China is chosen and TerraSAR-X images and Tandem-X for this area have been used. There is the Dashengguan bridge in high speed railway in this area as study object to evaluate this method. Experiment results indicate that the proposed method can effectively extract the long-term deformation of long-span high-speed railway bridge with higher accuracy.

A METHOD FOR THE EXTRACTION OF LONG-TERM DEFORMATION CHARACTERISTICS OF LONG-SPAN HIGH-SPEED RAILWAY BRIDGES USING HIGH-RESOLUTION SAR IMAGES

OpenAIRE

Jia, H. G.; Liu, L. Y.

2016-01-01

Natural causes and high-speed train load will result in the structural deformation of long-span bridges, which greatly influence the safety operation of high-speed railway. Hence it is necessary to conduct the deformation monitoring and regular status assessment for long-span bridges. However for some traditional surveying technique, e.g. control-point-based surveying techniques, a lot of human and material resources are needed to perform the long-term monitoring for the whole bridge. In this...

Seismic assessment of a multi-span steel railway bridge in Turkey based on nonlinear time history

Directory of Open Access Journals (Sweden)

M. F. Yılmaz

2018-01-01

Full Text Available Many research studies have shown that bridges are vulnerable to earthquakes, graphically confirmed by incidents such as the San Fernando (1971 USA, Northridge (1994 USA, Great Hanshin (1995 Japan, and Chi-Chi (1999 Taiwan earthquakes, amongst many others. The studies show that fragility curves are useful tools for bridge seismic risk assessments, which can be generated empirically or analytically. Empirical fragility curves can be generated where damage reports from past earthquakes are available, but otherwise, analytical fragility curves can be generated from structural seismic response analysis. Earthquake damage data in Turkey are very limited, hence this study employed an analytical method to generate fragility curves for the Alasehir bridge. The Alasehir bridge is part of the Manisa–Uşak–Dumlupınar–Afyon railway line, which is very important for human and freight transportation, and since most of the country is seismically active, it is essential to assess the bridge's vulnerability. The bridge consists of six 30 m truss spans with a total span 189 m supported by 2 abutments and 5 truss piers, 12.5, 19, 26, 33, and 40 m. Sap2000 software was used to model the Alasehir bridge, which was refined using field measurements, and the effect of 60 selected real earthquake data analyzed using the refined model, considering material and geometry nonlinearity. Thus, the seismic behavior of Alasehir railway bridge was determined and truss pier reaction and displacements were used to determine its seismic performance. Different intensity measures were compared for efficiency, practicality, and sufficiency and their component and system fragility curves derived.

Seismic enhancement of multi-span continuous bridges subjected to three-directional excitations

Science.gov (United States)

Aryan, H.; Ghassemieh, M.

2015-04-01

Considering the seismic ground motions as the excitations in only two principal horizontal directions of the bridges and ignoring the third vertical direction is a disregard for the seismic conditions of the region and the bridge distance from epicenter. Numerous cases of substantial damages have been reported among the bridges tremendously suffered from being exposed to the simultaneous three-directional seismic ground motions. Besides the significant compression and tension damages in the columns due to the presence of vertical excitation, it could lead to unexpected shear and flexural failures in the columns and other components as well. Because the axial force variation in the columns due to three-directional excitations, could affect the demands and capacities of the bridge’s components. With respect to this issue, several studies on the bridge damages during the earthquakes have urged researchers to offer efficient methods for bridges handling of the three-directional seismic excitations. Thus, this paper presents and evaluates a superelastic based system for designing as well as retrofitting the multi-span continuous (MSC) bridges that can cope with two- and three-directional seismic excitations. Efficiency evaluation of the proposed system is conducted through various nonlinear time history analyses on a three-dimensional model of a detailed MSC bridge using a suite of developed ground motions for the bridge region. Also, all the analyses are fulfilled based on variation of one influential design characteristic of the proposed system in order to achieve the optimal design. Several pertinent assessment parameters are used during the evaluation of the proposed system. Finally, the efficiency of the new system subjected to the vertical and horizontal seismic excitations is confirmed according to reduction of the bridge responses and improvement in nonlinear performance of the columns in comparison with the as-built bridge results.

Proposal of self-anchored cable-supported bridge with main span length of 500m; Chuo span 500m kibo no jiteishiki tsurigatashiki kyoryo ni kansuru teian

Energy Technology Data Exchange (ETDEWEB)

Fukasawa, Y.; Sugiyama, T. [Yamaguchi University, Yamaguchi (Japan). Faculty of Engineering; Kaneko, S.; Mukoyama, T.; Iwaki, T. [Pacific Consultants K.K., Tokyo (Japan)

1995-12-15

In order to investigate the feasibility of construction of cable-supported bridge at the site where ground condition is poor and/or air route restriction shoed be considered the static and dynamic characteristics of both self-anchored cable-stayed bridge with relatively low tower and self-anchored suspension bridge have been discussed. The main span length of bridge considered here is about 500 m because of the fact that stress resultant of main girder caused by design loads is considerably lower than its design strength in the existing cable-supported bridges of this scale. The result shows that the application of both types of cable-supported bridges to the above described site may be possible as enough static safety and economy are ensured. It has been also revealed that no problem may occur from both wind and earthquake resistant viewpoints. 10 refs., 24 figs., 8 tabs.

Post-tensioning and splicing of precast/prestressed bridge beams to extend spans

Science.gov (United States)

Collett, Brandon S.; Saliba, Joseph E.

2002-06-01

This paper explores the status and techniques of post-tensioning and splicing precast concrete I-beams in bridge applications. It will look at the current practices that have been used in the United States and comment on the advantages of these techniques. Representative projects are presented to demonstrate the application and success of specific methods used. To demonstrate the benefits of using post-tensioning and splicing to extend spans, multiple analysis of simple span post-tensioned I-beams were performed varying such characteristics as beam spacing, beam sections, beam depth and concrete strength. Tables were then developed to compare the maximum span length of a prestressed I-beam versus a one segment or a spliced three segment post-tensioned I-beam. The lateral stability of the beam during fabrication, transportation and erection is also examined and discussed. These tables are intended to aid designers and owners in preliminary project studies to determine if post-tensioning can be beneficial to their situation. AASHTO Standard Specifications(2) will be used as basic guidelines and specifications. In many cases, post-tensioning was found to extend the maximum span length of a typical 72-inch precast I-beam more than 40 feet over conventional prestress.

An assessment of the dynamic interaction of the rolling stock and the long-span bridges on high-speed railways

Directory of Open Access Journals (Sweden)

K. Dyachenko Leonid

2017-01-01

Full Text Available When the high-speed railway traffic is being organized, it becomes necessary to elaborate bridge design standards for high-speed railways. To ensure safety of traffic and reliability of bridges one needs to resolve the dynamic problems of various types of high-speed trains moving along the structures. The article analyzes the magnitude of inertial response as the function of the external stress parameters. A simplified structure assessment technique is offered based on the criterion of passenger comfort while crossing the bridges. The usefulness of the given research arises from the reduction of complexity of the complicated dynamic calculations needed to describe a high-speed train travelling along the artificial structures. Dependences of relative elastic deflection values from the span length are proposed, which allows designing and calculating long-span structures using the simplified dynamic models.

Evaluation of damping property of long-span prestressed concrete cable-stayed bridges; Chodai PC shachokyo no gensui tokusei ni kansuru kosatsu

Energy Technology Data Exchange (ETDEWEB)

Yamanobe, S.; Niihara, Y.; Minami, H.; Kono, T. [Kajima Corp., Tokyo (Japan)

1999-09-30

As to the dynamic design in the antiseismic design of PC cable-stayed bridges, evaluation of damping is important. Since it is difficult to evaluate damping property theoretically and analytically, a lot of studies have not been made about how to set up damping coefficients. In this study, using analytical models of existing long-span PC cable-stayed bridges, to clarify causes of damping of long-span PC cable-stayed bridge, the rate of strain energy in each member was examined. Equivalent damping coefficients of each member, effects of friction in movable bearing, and effects of basically radiational damping were studied. The correspondence with the results of the vibration experiments conventionally made were studied. (translated by NEDO)

Traveling Wave Resonance and Simplified Analysis Method for Long-Span Symmetrical Cable-Stayed Bridges under Seismic Traveling Wave Excitation

Directory of Open Access Journals (Sweden)

Zhong-ye Tian

2014-01-01

Full Text Available The seismic responses of a long-span cable-stayed bridge under uniform excitation and traveling wave excitation in the longitudinal direction are, respectively, computed. The numerical results show that the bridge’s peak seismic responses vary significantly as the apparent wave velocity decreases. Therefore, the traveling wave effect must be considered in the seismic design of long-span bridges. The bridge’s peak seismic responses do not vary monotonously with the apparent wave velocity due to the traveling wave resonance. A new traveling wave excitation method that can simplify the multisupport excitation process into a two-support excitation process is developed.

Effect of Soil-Structure Interaction on Seismic Performance of Long-Span Bridge Tested by Dynamic Substructuring Method

Directory of Open Access Journals (Sweden)

Zhenyun Tang

2017-01-01

Full Text Available Because of the limitations of testing facilities and techniques, the seismic performance of soil-structure interaction (SSI system can only be tested in a quite small scale model in laboratory. Especially for long-span bridge, a smaller tested model is required when SSI phenomenon is considered in the physical test. The scale effect resulting from the small scale model is always coupled with the dynamic performance, so that the seismic performance of bridge considering SSI effect cannot be uncovered accurately by the traditional testing method. This paper presented the implementation of real-time dynamic substructuring (RTDS, involving the combined use of shake table array and computational engines for the seismic simulation of SSI. In RTDS system, the bridge with soil-foundation system is divided into physical and numerical substructures, in which the bridge is seen as physical substructures and the remaining part is seen as numerical substructures. The interface response between the physical and numerical substructures is imposed by shake table and resulting reaction force is fed back to the computational engine. The unique aspect of the method is to simulate the SSI systems subjected to multisupport excitation in terms of a larger physical model. The substructuring strategy and the control performance associated with the real-time substructuring testing for SSI were performed. And the influence of SSI on a long-span bridge was tested by this novel testing method.

Field performance of timber bridges. 9, Big Erick`s stress-laminated deck bridge

Science.gov (United States)

J. A. Kainz; J. P. Wacker; M. Nelson

The Big Erickas bridge was constructed during September 1992 in Baraga County, Michigan. The bridge is 72 ft long, 16 ft wide, and consists of three simple spans: two stress-laminated deck approach spans and a stress-laminated box center span. The bridge is unique in that it is one of the first known stress-laminated timber bridge applications to use Eastern Hemlock...

Field vibration test of a long-span cable-stayed bridge by large exciters. Daishinpuku kashin ni yoru chodai shachokyo no jikkyo shindo jikken

Energy Technology Data Exchange (ETDEWEB)

Okauchi, I. (Chuo University, Tokyo (Japan). Faculty of Science and Engineering); Miyata, T. (Yokohama National University, Yokohama (Japan). Faculty of Engineering); Sasaki, N. (Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)); Tatsumi, M.

1992-10-15

Long-span cable-stayed bridge requires indispensably discussions on safety against gale and earthquake, and correct assessment on its inherent vibration characteristics at the design stage is critical. However, theoretical assessment on structural decay is difficult, hence it is desirable to make measurement and verification upon its completion. This paper reports the result of measurements and considerations on a three-span continuous steel cable-stayed bridge with a length of 790 m (185 m + 420 m + 185 m) spanning between Hitsuishi Island and Iwakuro Island in the Kojima-Sakaide route of the Honshu-Shikoku connecting bridge. Large shaking machines were used to give girders vibrations with large amplitudes (10 cm at maximum), and high-accuracy measurements were made. The measurements verified the reasonability of the dynamic design for the bridge. The measured value of the logarithmic decay rate [delta] as the major experimental data presented that bending vibration is large as a whole, with torsional vibration somewhat smaller, and all the design values were on safety side. Confirmation was made on amplitude dependence of the decay rate, the inherent modes of low-order vibrations, and coupled behaviors among the girders, cables, and towers. 16 refs., 13 figs., 3 tabs.

Investigation of the Stability of a Two-Span Bridge with the use of a High-Precision Laser Displacement Sensors

Science.gov (United States)

Poddaeva, O.; Churin, P.; Fedosova, A.; Truhanov, S.

2018-03-01

Studies of aerodynamics of bridge structures are an actual problem. Such attention is paid to the study of wind influence on bridge structures not at all by chance; a large number of cases of loss of stability of such structures are known under the influence of wind up to their complete destruction. The development of non-contact systems of measuring equipment allows solving this problem with a high level of accuracy and reliability. This article presents the results of experimental studies of wind impact on a two-span bridge using specialized measuring system based on high-precision laser displacement sensors.

Deck and Cable Dynamic Testing of a Single-span Bridge Using Radar Interferometry and Videometry Measurements

Science.gov (United States)

Piniotis, George; Gikas, Vassilis; Mpimis, Thanassis; Perakis, Harris

2016-03-01

This paper presents the dynamic testing of a roadway, single-span, cable-stayed bridge for a sequence of static load and ambient vibration monitoring scenarios. Deck movements were captured along both sideways of the bridge using a Digital Image Correlation (DIC) and a Ground-based Microwave Interfererometer (GBMI) system. Cable vibrations were measured at a single point location on each of the six cables using the GBMI technique. Dynamic testing involves three types of analyses; firstly, vibration analysis and modal parameter estimation (i. e., natural frequencies and modal shapes) of the deck using the combined DIC and GBMI measurements. Secondly, dynamic testing of the cables is performed through vibration analysis and experimental computation of their tension forces. Thirdly, the mechanism of cable-deck dynamic interaction is studied through their Power Spectra Density (PSD) and the Short Time Fourier Transform (STFT) analyses. Thereby, the global (deck and cable) and local (either deck or cable) bridge modes are identified, serving a concrete benchmark of the current state of the bridge for studying the evolution of its structural performance in the future. The level of synergy and complementarity between the GBMI and DIC techniques for bridge monitoring is also examined and assessed.

Structural Behavior of a Long-Span Partially Earth-Anchored Cable-Stayed Bridge during Installation of a Key Segment by Thermal Prestressing

Directory of Open Access Journals (Sweden)

Sang-Hyo Kim

2016-08-01

Full Text Available This study investigated structural behavior of long-span partially earth-anchored cable-stayed bridges with a main span length of 810 m that use a new key segment closing method based on a thermal prestressing technique. A detailed construction sequence analysis matched with the free cantilever method (FCM was performed using a three-dimensional finite element (FE model of a partially earth-anchored cable-stayed bridge. The new method offers an effective way of connecting key segments by avoiding large movements resulting from the removal of the longitudinal restraint owing to the asymmetry of axial forces in the girders near the pylons. The new method develops new member forces through the process of heating the cantilever system before installing the key segment and cooling the system continuously after installing key segments. The resulting forces developed by the thermal process enhance the structural behavior of partially earth-anchored cable-stayed bridges owing to decreased axial forces in the girders.

Finite element model updating of multi-span steel-arch-steel-girder bridges based on ambient vibrations

Science.gov (United States)

Hou, Tsung-Chin; Gao, Wei-Yuan; Chang, Chia-Sheng; Zhu, Guan-Rong; Su, Yu-Min

2017-04-01

The three-span steel-arch-steel-girder Jiaxian Bridge was newly constructed in 2010 to replace the former one that has been destroyed by Typhoon Sinlaku (2008, Taiwan). It was designed and built to continue the domestic service requirement, as well as to improve the tourism business of the Kaohsiung city government, Taiwan. This study aimed at establishing the baseline model of Jiaxian Bridge for hazardous scenario simulation such as typhoons, floods and earthquakes. Necessities of these precaution works were attributed to the inherent vulnerability of the sites: near fault and river cross. The uncalibrated baseline bridge model was built with structural finite element in accordance with the blueprints. Ambient vibration measurements were performed repeatedly to acquire the elastic dynamic characteristics of the bridge structure. Two frequency domain system identification algorithms were employed to extract the measured operational modal parameters. Modal shapes, frequencies, and modal assurance criteria (MAC) were configured as the fitting targets so as to calibrate/update the structural parameters of the baseline model. It has been recognized that different types of structural parameters contribute distinguishably to the fitting targets, as this study has similarly explored. For steel-arch-steel-girder bridges in particular this case, joint rigidity of the steel components was found to be dominant while material properties and section geometries relatively minor. The updated model was capable of providing more rational elastic responses of the bridge superstructure under normal service conditions as well as hazardous scenarios, and can be used for manage the health conditions of the bridge structure.

Structural observation of long-span suspension bridges for safety assessment: implementation of an optical displacement measurement system

International Nuclear Information System (INIS)

Martins, L Lages; Ribeiro, A Silva; Rebordão, J M

2015-01-01

This paper addresses the implementation of an optical displacement measurement system in the observation scenario of a long-span suspension bridge and its contribution for structural safety assessment. The metrological background required for quality assurance of the measurements is described, namely, the system's intrinsic parameterization and integration in the SI dimensional traceability chain by calibration, including its measurement uncertainty assessment

Integral Abutment and Jointless Bridges

Directory of Open Access Journals (Sweden)

Cristian-Claudiu Comisu

2005-01-01

Full Text Available 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 that have their superstructure cast integrally with their substructure. The jointless bridges cost less to construct and require less maintenance then equivalent bridges with expansion joints. Integral bridges present a challenge for load distribution calculations because the bridge deck, piers, abutments, embankments and soil must all be considered as single compliant system. This paper presents some of the important features of integral abutment and jointless bridge design and some guidelines to achieve improved design. The goal of this paper is to enhance the awareness among the engineering community to use integral abutment and jointless bridges in Romania.

Economic impact of multi-span, prestressed concrete girder bridges designed as simple span versus continuous span : final report.

Science.gov (United States)

2016-10-01

The objective of this study was to determine the economic impact of designing pre-tensioned prestressed concrete beam (PPCB) : bridges utilizing the continuity developed in the bridge deck as opposed to the current Iowa Department of Transportation (...

Economic impact of multi-span, prestressed concrete girder bridges designed as simple span versus continuous span : tech transfer summary.

Science.gov (United States)

2016-10-01

The objective of this study was to determine the economic impact of : designing pre-tensioned prestressed concrete beam (PPCB) bridges : utilizing the continuity developed in the bridge deck as opposed to the : current Iowa Department of Transportati...

The Akashi Kaikyo Bridge and the Storebælt Bridge

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

1999-01-01

With the completion of the Akashi Kaikyo Bridge and the Storebælt East Bridge the development of the suspension bridge technology in the 20th century has manifested itself in two impressive structures. With the present echnology may bridges of similar (and also more modest) dimensions...... will undoubtedly be built far into the next century. For bridges going beyond the spans of existing bridges it is, however, likely that new concepts will be developed....

Wind effects on long-span bridges: Probabilistic wind data format for buffeting and VIV load assessments

Science.gov (United States)

Hoffmann, K.; Srouji, R. G.; Hansen, S. O.

2017-12-01

The technology development within the structural design of long-span bridges in Norwegian fjords has created a need for reformulating the calculation format and the physical quantities used to describe the properties of wind and the associated wind-induced effects on bridge decks. Parts of a new probabilistic format describing the incoming, undisturbed wind is presented. It is expected that a fixed probabilistic format will facilitate a more physically consistent and precise description of the wind conditions, which in turn increase the accuracy and considerably reduce uncertainties in wind load assessments. Because the format is probabilistic, a quantification of the level of safety and uncertainty in predicted wind loads is readily accessible. A simple buffeting response calculation demonstrates the use of probabilistic wind data in the assessment of wind loads and responses. Furthermore, vortex-induced fatigue damage is discussed in relation to probabilistic wind turbulence data and response measurements from wind tunnel tests.

Construction Technology of Long Span Bridges

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

2000-01-01

A large variety of construction methods are used during construction of major bridges, and in many cases the final structural system must be chosen with due respect to the construction process. Today the preferred construction methods are: the free-cantilever method, the launching method...

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.

33 CFR 118.80 - Lights on bascule bridges.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on bascule bridges. 118.80 Section 118.80 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.80 Lights on bascule bridges. (a) Lift span lights. Each lift span of...

33 CFR 118.85 - Lights on vertical lift bridges.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

Verification of LRFD Bridge Design and Analysis Software for INDOT

OpenAIRE

Varma, Amit H.; Seo, Jungil

2009-01-01

NCHRP Process 12-50 was implemented to evaluate and verify composite steel I-girder bridge design software used commonly in Indiana. A test-bed of twenty one bridges was developed with the guidance from an Indiana Department of Transportation appointed research advisory panel (RAP). The test-bed included five simple-span and sixteen multi-span bridge superstructures. More than 80 parameters were required to define a bridge and they include bridge span, girder spacing, number of beams, section...

Modal analysis of cable-stayed UHPC bridge

Directory of Open Access Journals (Sweden)

Tej Petr

2017-01-01

Full Text Available This paper deals with the dynamic analysis of cable-stayed UHPC bridge over the Vltava river near town Melnik in Czech Republic, Europe. Bridge serves for pedestrians and cyclists. This work aims to familiarize the reader with dynamic calculations carried out and the results obtained, describing the dynamic properties of proposed bridge. The construction of bridge is designed as a cable-stayed structure with prestressed bridge deck consisting of prefabricated UHPC panels and reversed “V” shaped steel pylon with height of approximately 40 meters. The deck is anchored using 24 steel hangers in one row in a steel pylon - 17 ropes in the main span and 7 cables on the other side. Range of the main span is 99.18 meters and the secondary span is 31.9 m. Deck width is 4.5 meters with 3.0 meters passing space. The bridge is designed for the possibility of passage of vehicles weighting up to 3.5 tonnes. Deck panels are made of UHPC with reinforcement. At the edge of the bridge on the side of the shorter span the bridge deck is firmly connected with abutment and on the other deck it is stored using a pair of sliding bearings.

Fuzzy stochastic analysis of serviceability and ultimate limit states of two-span pedestrian steel bridge

Science.gov (United States)

Kala, Zdeněk; Sandovič, GiedrÄ--

2012-09-01

The paper deals with non-linear analysis of ultimate and serviceability limit states of two-span pedestrian steel bridge. The effects of random material and geometrical characteristics on limit states are analyzed. The Monte Carlo method was applied to stochastic analysis. For the serviceability limit state, also influence of fuzzy uncertainty of the limit deflection value on random characteristics of load capacity of variable action was studied. The results prove that, for the type of structure studied, the serviceability limit state is decisive from the point of view of design. The present paper opens a discussion on the use of stochastic analysis to verify the limit deflections given in the standards EUROCODES.

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...

Field performance of timber bridges. 4, Graves Crossing stress-laminated deck bridge

Science.gov (United States)

J. P. Wacker; M. A. Ritter

The Graves Crossing bridge was constructed October 1991 in Antrim County, Michigan, as part of the demonstration timber bridge program sponsored by the USDA Forest Service. The bridge is a two-span continuous, stress-laminated deck superstructure and it is 36-ft long and 26-ft wide. The bridge is one of the first stress-laminated deck bridges to be built of sawn lumber...

Field performance of timber bridges. 6, Hoffman Run stress-laminated deck bridge

Science.gov (United States)

M. A. Ritter; P. D. Hilbrich Lee; G. J. Porter

The Hoffman Run bridge, located just outside Dahoga, Pennsylvania, was constructed in October 1990. The bridge is a simple-span, single-lane, stress-laminated deck superstructure that is approximately 26 ft long and 16 ft wide. It is the second stress-laminated timber bridge to be constructed of hardwood lumber in Pennsylvania. The performance of the bridge was...

Precast concrete elements for accelerated bridge construction : laboratory testing, field testing, evaluation of a precast concrete bridge, Madison County bridge.

Science.gov (United States)

2009-01-01

The importance of rapid construction technologies has been recognized by the Federal Highway Administration (FHWA) and the Iowa : DOT Office of Bridges and Structures. Recognizing this a two-lane single-span precast box girder bridge was constructed ...

Field performance of timber bridges. 5, Little Salmon Creek stress-laminated deck bridge

Science.gov (United States)

M. A. Ritter; J. A. Kainz; G. J. Porter

The Little Salmon Creek bridge was constructed in November 1988 on the Allegheny National Forest in Pennsylvania. The bridge is a simple span, single-lane, stress-laminated deck superstructure that is approximately 26-ft long and 16-ft wide. The bridge is unique in that it is the first known stress-laminated timber bridge to be constructed of hardwood lumber. The...

Optimum design of large span concrete filled steel tubular arch bridge based on static, stability and modal analysis

Institute of Scientific and Technical Information of China (English)

赵长军; 胡隽; 徐兴

2002-01-01

A three-dimensional finite element model was established for a large span concrete filled steel tubular (CFST) arch bridge which is currently under construction. The arch rib, the spandrel columns, the prestressed concrete box-beam, the cast-in-situ concrete plate of bridge deck, the steel box-beam and the crossbeams connecting the two pieces of arch ribs, were modeled by three-dimensional Timoshenko beam elements (3DTBE). The suspenders were modeled by three-dimensional cable elements (3DCE). Both geometric nonlinearity and prestress effect could be included in each kind of element. At the same time a second finite element model with the same geometric and material properties excepted for the sectional dimension of arch rib was set up. Static dynamic analyses were performed to determine the corresponding characteristics of the structure. The results showed that the arch rib's axial rigidity could be determined by static analysis. The stability and vibration of this system could be separated into in-plane modes, out-of-plane modes and coupled modes. The in-plane stability and dynamic characteristics are determined by the arch rib's vertical stiffness and that of out-of-plane is determined by the crossbeams' stiffness and arch rib's lateral stiffness mainly. The in-plane stiffness is much greater than that of out-of-plane for this kind of bridge . The effect of geometric nonlinearity and prestress effect on bridge behavior is insignificant.

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....

Assessment of Replacement Bridge using Proof Load Test

Science.gov (United States)

Sundru, Saibabu

2017-11-01

This work begins with an overview of the condition assessment of old bridge and explained reasons for demolishing of the bridge. Briefly presented flexural analysis of two stage post-tensioned prestressed concrete girder, which will be replace the old (new bridge). Construction of I-girder and composite girder at first stage and second stage prestressing respectively is explained with figures. Assessment of the load-caring capacity of the one span of the replacement bridge with simple supports using proof load test is presented which is mandatory according to Indian standards. Weighted sand bags were used to load the bridge up to a predetermined service load with impact factor. Deflections of the I-girders of the bridge were measured at selected locations along and across the bridge span and compared with computed values. Linear response was observed during loading and unloading. Considering the load test results, theoretical estimation and criteria as stipulated in codes of practice, it can be inferred that prestressed concrete I-girder bridge span has adequate capacity to carry the loads and hence, deemed to have passed the test.

Aerodynamic stability study of a long-span prestressed concrete cable-stayed bridge. Aerodynamic behavior of edge box girder under uniform flow; Chodai PC shachokyo no taifu anteisei ni kansuru kenkyu. Ichiyoryuchu ni okeru edge girder keishiki no kuriki tokusei

Energy Technology Data Exchange (ETDEWEB)

Nomura, T. [Obayashi Corp., Tokyo (Japan)

1999-01-10

In recent years, the construction of long-span bridges is on the increase. Prestressed concrete cable-stayed bridges are dynamically very efficient structures of relatively low cost that blend in well with the landscape. Maintenance is also easy. Consequently, the adoption of edge box girders for cable-stayed bridges is increasing worldwide, but problems related to the aerodynamic stability of the structure have emerged. The aerodynamic stability of edge box girders for a prestressed concrete cable-stayed bridge was investigated under uniform flow conditions by conducting several wind tunnel experiments. As a result, the section of the bridge deck was optimized to prevent torsional flutter within an angle of attack varying from -5 to +5 degrees. It is therefore possible to guarantee the aerodynamic stability of long-span prestressed concrete cable-stayed bridges. (author)

Super-bridges suspended over carbon nanotube cables

Science.gov (United States)

Carpinteri, Alberto; Pugno, Nicola M.

2008-11-01

In this paper the new concept of 'super-bridges', i.e. kilometre-long bridges suspended over carbon nanotube cables, is introduced. The analysis shows that the use of realistic (thus defective) carbon nanotube bundles as suspension cables can enlarge the current limit main span by a factor of ~3. Too large compliance and dynamic self-excited resonances could be avoided by additional strands, rendering the super-bridge anchored as a spider's cobweb. As an example, we have computed the limit main spans of the current existing 19 suspended-deck bridges longer than 1 km assuming them to have substituted their cables with carbon nanotube bundles (thus maintaining the same geometry, with the exception of the length) finding spans of up to ~6.3 km. We thus suggest that the design of the Messina bridge in Italy, which would require a main span of ~3.3 km, could benefit from the use of carbon nanotube bundles. We believe that their use represents a feasible and economically convenient solution. The plausibility of these affirmations is confirmed by a statistical analysis of the existing 100 longest suspended bridges, which follow a Zipf's law with an exponent of 1.1615: we have found a Moore-like (i.e. exponential) law, in which the doubling of the capacity (here the main span) per year is substituted by the factor 1.0138. Such a law predicts that the realization of the Messina bridge using conventional materials will only occur around the middle of the present century, whereas it could be expected in the near future if carbon nanotube bundles were used. A simple cost analysis concludes the paper.

Super-bridges suspended over carbon nanotube cables

International Nuclear Information System (INIS)

Carpinteri, Alberto; Pugno, Nicola M

2008-01-01

In this paper the new concept of 'super-bridges', i.e. kilometre-long bridges suspended over carbon nanotube cables, is introduced. The analysis shows that the use of realistic (thus defective) carbon nanotube bundles as suspension cables can enlarge the current limit main span by a factor of ∼3. Too large compliance and dynamic self-excited resonances could be avoided by additional strands, rendering the super-bridge anchored as a spider's cobweb. As an example, we have computed the limit main spans of the current existing 19 suspended-deck bridges longer than 1 km assuming them to have substituted their cables with carbon nanotube bundles (thus maintaining the same geometry, with the exception of the length) finding spans of up to ∼6.3 km. We thus suggest that the design of the Messina bridge in Italy, which would require a main span of ∼3.3 km, could benefit from the use of carbon nanotube bundles. We believe that their use represents a feasible and economically convenient solution. The plausibility of these affirmations is confirmed by a statistical analysis of the existing 100 longest suspended bridges, which follow a Zipf's law with an exponent of 1.1615: we have found a Moore-like (i.e. exponential) law, in which the doubling of the capacity (here the main span) per year is substituted by the factor 1.0138. Such a law predicts that the realization of the Messina bridge using conventional materials will only occur around the middle of the present century, whereas it could be expected in the near future if carbon nanotube bundles were used. A simple cost analysis concludes the paper.

Structural identification of short/middle span bridges by rapid impact testing: theory and verification

Science.gov (United States)

Zhang, Jian; Zhang, Q. Q.; Guo, S. L.; Xu, D. W.; Wu, Z. S.

2015-06-01

A structural strain flexibility identification method by processing the multiple-reference impact testing data is proposed. First, a kind of novel long-gauge fiber optic sensor is developed for structural macro-strain monitoring. Second, the multiple-reference impact testing technology is employed, during which both the impacting force and structural strain responses are measured. The impact testing technology has unique merit because it is able to extract exact structural frequency response functions (FRFs), while other test methods, for instance ambient tests, can only output the FRFs with scaled magnitudes. Most importantly, the originality of the article is that a method of identifying the structural strain flexibility characteristic from the impact test data has been proposed, which is useful for structural static strain prediction and capacity evaluation. Examples of a six meter simple supported beam and a multiple-span continuous beam bridge have successfully verified the effectiveness of the proposed method.

Structural identification of short/middle span bridges by rapid impact testing: theory and verification

International Nuclear Information System (INIS)

Zhang, Jian; Wu, Z S; Zhang, Q Q; Guo, S L; Xu, D W

2015-01-01

A structural strain flexibility identification method by processing the multiple-reference impact testing data is proposed. First, a kind of novel long-gauge fiber optic sensor is developed for structural macro-strain monitoring. Second, the multiple-reference impact testing technology is employed, during which both the impacting force and structural strain responses are measured. The impact testing technology has unique merit because it is able to extract exact structural frequency response functions (FRFs), while other test methods, for instance ambient tests, can only output the FRFs with scaled magnitudes. Most importantly, the originality of the article is that a method of identifying the structural strain flexibility characteristic from the impact test data has been proposed, which is useful for structural static strain prediction and capacity evaluation. Examples of a six meter simple supported beam and a multiple-span continuous beam bridge have successfully verified the effectiveness of the proposed method. (paper)

Field performance of timber bridges. 16, North Siwell Road stress-laminated bridge

Science.gov (United States)

J. A. Kainz

The North Siwell Road bridge was constructed during December 1994 in Hinds County, Mississippi. The bridge is a single-span, stress-laminated T-beam structure that measures 9.1 m (30 ft) long and 8.7 m (28.5 ft) wide. Performance of the bridge was monitored for 24 months, beginning at the time of installation. Monitoring involved gathering and evaluating data relative...

Field performance of timber bridges. 10, Sanborn Brook stress-laminated deck bridge

Science.gov (United States)

P. D. Hilbrich Lee; J. P. Wacker; M. A. Ritter

The Sanborn Brook bridge was constructed in August 1991, 10 miles northeast of Concord, New Hampshire, as part of the demonstration timber bridge program of the USDA Forest Service. The bridge is a simple-span, double-lane, stress-laminated deck superstructure constructed from Southern Pine lumber and is approximately 25 ft long and 28 ft wide with a skew of 14 degrees...

Spread prestressed concrete slab beam bridges.

Science.gov (United States)

2015-04-01

TxDOT uses prestressed slab beam bridges for short-span bridges ranging from approximately 3050 ft in : length. These bridges have precast, pretensioned slab beams placed immediately adjacent to one another : with a cast-in-place slab made composi...

SURVEY RESULTS AND TESTING OF RAILWAY BRIDGES

Directory of Open Access Journals (Sweden)

I. H. Haniiev

2010-03-01

Full Text Available The article is devoted to the survey and testing of railway bridges by the State Joint-Stock Railway Company «Uzbekiston Temir Yollari» («Uzbekistan Railways». It is stated that in the existing rules on determination of the capacity of bridges the recommendations on taking into account the cumulative deflection to the moment of technical diagnostics of spans on the bridge capacity are absent. The author states on the need to develop a method for determining the wear of spans on restriction of the residual deflection in the bridge floor slabs.

Field performance of timber bridges. 17, Ciphers stress-laminated deck bridge

Science.gov (United States)

James P. Wacker; James A. Kainz; Michael A. Ritter

In September 1989, the Ciphers bridge was constructed within the Beltrami Island State Forest in Roseau County, Minnesota. The bridge superstructure is a two-span continuous stress-laminated deck that is approximately 12.19 m long, 5.49 m wide, and 305 mm deep (40 ft long, 18 ft wide, and 12 in. deep). The bridge is one of the first to utilize red pine sawn lumber for...

Field performance of timber bridges. 8, Lynches Woods Park stress-laminated deck bridge

Science.gov (United States)

J. P. Wacker; M. A. Ritter; D. Conger

The Lynches Woods Park bridge was constructed during the summer of 1990 in Newberry, South Carolina. It is a single-span, single-lane, stress-laminated deck superstructure that measures approximately 30 ft long, 16 ft wide, and 14 in. deep. The bridge is unique in that is one of the first known stress-laminated deck bridges to be constructed of Southern Pine lumber...

Suspension Bridge Flutter for Girder with Separate Control Flaps

DEFF Research Database (Denmark)

Huynh, T.; Thoft-Christensen, Palle

Active vibration control of long span suspension bridge flutter using separated control flaps (SFSC) has shown to increase effectively the critical wind speed of bridges. In this paper, an SFSC calculation based on modal equations of the vertical and torsional motions of the bridge girder including...... the flaps is presented. The length of the flaps attached to the girder, the flap configuration and the flap rotational angles are parameters used to increase the critical wind speed of the bridge. To illustrate the theory a numerical example is shown for a suspension bridge of 1000m+2500m+1000m span based...... on the Great Belt Bridge streamlined girder....

Reduction of seismic response long-span PC cable-stayed bridge by passive dampers; Damper ni yoru saidai PC shachokyo no jishinji oto no teigen

Energy Technology Data Exchange (ETDEWEB)

Takeda, T.; Yamanobe, S.; Niihara, Y. [Kajima Corp., Tokyo (Japan)

1994-10-31

It is important in designing a PC cable-stayed bridge to properly estimate the seismic response of the bridge for reduction of the response. In this paper, an improvement of the seismic resistance of PC cable-stayed bridges when dampers are installed between the deck and piers and lateral vibration of the deck is restricted is investigated using a time history response model. PC cable-stayed bridges with a span length of 400 m, particularly two types of bridges of harp and semi-harp are investigated and the following is found by analyzing the case where there are installed hysteresis type dampers (with 1 cm yield displacement and secondary rigidity assumed to be 1/10 times that of initial rigidity, the initial rigidity being parametrically changed.) or viscous type dampers (a damping factor is changed.) The result shows that the dampers can reduce the seismic response of a PC cable-stayed bridge and that a semi-harp configuration of stay cables where stay cable members are substantially vertically arranged is more effective than a harp configuration for the seismic performance of PC cable-stayed bridges. The damper partly bear inertial force of the bridge upon earthquake whereby tension of the stay cable members is reduced and bending moment of the deck is reduced. There is existing an optimum characteristic value of the damper concerning the bending moment of the piers. 5 refs., 7 figs., 2 tabs.

PARAMETRIC STUDY OF SKEW ANGLE ON BOX GIRDER BRIDGE DECK

OpenAIRE

Shrikant D. Bobade *, Dr. Valsson Varghese

2016-01-01

Box girder bridge deck, is the most common type of bridges in world and India, it consists of several Slab or girders. The span in the direction of the roadway and connected across their tops and bottoms by a thin continuous structural stab, the longitudinal box girders can be made of steel or concrete. The Simple supported single span concrete bridge deck is presented in present study. Skewed bridges are suitable in highway design when the geometry of straight bridges is not possible. The sk...

New technique of railway bridges in Hokuriku Shinkansen; Hokuriku Shinkansen tetsudokyo no gijutsu

Energy Technology Data Exchange (ETDEWEB)

Miyabayashi, H. [Japan Railway Construction Public Corp., Tokyo (Japan)

1996-09-01

This paper presents new technologies of the railway bridges in Hokuriku Shinkansen. Hokuriku Shinkansen of 117km between Takasaki and Nagano is a part of Shinkansen connecting Tokyo with Nagano by nearly 1.5 hours. Its construction is in promotion under severe financial condition, and cost reduction is an essential target. Among the concrete bridges in this section, Kirizumigawa bridge, a prestressed concrete strutted 3-span continuous beam bridge, adopted a lowering erection method for its slant pier. In this method featured by high safety and profitability, the rib component of a concrete arch bridge is vertically erected on a arch support, and installed by swinging it toward the central span. In addition, a cantilever method was adopted to keep the scenery of a national park. Daini Chikumagawa bridge with the longest span of 133.9m among concrete railway bridges is the first cable-stayed prestressed concrete bridge in Shinkansen. Yashiro Minami and Kita bridges of 105m and 90m in central span are the extradosed bridges which were adopted as optimum structure for lowering the beam height of meddle-sized railway bridges. 3 refs., 12 figs., 2 tabs.

Field performance of timber bridges. 12, Christian Hollow stress-laminated box-beam bridge

Science.gov (United States)

J. P. Wacker; S. C. Catherman; R. G. Winnett

In January 1992, the Christian Hollow bridge was constructed in Steuben County, New York. The bridge is a single-span, stress-laminated box-beam superstructure that is 9.1 m long, 9.8 m wide, and 502 mm deep (30 ft long, 32 ft wide, and 19-3/4 in. deep). The performance of the bridge was continuously monitored for 28 months, beginning shortly after installation....

Geometric nonlinear analysis of self-anchored cable-stayed suspension bridges.

Science.gov (United States)

Hui-Li, Wang; Yan-Bin, Tan; Si-Feng, Qin; Zhe, Zhang

2013-01-01

Geometric nonlinearity of self-anchored cable-stayed suspension bridges is studied in this paper. The repercussion of shrinkage and creep of concrete, rise-to-span ratio, and girder camber on the system is discussed. A self-anchored cable-stayed suspension bridge with a main span of 800 m is analyzed with linear theory, second-order theory, and nonlinear theory, respectively. In the condition of various rise-to-span ratios and girder cambers, the moments and displacements of both the girder and the pylon under live load are acquired. Based on the results it is derived that the second-order theory can be adopted to analyze a self-anchored cable-stayed suspension bridge with a main span of 800 m, and the error is less than 6%. The shrinkage and creep of concrete impose a conspicuous impact on the structure. And it outmatches suspension bridges for system stiffness. As the rise-to-span ratio increases, the axial forces of the main cable and the girder decline. The system stiffness rises with the girder camber being employed.

Geometric Nonlinear Analysis of Self-Anchored Cable-Stayed Suspension Bridges

Directory of Open Access Journals (Sweden)

Wang Hui-Li

2013-01-01

Full Text Available Geometric nonlinearity of self-anchored cable-stayed suspension bridges is studied in this paper. The repercussion of shrinkage and creep of concrete, rise-to-span ratio, and girder camber on the system is discussed. A self-anchored cable-stayed suspension bridge with a main span of 800 m is analyzed with linear theory, second-order theory, and nonlinear theory, respectively. In the condition of various rise-to-span ratios and girder cambers, the moments and displacements of both the girder and the pylon under live load are acquired. Based on the results it is derived that the second-order theory can be adopted to analyze a self-anchored cable-stayed suspension bridge with a main span of 800 m, and the error is less than 6%. The shrinkage and creep of concrete impose a conspicuous impact on the structure. And it outmatches suspension bridges for system stiffness. As the rise-to-span ratio increases, the axial forces of the main cable and the girder decline. The system stiffness rises with the girder camber being employed.

0-6722 : spread prestressed concrete slab beam bridges.

Science.gov (United States)

2014-08-01

The Texas Department of Transportation uses : precast prestressed concrete slab beam bridges for : shorter-span bridges of approximately 3050 ft in : length. Conventional slab beam bridges have slab : beams placed immediately adjacent to one anoth...

33 CFR 118.70 - Lights on swing bridges.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on swing bridges. 118.70 Section 118.70 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.70 Lights on swing bridges. (a) Swing span lights on through bridges. Each...

33 CFR 118.65 - Lights on fixed bridges.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on fixed bridges. 118.65 Section 118.65 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable...

Continuity diaphragm for skewed continuous span precast prestressed concrete girder bridges.

Science.gov (United States)

2004-10-01

Continuity diaphragms used on skewed bents in prestressed girder bridges cause difficulties in detailing and : construction. Details for bridges with large diaphragm skew angles (>30) have not been a problem for LA DOTD. : However, as the skew angl...

Non-Flutter Design Principle for long Span Bridges

DEFF Research Database (Denmark)

Johansson, Jens; Andersen, Michael Styrk; Starch Øvre, Michele

velocity for a thin airfoil shows an asymptotical behavior. In traditional bridge design the torsional-to-vertical frequency ratio is increased to obtain higher flutter wind velocities. In the present study, we investigate, what we will label the non-flutter design principle, in which the torsional...

Field performance of timber bridges. 13, Mohawk Canal stress-laminated bridge

Science.gov (United States)

P. D. Hilbrich Lee; X. Lauderdale

The Mohawk Canal bridge was constructed in August 1994, just outside Roll, Arizona. It is a simple-span, double-lane, stress-laminated deck superstructure, approximately 6.4 m (21 ft) long and 10.4 m (34 ft) wide and constructed with Combination 16F-V3 Douglas Fir glued-laminated timber beam laminations. The performance of the bridge was monitored continuously for 2...

Steel-soil composite bridge

DEFF Research Database (Denmark)

Du, Guangli; Pettersson, Lars; Karoumi, Raid

2017-01-01

viability, while their environmental performance is overlooked. Today’s designers are urged to seek new design options to reduce the environmental burdens. Sweden owns more than 24574 bridges and most of them are short spans. Among them, the slab frame bridge (CFB) is a common solution. Soil steel composite...... bridge (SSCB), alternatively, is a functionally equivalent solution to CFB and shows advantages in low cost and easy construction. This paper compares the environmental performance between these two bridge types based on life cycle assessment (LCA). The analysis and result shows that, the SSCB...

VARIANTS OF ASSEMBLED TEMPORARY BRIDGES AS ELEMENTS OF TRANSPORT COMMUNICATION

Directory of Open Access Journals (Sweden)

D. E. Gusev

2010-01-01

Full Text Available The paper provides results of investigations and analysis of the possibility to use metal span structure sections of floating railway bridges FRB-56 as span structures of pedestrian, communication and road bridges and optimal parameters for their application are determined in the paper.

Construction of a composite cable stayed bridge. Karnali river bridge in Nepal. Gosei shachokyo no kensetsu. Karnali kawa kyoryo

Energy Technology Data Exchange (ETDEWEB)

Maeda, M.; Nakamura, K.; Shimodoi, H.; Amako, M.; Miyoshi, S.; Haruta, M.; Okada, S.; Kuroki, S. (Kawasaki Heavy Industries, Ltd., Tokyo (Japan))

1994-07-20

The present report reports the construction of Karnali River Bridge in Nepal by Kawasaki Heavy Industries, Ltd. The present bridge is a composite cable stayed bridge, two-spanned with a main span length of 325m and side span length of 175m. Having an about 125m-high single tower, it is 11.3m in breadth and 3m in main truss height. The main truss is supported by both faces of 30 cables per face, i.e., 60 cables. (Each of both main and side spans has 15 cables per face.) The design and construction are described with the following their itemization: design (bending moment properties in the erected system, composite structure of main truss and stress analysis at the time of erection). Wind resisting measures (measures for the wind resistant stability at the time of erection of both tower and main truss cantilever). Fabrication and transportation of steel structural members. Fabrication of precast floor plates (concrete mixing, and fabrication and curing of floor plates). Construction of tower foundation (tremie concrete and air concrete). Erection of upper structures (erection of tower, both main and side spans, and accuracy management). 14 figs., 4 tabs.

Chichibu park bridge, a Japan's longest PC cable suspension bridge that attaches importance to scenery. Keikan wo jushishita Nippon saidai no PC shachokyo 'Chichibu koenkyo'

Energy Technology Data Exchange (ETDEWEB)

1993-12-01

This paper introduces the feature of Chichibu Park Bridge, a Japan's longest PC cable suspension bridge that attaches importance to scenery. The maximum effective span of Chichibu Park Bridge which is a two-span continuous PC cable suspension bridge measures 195 m, that means the center span length is equivalent to about 400 m if converted to a three-span structure. With respect to the design that values the scenic effect, the main tower has relief engravings of stone carving tone using Chichibu Night Festival as a motif disposed around it; lighting up is applied to the main tower to highlight it so that it can be viewed from far away places; and a balcony is built on the center of the bridge. Chichibu Park Bridge has the bridge axial direction stagger with the river flow direction at 45[degree] to reduce water resistance. The tensile force generated at the corbel section according to the main tower reactive force is dealt with reinforced concrete rather than with prestressed concrete. The main tower adopts a two-chamber girder structure as its cross section shape from the view points of rigidity assurance and scenic effect. For construction control, micro computers are used to correct growing change in bend of the main girder due to temperature change and cable tension change. 6 figs., 4 tabs.

33 CFR 165.928 - Security Zone; Mackinac Bridge, Straits of Mackinac, Michigan.

Science.gov (United States)

2010-07-01

... arrests and whose duties involve the enforcement of criminal laws of the United States. (3) Navigable... vessels owned, chartered, or operated by the United States, or by a State or political subdivision thereof... responsible for the prevention and detection of crime and the enforcement of the general criminal laws of...

Sustainable Bridge Infrastructure Procurement

DEFF Research Database (Denmark)

Safi, Mohammed; Du, Guangli; Simonsson, Peter

2016-01-01

The lack of a flexible but systematic approach for integrating lifecycle aspects into bridge investment decisions is a major obstacle hindering the procurement of sustainable bridge infrastructures. This paper addresses this obstacle by introducing a holistic approach that agencies could use...... to procure the most “sustainable” (lifecycle-efficient) bridge through a fair design-build (D-B) tendering process, considering all the main aspects: life-cycle cost (LCC), service life-span, aesthetic demands and environmental impacts (LCA)....

A Highly Accurate and Efficient Analytical Approach to Bridge Deck Free Vibration Analysis

Directory of Open Access Journals (Sweden)

D.J. Gorman

2000-01-01

Full Text Available The superposition method is employed to obtain an accurate analytical type solution for the free vibration frequencies and mode shapes of multi-span bridge decks. Free edge conditions are imposed on the long edges running in the direction of the deck. Inter-span support is of the simple (knife-edge type. The analysis is valid regardless of the number of spans or their individual lengths. Exact agreement is found when computed results are compared with known eigenvalues for bridge decks with all spans of equal length. Mode shapes and eigenvalues are presented for typical bridge decks of three and four span lengths. In each case torsional and non-torsional modes are studied.

Monitoring and Evaluation of a Long-Span Raiway Bridge Using SENTINEL-1 Data

Science.gov (United States)

Huang, Q.; Crosetto, M.; Monserrat, O.; Crippa, B.

2017-09-01

This paper is focused on displacement monitoring of a bridge, which is one of the key aspects of its structural health monitoring. A simplified Persistent Scatterer Interferometry (PSI) approach is used to monitor the displacements of the Nanjing Dashengguan Yangtze River High-speed Railway Bridge (China). This bridge is 1272 m long and hosts a total of 6 railway lines. The analysis was based on a set of twenty-nine Sentinel-1A images, acquired from April 2015 to August 2016. A dense set of measurement points were selected on the bridge. The PSI results show a maximum longitudinal displacement of 150 mm, on each side of the bridge. The displacements are strongly correlated with the temperature, showing that they are due to thermal expansion. Using the PSI results, the Coefficient of Thermal Expansion (CTE) of the whole bridge was estimated. The result agrees well with the CTE of the bridge materials. Using a regression model, the PSI-measured displacements were compared with in-situ measurements. The paper proposes a procedure to assess the performance of the movable bearings of the bridge, which is based on the PSI measurements.

Field performance of timber bridges. 11, Spearfish Creek stress-laminated box-beam bridge

Science.gov (United States)

J. P. Wacker; M. A. Ritter; K. Stanfill-McMillan

The Spearfish Creek bridge was constructed in 1992 in Spearfish, South Dakota. It is a single-span, stress-laminated, box-beam superstructure. Performance of the bridge is being monitored for 5 years, beginning at installation. This report summarizes results for the first 3-1/2 years of monitoring and includes information on the design, construction, and field...

Estimating bridge stiffness using a forced-vibration technique for timber bridge health monitoring

Science.gov (United States)

James P. Wacker; Xiping Wang; Brian Brashaw; Robert J. Ross

2006-01-01

This paper describes an effort to refine a global dynamic testing technique for evaluating the overall stiffness of timber bridge superstructures. A forced vibration method was used to measure the frequency response of several simple-span, sawn timber beam (with plank deck) bridges located in St. Louis County, Minnesota. Static load deflections were also measured to...

Dynamic Response of Railway Bridges Subjected to Passing Vehicles

Directory of Open Access Journals (Sweden)

Moravčík Milan

2017-12-01

Full Text Available This paper discusses some issues related to dynamic effects in railway bridges focussed on the dynamic behaviour of the small and medium span simply supported railway bridges subjected to a series of moving vehicle. Presented parametric study is focused on the dynamic deflection of the simply supported railway bridge of the span Lb = 38 m, due to the series moving loads representing a conventional train with the IC-coaches, with the impact to the speed up to 160 km/h applied in Slovakia.

Exploring boundary-spanning practices among creativity managers

DEFF Research Database (Denmark)

Andersen, Poul Houman; Kragh, Hanne

2015-01-01

Purpose – External inputs are critical for organisational creativity. In order to bridge different thought worlds and cross-organisational barriers, managers must initiate and motivate boundary spanning processes. The purpose of this paper is to explore how boundary spanners manage creativity...... and observation. Findings – Three meta-practices used by managers to manage boundary-spanning creative projects are presented: defining the creative space, making space for creativity and acting in the creative space. These practices are detailed in seven case studies of creative projects. Research limitations...

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

OpenAIRE

An, Lipeng; Li, Dejian; Yu, Peng; Yuan, Peng

2016-01-01

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-posi...

Nondestructive testing for bridge diagnosis

International Nuclear Information System (INIS)

Oshima, Toshiyuki; Mikami, Shuichi; Yamazaki, Tomoyuki

1997-01-01

There are many motivations for bridge diagnosis using Nondestructive testing (NDT) to monitor its integrity. The measured frequency and damping on real bridge are compared in one figure as a function of span length and general aspects are explained. These date were measured in every construction of bridges and applied to design new bridges. Ultrasonic testing is also well used for concrete and steel members mainly to detect internal damages or delaminations. Detail analysis on reflected waves gives us more accurate information about the defect. Experimental results are shown as examples in this paper.

Wind tunnel test of musi VI bridge

Science.gov (United States)

Permata, Robby; Andika, Matza Gusto; Syariefatunnisa, Risdhiawan, Eri; Hermawan, Budi; Noordiana, Indra

2017-11-01

Musi VI Bridge is planned to cross the Musi River in Palembang City, South Sumatera Province, Indonesia. The main span is a steel arch type with 200 m length and side span length is 75 m. Finite element analysis results showed that the bridge has frequency ratio for torsional and heaving mode (torsional frequency/heaving frequency)=1.14. This close to unity value rises concern about aerodynamic behaviour and stability of the bridge deck under wind loading. Sectional static and free vibration wind tunnel test were performed to clarify this phenomena in B2TA3 facility in Serpong, Indonesia. The test followed the draft of Guide of Wind Tunnel Test for Bridges developed by Indonesian Ministry of Public Works. Results from wind tunnel testing show that the bridge is safe from flutter instability and no coupled motion vibration observed. Therefore, low value of frequency ratio has no effect to aerodynamic behaviour of the bridge deck. Vortex-induced vibration in heaving mode occurred in relatively low wind velocity with permissible maximum amplitude value.

APPLICATION OF ULTRA-HIGH PERFORMANCE CONCRETE TO PEDESTRIAN CABLE-STAYED BRIDGES

Directory of Open Access Journals (Sweden)

CHI-DONG LEE

2013-06-01

Full Text Available The use of ultra-high performance concrete (UHPC, which enables reducing the cross sectional dimension of the structures due to its high strength, is expected in the construction of the super-long span bridges. Unlike conventional concrete, UHPC experiences less variation of material properties such as creep and drying shrinkage and can reduce uncertainties in predicting time-dependent behavior over the long term. This study describes UHPC’s material characteristics and benefits when applied to super-long span bridges. A UHPC girder pedestrian cable-stayed bridge was designed and successfully constructed. The UHPC reduced the deflections in both the short and long term. The cost analysis demonstrates a highly competitive price for UHPC. This study indicates that UHPC has a strong potential for application in the super-long span bridges.

Structural health monitoring of bridge cables : An overview

OpenAIRE

DRISSI HABTI, Monssef; BETTI, Raimondo; YANEV, Bojidar

2009-01-01

Bridges are critical components of the civil infrastructure and are normally designed for a long life span. The life span of suspension bridges depends on the health of their cables, which, in turn, is a function of many factors. Therefore, continuous health monitoring (SHM) and regular condition assessment of cables is highly desirable. In this article, some SHM procedures based on direct, indirect non-destructive techniques NDT, and vibration theory are presented.

Experimental study of the semi-active control of a nonlinear two-span bridge using stochastic optimal polynomial control

Science.gov (United States)

El-Khoury, O.; Kim, C.; Shafieezadeh, A.; Hur, J. E.; Heo, G. H.

2015-06-01

This study performs a series of numerical simulations and shake-table experiments to design and assess the performance of a nonlinear clipped feedback control algorithm based on optimal polynomial control (OPC) to mitigate the response of a two-span bridge equipped with a magnetorheological (MR) damper. As an extended conventional linear quadratic regulator, OPC provides more flexibility in the control design and further enhances system performance. The challenges encountered in this case are (1) the linearization of the nonlinear behavior of various components and (2) the selection of the weighting matrices in the objective function of OPC. The first challenge is addressed by using stochastic linearization which replaces the nonlinear portion of the system behavior with an equivalent linear time-invariant model considering the stochasticity in the excitation. Furthermore, a genetic algorithm is employed to find optimal weighting matrices for the control design. The input current to the MR damper installed between adjacent spans is determined using a clipped stochastic optimal polynomial control algorithm. The performance of the controlled system is assessed through a set of shake-table experiments for far-field and near-field ground motions. The proposed method showed considerable improvements over passive cases especially for the far-field ground motion.

Experimental study of the semi-active control of a nonlinear two-span bridge using stochastic optimal polynomial control

International Nuclear Information System (INIS)

El-Khoury, O; Shafieezadeh, A; Hur, J E; Kim, C; Heo, G H

2015-01-01

This study performs a series of numerical simulations and shake-table experiments to design and assess the performance of a nonlinear clipped feedback control algorithm based on optimal polynomial control (OPC) to mitigate the response of a two-span bridge equipped with a magnetorheological (MR) damper. As an extended conventional linear quadratic regulator, OPC provides more flexibility in the control design and further enhances system performance. The challenges encountered in this case are (1) the linearization of the nonlinear behavior of various components and (2) the selection of the weighting matrices in the objective function of OPC. The first challenge is addressed by using stochastic linearization which replaces the nonlinear portion of the system behavior with an equivalent linear time-invariant model considering the stochasticity in the excitation. Furthermore, a genetic algorithm is employed to find optimal weighting matrices for the control design. The input current to the MR damper installed between adjacent spans is determined using a clipped stochastic optimal polynomial control algorithm. The performance of the controlled system is assessed through a set of shake-table experiments for far-field and near-field ground motions. The proposed method showed considerable improvements over passive cases especially for the far-field ground motion. (paper)

Estimation of Curvature Changes for Steel-Concrete Composite Bridge Using Fiber Bragg Grating Sensors

OpenAIRE

Kang, Donghoon; Chung, Wonseok

2013-01-01

This study is focused on the verification of the key idea of a newly developed steel-concrete composite bridge. The key idea of the proposed bridge is to reduce the design moment by applying vertical prestressing force to steel girders, so that a moment distribution of a continuous span bridge is formed in a simple span bridge. For the verification of the key technology, curvature changes of the bridge should be monitored sequentially at every construction stage. A pair of multiplexed FBG sen...

Planning of Tatara Bridge. Chodai shachokyo-Tataraohashi-no keikaku gaiyo

Energy Technology Data Exchange (ETDEWEB)

Okukawa, A. (Honshu-Shikoku Bridge Authority, Tokyo (Japan))

1991-12-05

The outline of the Tatara Bridge is given to introduce the features of the entire structural system and fundamental problems concerning the construction of the huge cable stayed bridge. The central span of the bridge is 890m. The topography and geological features of the bridging point are reviewed, and social conditions such as being in a national park, safety for sailing, etc. are taken into consideration for various technological studies on the construction of the huge bridge. Bridge piers are provided in the side spans and appropriate counter weight is loaded to design a more economical bridge which is more suitable for the topography as compared with a suspension bridge. The cable stayed bridge requires no anchorage which is necessary for a suspension bridge with very little topological alteration, and an excellent result is obtained both in cost and term of construction as compared with a suspension bridge. The rigidity of the cable stayed bridge is high, and the stability of the resistance to wind of the structure is also very satisfactory. As a result, it is concluded that the bridge can be designed and constructed using currently available technologies, and a cable stayed bridge is selected in August, 1990 as the type for the Tatara Bridge. 9 figs., 1 tab.

Collapse of the Tacoma· N arrows Bridge

Indian Academy of Sciences (India)

something was noticeably wrong with the bridge. The span ... So spectacular was the motion at times that the bridge was soon nicknamed Galloping. Gertie, and visitors ... A stranded car can be seen on the top right corner. ... home from Cal Tech a small rubber model of the bridge which one of my mechanics had made for ...

Vehicle - Bridge interaction, comparison of two computing models

Science.gov (United States)

Melcer, Jozef; Kuchárová, Daniela

2017-07-01

The paper presents the calculation of the bridge response on the effect of moving vehicle moves along the bridge with various velocities. The multi-body plane computing model of vehicle is adopted. The bridge computing models are created in two variants. One computing model represents the bridge as the Bernoulli-Euler beam with continuously distributed mass and the second one represents the bridge as the lumped mass model with 1 degrees of freedom. The mid-span bridge dynamic deflections are calculated for both computing models. The results are mutually compared and quantitative evaluated.

Polyurethane foam infill for fiber-reinforced polymer (FRP) bridge deck panels.

Science.gov (United States)

2014-05-01

Although still in their infancy, fiber-reinforced polymer (FRP) bridges have shown great promise in eliminating corrosion : concerns and meeting (or exceeding) FHWAs goal of 100-year life spans for bridges. While FRP bridges are cost-effective in ...

Study on the Old Girders in the Widening Hollow Slab Girder Bridge

Science.gov (United States)

Wang, Ying; Zhang, Li Fang; Ma, Hai Yan

2018-06-01

Taking the bridge widening project of Shanghai-Hangzhou-Ningbo expressway widening construction project (China) as the background in this paper, the variation law of the internal force of the old bridge in the widening hollow slab girder bridge under vehicle load is studied, which is under the condition of different span lengths and different widening widths. Three different span lengths of the pre-tensioned prestressed hollow slab girder bridges are selected, the spatial finite element models of both the old bridge and the whole structure of widening bridge are established and calculated respectively by Midas/Civil software. The influences of widening and load increasing on the old bridges under the vehicle load are compared and analyzed. In addition, the authors also analyze the influences of different widening widths on the force state of old bridges under the condition of widening the same number of lane. Moreover , the effects on the old bridges that are caused by the uneven foundation settlement of widening bridge structure are also studied in this paper. This paper can provide some references for widening design of hollow slab bridges.

Precision monitoring of bridge deck curvature change during replacement.

Science.gov (United States)

2016-05-01

This project was focused on development and deployment of a system for monitoring vertical : displacement in bridge decks and bridge spans. The system uses high precision wireless inclinometer : sensors to monitor inclinations at various points of a ...

Application of Composite Structures in Bridge Engineering. Problems of Construction Process and Strength Analysis

Science.gov (United States)

Flaga, Kazimierz; Furtak, Kazimierz

2015-03-01

Steel-concrete composite structures have been used in bridge engineering from decades. This is due to rational utilisation of the strength properties of the two materials. At the same time, the reinforced concrete (or prestressed) deck slab is more favourable than the orthotropic steel plate used in steel bridges (higher mass, better vibration damping, longer life). The most commonly found in practice are composite girder bridges, particularly in highway bridges of small and medium spans, but the spans may reach over 200 m. In larger spans steel truss girders are applied. Bridge composite structures are also employed in cable-stayed bridge decks of the main girder spans of the order of 600, 800 m. The aim of the article is to present the cionstruction process and strength analysis problems concerning of this type of structures. Much attention is paid to the design and calculation of the shear connectors characteristic for the discussed objects. The authors focused mainly on the issues of single composite structures. The effect of assembly states on the stresses and strains in composite members are highlighted. A separate part of problems is devoted to the influence of rheological factors, i.e. concrete shrinkage and creep, as well as thermal factors on the stresses and strains and redistribution of internal forces.

Bridge Deck Runoff: Water Quality Analysis and BMP Effectiveness

Science.gov (United States)

2010-12-01

The Alaska Department of Transportation (ADOT) is responsible for more than 700 bridges - most span water bodies. Are these water bodies affected by stormwater runoff from ADOT bridges? What are the regulatory and economic constraints on the ADOT reg...

Concrete-Filled Steel Tube Arch Bridges in China

Directory of Open Access Journals (Sweden)

Jielian Zheng

2018-02-01

Full Text Available In the past 20 years, great progress has been achieved in China in the construction of concrete-filled steel tube (CFST arch bridges and concrete arch bridges with a CFST skeleton. The span of these bridges has been increasing rapidly, which is rare in the history of bridge development. The large-scale construction of expressways and high-speed railways demands the development of long-span arch bridges, and advances in design and construction techniques have made it possible to construct such bridges. In the present study, the current status, development, and major innovative technologies of CFST arch bridges and concrete arch bridges with a CFST skeleton in China are elaborated. This paper covers the key construction technologies of CFST arch bridges, such as the design, manufacture, and installation of steel tube arch trusses, the preparation and pouring of in-tube concrete, and the construction of the world’s longest CFST arch bridge—the First Hejiang Yangtze River Bridge. The main construction technologies of reinforced concrete arch bridges are also presented, which include cable-stayed fastening-hanging cantilever assembly, adjusting the load by means of stay cables, surrounding the concrete for arch rib pouring, and so forth. In addition, the construction of two CFST skeleton concrete arch bridges—the Guangxi Yongning Yong River Bridge and the Yunnan–Guangxi Railway Nanpan River Bridge—is discussed. CFST arch bridges in China have already gained a world-leading position; with the continuous innovation of key technologies, China will become the new leader in promoting the development of arch bridges. Keywords: Concrete-filled steel tube (CFST arch bridge, Steel-reinforced concrete arch bridge, Cable-stayed fastening-hanging cantilever assembly, Vacuum-assisted pouring in-tube concrete, Adjusting load by stay cables

From the semicircular vault to the flattened vault in masonry bridges. The influence of rise/span ratio and the resistant backfill in the breaking load

Directory of Open Access Journals (Sweden)

J. R. Urruchi-Rojo

2017-04-01

Full Text Available The shape of the vaults in masonry bridges has evolved during the history, so that we can find bibliography where, besides recommending one way of build instead of others depending on the period, is also prescribed the way to carry out the backfill of the extrados. All of this emerged initially as a result of the experiences acquired during the construction and the observation of bridges. Hence, during the 18th century new formulations started to arise, but they led to one result in some cases and to the opposite in others. This article tries to make a comparison between some of these formulations, as well as carrying out an analysis of the influence of both, the lowering rise/span ratio of the vaults and the presence of a resistant backfill in its extrados, on the variation of the breaking load.

Evaluation of a highway bridge constructed using high strength lightweight concrete bridge girders.

Science.gov (United States)

2011-04-01

The use of high performance concretes to provide longer bridge spans has been limited due to the capacity of existing infrastructure to handle the load of the girders during transportation. The use of High Strength Lightweight Concrete (HSLW) can pro...

Design and construction of the Natorigawa Bridge; Natorigawa kyoryo no sekkei/seko

Energy Technology Data Exchange (ETDEWEB)

Murai, Y.; Oba, M.; Omurata, Y. [JR East Japan Railway Co., Tokyo (Japan); Miyauchi, M.; Iwasaki, I. [Taisei Corp., Tokyo (Japan)

1997-03-31

The Natorigawa Bridge is reconstructed. Out of the reconstruction work, a report is made mainly on the design of the superstructure work of the PC panel-stayed bridge and the details of the work. In selecting bridge type, PC simple through beam bridge, steel trussed bridge, PC cable-stayed bridge, and PC panel-stayed bridge are compared, and a 2-span continuous PC panel-stayed bridge is adopted. Its appearance resembles that of the cable-stayed bridge, but the structure resembles a girder bridge. The appropriate span length is the intermediate range between those of the girder bridge and the cable-stayed bridge. Its trafficability is excellent with little deformation by the running of trains because the main beam, diagonal panel, and the main tower are connected rigidly to provide high rigidity of the entire bridge. PRC structure is employed in consideration of the restriction to beam height and economical efficiency. Analyses by a FEM model using two dimensional plane elements and by a few plane frame models as well as comparison of sectional force are performed for this bridge, and a proper plane model is selected. Substructure work, superstructure work and measurement work are described. 3 refs., 16 figs., 6 tabs.

Coupling vibration research on Vehicle-bridge system

Science.gov (United States)

Zhou, Jiguo; Wang, Guihua

2018-01-01

The vehicle-bridge coupling system forms when vehicle running on a bridge. It will generate a relatively large influence on the driving comfort and driving safe when the vibration of the vehicle is bigger. A three-dimensional vehicle-bridge system with biaxial seven degrees of freedom has been establish in this paper based on finite numerical simulation. Adopting the finite element transient numerical simulation to realize the numerical simulation of vehicle-bridge system coupling vibration. Then, analyze the dynamic response of vehicle and bridge while different numbers of vehicles running on the bridge. Got the variation rule of vertical vibration of car body and bridge, and that of the contact force between the wheel and bridge deck. The research results have a reference value for the analysis about the vehicle running on a large-span cabled bridge.

78 FR 12260 - Regulated Navigation Area-Weymouth Fore River, Fore River Bridge Construction, Weymouth and...

Science.gov (United States)

2013-02-22

... bridge will reach the end of its useable life span in 2018 and the Massachusetts Department of... temporary existing bridge spans. D. Regulatory Analyses We developed this proposed rule after considering... unforeseen, that could pose an imminent hazard to persons and vessels operating in the area. This rule is...

Environmental comparison of a railway bridge with alternative designs

DEFF Research Database (Denmark)

Du, Guangli; Karoumi, Raid

2012-01-01

Railway bridges are complex structures that remain for a long life span and consume large amount of material and energy throughout the life span. All of those lead to considerable resource depletion and environmental burdens. Life Cycle Assessment (LCA) has proved to be a comprehensive tool...... for quantifying and assessing the environmental impacts of the products through its whole life cycle. This paper presents a comparative case study between two alternative designs of Banafjäl Bridge: ballast track design and fixed slab track design. The methodology of LCA is utilized as a supporting tool...

Full scale monitoring of wind and traffic induced response of a suspension bridge

Directory of Open Access Journals (Sweden)

Cheynet Etienne

2015-01-01

Full Text Available This paper presents a full-scale analysis of wind and traffic-induced vibrations of a long-span suspension bridge in complex terrain. Several wind and acceleration sensors have been installed along the main span on Lysefjord Bridge in Norway. In the present study, three days of continuous records are analysed. Traffic-induced vibrations are dominant at low and moderated wind speed, with non-negligible effects on the overall bridge response for heavy vehicles only. Traffic and wind-induced vibrations are compared in terms of root mean square of the acceleration response, and three simples approaches are proposed to isolate records dominated by wind-induced vibration. The first one relies on the separation of nocturnal and diurnal samples. The second one is based on the evaluation of the time-varying root mean square of the acceleration response. The last one evaluates the relative importance of the high frequency domain of the acceleration bridge response. It appears that traffic-induced vibrations may have to be taken into account for the buffeting analysis of long-span bridge under moderated wind.

Dynamic properties of stay cables on the Penobscot Narrows bridge.

Science.gov (United States)

2014-09-01

Cable-stayed bridges have been recognized as the most efficient and cost effective structural form for medium to long : span bridges over the past several decades. With their widespread use, cases of serviceability problems associated with : large am...

Expected damages of retrofitted bridges with RC jacketing

Science.gov (United States)

Montes, O.; Jara, J. M.; Jara, M.; Olmos, B. A.

2015-07-01

The bridge infrastructure in many countries of the world consists of medium span length structures built several decades ago and designed for very low seismic forces. Many of them are reinforced concrete structures that according to the current code regulations have to be rehabilitated to increase their seismic capacity. One way to reduce the vulnerability of the bridges is by using retrofitting techniques that increase the strength of the structure or by incorporating devices to reduce the seismic demand. One of the most common retrofit techniques of the bridges substructures is the use of RC jacketing; this research assesses the expected damages of seismically deficient medium length highway bridges retrofitted with reinforced concrete jacketing, by conducting a parametric study. We select a suite of twenty accelerograms of subduction earthquakes recorded close to the Pacific Coast in Mexico. The original structures consist of five 30 m span simple supported bridges with five pier heights of 5 m, 10 m, 15 m 20 and 25 m and the analyses include three different jacket thickness and three steel ratios. The bridges were subjected to the seismic records and non-linear time history analyses were carried out by using the OpenSEEs Plataform. Results allow selecting the reinforced concrete jacketing that better improves the expected seismic behavior of the bridge models.

Expected damages of retrofitted bridges with RC jacketing

International Nuclear Information System (INIS)

Montes, O; Jara, J M; Jara, M; Olmos, B A

2015-01-01

The bridge infrastructure in many countries of the world consists of medium span length structures built several decades ago and designed for very low seismic forces. Many of them are reinforced concrete structures that according to the current code regulations have to be rehabilitated to increase their seismic capacity. One way to reduce the vulnerability of the bridges is by using retrofitting techniques that increase the strength of the structure or by incorporating devices to reduce the seismic demand. One of the most common retrofit techniques of the bridges substructures is the use of RC jacketing; this research assesses the expected damages of seismically deficient medium length highway bridges retrofitted with reinforced concrete jacketing, by conducting a parametric study. We select a suite of twenty accelerograms of subduction earthquakes recorded close to the Pacific Coast in Mexico. The original structures consist of five 30 m span simple supported bridges with five pier heights of 5 m, 10 m, 15 m 20 and 25 m and the analyses include three different jacket thickness and three steel ratios. The bridges were subjected to the seismic records and non-linear time history analyses were carried out by using the OpenSEEs Plataform. Results allow selecting the reinforced concrete jacketing that better improves the expected seismic behavior of the bridge models. (paper)

Estimation of Curvature Changes for Steel-Concrete Composite Bridge Using Fiber Bragg Grating Sensors

Directory of Open Access Journals (Sweden)

Donghoon Kang

2013-01-01

Full Text Available This study is focused on the verification of the key idea of a newly developed steel-concrete composite bridge. The key idea of the proposed bridge is to reduce the design moment by applying vertical prestressing force to steel girders, so that a moment distribution of a continuous span bridge is formed in a simple span bridge. For the verification of the key technology, curvature changes of the bridge should be monitored sequentially at every construction stage. A pair of multiplexed FBG sensor arrays is proposed in order to measure curvature changes in this study. They are embedded in a full-scale test bridge and measured local strains, which are finally converted to curvatures. From the result of curvature changes, it is successfully ensured that the key idea of the proposed bridge, expected theoretically, is viable.

Building Bridges Using the Shriners Hospitals for Children/American Burn Association Burn Outcome Questionnaires to Follow Teenagers and Young Adults Across the Age Spans.

Science.gov (United States)

Kaat, Aaron J; Chen, Liang; Kazis, Lewis E; Lee, Austin F; Shapiro, Gabriel D; Sheridan, Robert L; Ryan, Colleen M; Schneider, Jeffrey C

2017-05-04

The Shriners Hospitals for Children/American Burn Association Burn Outcomes Questionnaires (BOQ) are well-established, reliable, and valid outcome measures. The adolescent (BOQ11-18 years) and young adult version (18-30 years) have similar overlapping domains, but the scores are not comparable. This study objective was to build bridges across these forms. Datasets were from the Multi-Center Benchmarking Study Group. The comparable subscales from the BOQ11-18 and the young adult version were bridged using item response theory cocalibration. The item response theory scale scores were then transformed into an expected raw score on the alternative form, from which normative scores are available. A sensitivity analysis using up to three time points, as opposed to one randomly selected occasion, was also conducted to ensure robust results. Data were available on 353 unique adolescents and 148 young adults. The comparable subscales were successfully bridged across forms (adolescent reliability from 0.67 to 0.85; young adult from 0.69 to 0.88). Compared with adolescents, young adults on average reported more pain and itch, less symptom and role satisfaction, and poorer work/school reintegration (Cohen's d = 0.39-0.77; P family/parental concern were comparable across ages (d = -0.01 to 0.09; P > .05). Family functioning was better for young adults than adolescents (d = -0.25; P = .006). BOQ11-18 scores can be mapped from adolescence into young adulthood. Physical and psychosocial outcomes change across this life span. Bridges provide a highly useful approach to track changes across this part of the lifespan.

Long term monitoring of carbon composite strands in the Penobscot-Narrows bridge.

Science.gov (United States)

2015-06-01

The Penobscot-Narrows Bridge was constructed between May 2003 and December 2006. The bridge is a cable-stayed design with twin pylons and a 2,120-foot span. This cable-stayed bridge features a cradle stay system that : allows for each cable strand in...

Dynamic analysis of 19-span continuous space frame bridge with lead rubber bearings based on vibration tests; 19 keikan renzoku rittai menshinkyo no shindo jikken ni motozuku doteki kaiseki

Energy Technology Data Exchange (ETDEWEB)

Kajikawa, Y.; Fukada, S. [Kanazawa Univ. (Japan); Sugimoto, M.; Hama, H

1998-10-21

The Hanshin/Awaji earthquake disaster caused extensive damage to many bridges of the Hanshin Expressway. N particular, falling-down of superstructures and other destructive damage occurred at Benten Kouku which located in downtown of Kobe. After the earthquake disaster, the continuous 19-span space frame bridge with lead rubber bearings which had approximate 565m bridge length was reconstructed in this region. It is the first trial in Japan to use large lead rubber bearings as an isolator or as a damper at the bottom of the steel pier for the purpose of reduction of seismic force acting on this bridge. As the lead rubber bearings, a spring member was used. In this study, by using jack with a raid releasing mechanism, monotonous loading tests loading statically at the bottom of the pier and rapid releasing tests deloading loads in a moment were carried out. Further, the simulation of the experiment was conducted on the analysis and the analytical model was established in comparison of the experimental data and the analytical data. Using this model, owing to carry out the seismic response analysis, more reliable analytical results were obtained. 22 refs., 24 figs., 3 tabs.

Quasi-Static Condensation of Aeroelastic Suspension Bridge Model

DEFF Research Database (Denmark)

Møller, Randi N.; Krenk, Steen; N. Svendsen, Martin

2017-01-01

For long span bridges the wind-induced dynamic response is a design driving factor and therefore continuously a subject for detailed analysis. Traditionally both buffeting and stability calculations have been considered in the frequency domain. However, this yields alimitation in accounting...... for turbulence when considering the stability limit and further it is not possible to account for non-linear effects. These limitations suggest to do simulations of the aeroelastic response of long span bridges in the time domain. For this it is of interest to have an efficient model while still maintaining...... sufficient accuracy. This contribution is on quasi-static reduction of an aeroelastic finite element model of a 3000m suspension bridge proposed for crossing Sulafjorden in Norway. The model is intended for stability limit calculation where the representation of higher modes is of less importance...

Flow field analysis of a pentagonal-shaped bridge deck by unsteady RANS

Directory of Open Access Journals (Sweden)

Md. Naimul Haque

2016-01-01

Full Text Available Long-span cable-stayed bridges are susceptible to dynamic wind effects due to their inherent flexibility. The fluid flow around the bridge deck should be well understood for the efficient design of an aerodynamically stable long-span bridge system. In this work, the aerodynamic features of a pentagonal-shaped bridge deck are explored numerically. The analytical results are compared with past experimental work to assess the capability of two-dimensional unsteady RANS simulation for predicting the aerodynamic features of this type of deck. The influence of the bottom plate slope on aerodynamic response and flow features was investigated. By varying the Reynolds number (2 × 104 to 20 × 104 the aerodynamic behavior at high wind speeds is clarified.

Continuity diaphragm for skewed continuous span precast prestressed concrete girder bridges : technical summary report.

Science.gov (United States)

2004-03-01

Most highway bridges are built as cast-in-place : reinforced concrete slabs and prestressed concrete : girders. The shear connectors on the top of the girders : assure composite action between the slabs and : girders. The design guidelines for bridge...

A technical report on structural evaluation of the Meade County reinforced concrete bridge : research [summary].

Science.gov (United States)

2009-01-01

Meade County Bridge is a two-lane highway reinforced concrete bridge with two girders each with 20 continuous spans. The bridge was built in 1965. It has been reported that in early years of the bridge service period, a considerable amount of cracks ...

Continuous prestressed concrete girder bridges, volume 2 : analysis, testing, and recommendations.

Science.gov (United States)

2016-12-01

The Texas Department of Transportation designs typical highway bridge structures as simple span systems using : standard precast, pretensioned girders. Spans are limited to about 150 ft due to weight and length restrictions on : transporting the prec...

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 analytical prediction methods. In this paper, an analytical model that departs from the strip assumption is used to describe the gust loading on a thin airfoil. A parallel is drawn between the analytical model and direct measurements of gust loading on motionless closed-box girder bridge decks. Empirical...

Vibration control of bridge subjected to multi-axle vehicle using multiple tuned mass friction dampers

Science.gov (United States)

Pisal, Alka Y.; Jangid, R. S.

2016-06-01

The effectiveness of tuned mass friction damper (TMFD) in reducing undesirable resonant response of the bridge subjected to multi-axle vehicular load is investigated. A Taiwan high-speed railway (THSR) bridge subjected to Japanese SKS (Salkesa) train load is considered. The bridge is idealized as a simply supported Euler-Bernoulli beam with uniform properties throughout the length of the bridge, and the train's vehicular load is modeled as a series of moving forces. Simplified model of vehicle, bridge and TMFD system has been considered to derive coupled differential equations of motion which is solved numerically using the Newmark's linear acceleration method. The critical train velocities at which the bridge undergoes resonant vibration are investigated. Response of the bridge is studied for three different arrangements of TMFD systems, namely, TMFD attached at mid-span of the bridge, multiple tuned mass friction dampers (MTMFD) system concentrated at mid-span of the bridge and MTMFD system with distributed TMFD units along the length of the bridge. The optimum parameters of each TMFD system are found out. It has been demonstrated that an optimized MTMFD system concentrated at mid-span of the bridge is more effective than an optimized TMFD at the same place with the same total mass and an optimized MTMFD system having TMFD units distributed along the length of the bridge. However, the distributed MTMFD system is more effective than an optimized TMFD system, provided that TMFD units of MTMFD system are distributed within certain limiting interval and the frequency of TMFD units is appropriately distributed.

RESEARCH ON THE ASEISMIC BEHAVIOR OF LONG-SPAN CABLE-STAYED BRIDGE WITH DAMPING EFFECT

Directory of Open Access Journals (Sweden)

Wu Fangwen

2016-07-01

Full Text Available The main beam of a cable-stayed bridge with a floating system may have a larger longitudinal displacement subject to earthquake effect. Thus, seismic control and isolation are crucial to bridge safety. This paper takes Huai’an Bridge, which has elastic coupling devices and viscous dampers set at the joint of the tower and the beam, as the research background. Its finite element model is established, and the elastic stiffness of elastic coupling devices and damper parameters are analyzed. Viscous damper and elastic coupling devices are simulated using Maxwell model and spring elements, and their damping effects are analyzed and compared through structural dynamic time-history analysis. Results show that viscous damper and elastic coupling device furnished at the joint of tower and beam of a cable-stayed bridge tower beam can effectively reduce the longitudinal displacement of the key part of the construction subject to earthquake effect, perfect the internal force distribution, and improve the aseismic performance. Between the two, viscous damper has better damping effects.

Christian Menn's recent bridge designs - Reducing structural elements to the simplest solution

OpenAIRE

Brühwiler, E.; Mahmoud, Khaled M.

2009-01-01

The conceptual designs by Christian Menn of four landmark bridges are presented: 1) a 350-m span cable-stayed bridge with jointless deck girder, 2) a cable-stayed bridge with a single “spindle-shaped” pylon, 3) a bridge with an arch reaching high above the deck (both carrying a horizontally curved deck girder), and 4) a cable stayed bridge with three pylons monolithically connected to the deck girder. All of the original bridge designs are driven by the aim to optimize the flow of force...

Performance evaluation of concrete bridge decks reinforced with MMFX and SSC rebars.

Science.gov (United States)

2006-01-01

This report investigates the performance of bridge decks reinforced with stainless steel clad (SSC) and micro-composite multistructural formable steel (MMFX) rebars. The two-span Galloway Road Bridge on route CR5218 over North Elkhorn Creek in Scott ...

Design Optimization of Hybrid FRP/RC Bridge

Science.gov (United States)

Papapetrou, Vasileios S.; Tamijani, Ali Y.; Brown, Jeff; Kim, Daewon

2018-04-01

The hybrid bridge consists of a Reinforced Concrete (RC) slab supported by U-shaped Fiber Reinforced Polymer (FRP) girders. Previous studies on similar hybrid bridges constructed in the United States and Europe seem to substantiate these hybrid designs for lightweight, high strength, and durable highway bridge construction. In the current study, computational and optimization analyses were carried out to investigate six composite material systems consisting of E-glass and carbon fibers. Optimization constraints are determined by stress, deflection and manufacturing requirements. Finite Element Analysis (FEA) and optimization software were utilized, and a framework was developed to run the complete analyses in an automated fashion. Prior to that, FEA validation of previous studies on similar U-shaped FRP girders that were constructed in Poland and Texas is presented. A finer optimization analysis is performed for the case of the Texas hybrid bridge. The optimization outcome of the hybrid FRP/RC bridge shows the appropriate composite material selection and cross-section geometry that satisfies all the applicable Limit States (LS) and, at the same time, results in the lightest design. Critical limit states show that shear stress criteria determine the optimum design for bridge spans less than 15.24 m and deflection criteria controls for longer spans. Increased side wall thickness can reduce maximum observed shear stresses, but leads to a high weight penalty. A taller cross-section and a thicker girder base can efficiently lower the observed deflections and normal stresses. Finally, substantial weight savings can be achieved by the optimization framework if base and side-wall thickness are treated as independent variables.

Research on Collapse Process of Cable-Stayed Bridges under Strong Seismic Excitations

Directory of Open Access Journals (Sweden)

Xuewei Wang

2017-01-01

Full Text Available In order to present the collapse process and failure mechanism of long-span cable-stayed bridges under strong seismic excitations, a rail-cum-road steel truss cable-stayed bridge was selected as engineering background, the collapse failure numerical model of the cable-stayed bridge was established based on the explicit dynamic finite element method (FEM, and the whole collapse process of the cable-stayed bridge was analyzed and studied with three different seismic waves acted in the horizontal longitudinal direction, respectively. It can be found from the numerical simulation analysis that the whole collapse failure process and failure modes of the cable-stayed bridge under three different seismic waves are similar. Furthermore, the piers and the main pylons are critical components contributing to the collapse of the cable-stayed bridge structure. However, the cables and the main girder are damaged owing to the failure of piers and main pylons during the whole structure collapse process, so the failure of cable and main girder components is not the main reason for the collapse of cable-stayed bridge. The analysis results can provide theoretical basis for collapse resistance design and the determination of critical damage components of long-span highway and railway cable-stayed bridges in the research of seismic vulnerability analysis.

Sustainability of bridge foundations using electrical resistivity imaging and induced polarization to support transportation safety.

Science.gov (United States)

2014-04-01

As of September 2007, there were 67,240 U.S. bridges in the National Bridge Inventory classified as having unknown : foundations (FHWA 2008). The bridges spanning rivers are of critical importance due to the risks of potential scour. In fact, it is :...

Design and construction of Chiburiko Bridge (stress ribbon bridge). Chiburiko bashi (tsurishoban kyo) no sekkei to seko

Energy Technology Data Exchange (ETDEWEB)

Kamisakoda, K; Tokuyama, S; Sano, K; Onuma, K [Kashima Corp., Tokyo (Japan)

1992-07-30

Chiburiko Bridge lies across Chiburiko which is a lake for agricultural water, and is used by people, carts and cars for administration. It is a stressed-ribbon bridge with the road surface made with concrete covered bands of cables stretched between abutments, and is the first highway bridge in Japan. A report is made on the plan and construction of the bridge. Integration of the precast slab with the cast-in-place concrete as well as mutual integration of the precast slabs are validated by the use of a reproduced model of a part of the bridge. Floor slabs are suspended by cables, and can be constructed with no form nor support by integrating cast-in-place concrete with the precast slabs on mutually joined precast slabs. It has been said that the stressed-ribbon bridge has a structure suitable for long span bridges because it has a simple structure. Studies, however, seems to be necessary on the impact caused by running of vehicles and on the wind resisting stability. 3 refs., 17 figs., 2 tabs.

Simple model of cable-stayed bridge deck subjected to static wind loading

Science.gov (United States)

Kang, Yi-Lung; Wang, Yang Cheng

1997-05-01

Cable-stayed bridges have been known since 18th century with aesthetics design. The structural system and the structural behavior are significantly different from those of continuous bridges. Compared to continuous bridge, cable- stayed bridges have more flexure bridge deck than those of continuous bridges.On the other hand, cable-stayed bridges have less stiffness to resist wind loading especially for lateral loads. The first considering of bridge engineering is safety. In 1940's, Tacoma Narrows Suspension Bridge destroyed by wind loading is a good example even though it is not a cable-stayed bridge. After the bridge was destroyed, a lot of research articles have been published regarding cable supported bridge subjected to wind loading. In recent days, high strength materials have been served. The bridge engineers use the advantages to expand the span length of cable-stayed bridges. Due to the span length increased and the use of high strength materials, cable- stayed bridges have more significant nonlinear behavior subjected to wind loading. In this paper, a slice bridge deck of cable-stayed bridge connected to internal support cables is considered. The deck has been considered to be subjected to lateral static wind loading. Since cables can not take compressive force, the deck has strongly nonlinear behavior even though the materials are linear elastic. Several primary load combinations have ben considered in this paper such as the bridge deck supposed to be moved horizontally without rotation or the bridge deck supposed to be moved horizontally with rotational deformation. The mathematical formulas and the numerical solutions are found and represented in graphical forms. The results can be provided to bridge designers and researchers for further study of this type of structure subjected to wind loading.

Study on the structural characteristics of extradosed concrete bridges; Ekusutoradozudo kyo no kozo tokusei ni kansuru ichikosatsu

Energy Technology Data Exchange (ETDEWEB)

Oka, Y. [Japan Highway Public Corp., Tokyo (Japan); Kasuga, A. [Sumitomo Construction Co. Ltd., Tokyo (Japan); Yamazaki, J. [Nihon Univ., Tokyo (Japan). Coll. of Science and Engineering

1997-03-31

Parameters are analyzed to provide data for deciding, in the planning and designing stages, whether a cable stayed bridge or an extradosed bridge should be adopted. Comparative investigation of the vibration properties of both types of bridges is also referred to. The result of the study on the structural properties of the cable stayed road bridge and the extradosed road bridge is introduced. Based on the concept of the extradosed bridge, designers are now able to select without restraint the after load sharing rate of the diagonal members. Parameter analysis of a diagonal member reinforced 3-span continuous beam is performed. By introducing indices showing the load sharing rate of the diagonal member, the cable stayed bridge can be distinguished logically from the extradosed bridge in designing. It is found important that the height of the main tower is set to approximately 10% the length of the center span for the construction of the extradosed bridge. The vibration properties of the cable stayed bridge and the extradosed bridge of the same scale are compared. 7 refs., 18 figs., 6 tabs.

Tresfjord Bridge - a human friendly and traffic efficient structure

Science.gov (United States)

Dahl, Kristian B.; Anta Magerøy Tønnessen, Aja; Toverud, Lars I.

2017-09-01

The E136 Tresfjord Bridge opened in October 2015, and crosses the Tresfjorden on the west coast of Norway. It is a concrete bridge with a total length of 1290 m, consisting of 19 viaduct spans, 60 m each, and a FCM (free cantilever method) main span of 160 m. The E136 is one of the most important transportation routes in the county of Møre and Romsdal and starts in Ålesund, and passes along Tresfjorden to Åndalsnes. The existing road is very narrow with speed limit of 60 km/h and characterizes by many accidents involving cars and people. The traffic flow is approximately ca 2500 vehicles a day, of this is 25% heavy vehicles. Those transport fresh salmon from the breeders in the fjords along the coast. To try to decrease the transportation time is very important for the fresh salmon. The bridge reduces the distance between Ålesund and Åndalsnes by 13 km. The speed limit is now 80 km/h, and with much less risk for accidents since there are separate lanes for cars and pedestrians over the whole bridge. This means that the bridge represents a human friendly and traffic efficient structure to the benefit for the people and the region.

A novel abutment construction technique for rapid bridge construction : controlled low strength Materials (CLSM) with full-height concrete panels.

Science.gov (United States)

2012-01-01

One of the major obstacles facing rapid bridge construction for typical span type bridges is the time required to construct bridge abutments and foundations. This can be remedied by using the controlled low strength materials (CLSM) bridge abutment. ...

Consideration on extradosed prestressed concrete road bridge; Dorokyo ni okeru daihenshin PC keburu kyo

Energy Technology Data Exchange (ETDEWEB)

Ogawa, A.; Honma, A. [Japan Highway Public Corp., Tokyo (Japan)

1997-03-31

The details of the investigation on the Odawara Blue Way Bridge for which extradosed type is employed are provided, and a report is made about the situation of the study on the future construction of the 2nd Tomei-Meishin Expressway. The extradosed PC bridge is considered to have intermediate structural characteristics of those of the conventional beam bridge and PC cable stayed bridge, and is expected to be applied to bridges having approximately from 100 to 200m span. The features of the extradosed PC bridge is outlined. Approximately 1/35 beam height on the intermediate support and 1/10 main tower height against the center span are considered to be proper. PC steel products can be used efficiently because stress fluctuation of diagonals and the load sharing rate of the diagonal member are less than those of the PC cable stayed bridge and safety factor similar to that of general internal cable can be adopted. Construction works for the main tower and the diagonal member are easy due to low height of the main tower, and the bridge is advantageous also in the maintenance control because no beam is required. 5 refs., 8 figs., 2 tabs.

Precast Pearl-Chain concrete arch bridges

DEFF Research Database (Denmark)

Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

2015-01-01

A Pearl-Chain Bridge is a closed-spandrel arch bridge consisting of a number of straight pre-fabricated so called Super-Light Deck elements put together in an arch shape by post-tensioning cables. Several Pearl-Chain arches can be positioned adjacent to each other by a crane to achieve a bridge...... of a desired width. On top of the arch is a filling material to level out the surface of the above road. The filling only transfers vertical loads to the arch. The geometry and material properties of Super-Light Decks are presented, and we refer to several fullscale tests of Pearl-Chain arches where...... the technology was used. We also study other important components and details in the Pearl-Chain Bridge concept and review the effects of different types of loads. A theoretical case study of a circular 30 m span Pearl-Chain Bridge is presented showing the influence of a number of parameters: The number of post...

Building a Straw Bridge

Science.gov (United States)

Teaching Science, 2015

2015-01-01

This project is for a team of students (groups of two or three are ideal) to design and construct a model of a single-span bridge, using plastic drinking straws as the building material. All steps of the design, construction, testing and critiquing stages should be recorded by students in a journal. Students may like to include labelled diagrams,…

Assessment of structural condition of Libeň Bridge

Directory of Open Access Journals (Sweden)

Kněž Petr

2017-01-01

Full Text Available The paper presents diagnostic and load tests of the Inundation bridge which is part of a group of bridges called The Libeň bridge group in Prague. The Libeň bridge group consists of two arched and several framed bridges spanning the Vltava river. One of the vaulted bridges consists of 5 arches and the other vaulted bridge (called Inundation bridge consists of only one arch. Arched bridges are extraordinary structures with both technical and historical value. Since the inundation bridge has the largest arch of whole group, it was selected for testing purposes. The bridge is assembled with three-hinged arch made of concrete. The hinges are made of reinforced concrete and lead contact slabs. Detailed measurements of geometry and material properties were made on the bridge. Based on these measurements a computer model was created to verify the behavior of the structure. Both static and dynamic calculations were performed. Measurements of dynamic characteristics were made during normal operation and with hydraulic vibration exciter. This article will focus on comparing the results of dynamic calculation of the modeled structure and properties measured on real structure excited by hydraulic vibration exciter.

Nondestructive assessment of timber bridges using a vibration-based method

Science.gov (United States)

Xiping Wang; James P. Wacker; Robert J. Ross; Brian K. Brashaw

2005-01-01

This paper describes an effort to develop a global dynamic testing technique for evaluating the overall stiffness of timber bridge superstructures. A forced vibration method was used to measure the natural frequency of single-span timber bridges in the laboratory and field. An analytical model based on simple beam theory was proposed to represent the relationship...

Evaluation of Dynamic Load Factors for a High-Speed Railway Truss Arch Bridge

Directory of Open Access Journals (Sweden)

Ding Youliang

2016-01-01

Full Text Available Studies on dynamic impact of high-speed trains on long-span bridges are important for the design and evaluation of high-speed railway bridges. The use of the dynamic load factor (DLF to account for the impact effect has been widely accepted in bridge engineering. Although the field monitoring studies are the most dependable way to study the actual DLF of the bridge, according to previous studies there are few field monitoring data on high-speed railway truss arch bridges. This paper presents an evaluation of DLF based on field monitoring and finite element simulation of Nanjing DaShengGuan Bridge, which is a high-speed railway truss arch bridge with the longest span throughout the world. The DLFs in different members of steel truss arch are measured using monitoring data and simulated using finite element model, respectively. The effects of lane position, number of train carriages, and speed of trains on DLF are further investigated. By using the accumulative probability function of the Generalized Extreme Value Distribution, the probability distribution model of DLF is proposed, based on which the standard value of DLF within 50-year return period is evaluated and compared with different bridge design codes.

Design and construction of superstructure in prestressed concrete cable-stayed bridge. ; Aomori Bay Bridge. PC shachokyo jobuko no sekkei to seko. ; Aomori Bay Bridge

Energy Technology Data Exchange (ETDEWEB)

Ishibashi, T.; Fujimori, S.; Oba, M.; Tsuyoshi, T. (East Japan Railway Co., Tokyo (Japan))

1991-12-01

Aomori Bay Bridge is a 1,219m long elevated bridge, a part of No.2 Bay Highway of 1,993m in total length crossing over Aomori railway station which was planned in ordecr to integrate the port facilities of Aomori Harbor and expedite cargo traffic smoothly. Of this Bay Bridge, its main bridge portion crossing over Aomori railway station and the sea area was planned as a continuous prestressed concrete cable-stayed bridge of 498m in total length and consisting of three portions including the central portion in which the main span between the central bridge piers was 240m. It is scheduled to open in the summer of 1992. With regard to the design of this bridge, special care for the view of the bridge has been taken covering from the structure style to the accessories. For this bridge, a large scale underground continuous wall solid base with a box-shaped section consisting of 6 chambers was adopted for the base of a main tower. It has the cantilever suspension structure of the wide girder with the inverted Y-shaped pylons. For its stav cable, was adopted a large capacity stay cable with standard tensile strength of 1,942 fabricated on the site and for its covering tube, a FRP tube was adopted. In this article, the construction of the main girder and stay cables, and the construction control during their installation by projection are reported. 7 refs., 14 figs., 9 tabs.

First-passage probability of the deflection of a cable-stayed bridge under long-term site-specific traffic loading

Directory of Open Access Journals (Sweden)

Naiwei Lu

2017-01-01

Full Text Available Long-span bridges suffer from higher traffic loads and the simultaneous presence of multiple vehicles, which in conjunction with the steady traffic growth may pose a threat to the bridge safety. This study presents a methodology for first-passage probability evaluation of long-span bridges subject to stochastic heavy traffic loading. Initially, the stochastic heavy traffic loading was simulated based on long-term weigh-in-motion measurements of a highway bridge in China. A computational framework was presented integrating Rice’s level-crossing theory and the first-passage criterion. The effectiveness of the computational framework was demonstrated through a case study of a cable-stayed bridge. Numerical results show that the upper tail fitting of the up-crossing rate is an appropriate description of probability characteristics of the extreme traffic load effects of long-span bridges. The average daily truck traffic growth increases the probability of exceedance due to an intensive heavy traffic flow and results in a higher first-passage probability, but this increased trend is weakening as the continuous increase of the traffic volume. Since the sustained growth of gross vehicle weight has a constant impact on the probability of failure, setting a reasonable threshold overload ratio is an effective scheme as a traffic management to ensure the bridge serviceability.

Disassembly of an arch bridge deformed due to landslide activity and the replacement of a new bridge in the same site. Jisuberi ni yori henkei shita arch bashi no kaitai to shinbashi no kakekae

Energy Technology Data Exchange (ETDEWEB)

Sano, S; Morimoto, C; Tomoda, T; Mizukawa, Y; Onushi, M; Ito, T [Kawasaki Heavy Industries, Ltd., Tokyo (Japan)

1991-10-20

This report describes the replacement process of an arch bridge deformed due to landslide activity, selection and contents of the disassembly method, and configuration of the new bridge and its design method. The Ryugu Bridge had been damaged by landslides over an extended period. It was a deck arch bridge having originally a span of 74 meters, but it had shortened by 424 mm due to landslide activity during 14 years since its completion. Then it was decided to be replaced by a new bridge having an adjustable structure to support the movement of its abutments. As disassembly of the deformed arch bridge could be dangerous, the best methodology was studied, and the disassembly was carried out by the cable method. The new bridge had box-girder parts in both side of the main truss, so as to be adjustable to the change of the span length, and the bridge was designed for a working life of 50 years if the bearing supports and expansion joints were reset every 10 years. Concerning the connecting parts between the box-girder and the main truss, appropriateness of the sectional configuration was verified by FEM analysis. 9 refs., 18 figs., 2 tab.

Dynamic Characterization of the Little Belt Suspension Bridge by Operational Modal Analysis

DEFF Research Database (Denmark)

Christensen, Silas Sverre; Brandt, Anders; Andersen, Michael Styrk

2019-01-01

. It was found that the first vertical bending mode was 0.156 Hz, which is very near the frequency predicted by the original scale model. In total nine modes are reported, with frequencies from 0.156 to 0.808 Hz, and with damping values between 0.38% and 9.74%. This paper also demonstrates and discusses the use......The (new) Little Belt Bridge, opened in 1970, is a Danish suspension bridge with largest span being 600 m, and a total length of 1700 m. During the design and construction phase, detailed analysis of the dynamic properties of the bridge were carried out both by hand calculations and by measurements...... on a scale model. Recently, the bridge was measured using a setup of 45 simultaneous responses, 30 vertical and 15 lateral, distributed over the main span. Operational modal analysis was carried out on the data set, and the first two vertical bending and torsional modes were compared to those of the model...

Monitoring Bridge Dynamic Responses Using Fiber Bragg Grating Tiltmeters.

Science.gov (United States)

Xiao, Feng; Chen, Gang S; Hulsey, J Leroy

2017-10-20

In bridge health monitoring, tiltmeters have been used for measuring rotation and curvature; however, their application in dynamic parameter identification has been lacking. This study installed fiber Bragg grating (FBG) tiltmeters on the bearings of a bridge and monitored the dynamic rotational angle. The dynamic features, including natural frequencies and mode shapes, have been identified successfully. The innovation presented in this paper is the first-time use of FBG tiltmeter readings to identify the natural frequencies of a long-span steel girder bridge. The identified results have been verified using a bridge finite element model. This paper introduces a new method for the dynamic monitoring of a bridge using FBG tiltmeters. Limitations and future research directions are also discussed in the conclusion.

Monitoring Bridge Dynamic Responses Using Fiber Bragg Grating Tiltmeters

Directory of Open Access Journals (Sweden)

Feng Xiao

2017-10-01

Full Text Available In bridge health monitoring, tiltmeters have been used for measuring rotation and curvature; however, their application in dynamic parameter identification has been lacking. This study installed fiber Bragg grating (FBG tiltmeters on the bearings of a bridge and monitored the dynamic rotational angle. The dynamic features, including natural frequencies and mode shapes, have been identified successfully. The innovation presented in this paper is the first-time use of FBG tiltmeter readings to identify the natural frequencies of a long-span steel girder bridge. The identified results have been verified using a bridge finite element model. This paper introduces a new method for the dynamic monitoring of a bridge using FBG tiltmeters. Limitations and future research directions are also discussed in the conclusion.

Bridge Deterioration Prediction Model Based On Hybrid Markov-System Dynamic

Directory of Open Access Journals (Sweden)

Widodo Soetjipto Jojok

2017-01-01

Full Text Available Instantaneous bridge failure tends to increase in Indonesia. To mitigate this condition, Indonesia’s Bridge Management System (I-BMS has been applied to continuously monitor the condition of bridges. However, I-BMS only implements visual inspection for maintenance priority of the bridge structure component instead of bridge structure system. This paper proposes a new bridge failure prediction model based on hybrid Markov-System Dynamic (MSD. System dynamic is used to represent the correlation among bridge structure components while Markov chain is used to calculate temporal probability of the bridge failure. Around 235 data of bridges in Indonesia were collected from Directorate of Bridge the Ministry of Public Works and Housing for calculating transition probability of the model. To validate the model, a medium span concrete bridge was used as a case study. The result shows that the proposed model can accurately predict the bridge condition. Besides predicting the probability of the bridge failure, this model can also be used as an early warning system for bridge monitoring activity.

Bio-based composite pedestrian bridge. Part 2: materials and production process

NARCIS (Netherlands)

Lepelaar, Mark; Hoogendoorn, Alwin; Blok, Rijk; Teuffel, Patrick; Kawaguchi, K.; Ohsaki, M.; Takeuchi, T.

2016-01-01

The Bio-based composite bridge is a 3TU project which aims to design and realize a 14m span pedestrian bridge made from fibre-reinforced polymers (FRP) and which is introduced in part 1 of this paper. Part 2 will focus on various studies about bio-based materials, which are suitable for structural

Construction of precast high performance concrete segmental bridges.

OpenAIRE

Ruiz Ripoll, Lidia

2016-01-01

The construction of both medium and long span precast concrete segmental bridges is widely spread throughout Spain. Usually, the segments have multiple-keyed epoxy joints, and are assembled by internal prestressing. Yet, there is a more recent type of bridge with dry joints and external prestressing. In these last ones, shear is transferred through physical support between keys and friction between faces of the compressed joint. This shear force is evaluated using friction coefficients from t...

Elastic, plastic, fracture analysis of masonry arches: A multi-span bridge case study

Science.gov (United States)

Lacidogna, Giuseppe; Accornero, Federico

2018-01-01

In this work a comparison is presented between elastic, plastic, and fracture analysis of the monumental arch bridge of Porta Napoli, Taranto (Italy). By means of a FEM model and applying the Mery's Method, the behavior of the curved structure under service loads is verified, while considering the Safe Theorem approach byHeyman, the ultimate carrying capacity of the structure is investigated. Moreover, by using Fracture Mechanics concepts, the damage process which takes place when the conditions assessed through linear elastic analysis are no longer valid, and before the set-in of the conditions established by means of the plastic limit analysis, is numerically analyzed. The study of these transitions returns an accurate and effective whole service life assessment of the Porta Napoli masonry arch bridge.

Study on the Spatial Stress of the Chongqing Yangtze River Bridge in China

Directory of Open Access Journals (Sweden)

Yan Li

2014-09-01

Full Text Available Continuous rigid-frame bridges are usually used in building bridges with long span and high piers. It is characterized by the consolidation between piers and beams in the middle of bridge piers and flexible bridge piers in the lower part. Among all the factors, curvature has the most obvious influence on the stress of curved continuous rigid-frame bridge, because of which, the curved beam bridge produces coupling effect of bending moment and receives complicated stress, leading to the deformation such as torsion and displacement of radial direction. No matter it is the castscaffold construction or cantilever construction, for continuous rigid-frame bridges, considering that after the long term creep of concrete, structure stress tends to be in a drop-frame state, so it is necessary to know the mechanical properties of the finished bridge. Taking the Chongqing Yangtze River Bridge as an example, this paper mainly analyzes the internal forces and deformations of a finished curved continuotus rigid-frame bridge by establishing a spatial finite element model with Midas Civil 2006 software and by changing the model’s radius of curvature. The results show that as the curvature increases, the vertical deformation and torsion angle of the long-span curved continuous rigid-frame bridge are both reduced under the effect of a dead load and prestressed load, presenting mechanical properties of bridge, namely, “coupling effect of bending moment”. In the model analyzed, the deformation of the bridge in the transverse direction also behaves a trend of gradual decrease with an increase in radius of curvature with the range 500–2000 m.

Durability of Materials in Pearl-Chain Bridges

DEFF Research Database (Denmark)

Lund, Mia Schou Møller

. The construction of the Pearl-Chain arch is simple. The arch is assembled on its side, next to the road that the bridge will span, by placing a number of plane prefabricated Super-Light Decks that consist of lightweight aggregate concrete and conventional concrete, in the desired arch shape. Mortar joints are cast...... is stabilized by casting a fill material between the spandrel walls of the arch. Finally, the road surface is cast on top of the fill material. New bridges are designed for a service lifetime of at least 100 years. Hence, the specifications of the materials used in Pearl-Chain Bridges are high. This PhD study...... and pervious concrete were also investigated. The most suitable fill material for Pearl-Chain Bridges depends on the particular bridge design; the results obtained and presented in the present PhD study provide guidance on how to decide which fill material is most suitable regarding strength, permeability...

Railway bridge monitoring during construction and sliding

Science.gov (United States)

Inaudi, Daniele; Casanova, Nicoletta; Kronenberg, Pascal; Vurpillot, Samuel

1997-05-01

The Moesa railway bridge is a composite steel concrete bridge on three spans of 30 m each. The 50 cm thick concrete deck is supported on the lower flanges of two continuous, 2.7 m high I-beams. The bridge has been constructed alongside an old metallic bridge. After demolishing this one, the new bridge has been slid for 5 m by 4 hydraulic jacks and positioned on the refurbished piles of the old bridge. About 30 fiber optic, low-coherence sensors were imbedded in the concrete deck to monitor its deformations during concrete setting and shrinkage, as well as during the bridge sliding phase. In the days following concrete pour it was possible to follow its thermal expansion due to the exothermic setting reaction and the following thermal and during shrinkage. The deformations induced by the additional load produced by the successive concreting phases were also observed. During the bridge push, which extended over six hours, the embedded and surface mounted sensors allowed the monitoring of the curvature variations in the horizontal plane due to the slightly uneven progression of the jacks. Excessive curvature and the resulting cracking of concrete could be ruled out by these measurements. It was also possible to observe the bridge elongation under the heating action of the sun.

Active Control of Long Bridges Using Flaps

DEFF Research Database (Denmark)

Hansen, H. I.; Thoft-Christensen, Palle

The main problem in designing ultra-long span suspension bridges is flutter. A solution to this problem might be to introduce an active flap control system to increase the flutter wind velocity. The investigated flap control system consists of flaps integrated in the bridge girder so each flap...... is the streamlined part of the edge of the girder. Additional aerodynamic derivatives are shown for the flaps and it is shown how methods already developed can be used to estimate the flutter wind velocity for a bridge section with flaps. As an example, the flutter wind velocity is calculated for different flap...... configurations for a bridge section model by using aerodynamic derivatives for a flat plate. The example shows that different flap configurations can either increase or decrease the flutter wind velocity. for optimal flap configurations flutter will not occur....

Statistical determination of significant curved I-girder bridge seismic response parameters

Science.gov (United States)

Seo, Junwon

2013-06-01

Curved steel bridges are commonly used at interchanges in transportation networks and more of these structures continue to be designed and built in the United States. Though the use of these bridges continues to increase in locations that experience high seismicity, the effects of curvature and other parameters on their seismic behaviors have been neglected in current risk assessment tools. These tools can evaluate the seismic vulnerability of a transportation network using fragility curves. One critical component of fragility curve development for curved steel bridges is the completion of sensitivity analyses that help identify influential parameters related to their seismic response. In this study, an accessible inventory of existing curved steel girder bridges located primarily in the Mid-Atlantic United States (MAUS) was used to establish statistical characteristics used as inputs for a seismic sensitivity study. Critical seismic response quantities were captured using 3D nonlinear finite element models. Influential parameters from these quantities were identified using statistical tools that incorporate experimental Plackett-Burman Design (PBD), which included Pareto optimal plots and prediction profiler techniques. The findings revealed that the potential variation in the influential parameters included number of spans, radius of curvature, maximum span length, girder spacing, and cross-frame spacing. These parameters showed varying levels of influence on the critical bridge response.

reliability assessment of stringers spacings in bridges as function

African Journals Online (AJOL)

user

A timber bridge deck is modelled on timber stringers in accordance with current .... simple linear formulation for supporting stringers ... new generation design codes, evaluation of existing ... transverse plank deck the span of the deck is.

Determination of in-situ strength on selected bridge element concrete girder and slab of Nagtahan bridge using rebound hammer test

International Nuclear Information System (INIS)

Uy, Bernadette Betsy B.; Banaga, Renato T.

2013-01-01

This study examined the extent of the damage due to fire on the affected areas of the bridge structure. The need to assess the damage of the Nagtahan Bridge is very useful to provide appropriate measures in the repair or in the reinforcement of the bridge, hence will ensure its strength and integrity. The study included two (2) spans of the bridge deck/slab with specific locations of the bridge that were subjected for testing. The Rebound Hammer was used as a preliminary test in evaluating the bridge condition. Its capability is to assess the in-place uniformity of concrete, to delineate regions in a structure of poor quality or deteriorated concrete, and to estimate the in-place strength; and ultimately, for relative comparison between the different structures of the bridge. With the use of the NDT Rebound Hammer Test, the researchers were able to determine whether or not the in-situ strength of the bridge's concrete has been weakened due to fire. The DPW-Standard Specification is the government acceptable manual, containing the acceptance criteria, used as the basis for standard construction procedures in the department.(author)

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.

Effect of Piers Shape on the Dynamic Structural Responses of Prestressed Concrete Bridge: Part II

Directory of Open Access Journals (Sweden)

Ali Fadhil Naser

2016-03-01

Full Text Available Pier of bridge is usually used as a general term for any type of substructure located between horizontal spans and foundations. Piers give vertical supports for spans at intermediate points and perform two main functions. The objective of this study is to inspect the effect of piers shape on the dynamic structural performance by adopting theoretical dynamic analysis. The results of dynamic analysis of 25 bridges models show that the maximum value of natural frequency is equal to 5.64Hz in two circles piers bridge model. Therefore, this type of model has good stiffness and bearing capacity. The two square piers model, the one circle pier model, and the two circles piers model appear good stiffness because of the natural frequencies (5.30Hz, 5.52Hz, and 5.64Hz are more than the maximum forced frequencies (4.52Hz, 5.45Hz, and 4.52Hz respectively. According to the comparison between all models results, the two circles piers model has the higher stiffness because of this model has the maximum value of natural frequency (5.64Hz and it is more than all forced vibration frequencies of all others models. Therefore, this study recommends that using the bridge model of two circles piers in the bridges construction that consists of three spans (30m+40m+30m with section of box girder.

Effect of Piers Shape on the Dynamic Structural Responses of Prestressed Concrete Bridge: Part II

Directory of Open Access Journals (Sweden)

Ali Fadhil Naser

2016-12-01

Full Text Available Pier of bridge is usually used as a general term for any type of substructure located between horizontal spans and foundations. Piers give vertical supports for spans at intermediate points and perform two main functions. The objective of this study is to inspect the effect of piers shape on the dynamic structural performance by adopting theoretical dynamic analysis. The results of dynamic analysis of 25 bridges models show that the maximum value of natural frequency is equal to 5.64Hz in two circles piers bridge model. Therefore, this type of model has good stiffness and bearing capacity. The two square piers model, the one circle pier model, and the two circles piers model appear good stiffness because of the natural frequencies (5.30Hz, 5.52Hz, and 5.64Hz are more than the maximum forced frequencies (4.52Hz, 5.45Hz, and 4.52Hz respectively. According to the comparison between all models results, the two circles piers model has the higher stiffness because of this model has the maximum value of natural frequency (5.64Hz and it is more than all forced vibration frequencies of all others models. Therefore, this study recommends that using the bridge model of two circles piers in the bridges construction that consists of three spans (30m+40m+30m with section of box girder.

Construction simulation analysis of 120m continuous rigid frame bridge based on Midas Civil

Science.gov (United States)

Shi, Jing-xian; Ran, Zhi-hong

2018-03-01

In this paper, a three-dimensional finite element model of a continuous rigid frame bridge with a main span of 120m is established by the simulation and analysis of Midas Civil software. The deflection and stress of the main beam in each construction stage of continuous beam bridge are simulated and analyzed, which provides a reliable technical guarantee for the safe construction of the bridge.

A static analysis method for barge impact design of bridges with consideration of dynamic amplification : summary.

Science.gov (United States)

2009-11-01

Several hundred Florida bridges span waterways deep enough for barge traffic. To ensure a bridge is capable of withstanding the potential impact of a barge collision, engineers use design specifications recommended by the American Association of Stat...

Effectiveness of Tuned Mass Dampers in Seismic Response Control of Isolated Bridges Including Soil-Structure Interaction

Directory of Open Access Journals (Sweden)

Said Elias

Full Text Available Abstract The effect of soil-structure interaction (SSI on the dynamic responses of seismically isolated three-span continuous reinforced concrete (RC bridge is investigated. Also, tuned mass damper(s (TMD/s is/are installed to control undesirable bearing displacement, even under the SSI effect. The TMDs are placed at the mid-span of the bridge and each tuned with a modal frequency, while controlling up to first few modes as desirable. The soil surrounding the foundation of pier is modeled by frequency independent coefficients. Dynamic analysis is carried out in time domain using direct integration method. In order to specify the effects of the SSI, the responses of the non-isolated, isolated, and controlled isolated bridge are compared. It is observed that the soil surrounding the pier has significant effects on the bearing displacement of the isolated RC bridges. In addition, it is observed that the seismic responses of isolated RC bridge reduced significantly with installation of the TMDs.

Big data and high-performance analytics in structural health monitoring for bridge management

Science.gov (United States)

Alampalli, Sharada; Alampalli, Sandeep; Ettouney, Mohammed

2016-04-01

Structural Health Monitoring (SHM) can be a vital tool for effective bridge management. Combining large data sets from multiple sources to create a data-driven decision-making framework is crucial for the success of SHM. This paper presents a big data analytics framework that combines multiple data sets correlated with functional relatedness to convert data into actionable information that empowers risk-based decision-making. The integrated data environment incorporates near real-time streams of semi-structured data from remote sensors, historical visual inspection data, and observations from structural analysis models to monitor, assess, and manage risks associated with the aging bridge inventories. Accelerated processing of dataset is made possible by four technologies: cloud computing, relational database processing, support from NOSQL database, and in-memory analytics. The framework is being validated on a railroad corridor that can be subjected to multiple hazards. The framework enables to compute reliability indices for critical bridge components and individual bridge spans. In addition, framework includes a risk-based decision-making process that enumerate costs and consequences of poor bridge performance at span- and network-levels when rail networks are exposed to natural hazard events such as floods and earthquakes. Big data and high-performance analytics enable insights to assist bridge owners to address problems faster.

Research on structural dynamic characteristics of continuous steel box girder-bridge with lager ratio of wide-span

Directory of Open Access Journals (Sweden)

Yin Haijun

2018-01-01

Full Text Available Structure natural frequency and mode of vibration can not only reflect the structure modal parameters of dynamic properties, but also incarnate the dynamic evaluation characteristics of bridge structure. This paper applies ANSYS to establish the finite element model based on a continuous steel box girder bridge in order to obtain the corresponding modal analysis parameters. Through the environmental stimulation test, The results show that height of the steel box girder and the setting of diaphragm plate is reasonable, transverse space of piers not merely provide enough support but also ensure lateral stability of the bridge, as well as offering aside the maximum lateral clearance of the existing road. Meanwhile, the calculation results have important engineering practical values. which can provide basic data for the design, construction and maintenance of similar Bridges.

Computer modeling of road bridge for simulation moving load

Directory of Open Access Journals (Sweden)

Miličić Ilija M.

2016-01-01

Full Text Available In this paper is shown computational modelling one span road structures truss bridge with the roadway on the upper belt of. Calculation models were treated as planar and spatial girders made up of 1D finite elements with applications for CAA: Tower and Bridge Designer 2016 (2nd Edition. The conducted computer simulations results are obtained for each comparison of the impact of moving load according to the recommendations of the two standards SRPS and AASHATO. Therefore, it is a variant of the bridge structure modeling application that provides Bridge Designer 2016 (2nd Edition identical modeled in an environment of Tower. As important information for the selection of a computer applications point out that the application Bridge Designer 2016 (2nd Edition we arent unable to treat the impacts moving load model under national standard - V600. .

Teknologvurdering, Broer og Brugere (Technology Assessment: Bridges and Users)

DEFF Research Database (Denmark)

Munch, Birgitte

A critique of the scientific approaches grounding Danish technology assessments for beingnon-reflexive upon the consequences of its biased treatment of who and how some countsas ‘users'. Implications and new approaches are outlined in a story of engineering designers conceptualization of ships pa...... passing the Great Belt - the ‘sailing users' - during the constructionof the suspension bridge across the east channel. A story about 'How the Great BeltEast bridge main span got the length of 1624m....

Computational and experimental investigation of free vibration and flutter of bridge decks

Science.gov (United States)

Helgedagsrud, Tore A.; Bazilevs, Yuri; Mathisen, Kjell M.; Øiseth, Ole A.

2018-06-01

A modified rigid-object formulation is developed, and employed as part of the fluid-object interaction modeling framework from Akkerman et al. (J Appl Mech 79(1):010905, 2012. https://doi.org/10.1115/1.4005072) to simulate free vibration and flutter of long-span bridges subjected to strong winds. To validate the numerical methodology, companion wind tunnel experiments have been conducted. The results show that the computational framework captures very precisely the aeroelastic behavior in terms of aerodynamic stiffness, damping and flutter characteristics. Considering its relative simplicity and accuracy, we conclude from our study that the proposed free-vibration simulation technique is a valuable tool in engineering design of long-span bridges.

Extension of POA based on Fiber Element to Girder Bridge

International Nuclear Information System (INIS)

Li Zhenxin; Qiang Shizhong

2010-01-01

Because of its main advantage of simplicity, practicality, lower computational cost and relative good results Pushover analysis (POA) has become an effective analytical tool during the last decade for the seismic assessment of buildings. But such work on bridges has been very limited. Hence, the aim of this study is to adapt POA for nonlinear seismic analysis of girder bridges, and investigate its applicability in the case of an existing river-spanning approach bridge. To three different types bridge models the nonlinear POA, which adopts fiber model nonlinear beam-column element based on flexibility approach, with return period about 2500 years is carried out. It can be concluded that POA is applicable for bridges, with some shortcomings associated with the method in general, even when it is applied for buildings. Finally the applicable selection for monitoring point and lateral load pattern is suggested according to dynamic characteristic of girder bridges.

Dynamic Response of a Long-Span Concrete-Filled Steel Tube Tied Arch Bridge and the Riding Comfort of Monorail Trains

Directory of Open Access Journals (Sweden)

Hongye Gou

2018-04-01

Full Text Available In this study, a dynamic response analysis procedure is proposed and applied to investigate the dynamic responses of a straddle-type concrete-filled steel tube tied arch bridge under train and truck loadings. A numerical model of the coupled monorail train–bridge system is established to investigate the dynamic behaviors of the bridge under moving trains. A refined three-dimensional finite element model is built for the bridge and a 15 degrees-of-freedom vehicle model is presented for the train. The numerical model is validated using in-situ test results and then used to analyze the dynamic displacement and acceleration of the bridge and the trains on the bridge. Based on the simulation results, the impact factor of the bridge is investigated and the riding comfort of the trains is evaluated. The investigation results show that the impact factor of vehicle loads reaches the maximum value when the resonance of the bridge is induced by the moving vehicles. The effect of train braking predominates the longitudinal vibration of the bridge but is negligible in the transverse and vertical directions. The vehicle speed is the dominating factor for the riding comfort of the train.

Bridges Dynamic Parameters Identification Based On Experimental and Numerical Method Comparison in Regard with Traffic Seismicity

Science.gov (United States)

Krkošková, Katarína; Papán, Daniel; Papánová, Zuzana

2017-10-01

The technical seismicity negatively affects the environment, buildings and structures. Technical seismicity means seismic shakes caused by force impulse, random process and unnatural origin. The vibration influence on buildings is evaluated in the Eurocode 8 in Slovak Republic, however, the Slovak Technical Standard STN 73 0036 includes solution of the technical seismicity. This standard also classes bridges into the group of structures that are significant in light of the technical seismicity - the group “U”. Using the case studies analysis by FEM simulation and comparison is necessary because of brief norm evaluation of this issue. In this article, determinate dynamic parameters by experimental measuring and numerical method on two real bridges are compared. First bridge, (D201 - 00) is Scaffold Bridge on the road I/11 leading to the city of Čadca and is situated in the city of Žilina. It is eleven - span concrete road bridge. The railway is the obstacle, which this bridge spans. Second bridge (M5973 Brodno) is situated in the part of Žilina City on the road of I/11. It is concrete three - span road bridge built as box girder. The computing part includes 3D computational models of the bridges. First bridge (D201 - 00) was modelled in the software of IDA Nexis as the slab - wall model. The model outputs are natural frequencies and natural vibration modes. Second bridge (M5973 Brodno) was modelled in the software of VisualFEA. The technical seismicity corresponds with the force impulse, which was put into this model. The model outputs are vibration displacements, velocities and accelerations. The aim of the experiments was measuring of the vibration acceleration time record of bridges, and there was need to systematic placement of accelerometers. The vibration acceleration time record is important during the under - bridge train crossing, about the first bridge (D201 - 00) and the vibration acceleration time domain is important during deducing the force

ABOUT THE DEVELOPMENT OF SPATIAL METHODS OF CALCULATING SPANS OF HIGHWAY BRIDGES

Directory of Open Access Journals (Sweden)

V. P. Kozhushko

2007-10-01

Full Text Available The problem of methods of spatial computation of spans of different structures has been considered. The possibility of application of simplified computation methods allowing to take into account both resilient and non-linear deformations as well as to estimate other factors affecting the stressed-and-strained state of a system without accuracy loss for results obtained has been presented.

The Challenges of Rehabilitating the Hercilio Luz Suspension Bridge

Directory of Open Access Journals (Sweden)

Hermes Carvalho

Full Text Available Abstract The Hercílio Luz suspension bridge, built in 1926, has been out of service since 1991 due to high corrosion levels and structural element impairment. A complete rehabilitation project was developed which included the replacement of the impaired items and foundation strengthening. For this, an auxiliary structure was employed to support the central span during the rehabilitation process. A carefully studied load transfer process, where the central span loading is transferred from the eye-bar towards the auxiliary structure will be performed. For this purpose, a synchronized jacking sequence will be used, which was predefined by means of numerical model analysis. All structural elements had their designs evaluated and some geometric changes were implemented. This paper presents all the methodology developed in the rehabilitation project of Hercilio Luz bridge, as well as the development stages up to the present date.

Construction work of superstructure of twin harp bridge. Twin harp kyo jobuko no seko

Energy Technology Data Exchange (ETDEWEB)

Sasaki, H.; Sato, Y.; Kanazawa, Y. (Sumitomo Construction Kajima Corp. Dopy Construction Co. Ltd. Nihon Koatsu Concrete Co. Ltd. Joint Venture, Tokyo (Japan)); Sema, M. (Sumitomo Construction Co. Ltd., Tokyo (Japan))

1991-11-30

Construction plan outline of PC cable stayed bridge with main tower having one pillar structure is introduced and this is the first type of bridge in Japan with three continuous span design. Construction was commenced on 7 July, 1989 and was completed on 8 August, 1991 at south east of Ashahikawa, Hokkaido. Construction outline is consisted of Principal specifications, general layout of structure, construction order and overall stage of the construction work. Main tower is described by its outline, jump system, installation of diagonal member anchorage device, formwork and concrete structure, and cross beam construction has included four parts which are outline, capital part, projected part construction, lateral span and closure part, and central control span and closure part. Outline, cable guard and erection work, cable work, work Procedure of cable taut construction using total taut method, tension adjustment of cable and grouting, for diagonal member are explained. The construction control items specific to cable stayed bridge are diagonal member tension control( control of applied tension, change of tension with time and test taut ) and camber control. Practical vibration test was carried out on March, 1991. 8 refs., 15 figs., 5 tabs.

Design and construction of the Daini-Chikumagawa bridge; Dai ni Chikumagawa kyoryo no sekkei to seko

Energy Technology Data Exchange (ETDEWEB)

Inaba, N.; Takasusuki, K.; Hirasawa, T.; Kanamori, M.

1996-01-30

The Daini-Chikumagawa bridge, having spans of 134m {times} 2 which is the largest in Japan as the concrete railroad, is a prestressed concrete (PC) oblique cable-stayed bridge building on the Hokuriku Shinkansen express line which is constructing towards Nagano Olympic (Feb.1998). Regarding adoption of the oblique cable-stayed bridge for the railroad bridge, there are very few examples on a global scale and in Japan besides this bridge there is only one example (Omoto bridge (Iwate pref.), span = 85m). One H type tower (H = 65m from the surface of bridge) is erected at the center of the Chikuma river and then main girders are built at the front and rear of this tower. These main girders, being separated into 5m {times} 24 blocks per one side excepting surroundings of the tower, are fabricated as a three room box type PC block (total width 12.8m; height 3.0m) each on the river beach near the spot. These blocks are jointed from the tower side by the overhanging work using the constructing vehicles and are fixed with oblique materials (cables; two face hanging system) at intervals of 10m. 4 refs., 16 figs., 5 tabs.

Thermal response of integral abutment bridges with mechanically stabilized earth walls.

Science.gov (United States)

2013-03-01

The advantages of integral abutment bridges (IABs) include reduced maintenance costs and increased useful life spans. : However, improved procedures are necessary to account for the impacts of cyclic thermal displacements on IAB components, : includi...

Bridge continuous deformation measurement technology based on fiber optic gyro

Science.gov (United States)

Gan, Weibing; Hu, Wenbin; Liu, Fang; Tang, Jianguang; Li, Sheng; Yang, Yan

2016-03-01

Bridge is an important part of modern transportation systems and deformation is a key index for bridge's safety evaluation. To achieve the long span bridge curve measurement rapidly and timely and accurately locate the bridge maximum deformation, the continuous deformation measurement system (CDMS) based on inertial platform is presented and validated in this paper. Firstly, based on various bridge deformation measurement methods, the method of deformation measurement based on the fiber optic gyro (FOG) is introduced. Secondly, the basic measurement principle based on FOG is presented and the continuous curve trajectory is derived by the formula. Then the measurement accuracy is analyzed in theory and the relevant factors are presented to ensure the measurement accuracy. Finally, the deformation measurement experiments are conducted on a bridge across the Yangtze River. Experimental results show that the presented deformation measurement method is feasible, practical, and reliable; the system can accurately and quickly locate the maximum deformation and has extensive and broad application prospects.

INVESTIGATION OF LAUNCHING PROCESS FOR STEEL REINFORCED CONCRETE FRAMEWORK OF LARGE BRIDGES

Directory of Open Access Journals (Sweden)

V. A. Grechukhin

2017-01-01

Full Text Available Bridges are considered as the most complicated, labour-consuming and expensive components in roadway network of the Republic of Belarus. So their construction and operation are to be carried out at high technological level. One of the modern industrial methods is a cyclic longitudinal launching of large frameworks which provide the possibility to reject usage of expensive auxiliary facilities and reduce a construction period. There are several variants of longitudinal launching according to shipping conditions and span length: without launching girder, with launching girder, with top strut-framed beam in the form of cable-stayed system, with strut-framed beam located under span. While using method for the cyclic longitudinal launching manufacturing process of span is concentrated on the shore. The main task of the investigations is to select economic, quick and technologically simple type of the cyclic longitudinal launching with minimum resource- and labour inputs. Span launching has been comparatively analyzed with temporary supports being specially constructed within the span and according to capital supports with the help of launching girder. Conclusions made on the basis of calculations for constructive elements of span according to bearing ability of element sections during launching and also during the process of reinforced concrete plate grouting and at the stage of operation have shown that span assembly with application of temporary supports does not reduce steel spread in comparison with the variant excluding them. Results of the conducted investigations have been approbated in cooperation with state enterprise “Belgiprodor” while designing a bridge across river Sozh.

Measurement of Non-Stationary Characteristics of a Landfall Typhoon at the Jiangyin Bridge Site

OpenAIRE

He, Xuhui; Qin, Hongxi; Tao, Tianyou; Liu, Wenshuo; Wang, Hao

2017-01-01

The wind-sensitive long-span suspension bridge is a vital element in land transportation. Understanding the wind characteristics at the bridge site is thus of great significance to the wind- resistant analysis of such a flexible structure. In this study, a strong wind event from a landfall typhoon called Soudelor recorded at the Jiangyin Bridge site with the anemometer is taken as the research object. As inherent time-varying trends are frequently captured in typhoon events, the wind characte...

Design and construction of PC cable-stayed bridge reducing the weight of dead load (Minamitabaru No. 1 Bridge). Shuko danmen no keiryoka wo hakatta PC shachokyo (kasho Minamitabaru 1 go kyo)

Energy Technology Data Exchange (ETDEWEB)

Otsuka, H. (Building Research Inst., Tokyo (Japan)); Ikari, K.; Ono, Y. (Ministry of Construction, Tokyo (Japan)); Hirano, A.

1993-03-15

The Minamitabaru No.1 bridge is a PC cable-stayed bridge with a 170m center span. The cross section dead load weight of the main beam in the center span is reduced to decrease the unbalance moment during construction and the negative reaction force after the completion. As a result, the average volume of concrete in the center span becomes 0.55m[sup 3]/m[sup 2] which is less by about 20% in comparison with a PC cable-stayed bridge of the similar scale. Separated 2 chamber box girder cross section is adopted for the shape of the main beam cross section to reduce the dead load weight of the cross section, and to improve the rigidity of the cross section and wind resisting stability, etc. In addition, a cross beam is provided in the diagonal member anchorage position to integrate the two box beams. A wind tunnel test is performed using a 1/30 scale model to confirm the wind resisting stability. The diagonal member is structured with several PC steel members. At the same time, a stretching work carriage is developed and used which can establish 3 dimensional position and direction by a hydraulic jack. 7 figs.

Ambient Modal Testing of the Vestvej Bridge using Random Decrement

DEFF Research Database (Denmark)

Asmussen, J. C.; Brincker, Rune; Rytter, A.

This paper presents an ambient vibration study of the Vestvej Bridge. The bridge is a typically Danish two-span concrete bridge which crosses a highway. The purpose of the study is to perform a pre-investigation of the dynamic behavior to obtain information for the design of a demonstration project...... concerning application of vibration based inspection of bridges. The data analysis process of ambient vribration testing of bridges has traditionally been based on auto and cross spectral densities estimated using an FFT algorithm. In the pre-analysis state the spectral densities are all averaged to obtain...... measurements might have a low signal to noise ratio. Thus, it might be difficult clearly to identify physical modes from the spectral densities. The Random Decrement (RD) technique is another method to perform the data analysis process in the time domain only. It is basically a very simple and very easily...

Ambient Modal Testing of the Vestvej Bridge using Random Decrement

DEFF Research Database (Denmark)

Asmussen, J. C.; Brincker, Rune; Rytter, A.

1998-01-01

This paper presents an ambient vibration study of the Vestvej Bridge. The bridge is a typically Danish two-span concrete bridge which crosses a highway. The purpose of the study is to perform a pre-investigation of the dynamic behavior to obtain information for the design of a demonstration project...... concerning application of vibration based inspection of bridges. The data analysis process of ambient vribration testing of bridges has traditionally been based on auto and cross spectral densities estimated using an FFT algorithm. In the pre-analysis state the spectral densities are all averaged to obtain...... measurements might have a low signal to noise ratio. Thus, it might be difficult clearly to identify physical modes from the spectral densities. The Random Decrement (RD) technique is another method to perform the data analysis process in the time domain only. It is basically a very simple and very easily...

Simulation Study on Train-Induced Vibration Control of a Long-Span Steel Truss Girder Bridge by Tuned Mass Dampers

Directory of Open Access Journals (Sweden)

Hao Wang

2014-01-01

Full Text Available Train-induced vibration of steel truss bridges is one of the key issues in bridge engineering. This paper talks about the application of tuned mass damper (TMD on the vibration control of a steel truss bridge subjected to dynamic train loads. The Nanjing Yangtze River Bridge (NYRB is taken as the research object and a recorded typical train load is included in this study. With dynamic finite element (FE method, the real-time dynamic responses of NYRB are analyzed based on a simplified train-bridge time-varying system. Thereinto, two cases including single train moving at one side and two trains moving oppositely are specifically investigated. According to the dynamic characteristics and dynamic responses of NYRB, the fourth vertical bending mode is selected as the control target and the parameter sensitivity analysis on vibration control efficiency with TMD is conducted. Using the first-order optimization method, the optimal parameters of TMD are then acquired with the control efficiency of TMD, the static displacement of Midspan, expenditure of TMDs, and manufacture difficulty of the damper considered. Results obtained in this study can provide references for the vibration control of steel truss bridges.

Monitoring of the new Arsta railway bridge using traditional and fiber optic sensors

Science.gov (United States)

Enckell-El Jemli, Merit; Karoumi, Raid; Lanaro, Flavio

2003-08-01

Stockholm consists of several islands connected by a number of bridges. Many of these bridges need to be repaired or replaced because of their age. Replacing and repairing existing bridges are of economic concern for many local authorities and governments. In order to minimize the costs for reparation and maintenance and to ensure the safety of civil infrastructures, there is an increasing need in our society for health monitoring of bridges. Monitoring helps us to understand the real behavior of the structure and lets us verify the design uncertainties. It is clear that monitoring will have a major role in the design of the future structures, and suitable monitoring systems will be designed together with the structures. The new Årsta Railway Bridge, which is under construction in Stockholm, is an optimized and very complex ten-span pre-stressed concrete structure. Each span has a length of 78 meters. The Swedish National Railway Administration (Banverket) has initiated a measuring campaign in order to study and understand the dynamic and static behavior of the bridge. The main objectives are: firstly, to monitor the bridge during the first 10 years including construction and testing period, and secondly, for the static study, to compare traditional measuring technique using strain transducers developed at Royal Institute of Technology, KTH, Sweden, with the fiber optic sensors developed by SMARTEC, Switzerland. After a short overview of the existing measurement systems and technique for measuring civil infrastructures, the paper illustrates the installation of KTH's and SMARTEC's monitoring systems. In addition, some very early results are included.

Design and Implementation of a New System for Large Bridge Monitoring—GeoSHM

Directory of Open Access Journals (Sweden)

Xiaolin Meng

2018-03-01

Full Text Available Structural Health Monitoring (SHM is a relatively new branch of civil engineering that focuses on assessing the health status of infrastructure, such as long-span bridges. Using a broad range of in-situ monitoring instruments, the purpose of the SHM is to help engineers understand the behaviour of structures, ensuring their structural integrity and the safety of the public. Under the Integrated Applications Promotion (IAP scheme of the European Space Agency (ESA, a feasibility study (FS project that used the Global Navigation Satellite Systems (GNSS and Earth Observation (EO for Structural Health Monitoring of Long-span Bridges (GeoSHM was initiated in 2013. The GeoSHM FS Project was led by University of Nottingham and the Forth Road Bridge (Scotland, UK, which is a 2.5 km long suspension bridge across the Firth of Forth connecting Edinburgh and the Northern part of Scotland, was selected as the test structure for the GeoSHM FS project. Initial results have shown the significant potential of the GNSS and EO technologies. With these successes, the FS project was further extended to the demonstration stage, which is called the GeoSHM Demo project where two other long-span bridges in China were included as test structures. Led by UbiPOS UK Ltd. (Nottingham, UK, a Nottingham Hi-tech company, this stage focuses on addressing limitations identified during the feasibility study and developing an innovative data strategy to process, store, and interpret monitoring data. This paper will present an overview of the motivation and challenges of the GeoSHM Demo Project, a description of the software and hardware architecture and a discussion of some primary results that were obtained in the last three years.

Lifecycle Assessments of Railway Bridge Transitions Exposed to Extreme Climate Events

Directory of Open Access Journals (Sweden)

Sadudee Setsobhonkul

2017-06-01

Full Text Available Railway track components located at bridge transition zones or approach areas suffer from impact load and vibrations caused by abrupt changes in track stiffness on the bridge and the subgrade. The numerous strategies that can be used to mitigate these abrupt track stiffness changes rely on one of two concepts. The first concept is that of providing a gradual stiffness change, and the second is that of equalizing the track stiffness. A number of such mitigation methods have been developed and implemented over recent decades. Construction activities associated with these methods require various materials, processes, and uses of time, costs, and carbon emissions. In this study, eight of the most common techniques for railway bridge transition mitigation, including under ballast mats (UBMs, soft baseplates, under sleeper pads (USPs, rail pads, embankment treatments, transition slabs, ballast bonding, and wide sleepers, are compared. This study benchmarks the costs and carbon emissions of these eight mitigation techniques over the 50-year lifespan of a railway system subject to identical probabilities of four environmental scenarios: a control case, extremely high temperatures, extremely low temperatures, and flash flooding. This unprecedented study systemically investigates the effectiveness of the mitigation methods while considering the effects of 30 and 100 m bridge span lengths. Our results indicate that railway engineers should adopt different mitigation methods for different scenarios. The soft baseplate is the most appropriate method for a short-span bridge in the control case and the case of flash flooding, while ballast bonding is better for long-span railway bridges. Embankment treatment is recommended for both high- and low-extreme temperatures. However, its applicability is limited when the differential track stiffness is extremely high. Hence, alternatives that are 5–25% more expensive are proposed in parallel. The alternative

Risk Assessment for Bridges Safety Management during Operation Based on Fuzzy Clustering Algorithm

Directory of Open Access Journals (Sweden)

Xia Hanyu

2016-01-01

Full Text Available In recent years, large span and large sea-crossing bridges are built, bridges accidents caused by improper operational management occur frequently. In order to explore the better methods for risk assessment of the bridges operation departments, the method based on fuzzy clustering algorithm is selected. Then, the implementation steps of fuzzy clustering algorithm are described, the risk evaluation system is built, and Taizhou Bridge is selected as an example, the quantitation of risk factors is described. After that, the clustering algorithm based on fuzzy equivalence is calculated on MATLAB 2010a. In the last, Taizhou Bridge operation management departments are classified and sorted according to the degree of risk, and the safety situation of operation departments is analyzed.

Structural Performance Evaluation of Tsing MA Bridge Deck Using Long-Term Monitoring Data

Science.gov (United States)

Ni, Y. Q.; Xia, H. W.; Ko, J. M.

The Tsing Ma Bridge in Hong Kong is suspension bridge with a main span of 1377 m carrying both highway and railway traffic. After completing its construction in 1997, the bridge was instrumented by the Hong Kong SAR Government Highways Department with a long-term structural health monitoring system comprising about 300 sensors permanently installed on the bridge. As part of this monitoring system, a total of 110 strain gauges have been installed to measure strain at the deck cross-sections and bearings. In this study, a method for real-time structural performance evaluation of the stiffening deck system making use of long-term strain measurement data is proposed and verified using the strain monitoring data from a typical deck cross-section of the Tsing Ma Bridge.

Functional Outcomes After Temporary Bridging With Locking Plates in Lisfranc Injuries

NARCIS (Netherlands)

van Koperen, Paul J.; de Jong, Vincent M.; Luitse, Jan S. K.; Schepers, Tim

2016-01-01

The standard operative treatment of Lisfranc fracture dislocations currently consists of open reduction and transarticular fixation. Recently, bridge plating has been used more often. Using joint spanning, the reduced fracture dislocation is temporary stabilized to minimize articular damage. The

Constitutive and numerical modeling of soil and soil-pile interaction for 3D applications and Kealakaha stream bridge case study.

Science.gov (United States)

2011-12-01

This study is concerned with developing new modeling tools for predicting the response of the new Kealakaha : Stream Bridge to static and dynamic loads, including seismic shaking. The bridge will span 220 meters, with the : deck structure being curve...

Special heavy plates and steel solutions for bridge building

Science.gov (United States)

Lehnert, Tobias

2017-09-01

In many European countries infrastructure, -road as well as railway infrastructure-, needs intensive investments to follow the growing demands of mobility and goods traffic. Steel or steel composite bridges offer in this context viable and very sustainable solutions. Due to its unlimited recyclability steel can in general be seen as the ideal material for such sustainable constructions, but especially when designers or fabricators exploit the nowadays available possibilities of steel industry very cost-efficient and remarkable constructions are realizable. This paper will highlight some of these newest developments in heavy plates for bridge building. For example, for small span railway bridges the so-called thick plate trough bridges have proven to be a favourable concept. Very heavy plates with single plate weights up to 42 t allow building these bridges very efficiently out of one or very few single plates. Another interesting development is the so-called longitudinally profiled plates which allow a varying plate thickness along the actual loading profile. As last point the rising entry of higher strength steels in bridge building will be discussed and it will be shown why thermomechanically rolled plates are the ideal solution for these demands.

Study of displacements of a bridge abutment using FEM

Science.gov (United States)

Wymysłowski, Michał; Kurałowicz, Zygmunt

2016-06-01

Steel sheet piles are often used to support excavations for bridge foundations. When they are left in place in the permanent works, they have the potential to increase foundation bearing capacity and reduce displacements; but their presence is not usually taken into account in foundation design. In this article, the results of finite element analysis of a typical abutment foundation, with and without cover of sheet piles, are presented to demonstrate these effects. The structure described is located over the Więceminka river in the town of Kołobrzeg, Poland. It is a single-span road bridge with reinforced concrete slab.

Efficient field testing for load rating railroad bridges

Science.gov (United States)

Schulz, Jeffrey L.; Brett C., Commander

1995-06-01

As the condition of our infrastructure continues to deteriorate, and the loads carried by our bridges continue to increase, an ever growing number of railroad and highway bridges require load limits. With safety and transportation costs at both ends of the spectrum. the need for accurate load rating is paramount. This paper describes a method that has been developed for efficient load testing and evaluation of short- and medium-span bridges. Through the use of a specially-designed structural testing system and efficient load test procedures, a typical bridge can be instrumented and tested at 64 points in less than one working day and with minimum impact on rail traffic. Various techniques are available to evaluate structural properties and obtain a realistic model. With field data, a simple finite element model is 'calibrated' and its accuracy is verified. Appropriate design and rating loads are applied to the resulting model and stress predictions are made. This technique has been performed on numerous structures to address specific problems and to provide accurate load ratings. The merits and limitations of this approach are discussed in the context of actual examples of both rail and highway bridges that were tested and evaluated.

Nonlinear seismic analysis of continuous RC bridge

Directory of Open Access Journals (Sweden)

Čokić Miloš M.

2017-01-01

Full Text Available Nonlinear static analysis, known as a pushover method (NSPA is oftenly used to study the behaviour of a bridge structure under the seismic action. It is shown that the Equivalent Linearization Method - ELM, recommended in FEMA 440, is appropriate for the response analysis of the bridge columns, with different geometric characteristics, quantity and distribution of steel reinforcement. The subject of analysis is a bridge structure with a carriageway plate - a continuous beam with three spans, with the 24 + 40 + 24 m range. Main girder is made of prestressed concrete and it has a box cross section of a constant height. It is important to study the behaviour, not only in the transverse, but also in the longitudinal direction of the bridge axis, when analysing the bridge columns exposed to horizontal seismic actions. The columns were designed according to EN1992, parts 1 and 2. Seismic action analysis is conducted according to EN 1998: 2004 standard. Response spectrum type 1, for the ground type B, was applied and the analysis also includes 20% of traffic load. The analysis includes the values of columns displacement and ductility. To describe the behaviour of elements under the earthquake action in both - longitudinal and transverse direction, pushover curves were formed.

Development of flexural vibration inspection techniques to rapidly assess the structural health of timber bridge systems

Science.gov (United States)

Xiping Wang; James P. Wacker; Robert J. Ross; Brian K. Brashaw; Robert Vatalaro

2005-01-01

This paper describes an effort to develop a global dynamic testing technique for evaluating the overall stiffness of timber bridge superstructures. A forced vibration method was used to measure the natural frequency of single-span timber bridges in the laboratory and field. An analytical model based on simple beam theory was proposed to represent the relationship...

Erection of the stiffening girder of the Akashi Kaikyo bridge; Akashi Kaikyo Ohashi hokoketa (sono 2) koji no genchi seko

Energy Technology Data Exchange (ETDEWEB)

Otsuki, M.; Inoue, M.; Ueno, Y.; Matsumura, T.; Oe, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1998-12-20

The Akashi Kaikyo Bridge is 3,911m long with a center span of 1,991m, making it the longest suspension bridge in the world. Much careful attention has been given to the erection planning details in order to construct the bridge to withstand the harsh environmental conditions of that area. This report details the characteristics of the bridge stiffening girder and erection procedure, and the effects of the Hyogoken-Nanbu Earthquake. (author)

Advanced materials for control of post-earthquake damage in bridges

International Nuclear Information System (INIS)

Shrestha, Kshitij C; Saiidi, M Saiid; Cruz, Carlos A

2015-01-01

This paper presents analytical modeling to study the seismic response of bridge systems with conventional and advanced details. For validation, a 33 m quarter-scale model of a four-span bridge incorporating innovative materials and details seismically tested on the shake tables at the University of Nevada, Reno was taken. The bridge specimen involved use of advanced materials and details to reduce damage at plastic hinges and minimize residual displacements. A three-dimensional, nonlinear model incorporating the response of the innovative materials was developed to study the bridge response using the finite-element software OpenSees. Existing finite-element formulations were used to capture the response of the advanced materials used in the bridge. The analytical model was found to be able to reproduce comparable bent displacements and bent shear forces within reasonable accuracy. The validated model was further used to study different types of bridges under suite of scaled bi-directional near-fault ground motions. Comparisons were made on behavior of five different bridge types, first conventional reinforced concrete bridge, second post-tensioned column bridge, third bridge with elastomeric rubber elements at the plastic hinge zone, fourth bridge with nickel–titanium superelastic shape memory alloy (SMA) reinforcing bar and fifth bridge with CuAlMn superelastic SMA reinforcing bar. Both the SMA used bridges also utilized engineered cementitious composite element at the plastic hinge zone. The results showed effectiveness of the innovative interventions on the bridges in providing excellent recentering capabilities with minimal damage to the columns. (paper)

Super-long bridges with floating towers: the role of multi-box decks and Hardware-In-the-Loop technology for wind tunnel tests

Science.gov (United States)

Zasso, A.; Argentini, T.; Bayati, I.; Belloli, M.; Rocchi, D.

2017-12-01

The super long fjord crossings in E39 Norwegian project pose new challenges to long span bridge design and construction technology. Proposed solutions should consider the adoption of bridge deck with super long spans or floating solutions for at least one of the towers, due to the relevant fjord depth. At the same time, the exposed fjord environment, possibly facing the open ocean, calls for higher aerodynamic stability performances. In relation to this scenario, the present paper addresses two topics: 1) the aerodynamic advantages of multi-box deck sections in terms of aeroelastic stability, and 2) an experimental setup in a wind tunnel able to simulate the aeroelastic bridge response including the wave forcing on the floating.

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

Damage Detection Sensitivity of a Vehicle-based Bridge Health Monitoring System

Science.gov (United States)

Miyamoto, Ayaho; Yabe, Akito; Lúcio, Válter J. G.

2017-05-01

As one solution to the problem for condition assessment of existing short and medium span (10-30m) reinforced/prestressed concrete bridges, a new monitoring method using a public bus as part of a public transit system (called “Bus monitoring system”) was proposed, along with safety indices, namely, “characteristic deflection”, which is relatively free from the influence of dynamic disturbances due to such factors as the roughness of the road surface, and a structural anomaly parameter. In this study, to evaluate the practicality of the newly developed bus monitoring system, it has been field-tested over a period of about four years by using an in-service fixed-route bus operating on a bus route in the city of Ube, Yamaguchi Prefecture, Japan. In here, although there are some useful monitoring methods for short and medium span bridges based on the qualitative or quantitative information, the sensitivity of damage detection was newly discussed for safety assessment based on long term health monitoring data. The verification results thus obtained are also described in this paper, and also evaluates the sensitivity of the “characteristic deflection”, which is a bridge (health) condition indicator used by the bus monitoring system, in damage detection. Sensitivity of “characteristic deflection” is verified by introducing artificial damage into a bridge that has ended its service life and is awaiting removal. Furthermore, the sensitivity of “characteristic deflection” is verified by 3D FEM analysis.

Condition Assessment of PCI Bridge Girder a Result of The Reduction Prestressing Force

Directory of Open Access Journals (Sweden)

Suangga Made

2014-03-01

Full Text Available PCI bridge girders is known and widely used for many construction e.g.: bridge, wharf, flyover, and other application. PC Bridge girders have two types: Pre - tensioned girders and post - tensioned girders. In pre tensioned girders, prestressing in carried out first then after that the fresh concrete poured. The prestressing process in only carried off after the concrete has sufficient strength. In this study, analysis was conducted for PCI bridge girder with span is 40 meters. Based on the data geometry bridge dimension girder, material girder, and material strands cable, it will be analyzed to calculate the natural frequencies and moment capacity using finite element program (Midas/Civil program. So it can be estimated how much the percentage reduction prestress force on the bridge until PCI bridge structure collapses. From the calculation, it found that the pattern comparison between reduction prestressing force and natural frequency are linear. These results are also similar for natural frequency versus moment capacity.PCI bridge will collapse when the reduction prestreesing force of 45 % to 50 % from the total loss of prestressing.

Longest cable-stayed bridge TATARA; Longest shachokyo Tatara Ohashi

Energy Technology Data Exchange (ETDEWEB)

Fujii, K. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering

1998-06-15

The world`s longest cable-stayed bridge Tatara having a central span of 890 m had the both ends closed in August 1997, linking Namakuchi Island and Omishima Island. Final finishing work is continuing for opening of the West Seto Expressway in the spring of 1999. A cable-stayed bridge supports the bridge girders by perpendicular components of tensile force of cables stayed obliquely. On the other hand, there is a concern that the girders may have axial compression force generated due to horizontal components of the force from the cable tensile force, which can cause buckling of the girders. Therefore, in order to suspend the girders efficiently by increasing the perpendicular components of the cable force, and moreover to suppress the axial compression force on the girders, it is more advantageous to make bridge towers high, hence the towers of this bridge are highest among the bridges on the Shimanami Ocean Road. This bridge whose long girders are stayed with 21-stage multi cables presented a problem in designing the buckling in steel girders near the towers due to the horizontal components of the force generated by the bridge. Discussions were given, therefore, by using load withstanding force experiments using a whole bridge model of 1/50 scale, buckling experiments on full-size reinforcing plate models, and load withstanding force analysis using a tower model. A number of other technical discussions were repeated, by which the world`s longest cable-stayed bridge was completed. 9 figs., 1 tab.

Structural covariance networks across the life span, from 6 to 94 years of age.

Science.gov (United States)

DuPre, Elizabeth; Spreng, R Nathan

2017-10-01

Structural covariance examines covariation of gray matter morphology between brain regions and across individuals. Despite significant interest in the influence of age on structural covariance patterns, no study to date has provided a complete life span perspective-bridging childhood with early, middle, and late adulthood-on the development of structural covariance networks. Here, we investigate the life span trajectories of structural covariance in six canonical neurocognitive networks: default, dorsal attention, frontoparietal control, somatomotor, ventral attention, and visual. By combining data from five open-access data sources, we examine the structural covariance trajectories of these networks from 6 to 94 years of age in a sample of 1,580 participants. Using partial least squares, we show that structural covariance patterns across the life span exhibit two significant, age-dependent trends. The first trend is a stable pattern whose integrity declines over the life span. The second trend is an inverted-U that differentiates young adulthood from other age groups. Hub regions, including posterior cingulate cortex and anterior insula, appear particularly influential in the expression of this second age-dependent trend. Overall, our results suggest that structural covariance provides a reliable definition of neurocognitive networks across the life span and reveal both shared and network-specific trajectories.

Effective way to reconstruct arch bridges using concrete walls and transverse strands

Science.gov (United States)

Klusáček, Ladislav; Pěkník, Robin; Nečas, Radim

2017-09-01

There are more than 500 masonry arch bridges in the Czech Road system and about 2500 in the Czech Railway system. Many of them are cracked in the longitudinal (span) direction. The barrel vaults are separated by the cracks into partial masonry arches without load bearing connection in transverse direction. These constructions are about 150 years old and they are also too narrow for the current road system. This paper presents a strengthening method for masonry arch bridges using transverse post-tensioning. This method is very useful not only for strengthening in the transverse direction, but widening of masonry arches can be taken as secondary effect especially in case of road bridges. Several bridges were successfully repaired with the use of this system which seems to be effective and reliable.

Finite element modelling for fatigue stress analysis of large suspension bridges

Science.gov (United States)

Chan, Tommy H. T.; Guo, L.; Li, Z. X.

2003-03-01

Fatigue is an important failure mode for large suspension bridges under traffic loadings. However, large suspension bridges have so many attributes that it is difficult to analyze their fatigue damage using experimental measurement methods. Numerical simulation is a feasible method of studying such fatigue damage. In British standards, the finite element method is recommended as a rigorous method for steel bridge fatigue analysis. This paper aims at developing a finite element (FE) model of a large suspension steel bridge for fatigue stress analysis. As a case study, a FE model of the Tsing Ma Bridge is presented. The verification of the model is carried out with the help of the measured bridge modal characteristics and the online data measured by the structural health monitoring system installed on the bridge. The results show that the constructed FE model is efficient for bridge dynamic analysis. Global structural analyses using the developed FE model are presented to determine the components of the nominal stress generated by railway loadings and some typical highway loadings. The critical locations in the bridge main span are also identified with the numerical results of the global FE stress analysis. Local stress analysis of a typical weld connection is carried out to obtain the hot-spot stresses in the region. These results provide a basis for evaluating fatigue damage and predicting the remaining life of the bridge.

Study of displacements of a bridge abutment using FEM

Directory of Open Access Journals (Sweden)

Wymysłowski Michał

2016-06-01

Full Text Available Steel sheet piles are often used to support excavations for bridge foundations. When they are left in place in the permanent works, they have the potential to increase foundation bearing capacity and reduce displacements; but their presence is not usually taken into account in foundation design. In this article, the results of finite element analysis of a typical abutment foundation, with and without cover of sheet piles, are presented to demonstrate these effects. The structure described is located over the Więceminka river in the town of Kołobrzeg, Poland. It is a single-span road bridge with reinforced concrete slab.

Live-Load Testing Application Using a Wireless Sensor System and Finite-Element Model Analysis of an Integral Abutment Concrete Girder Bridge

Directory of Open Access Journals (Sweden)

Robert W. Fausett

2014-01-01

Full Text Available As part of an investigation on the performance of integral abutment bridges, a single-span, integral abutment, prestressed concrete girder bridge near Perry, Utah was instrumented for live-load testing. The live-load test included driving trucks at 2.24 m/s (5 mph along predetermined load paths and measuring the corresponding strain and deflection. The measured data was used to validate a finite-element model (FEM of the bridge. The model showed that the integral abutments were behaving as 94% of a fixed-fixed support. Live-load distribution factors were obtained using this validated model and compared to those calculated in accordance to recommended procedures provided in the AASHTO LRFD Bridge Design Specifications (2010. The results indicated that if the bridge was considered simply supported, the AASHTO LRFD Specification distribution factors were conservative (in comparison to the FEM results. These conservative distribution factors, along with the initial simply supported design assumption resulted in a very conservative bridge design. In addition, a parametric study was conducted by modifying various bridge properties of the validated bridge model, one at a time, in order to investigate the influence that individual changes in span length, deck thickness, edge distance, skew, and fixity had on live-load distribution. The results showed that the bridge properties with the largest influence on bridge live-load distribution were fixity, skew, and changes in edge distance.

Bridge Condition Assessment based on Vibration Responses of Passenger Vehicle

International Nuclear Information System (INIS)

Miyamoto, Ayaho; Yabe, Akito

2011-01-01

In this paper, we propose a new method of assessing the condition of existing short- and medium-span reinforced/prestressed concrete bridges based on vibration monitoring data obtained from a public bus. This paper not only describes details of a prototype monitoring system that uses information technology and sensors capable of providing more accurate knowledge of bridge performance than conventional ways but also shows a few specific examples of bridge condition assessment based on vehicle vibrations measured by using an in-service public bus equipped with vibration measurement instrumentation. This paper also describes a sensitivity analysis of deteriorating bridges based on simulation of the acceleration response of buses conducted by the 'substructure method' employing a finite element model to verify the above bridge performance results. The main conclusions obtained in this study can be summarized as follows: (1) Because the vibration responses of passenger vehicles, such as buses, have a good linear relationship with the vibration responses of the target bridges, the proposed system can be used as a practical monitoring system for bridge condition assessment. (2) The results of sensitivity analysis performed by the substructure method show that bus vibration responses are useful for evaluating target bridge performance. (3) The proposed method was applied to a network of real bridges in a local area to evaluate its effectiveness. The results indicate that the proposed method can be used to prioritize the repair/strengthening works of existing bridges based on various vibration information in order to help bridge administrators establish rational maintenance strategies.

Two-course bonded concrete bridge deck construction : condition and performance after six years.

Science.gov (United States)

1981-01-01

This report presents the findings from a six-year study of two-course bonded concrete bridge decks constructed in Virginia. Each of three special portland cement concretes was applied as an overlay, or wearing course, on two experimental spans. The o...

Applications of Non-destructive methods (GPR and 3D Laser Scanner) in Historic Masonry Arch Bridge Assessment

Science.gov (United States)

Alani, Amir; Banks, Kevin

2014-05-01

There exist approximately 70,000 masonry arch bridge spans (brick and stone) in the UK with tens of thousands more throughout Europe. A significant number of these bridges are still in operation and form part of the road and rail network systems in many countries. A great majority of these bridges are in desperate need of repair and maintenance. Applications of non-destructive testing methods such as ground penetrating radar (GPR), 3D laser scanning, accelerometer sensors and vibration detecting sensors amongst many others have been used to assess and monitor such structures in the past few years. This presentation provides results of the applications of a 2GHz GPR antenna system and a 3D laser scanner on a historic masonry arch bridge (the Old Bridge, Aylesford) located in Kent, in the south east of England. The older part of the bridge (the mid-span) is 860 years old. The bridge was the subject of a major alteration in 1811. This presentation forms part of a larger ongoing study which is using the two above mentioned non-destructive methods for long-term monitoring of the bridge. The adopted survey planning strategy and technique, data acquisition and processing as well as challenges encountered during actual survey and fieldworks have been discussed in this presentation. As a result of this study the position of different layers of the deck structure has been established with the identification of the original stone base of the bridge. This information in addition to the location of a number of structural ties (anchors - remedial work carried out previously) in the absence of reliable and accurate design details proved to be extremely useful for the modelling of the bridge using the finite element method. Results of the 3D laser scanning of the bridge have also been presented which have provided invaluable data essential for the accurate modelling of the bridge as well as the long term monitoring of the bridge. 2014 EGU-GA GI3.1 Session, organised by COST Action

Effect of Concrete Creep on the displacement of single tower single cable plane Extradosed Cable-stayed Bridge

Science.gov (United States)

Shi, Jing-xian; Ran, Zhi-hong

2018-03-01

Extradossed Cable-stayed Bridge is both cable-stayed Bridge and Continuous rigid frame bridge mechanics feature, Beam is the main force components, cable is supplement.This article combined with a single tower and single cable plane Extradossed cable-stayed bridge in Yunnan, use different creep calculation models and analysis deflection caused by creep effects. The results showing that deflection caused by creep effect is smaller than the same span continuous rigid frame bridge, the value is about 2cm. On the other hand the deflection is increasing with ambient humidity decreases, therefore in the dry environment the calculation model is relatively large in the pre-camber. In the choice of RC creep model is significant in the dry areas.

Effect of Ground Motion Characteristics on the Seismic Response of a Monumental Concrete Arch Bridge

Science.gov (United States)

Caglayan, B. Ozden; Ozakgul, Kadir; Tezer, Ovunc

2008-07-01

Railway network in Turkey dates back to more than a hundred years ago and according to official records, there are approximately 18,000 railway bridges with spans varying between 50 cm up to 150 meters. One of them is a monumental concrete arch bridge with a total length of 210 meters having three major spans of 30 meters and a height of 65 meters, located in an earthquake-prone region in southern part of the country. Three-dimensional finite element model of the bridge was generated using a commercially available general finite element analysis software and based on the outcomes of a series of in-depth acceleration measurements that were conducted on-site, the model was refined. Types of ground motion records were used to investigate the seismic response and vulnerability of this massive structure in order to provide information regarding (i) damage-susceptible regions of the structure for monitoring purposes, and, (ii) seismic loads to be taken into account during evaluation and possible strengthening phases for this type of structures.

Effect of Ground Motion Characteristics on the Seismic Response of a Monumental Concrete Arch Bridge

International Nuclear Information System (INIS)

Caglayan, B. Ozden; Ozakgul, Kadir; Tezer, Ovunc

2008-01-01

Railway network in Turkey dates back to more than a hundred years ago and according to official records, there are approximately 18,000 railway bridges with spans varying between 50 cm up to 150 meters. One of them is a monumental concrete arch bridge with a total length of 210 meters having three major spans of 30 meters and a height of 65 meters, located in an earthquake-prone region in southern part of the country. Three-dimensional finite element model of the bridge was generated using a commercially available general finite element analysis software and based on the outcomes of a series of in-depth acceleration measurements that were conducted on-site, the model was refined. Types of ground motion records were used to investigate the seismic response and vulnerability of this massive structure in order to provide information regarding (i) damage-susceptible regions of the structure for monitoring purposes, and, (ii) seismic loads to be taken into account during evaluation and possible strengthening phases for this type of structures

Parametric Study on Responses of a Self-Anchored Suspension Bridge to Sudden Breakage of a Hanger

Directory of Open Access Journals (Sweden)

Wenliang Qiu

2014-01-01

Full Text Available The girder of self-anchored suspension bridge is subjected to large compression force applied by main cables. So, serious damage of the girder due to breakage of hangers may cause the collapse of the whole bridge. With the time increasing, the hangers may break suddenly for their resistance capacities decrease due to corrosion. Using nonlinear static and dynamic analysis methods and adopting 3D finite element model, the responses of an actual self-anchored suspension bridge to sudden breakage of hangers are studied in this paper. The results show that the sudden breakage of a hanger causes violent vibration and large changes in internal forces of the bridge. In the process of the vibration, the maximum tension of hanger produced by breakage of a hanger exceeds 2.22 times its initial value, and the reaction forces of the bearings increase by more than 1.86 times the tension of the broken hanger. Based on the actual bridge, the influences of some factors including flexural stiffness of girder, torsion stiffness of girder, flexural stiffness of main cable, weight of girder, weight of main cable, span to sag ratio of main cable, distance of hangers, span length, and breakage time of hanger on the dynamic responses are studied in detail, and the influencing extent of the factors is presented.

Parametric study on responses of a self-anchored suspension bridge to sudden breakage of a hanger.

Science.gov (United States)

Qiu, Wenliang; Jiang, Meng; Huang, Cailiang

2014-01-01

The girder of self-anchored suspension bridge is subjected to large compression force applied by main cables. So, serious damage of the girder due to breakage of hangers may cause the collapse of the whole bridge. With the time increasing, the hangers may break suddenly for their resistance capacities decrease due to corrosion. Using nonlinear static and dynamic analysis methods and adopting 3D finite element model, the responses of an actual self-anchored suspension bridge to sudden breakage of hangers are studied in this paper. The results show that the sudden breakage of a hanger causes violent vibration and large changes in internal forces of the bridge. In the process of the vibration, the maximum tension of hanger produced by breakage of a hanger exceeds 2.22 times its initial value, and the reaction forces of the bearings increase by more than 1.86 times the tension of the broken hanger. Based on the actual bridge, the influences of some factors including flexural stiffness of girder, torsion stiffness of girder, flexural stiffness of main cable, weight of girder, weight of main cable, span to sag ratio of main cable, distance of hangers, span length, and breakage time of hanger on the dynamic responses are studied in detail, and the influencing extent of the factors is presented.

78 FR 13747 - Safety Advisory 2013-01; Passing Stop Signals Protecting Movable Bridges

Science.gov (United States)

2013-02-28

... Association Manual for Railway Engineering. 2. Evaluate operating rules and procedures that permit the...: (1) Evaluate the design and construction of existing movable bridges to determine if effective span... perform these duties. FOR FURTHER INFORMATION CONTACT: Carlo M. Patrick, Staff Director, Rail and...

High energy x-ray radiography and computed tomography of bridge pins

International Nuclear Information System (INIS)

Green, R E; Logan, C M; Martz, H E; Updike, E; Waters, A M

1999-01-01

Bridge pins were used in the hanger assemblies for some multi-span steel bridges built prior to the 1980's, and are sometimes considered fracture critical elements of a bridge. During a test on a bridge conducted by the Federal Highway Administration (FHWA), ultrasonic field inspection results indicated that at least two pins contained cracks. Several pins were removed and selected for further examination. This provided an excellent opportunity to learn more about these pins and the application of x-ray systems at Lawrence Livermore National Laboratory (LLNL), as well as to learn more about the application of different detectors recently obtained by LLNL. Digital radiographs and computed tomography (CT) were used to characterize the bridge pins, using a LINAC x-ray source with a 9-MV bremsstrahlung spectrum. We will describe the performance of two different digital radiographic detectors. One is a detector system frequently used at LLNL consisting of a scintillator glass optically coupled to a CCD camera. The other detector is a new amorphous silicon detector recently acquired by LLNL

Aeroelastic Stability of Suspension Bridges using CFD

DEFF Research Database (Denmark)

Stærdahl, Jesper Winther; Sørensen, Niels; Nielsen, Søren R.K.

2007-01-01

using CFD models and the aeroelastic stability boundary has been successfully determined when comparing two-dimensional flow situations using wind tunnel test data and CFD methods for the flow solution and two-degrees-of-freedom structural models in translation perpendicular to the flow direction......In recent years large span suspension bridges with very thin and slender profiles have been built without proportional increasing torsional and bending stiffness. As a consequence large deformations at the mid-span can occur with risk of aeroelastic instability and structural failure. Analysis...... of aeroelastic stability also named flutter stability is mostly based on semi-empirical engineering models, where model specific parameters, the so-called flutter derivatives, need calibration from wind tunnel tests or numerical methods. Several papers have been written about calibration of flutter derivatives...

Validation of a Numerical Model for Dynamic Three-Dimensional Railway Bridge Analysis by Comparison with a Small-Scale Laboratory Model

DEFF Research Database (Denmark)

Bucinskas, Paulius; Sneideris, Jonas; Agapii, Liuba

2018-01-01

The aim of the paper is analyse to what extent a small-scale experimental model can be applied in order to develop and validate a numerical model for dynamic analysis of a multi-span railway bridge interacting with the underlying soil. For this purpose a small-scale model of a bridge structure is...

Carbon Fiber Reinforced Polymer Grids for Shear and End Zone Reinforcement in Bridge Beams

Science.gov (United States)

2018-01-01

Corrosion of reinforcing steel reduces life spans of bridges throughout the United States; therefore, using non-corroding carbon fiber reinforced polymer (CFRP) reinforcement is seen as a way to increase service life. The use of CFRP as the flexural ...

Cable-stayed bridge No. 1 Hikihara bridge'' ( Karauko bridge'') for Kinki construction bureau, ministry of construction. Kensetsusho kinki chiho kensetsukyoku (Hikihara 1 gobashi (Karauko ohashi))no shiko

Energy Technology Data Exchange (ETDEWEB)

1991-11-01

This paper summarizes the design, fabrication and erection of a back-anchor integrated single span cable suspension bridge (178 m long and 9.7 m wide) constructed over an ordinary road crossing a reservoir. This type of structure was adopted because the locational condition does not allow a bridge pier to be erected in the center of the pond, and the topography in the construction starting side has steep slopes and many places having fragile ground beds. This bridge employed precast floor plates using the Compo-Slab (manufactured by Ishikawajima Building Material Company). Main points which require attentions are listed in designing and fabricating the main towers (48 m high), main girders, and cables, as well as fabricating the precast cast floor plates (a panel has a length of 9.7 m, maximum width of 2 m, and maximum weight of 10 tons). The main towers were erected using 160-tf truck cranes, and the main girders were erected by the overhang method using 20-tf gate-type travel cranes. 3 refs., 14 figs.

Seismic response of cable stayed bridges under multi support excitation

Directory of Open Access Journals (Sweden)

Mahmoud Reza ُُShiravand

2017-07-01

Full Text Available In this Study, the seismic response of cable stayed bridges have been evaluated under multi-support excitations. There are three sources that cause the earthquake wave characteristics change during its propagation path. Local site effect, loss of coherency and wave passage effect are three sources of spatial variation of seismic ground motions. In long span structures, such as cable supported bridges, this phenomenon is more evident and traditional analyzing (uniform excitation may not be valid and be conservative. Thus, it is necessary to investigate the response of cable stayed bridges under non-uniform excitations. For this purpose, the non-uniform time histories were artificially generated using Kriging method based on a set of known time history in the west support of bridge. Nonlinear time history analysis was performed and cables axial force, deck moment, pylons moment and finally drift ratio of bridge have been examined in order to investigate how non-uniform excitation change the seismic response of bridge compared with uniform excitations. Results show non-uniform excitation in some bridge components increase responses and decreases in the others. In non-uniform excitation, although total time history energy is lesser than uniform excitation, it can significantly change the distribution of the forces and makes differential displacement between cables supports and increase the possibility of failure.

A new multiconstraint method for determining the optimal cable stresses in cable-stayed bridges.

Science.gov (United States)

Asgari, B; Osman, S A; Adnan, A

2014-01-01

Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM). The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

A New Multiconstraint Method for Determining the Optimal Cable Stresses in Cable-Stayed Bridges

Directory of Open Access Journals (Sweden)

B. Asgari

2014-01-01

Full Text Available Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM. The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

Bridge condition assessment based on long-term strain monitoring

Science.gov (United States)

Sun, LiMin; Sun, Shouwang

2011-04-01

In consideration of the important role that bridges play as transportation infrastructures, their safety, durability and serviceability have always been deeply concerned. Structural Health Monitoring Systems (SHMS) have been installed to many long-span bridges to provide bridge engineers with the information needed in making rational decisions for maintenance. However, SHMS also confronted bridge engineers with the challenge of efficient use of monitoring data. Thus, methodologies which are robust to random disturbance and sensitive to damage become a subject on which many researches in structural condition assessment concentrate. In this study, an innovative probabilistic approach for condition assessment of bridge structures was proposed on the basis of long-term strain monitoring on steel girder of a cable-stayed bridge. First, the methodology of damage detection in the vicinity of monitoring point using strain-based indices was investigated. Then, the composition of strain response of bridge under operational loads was analyzed. Thirdly, the influence of temperature and wind on strains was eliminated and thus strain fluctuation under vehicle loads is obtained. Finally, damage evolution assessment was carried out based on the statistical characteristics of rain-flow cycles derived from the strain fluctuation under vehicle loads. The research conducted indicates that the methodology proposed is qualified for structural condition assessment so far as the following respects are concerned: (a) capability of revealing structural deterioration; (b) immunity to the influence of environmental variation; (c) adaptability to the random characteristic exhibited by long-term monitoring data. Further examination of the applicability of the proposed methodology in aging bridge may provide a more convincing validation.

Vibration based structural assessment of the rehabilitation intervention in r.c. segmental bridge

OpenAIRE

Franchetti Paolo; Frizzarin Michele; Leonardi Andrea; Zeni Fabio

2015-01-01

A vibration based structural assessment campaign was carried out on a r.c. segmental bridge in North East Italy. The bridge has a cantilever static scheme, fixed at the top of the piers and with a hinge at the centre of the span. The particular configuration of the hinge consists in a couple of steel elements, each one composed by a tongue and groove joint. Since the year 1960, the hinge was subjected to consumption and degradation, that caused a malfunctioning of the device. An intervention ...

Construction of cable-stayed prestressed concrete bridge, having Japan`s first independent single slanted tower; Nippon hatsu no keisha shuto wo motsu PC shachokyo no seko

Energy Technology Data Exchange (ETDEWEB)

Sanada, Y.; Naito, H. [Penta-Ocean Construction Co. Ltd., Tokyo (Japan); Takeuchi, H.; Mikami, T.

1994-08-01

In the Hachinoe Harbor, Aomori prefecture, a man-made island (Hachinoe Port Island) is being constructed by reclamation. When proceeding this undertaking plan, a construction of the Hachinoe Harbor Port Island connection bridge, which connects the man-made island with the existing harbor district, was made an urgent necessity. This connecting bridge is a bridge with a total length of 256.56m, and is constituted of two span continuous PC slanted bridge and three span continuous PC box girder bridge. This slanted bridge has become an asymmetrical structure due to several conditions coming from a plan, and moreover it has the first structural shape as a road bridge in Japan, of which main tower is 15{degree} slanted independent single tower type, there are more problems for the work execution compared with other normal slanted bridges. In addition, because it is situated in an extremely cruel environment like in the cold region and in the marine environment, a sufficient consideration is required for its design and work execution in order to insure a durability. In this report, an outline of work execution content about PC slanted bridge part currently under a construction zealously aiming at a completion in the end of the fiscal year 1994 is introduced. 2 refs., 14 figs., 4 tabs.

Statistical Analysis of Stress Signals from Bridge Monitoring by FBG System

Directory of Open Access Journals (Sweden)

Xiao-Wei Ye

2018-02-01

Full Text Available In this paper, a fiber Bragg grating (FBG-based stress monitoring system instrumented on an orthotropic steel deck arch bridge is demonstrated. The FBG sensors are installed at two types of critical fatigue-prone welded joints to measure the strain and temperature signals. A total of 64 FBG sensors are deployed around the rib-to-deck and rib-to-diagram areas at the mid-span and quarter-span of the investigated orthotropic steel bridge. The local stress behaviors caused by the highway loading and temperature effect during the construction and operation periods are presented with the aid of a wavelet multi-resolution analysis approach. In addition, the multi-modal characteristic of the rainflow counted stress spectrum is modeled by the method of finite mixture distribution together with a genetic algorithm (GA-based parameter estimation approach. The optimal probability distribution of the stress spectrum is determined by use of Bayesian information criterion (BIC. Furthermore, the hot spot stress of the welded joint is calculated by an extrapolation method recommended in the specification of International Institute of Welding (IIW. The stochastic characteristic of stress concentration factor (SCF of the concerned welded joint is addressed. The proposed FBG-based stress monitoring system and probabilistic stress evaluation methods can provide an effective tool for structural monitoring and condition assessment of orthotropic steel bridges.

Dynamic Behaviour of Different Types of Cable-Stayed Bridges Due to Earthquake Loads

Directory of Open Access Journals (Sweden)

Alireza Mirza Goltabar Roshan

2016-12-01

Full Text Available Construction of large-scale structures has been considered as one of the human's main achievements.  With their suitable view and high economical aspects, High-strength steel cables have been developed for analysis and erection of cable-stayed bridges in light of high speed development in computer technology. This type of bridges, while providing different behavior due to cable flexibility, has been recognized as one of the most practical choices for mid to large span bridges. This paper studies the non-linear dynamic behavior of cable bridges and the effect of some parameters (such as cable arrangement and shape of pylon on them. For this purpose, CSI Bridge software with the direct integration method of dynamic analysis has been used and the behavior of structure under different earthquake components has been analyzed for various conditions of cable arrangements and pylon shapes. Results indicate that the most suitable behavior would be for cable bridges with H-shape pylons arranged in series and also with A-shape pylons in radial arrangement.

Probabilistic Fatigue Life Prediction of Bridge Cables Based on Multiscaling and Mesoscopic Fracture Mechanics

Directory of Open Access Journals (Sweden)

Zhongxiang Liu

2016-04-01

Full Text Available Fatigue fracture of bridge stay-cables is usually a multiscale process as the crack grows from micro-scale to macro-scale. Such a process, however, is highly uncertain. In order to make a rational prediction of the residual life of bridge cables, a probabilistic fatigue approach is proposed, based on a comprehensive vehicle load model, finite element analysis and multiscaling and mesoscopic fracture mechanics. Uncertainties in both material properties and external loads are considered. The proposed method is demonstrated through the fatigue life prediction of cables of the Runyang Cable-Stayed Bridge in China, and it is found that cables along the bridge spans may have significantly different fatigue lives, and due to the variability, some of them may have shorter lives than those as expected from the design.

Research of diagnosis sensors fault based on correlation analysis of the bridge structural health monitoring system

Science.gov (United States)

Hu, Shunren; Chen, Weimin; Liu, Lin; Gao, Xiaoxia

2010-03-01

Bridge structural health monitoring system is a typical multi-sensor measurement system due to the multi-parameters of bridge structure collected from the monitoring sites on the river-spanning bridges. Bridge structure monitored by multi-sensors is an entity, when subjected to external action; there will be different performances to different bridge structure parameters. Therefore, the data acquired by each sensor should exist countless correlation relation. However, complexity of the correlation relation is decided by complexity of bridge structure. Traditionally correlation analysis among monitoring sites is mainly considered from physical locations. unfortunately, this method is so simple that it cannot describe the correlation in detail. The paper analyzes the correlation among the bridge monitoring sites according to the bridge structural data, defines the correlation of bridge monitoring sites and describes its several forms, then integrating the correlative theory of data mining and signal system to establish the correlation model to describe the correlation among the bridge monitoring sites quantificationally. Finally, The Chongqing Mashangxi Yangtze river bridge health measurement system is regards as research object to diagnosis sensors fault, and simulation results verify the effectiveness of the designed method and theoretical discussions.

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.

Study on seismic behaviour of integral concrete bridges with different skew angles through fragility curves

Directory of Open Access Journals (Sweden)

Mahmoud Reza ُُShiravand

2017-12-01

Full Text Available Bridges are key elements in urban transportation system and should be designed to sustain earthquake induced damages to be utilized after earthquake. Extensive damages during last earthquakes highlighted the importance of seismic assessment and damage estimation of bridges. Skewness is one of the primary parameters effects on seismic behavior of bridges. Skew bridges are defined as bridges with skew angle piers and abutments. In these bridges, the piers have some degrees of skewness due to construction restrictions, such as those caused by crossing a waterway, railway line or road. This paper aims to investigate seismic behavior of skew concrete bridges using damage criteria and estimate probability of piers damage with fragility curves. To this end, three types of concrete bridges with two, three and four spans and varying skew angles of 00 ,100, 200 and 300 are modeled with finite element software. Seismic responses of bridge piers under 10 earthquake ground motion records are calculated using incremental dynamic analysis. Following, damage criteria proposed by Mackie and Stojadinovic are used to define damage limits of bridge piers in four damage states of slight, moderate, extensive and complete and bridge fragility curves are developed. The results show that increasing skew angles increases the probability of damage occurrence, particularly in extensive and complete damage states.

Design, fabrication, erection of Yuge-Ohashi bridge; Yuge ohashi no sekkei seisaku kasetsu

Energy Technology Data Exchange (ETDEWEB)

Nagamine, T.; Konishi, T.; Sasaki, K.; Miyakawa, T. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

1995-12-20

Introduced herein is the construction of Yuge-Ohashi Bridge, a 325-meter long three-span cable-stayed structure. Each tower is provided with deflectors to prevent galloping vibration that the bridge may experience after completion. Because it was afraid that the towers during the erection process would experience at the base sections a bend that would be greater than their withstand strength, vibration dampers TMDs (Tuned Mass Dampers) were installed. To enable the spars to withstand strong wind after completion, wing-type flaps were arranged on their sides. To damp vibration during the spar cantilever erection process, TMDs of the cantilever type were provided capable of responding to the vertical direction vibration, for which weights were caused to travel along the arms for tuning. To prevent the top-stage cables from rain caused vibration, U-shape grooves were provided. To prevent the intermediate-stage cables from rain caused vibration, high-attenuation rubber dampers were installed. A side span spar and a tower were installed en bloc by FC (Floating Crane) boats, and the central span spar was installed by cantilever erection. Thanks to the fuzzy control-aided accuracy management system, cable adjustment was efficiently accomplished and the accuracy fell within the target value range. 4 refs., 5 figs.

In-service performance evaluation and monitoring of a hybrid composite beam bridge system : final report.

Science.gov (United States)

2017-10-01

The hybrid composite beam (HCB) technology has been presented as a system for short and medium span beam bridges as an alternative to traditional materials such as concrete and steel. An HCB consists of a concrete tied arch encased in a fiber reinfor...

Experimental Validation of a Numerical Model for Three-Dimensional High-Speed Railway Bridge Analysis by Comparison with a Small-Scale Model

DEFF Research Database (Denmark)

Sneideris, J.; Bucinskas, Paulius; Agapii, L.

2015-01-01

The aim of this paper is to perform dynamic analysis of a multi-span railway bridge interacting with the underlying soil. A small-scale model of a bridge structure is constructed for experimental testing and the results are compared with a computational model. The computational model in this paper...... dimensional 10-degrees-of-freedom system. The subsoil model utilizes Green’s function for a horizontally layered half-space. The small-scale experimental model consists of bridge deck, columns and footings which are made from Plexiglas. An electric vehicle travels along the bridge deck on a track to simulate...

Modeling Main Body of Overcrossing Bridge Based on Vehicle-Borne Laser Scanning Data

Science.gov (United States)

Chen, X.; Chen, M.; Wei, Z.; Zhong, R.

2017-09-01

Vehicle-borne laser scanning (VBLS) is widely used to collect urban data for various mapping and modelling systems. This paper proposes a strategy of feature extraction and 3d model reconstruction for main body of overcrossing bridges based on VBLS point clouds. As the bridges usually have a large span, and the clouds data is often affected by obstacles, we have to use round-trip cloud data to avoid missing part. To begin with, pick out the cloud of the bridge body by an interactive clip-box, and group points by scan-line, then sort the points by scanning angle on each scan line. Since the position under the vehicle have a fixed scan-angle, a virtual path can be obtained. Secondly, extract horizontal line segments perpendicular to the virtual path along adjacent scan-lines, and then cluster line segments into long line-strings, which represent the top and bottom edge. Finally, regularize the line-strings and build 3d surface model of the bridge body. Experimental studies have demonstrated its efficiency and accuracy in case of building bridge model. Modelling the stairs at the both end of the bridge will be the direction of the next step.

Simplified method for the transverse bending analysis of twin celled concrete box girder bridges

Science.gov (United States)

Chithra, J.; Nagarajan, Praveen; S, Sajith A.

2018-03-01

Box girder bridges are one of the best options for bridges with span more than 25 m. For the study of these bridges, three-dimensional finite element analysis is the best suited method. However, performing three-dimensional analysis for routine design is difficult as well as time consuming. Also, software used for the three-dimensional analysis are very expensive. Hence designers resort to simplified analysis for predicting longitudinal and transverse bending moments. Among the many analytical methods used to find the transverse bending moments, SFA is the simplest and widely used in design offices. Results from simplified frame analysis can be used for the preliminary analysis of the concrete box girder bridges.From the review of literatures, it is found that majority of the work done using SFA is restricted to the analysis of single cell box girder bridges. Not much work has been done on the analysis multi-cell concrete box girder bridges. In this present study, a double cell concrete box girder bridge is chosen. The bridge is modelled using three- dimensional finite element software and the results are then compared with the simplified frame analysis. The study mainly focuses on establishing correction factors for transverse bending moment values obtained from SFA.

Structural Health Monitoring and Time-Dependent Effects Analysis of Self-Anchored Suspension Bridge with Extra-Wide Concrete Girder

Directory of Open Access Journals (Sweden)

Guangpan Zhou

2018-01-01

Full Text Available The present work is aimed at studying the structural health status of Hunan Road Bridge, which is currently the widest concrete self-anchored suspension bridge in China. The monitoring data included the structural deformations, internal forces, and vibration characteristics from April 2015 to April 2016 were analyzed to evaluate the structural changes and safety. The influences brought by the ambient temperature changes and the dual effects composed of concrete shrinkage & creep (S&C and seasonal temperature changes were analyzed based on the measured data. The long-time effects of concrete S&C were predicted using the CEB-FIP 90 model and the age-adjusted effective modulus method based on the ANSYS beam finite element model. The measured data showed that the transverse displacements of towers were more significant than the longitudinal ones. The spatial effect of the extra-wide girder is significant, which performs as the longitudinal stresses change unevenly along the transverse direction. The seasonal ambient warming caused overall increases in girder compressive stresses, and the cooling resulted in decreases along with significant temperature gradient effects. The prediction results show that the cable anchoring positions at girder ends and tower tops will move towards the mid-span affected by concrete S&C. In terms of the middle region of mid-span girder, significant increases in longitudinal stresses of top plate and decreases in the ones of bottom plate will be caused by the significant deflection. Comprehensively, the increases in the girder compressive stresses of side-span bottom plate and mid-span top plate are worthy of attention when confronted with extreme high temperature during the bridge service life cycle.

Structural covariance networks across the life span, from 6 to 94 years of age

Directory of Open Access Journals (Sweden)

Elizabeth DuPre

2017-10-01

Full Text Available Structural covariance examines covariation of gray matter morphology between brain regions and across individuals. Despite significant interest in the influence of age on structural covariance patterns, no study to date has provided a complete life span perspective—bridging childhood with early, middle, and late adulthood—on the development of structural covariance networks. Here, we investigate the life span trajectories of structural covariance in six canonical neurocognitive networks: default, dorsal attention, frontoparietal control, somatomotor, ventral attention, and visual. By combining data from five open-access data sources, we examine the structural covariance trajectories of these networks from 6 to 94 years of age in a sample of 1,580 participants. Using partial least squares, we show that structural covariance patterns across the life span exhibit two significant, age-dependent trends. The first trend is a stable pattern whose integrity declines over the life span. The second trend is an inverted-U that differentiates young adulthood from other age groups. Hub regions, including posterior cingulate cortex and anterior insula, appear particularly influential in the expression of this second age-dependent trend. Overall, our results suggest that structural covariance provides a reliable definition of neurocognitive networks across the life span and reveal both shared and network-specific trajectories. The importance of life span perspectives is increasingly apparent in understanding normative interactions of large-scale neurocognitive networks. Although recent work has made significant strides in understanding the functional and structural connectivity of these networks, there has been comparatively little attention to life span trajectories of structural covariance networks. In this study we examine patterns of structural covariance across the life span for six neurocognitive networks. Our results suggest that networks exhibit

75 FR 21394 - Endangered and Threatened Wildlife and Plants; Final Revised Critical Habitat for Hine's Emerald...

Science.gov (United States)

2010-04-23

... critical habitat units are located in Cook, DuPage, and Will Counties in Illinois; Alpena, Mackinac, and... News- Graphic, St. Ignace News, Door County Advocate, Alpena News, Ozaukee Press, and Joliet Herald... commenter asserts that there is little (if any) economic activity in Alpena, Mackinac, or Presque Isle...

Development of a new-type super-long bridge; Chochotaikyo ni tekigoshita shinkeishiki kyoryo no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Ogawa, K.; Shimodoio, H.; Saito, T.; Nogami, C.; Oryu, T.; Morikawa, M. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1998-12-20

In order to realize large strait-crossing projects in the near future, it is necessary to develop a new type of super-long span bridge, which has a superior aerodynamic stability and is cost effective. We have been proposed a new type of suspension bridge using a 2-box and 1-box combined girder to apply to such a project And this time, we propose the cable stayed suspension bridge using a 2- box and 1-box combined girder aiming for improvement of aerodynamic stability with increase of torsional rigidity. This paper describes the performance of this cable stayed suspension bridge obtained from aerodynamic analysis. As a result, it can be confirmed that this newly developed cable stayed suspension system has fine characteristics and shows more potential for economical construction than the early proposed suspension system. (author)

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.

Dynamic response of the train-track-bridge system subjected to derailment impacts

Science.gov (United States)

Ling, Liang; Dhanasekar, Manicka; Thambiratnam, David P.

2018-04-01

Derailments on bridges, although not frequent, when occurs due to a complex dynamic interaction of the train-track-bridge structural system, are very severe. Furthermore, the forced vibration induced by the post-derailment impacts can toss out the derailed wagons from the bridge deck with severe consequences to the traffic underneath and the safety of the occupants of the wagons. This paper presents a study of the train-track-bridge interaction during a heavy freight train crossing a concrete box girder bridge from a normal operation to a derailed state. A numerical model that considers the bridge vibration, train-track interaction and the train post-derailment behaviour is formulated based on a coupled finite-element - multi-body dynamics (FE-MBD) theory. The model is applied to predict the post-derailment behaviour of a freight train composed of one locomotive and several wagons, as well as the dynamic response of a straight single-span simply supported bridge containing ballast track subjected to derailment impacts. For this purpose, a typical derailment scenario of a heavy freight train passing over a severe track geometry defect is introduced. The dynamic derailment behaviour of the heavy freight train and the dynamic responses of the rail bridge are illustrated through numerical examples. The results exhibit the potential for tossing out of the derailed trains from the unstable increase in the yaw angle signature and a lower rate of increase of the bridge deck bending moment compared to the increase in the static axle load of the derailed wheelset.

Critical traffic loading for the design of prestressed concrete bridge

International Nuclear Information System (INIS)

Hassan, M.I.U.

2009-01-01

A study has been carried out to determine critical traffic loadings for the design of bridge superstructures. The prestressed concrete girder bridge already constructed in Lahore is selected for the analysis as an example. Standard traffic loadings according to AASHTO (American Association of State Highway and Transportation Officials) and Pakistan Highway Standards are used for this purpose. These include (1) HL-93 Truck, (2) Lane and (3) Tandem Loadings in addition to (4) Military tank loading, (5) Class-A, (6) Class-B and (7) Class-AA loading, (8) NLC (National Logistic Cell) and (9) Volvo truck loadings. Bridge superstructure including transom beam is analyzed Using ASD and LRFD (Load and Resistance Factor Design) provisions of AASHTO specifications. For the analysis, two longer and shorter spans are selected. This includes the analysis of bridge deck; interior and exterior girder; a typical transom beam and a pier. Dead and live loading determination is carried out using both computer aided and manual calculations. Evaluation of traffic loadings is done for all the bridge components to find out the critical loading. HL-93 loading comes out to be the most critical loading and where this loading is not critical in case of bridge decks; a factor of 1.15 is introduced to make it equivalent with HL-93 -Ioading. SAP-2000 (Structural Engineering Services of Pakistan) and MS-Excel is employed for analysis of bridge superstructure subjected to this loading. Internal forces are obtained for the structural elements of the bridge for all traffic loadings mentioned. It is concluded that HL-93 loading can be used for the design of prestressed concrete girder bridge. Bridge design authorities like NHA (National Highway Authority) and different cities development authorities are using different standard traffic loadings. A number of suggestions are made from the results of the research work related to traffic loadings and method of design. These recommendations may be

Span of control matters.

Science.gov (United States)

Cathcart, Deb; Jeska, Susan; Karnas, Joan; Miller, Sue E; Pechacek, Judy; Rheault, Lolita

2004-09-01

Prompted by manager concerns about span of control, a large, integrated health system set out to determine if span of control really mattered. Was there something to it, or was it just an excuse for poor performance? A team of middle managers studied the problem and ultimately demonstrated a strong relationship between span of control and employee engagement. Consequently, it was decided to add 4 management positions to note the effect. One year later, positive changes were observed in employee engagement scores in all 4 areas. This study suggests careful review of manager spans of control to address the untoward effects of large spans of control on employee engagement.

Aeroelastic Response from Indicial Functions with a Finite Element Model of a Suspension Bridge

Science.gov (United States)

Mikkelsen, O.; Jakobsen, J. B.

2017-12-01

The present paper describes a comprehensive analysis of the aeroelastic bridge response in time-domain, with a finite element model of the structure. The main focus is on the analysis of flutter instability, accounting for the wind forces generated by the bridge motion, including twisting as well as vertical and horizontal translation, i.e. all three global degrees of freedom. The solution is obtained by direct integration of the equations of motion for the bridge-wind system, with motion-dependent forces approximated from flutter derivatives in terms of rational functions. For the streamlined bridge box-girder investigated, the motion dependent wind forces related to the along-wind response are found to have a limited influence on the flutter velocity. The flutter mode shapes in the time-domain and the frequency domain are consistent, and composed of the three lowest symmetrical vertical modes coupled with the first torsional symmetric mode. The method applied in this study provides detailed response estimates and contributes to an increased understanding of the complex aeroelastic behaviour of long-span bridges.

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.

Soil Structure Interaction for Integral Abutment Bridge Using Spring Analogy Approach

International Nuclear Information System (INIS)

Thanoon, W A; Abdulrazeg, A A; Jaafar, M S; Kohnehpooshi, O; Noorzaei, J

2011-01-01

The reaction of the backfill behind the abutments and adjacent to the piles plays a significant role in the behavior of the Integral bridge. The handling of soil-structure interaction in the analysis and design of integral abutment bridges has always been problematic due to its complexity. This study describes the implementation of a 2-D finite element model of IAB system which explicitly incorporates the soil response. The superstructure members and the pile have been represented by means of three-node isoperimetric beam elements with three degree of freedom per node. The Eight node isoperimetric quadrilateral element has been used to model the abutment. The backfill was idealized by uncoupled 'Winkler' spring. The applic1ability of this model is demonstrated by analyzing a single span IA bridge. The results have shown that the shear forces at the tops of the supported piles were only 12% to 16% of the load which at the top of abutment.

Soil Structure Interaction for Integral Abutment Bridge Using Spring Analogy Approach

Energy Technology Data Exchange (ETDEWEB)

Thanoon, W A [Faculty Engineering, Nizwa University (Oman); Abdulrazeg, A A; Jaafar, M S; Kohnehpooshi, O [Department of Civil Engineering, University Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Noorzaei, J, E-mail: jamal@eng.upm.edu.my [Institute of Advance Technology, University Putra Malaysia, 43400 Serdang, Selangor (Malaysia)

2011-02-15

The reaction of the backfill behind the abutments and adjacent to the piles plays a significant role in the behavior of the Integral bridge. The handling of soil-structure interaction in the analysis and design of integral abutment bridges has always been problematic due to its complexity. This study describes the implementation of a 2-D finite element model of IAB system which explicitly incorporates the soil response. The superstructure members and the pile have been represented by means of three-node isoperimetric beam elements with three degree of freedom per node. The Eight node isoperimetric quadrilateral element has been used to model the abutment. The backfill was idealized by uncoupled 'Winkler' spring. The applic1ability of this model is demonstrated by analyzing a single span IA bridge. The results have shown that the shear forces at the tops of the supported piles were only 12% to 16% of the load which at the top of abutment.

Conceptual design for the thermal shield bridges and multilayer insulation in the interconnect region for the SSC

International Nuclear Information System (INIS)

Baritchi, D.; Nicol, T.; Boroski, W.

1991-01-01

The interconnect region serves as the connection area between magnets. In order to minimize radiant heat transfer in the interconnect area, the authors used shield bridges which span the 80K and 20K shield gap between adjacent magnets. A sliding joint between bridge sections on adjacent magnets accommodates contraction during cool-down. An investigation was done to determine which attachment schemes (riveted or bolted versus welded) are better for heat transfer. Each shield bridge is covered with the same multilayer insulation scheme used throughout the body of the magnet. These shield bridges also contain pressure reliefs for each shield in the event of an internal piping failure. The reliefs are located in the upper half of the shield section in order to prevent liquid spills from impinging directly onto the vacuum vessel wall

Bridges for Pedestrians with Random Parameters using the Stochastic Finite Elements Analysis

Science.gov (United States)

Szafran, J.; Kamiński, M.

2017-02-01

The main aim of this paper is to present a Stochastic Finite Element Method analysis with reference to principal design parameters of bridges for pedestrians: eigenfrequency and deflection of bridge span. They are considered with respect to random thickness of plates in boxed-section bridge platform, Young modulus of structural steel and static load resulting from crowd of pedestrians. The influence of the quality of the numerical model in the context of traditional FEM is shown also on the example of a simple steel shield. Steel structures with random parameters are discretized in exactly the same way as for the needs of traditional Finite Element Method. Its probabilistic version is provided thanks to the Response Function Method, where several numerical tests with random parameter values varying around its mean value enable the determination of the structural response and, thanks to the Least Squares Method, its final probabilistic moments.

Bridges for Pedestrians with Random Parameters using the Stochastic Finite Elements Analysis

Directory of Open Access Journals (Sweden)

Szafran J.

2017-02-01

Full Text Available The main aim of this paper is to present a Stochastic Finite Element Method analysis with reference to principal design parameters of bridges for pedestrians: eigenfrequency and deflection of bridge span. They are considered with respect to random thickness of plates in boxed-section bridge platform, Young modulus of structural steel and static load resulting from crowd of pedestrians. The influence of the quality of the numerical model in the context of traditional FEM is shown also on the example of a simple steel shield. Steel structures with random parameters are discretized in exactly the same way as for the needs of traditional Finite Element Method. Its probabilistic version is provided thanks to the Response Function Method, where several numerical tests with random parameter values varying around its mean value enable the determination of the structural response and, thanks to the Least Squares Method, its final probabilistic moments.

Vibration characteristics and dynamic increment factor of 2 span continuous PC cable-stayed bridge under moving vehicles; 2 keikan renzoku PC shachokyo no sharyo sokoji no shindo tokusei to doteki zofukuritsu

Energy Technology Data Exchange (ETDEWEB)

Fukada, S.; Kajikawa, Y. [Kanazawa Univ. (Japan)] Tsunomoto, M. [Oriental Construction Co. Ltd., Tokyo (Japan)

1998-10-21

In this study, experiments on and simulation analyses of the travels of vehicles on a 2 span continuous PC cable-stayed bridge were conducted, and the propriety of the analysis method, vibration characteristics of traveling vehicles, and characteristics of the effective amplitude and dynamic increment factor concerning various traveling states were discussed. The results show that actually measured value of strain to a dynamic load substantially agreed with the value of strain obtained in the case of analysis in which the end fulcrums were movable. The actually measured value of natural frequency was between the value of natural frequency in the case of analysis in which the end fulcrums were movable and the value in the case of analysis in which the end fulcrums were in a pin state. The actually measured value of mode damping constant agreed exactly with the value of mode damping constant calculated on the assumption that the damping constant of the main beam is 1.0%, those of the main tower and bridge pier 5.0%, and that of the cables 0.1%. Therefore, the damping matrix in the dynamic response analysis was determined on the basis of the damping constants of these members. The characteristics of the effective amplitude and dynamic increment factor in various traveling states of the results of the simulation analysis are in comparatively good agreement with those of experiments. 20 refs., 17 figs., 5 tabs.

MODELING MAIN BODY OF OVERCROSSING BRIDGE BASED ON VEHICLE-BORNE LASER SCANNING DATA

Directory of Open Access Journals (Sweden)

X. Chen

2017-09-01

Full Text Available Vehicle-borne laser scanning (VBLS is widely used to collect urban data for various mapping and modelling systems. This paper proposes a strategy of feature extraction and 3d model reconstruction for main body of overcrossing bridges based on VBLS point clouds. As the bridges usually have a large span, and the clouds data is often affected by obstacles, we have to use round-trip cloud data to avoid missing part. To begin with, pick out the cloud of the bridge body by an interactive clip-box, and group points by scan-line, then sort the points by scanning angle on each scan line. Since the position under the vehicle have a fixed scan-angle, a virtual path can be obtained. Secondly, extract horizontal line segments perpendicular to the virtual path along adjacent scan-lines, and then cluster line segments into long line-strings, which represent the top and bottom edge. Finally, regularize the line-strings and build 3d surface model of the bridge body. Experimental studies have demonstrated its efficiency and accuracy in case of building bridge model. Modelling the stairs at the both end of the bridge will be the direction of the next step.

Fatigue analysis and life prediction of composite highway bridge decks under traffic loading

Directory of Open Access Journals (Sweden)

Fernando N. Leitão

Full Text Available Steel and composite (steel-concrete highway bridges are currently subjected to dynamic actions of variable magnitude due to convoy of vehicles crossing on the deck pavement. These dynamic actions can generate the nucleation of fractures or even their propagation on the bridge deck structure. Proper consideration of all of the aspects mentioned pointed our team to develop an analysis methodology with emphasis to evaluate the stresses through a dynamic analysis of highway bridge decks including the action of vehicles. The design codes recommend the application of the curves S-N associated to the Miner's damage rule to evaluate the fatigue and service life of steel and composite (steel-concrete bridges. In this work, the developed computational model adopted the usual mesh refinement techniques present in finite element method simulations implemented in the ANSYS program. The investigated highway bridge is constituted by four longitudinal composite girders and a concrete deck, spanning 40.0m by 13.5m. The analysis methodology and procedures presented in the design codes were applied to evaluate the fatigue of the bridge determining the service life of the structure. The main conclusions of this investigation focused on alerting structural engineers to the possible distortions, associated to the steel and composite bridge's service life when subjected to vehicle's dynamic actions.

Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure

Science.gov (United States)

Wu, Lai-Yi

2015-01-01

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. PMID:26451387

Design, fabrication and erection of Queen Mall Bridge; Queen mall kyo no sekkei seisaku kasetsu

Energy Technology Data Exchange (ETDEWEB)

Arai, M.; Ishii, A.; Shinohara, T. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

1997-12-20

This paper describes design, fabrication and erection of Queen Mall Bridge, which is a new landmark in Minato-Mirai Yokohama. This bridge is two-span continuous cable stayed pedestrian bridge with a roof, and has a length 72.2 m, a width 18 m and a weight about 1,050 t. This bridge connects between the Queen`s Square and the second floor of Pacifico Yokohama. Achieving harmonious impression of the newly designed bridge in this area, glass roof was employed and all-weld method was applied to the in-site jointing of main girders and main tower in addition to the essential structural design. Since all-weld method was applied to the in-site jointing, highly accurate fabrication was considered during the in-site jointing. Due to the heavy traffic of the road below the bridge, the erection time was shortened under the severe erection conditions at night by large block method. Especially, accuracy control was considered for the whole shape management. Pre-assemble of all members was conducted just near the erection site, only 500 m away from the site, to shorten the construction time. 1 ref., 5 figs.

Construction of the Usui bridge. Chodai PC shachokyo no kensetsu (Joshin'etsu jidoshado Usuikyo)

Energy Technology Data Exchange (ETDEWEB)

Otani, S.; Ogata, T. (Japan Highway Public Corp., Tokyo (Japan))

1993-10-01

The Usui Bridge is a long bridge located at the Usui mountain pass on the Joshinetsu Expressway, completed in March 1993. This paper reports from its planning to the design, construction work, and construction management. The bridge is a first two-span continuous prestressed concrete cable-stayed bridge (with a length of 222 m) with one central cable plane ever constructed as a highway bridge in Japan. Its bridge construction features are represented by the main girder consisted of three-chamber type box girder, and the main tower of reversed Y-letter concrete structure. For the fan-shaped stay cable (9-step double cable), a large capacity cable of non-grouting type fabricated at a factory (with a tensile strength of 1500 tf class) was used to simplify the installation work at the site. The one-plane structure utilizing the center belt as a stay cable fixing portion was adopted because of its economic performance superior to a two-plane structure, easiness in consolidating construction works, and assurance of more open space for car traffic. After the completion, the bridge construction has been awarded with the Tanaka Prize of Japan Society of Civil Engineers and the PC Technology Association prize. 26 figs., 4 tabs.

Boundary Spanning

DEFF Research Database (Denmark)

Zølner, Mette

The paper explores how locals span boundaries between corporate and local levels. The aim is to better comprehend potentialities and challenges when MNCs draws on locals’ culture specific knowledge. The study is based on an in-depth, interpretive case study of boundary spanning by local actors in...... approach with pattern matching is a way to shed light on the tacit local knowledge that organizational actors cannot articulate and that an exclusively inductive research is not likely to unveil....

Impact of measurement uncertainty from experimental load distribution factors on bridge load rating

Science.gov (United States)

Gangone, Michael V.; Whelan, Matthew J.

2018-03-01

Load rating and testing of highway bridges is important in determining the capacity of the structure. Experimental load rating utilizes strain transducers placed at critical locations of the superstructure to measure normal strains. These strains are then used in computing diagnostic performance measures (neutral axis of bending, load distribution factor) and ultimately a load rating. However, it has been shown that experimentally obtained strain measurements contain uncertainties associated with the accuracy and precision of the sensor and sensing system. These uncertainties propagate through to the diagnostic indicators that in turn transmit into the load rating calculation. This paper will analyze the effect that measurement uncertainties have on the experimental load rating results of a 3 span multi-girder/stringer steel and concrete bridge. The focus of this paper will be limited to the uncertainty associated with the experimental distribution factor estimate. For the testing discussed, strain readings were gathered at the midspan of each span of both exterior girders and the center girder. Test vehicles of known weight were positioned at specified locations on each span to generate maximum strain response for each of the five girders. The strain uncertainties were used in conjunction with a propagation formula developed by the authors to determine the standard uncertainty in the distribution factor estimates. This distribution factor uncertainty is then introduced into the load rating computation to determine the possible range of the load rating. The results show the importance of understanding measurement uncertainty in experimental load testing.

Assessment of vehicular live load and load factors for design of short-span bridges according to the new Egyptian Code

Directory of Open Access Journals (Sweden)

Hatem M. Seliem

2015-04-01

The study shows that concrete box-girders designed according to ECP-201:2012 and ECP-201:2003 using the ultimate limit state method yield almost the same demand. Despite the increase in the VLL of ECP-201:2012, and consequently the live load forces, concrete I-shaped girder bridges will be subjected to less total factored internal forces in comparison to ECP-201:2003 This is attributed to the interaction between the live to dead loads ratio and the load combinations. Design of composite steel plate girder bridges according to ECP-201:2012 using the allowable stress design method yields over designed sections.

Monitoring system for assessment of prestressed railway bridges in the new Lehrter Bahnhof in Berlin

Science.gov (United States)

Habel, Wolfgang R.; Kohlhoff, H.; Knapp, J.; Helmerich, R.

2003-03-01

A new central railway station - Lehrter Bahnhof - is being built in Berlin. Because of construction activities in immediate vicinity and because of difficult soil conditions, vertical displacements will be expected. In order to avoid damage to the bridges and to a widely spanned glass roof which will be supported by two concrete bridges these two bridges have to be monitored right from the beginning of construction until commissioning as well as later on for several years. For this purpose, a long-term monitoring concept has been developed. Sensors with excellent long-term stabilty have been chosen to carry out the concept. This paper describes the measuring concept as well as components of the system. Especially techniques to monitor settlements and heaves and to measure strain and inclination of the prestressed concrete bridges are described. All measures are redundantly monitored. Measurements on-site are referenced by measurements on two large-scale beam models well-defined loaded under laboratory and field conditions.

Relationship between ancient bridges and population dynamics in the lower Yangtze River Basin, China.

Science.gov (United States)

Zhao, Yang; Jia, Xin; Lee, Harry F; Zhao, Hongqiang; Cai, Shuliang; Huang, Xianjin

2017-01-01

It has been suggested that population growth dynamics may be revealed by the geographic distribution and the physical structure of ancient bridges. Yet, this relationship has not been empirically verified. In this study, we applied the archaeological records for ancient bridges to reveal the population growth dynamics in the lower Yangtze River Basin in late imperial China. We investigated 89 ancient bridges in Yixing that were built during the Ming and Qing dynasties (AD1368-1911). Global Position System information and structure (length, width, and span) of those bridges was measured during our field investigations. Their distribution density was calculated by ArcGIS. The historical socio-economic dynamics of Yixing was inferred from the distribution and structure of ancient bridges. Based on the above information, the population growth dynamics in Yixing was projected. Our results show that 77 bridges were built in Yixing during the Qing dynasty, which is 6.41 times more than the number built during the Ming dynasty. In the Ming dynasty, bridges were built on pivotal routes; in the Qing dynasty, bridges were scattered across various places. Over the period, the density distribution of bridges shifted northwestward, while the average length and width of bridges decreased. The increasing number of bridges corresponded to population growth, largely attributable to massive clan migration from northern China during the Little Ice Age. The shift in the density distribution of bridges corresponded to the formation of settlements of large clans and the blossoming of Yixing Teapot handicrafts. The scattering and the reduction in average length and width of bridges was due to the dispersal of population and the associated formation of small settlements in the latter period. Our approach is innovative and robust, and could be employed to recover long-term historical population growth dynamics in other parts of China.

Relationship between ancient bridges and population dynamics in the lower Yangtze River Basin, China.

Directory of Open Access Journals (Sweden)

Yang Zhao

Full Text Available It has been suggested that population growth dynamics may be revealed by the geographic distribution and the physical structure of ancient bridges. Yet, this relationship has not been empirically verified. In this study, we applied the archaeological records for ancient bridges to reveal the population growth dynamics in the lower Yangtze River Basin in late imperial China. We investigated 89 ancient bridges in Yixing that were built during the Ming and Qing dynasties (AD1368-1911. Global Position System information and structure (length, width, and span of those bridges was measured during our field investigations. Their distribution density was calculated by ArcGIS. The historical socio-economic dynamics of Yixing was inferred from the distribution and structure of ancient bridges. Based on the above information, the population growth dynamics in Yixing was projected. Our results show that 77 bridges were built in Yixing during the Qing dynasty, which is 6.41 times more than the number built during the Ming dynasty. In the Ming dynasty, bridges were built on pivotal routes; in the Qing dynasty, bridges were scattered across various places. Over the period, the density distribution of bridges shifted northwestward, while the average length and width of bridges decreased. The increasing number of bridges corresponded to population growth, largely attributable to massive clan migration from northern China during the Little Ice Age. The shift in the density distribution of bridges corresponded to the formation of settlements of large clans and the blossoming of Yixing Teapot handicrafts. The scattering and the reduction in average length and width of bridges was due to the dispersal of population and the associated formation of small settlements in the latter period. Our approach is innovative and robust, and could be employed to recover long-term historical population growth dynamics in other parts of China.

Displacement monitoring and modelling of a high-speed railway bridge using C-band Sentinel-1 data

Science.gov (United States)

Huang, Qihuan; Crosetto, Michele; Monserrat, Oriol; Crippa, Bruno

2017-06-01

Bridge displacement monitoring is one of the key components of bridge structural health monitoring. Traditional methods, usually based on limited sets of sensors mounted on a given bridge, collect point-like deformation information and have the disadvantage of providing incomplete displacement information. In this paper, a Persistent Scatterer Interferometry (PSI) approach is used to monitor the displacements of the Nanjing Dashengguan Yangtze River high-speed railway bridge. Twenty-nine (29) European Space Agency Sentinel-1A images, acquired from April 25, 2015 to August 5, 2016, were used in the PSI analysis. A total of 1828 measurement points were selected on the bridge. The results show a maximum longitudinal displacement of about 150 mm on each side of the bridge. The measured displacements showed a strong correlation with the environmental temperature at the time the images used were acquired, indicating that they were due to thermal expansion of the bridge. At each pier, a regression model based on the PSI-measured displacements was compared with a model based on in-situ measurements. The good agreement of these models demonstrates the capability of the PSI technique to monitor long-span railway bridge displacements. By comparing the modelled displacements and dozens of PSI measurements, we show how the performance of movable bearings can be evaluated. The high density of the PSI measurement points is advantageous for the health monitoring of the entire bridge.

Construction of Daiichi Tamagawa bridge; Daiichi Tamagawa kyoryo no seko

Energy Technology Data Exchange (ETDEWEB)

Watanabe, O.; Tsuyoshi, T. [East Japan Railway Company, Tokyo (Japan); Ota, T.; Sato, S. [Tekken Corp., Tokyo (Japan)

1997-05-30

This paper describes the construction of Daiichi Tamagawa Bridge for JR Tazawako Line, which was reconstructed with the Akita Shinkansen Project apart from the existing line. This bridge is a three-span continuous PC cable stayed bridge. To avoid operation accidents due to snow and ice, independent two-column type with a height of 11 m without beam was employed for the main tower. For the construction of upper part, overhang election construction method was adopted, which can be applied all the year round. The main girder has a single box cross section, and a width of 5.5 m and a beam height of 2.3 m. This was also constructed by the overhang construction method. To reduce the construction period, the main tower was constructed by the precast block construction method. The whole bridge was divided into six blocks by considering the hoist performance of cranes. Reinforcement against bearing pressure and cleavage due to the cable tensile force was conducted by adopting saddle structure for the main tower. Oblique members were jointed with the main girder using lateral beams projected from lateral side of girder. Totally seven PC cables were used for each oblique member. Measurements and management during the overhang construction were also described. The construction was over without problems in August, 1996. This bridge is under test operation using test run vehicles. 2 refs., 20 figs., 7 tabs.

47 CFR 80.1007 - Bridge-to-bridge radiotelephone installation.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge radiotelephone installation. 80.1007 Section 80.1007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND... Bridge-to-Bridge Act § 80.1007 Bridge-to-bridge radiotelephone installation. Use of the bridge-to-bridge...

Field dynamic testing on a Cyprus concrete highway bridge using Wireless Sensor Network (WSN)

Science.gov (United States)

Votsis, Renos A.; Kyriakides, Nicholas; Tantele, Elia A.; Chrysostomou, Christis Z.; Onoufriou, Toula

2014-08-01

The aims of the bridge management authorities are to ensure that bridges fulfil their purpose and functionality during their design life. So, it is important to identify and quantify the deterioration of the structural condition early so that a timely application of an intervention will avoid more serious problems and increased costs at a later stage. A measure to enhance the effectiveness of the existing structural evaluation by visual inspection is instrumental monitoring using sensors. The activities performed in this process belong to the field of Structural Health Monitoring (SHM). The SHM offers opportunities for continuous or periodic monitoring on bridges and technological advances allow nowadays the employment of wireless sensors networks (WSN) for this task. A SHM application using WSN was implemented on a multi-span reinforced concrete (RC) highway bridge in Limassol with the objective to study its dynamic characteristics and performance. Part of the specific bridge will be replaced and this offered a unique opportunity for measurements before and after construction so that apparent changes in the dynamic characteristics of the bridge will be identified after the repairing work. The measurements provided indications on the frequencies and mode shapes of the bridge and the response amplitude during the passing of traffic. The latter enabled the investigation of the dependency of the bridge's structural damping to the amplitude of vibration induced by the passing of traffic. The results showed that as the excitation increases the magnitude of modal damping increases as well.

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.

CF60 Concrete Composition Design and Application on Fudiankou Xijiang Super Large Bridge

Science.gov (United States)

Qiu, Yi Mei; Wen, Sen Yuan; Chen, Jun Xiang

2018-06-01

Guangxi Wuzhou City Ring Road Fudiankou Xijiang super large bridge CF60 concrete is a new multi-phase composite high-performance concrete, this paper for the Fudiankou Xijiang bridge structure and characteristics of the project, in accordance with the principle of local materials and technical specification requirements, combined with the site conditions of CF60 engineering high performance concrete component materials, proportion and the technical performance, quantify the main physical and mechanical performance index. Analysis main influencing factors of the technical indicators, reasonable adjustment of concrete mix design parameters, and the use of technical means of admixture and multi-function composite admixture of concrete, obtain the optimal proportion of good work, process, mechanical properties stability and durability of engineering properties, recommend and verification of concrete mix; to explore the CF60 high performance concrete Soil in the Fudiankou Xijiang bridge application technology, detection and tracking the quality of concrete construction, concrete structure during the construction of the key technology and control points is proposed, evaluation of CF60 high performance concrete in the actual engineering application effect and benefit to ensure engineering quality of bridge structure and service life, and super long span bridge engineering construction to provide basis and reference.

Vibration based structural assessment of the rehabilitation intervention in r.c. segmental bridge

Directory of Open Access Journals (Sweden)

Franchetti Paolo

2015-01-01

Full Text Available A vibration based structural assessment campaign was carried out on a r.c. segmental bridge in North East Italy. The bridge has a cantilever static scheme, fixed at the top of the piers and with a hinge at the centre of the span. The particular configuration of the hinge consists in a couple of steel elements, each one composed by a tongue and groove joint. Since the year 1960, the hinge was subjected to consumption and degradation, that caused a malfunctioning of the device. An intervention of rehabilitation of the bridge led to a reinforcement of the existing hinges with the coupling of new metallic devices: new tongue and groove hinges were applied, that by one side allow the horizontal displacements and rotation, by the other side strongly reduce the relative vertical displacements of the two parts of the bridge. A dynamic test campaign was set up in order to assess the effectiveness of the intervention. The principal dynamic parameters were calculated and analysed with respect to the intervention that was realized. The tests clearly showed the effectiveness of the intervention, and helped the designer to have a better understanding of the structural behaviour of the bridge.

Repair and Protection of Small Railway Viaduct with Jammed Span at the Mining Influence

Science.gov (United States)

Bętkowski, Piotr

2017-10-01

This paper is about the maintenance of bridge objects on mining areas. Based on several years of observation is shown as functional parameters and technical conditions were deteriorated. As a result of the mining area deformations appeared among others following damages: block of bearings, jam of span, cracks on the abutments. The article describes series of clever maintenance repairs (such as the restoration of displacement freedom on non-standard tangent bearings) which enabled the exploitation of the viaduct without interruptions of railway communication. The region of the bridge is planned to further mining activities, which prejudged, that a repair of the viaduct was necessary to realization. The article discusses the predicted mining area deformation and analyses their influence on the bridge structure. Repair of the viaduct is a comprehensive example of the mining facility protection with the restoration of the expansion joints, bearings replacement, widening benches under bearings, stitching cracks and strengthening abutments, recreating the isolation and the drainage system damaged by mining influences, performance strut in the foundation level. An important element in determining the durability of repair is the selection of appropriate materials and repair technology, which is analysed in the article. All of these tasks completed in less than four months. Article illustrates the photo documentation made before and after repairs and technical drawings that show the range of the repairs.

A Multimode Adaptive Pushover Procedure for Seismic Assessment of Integral Bridges

Directory of Open Access Journals (Sweden)

Ehsan Mohtashami

2013-01-01

Full Text Available This paper presents a new adaptive pushover procedure to account for the effect of higher modes in order to accurately estimate the seismic response of bridges. The effect of higher modes is considered by introducing a minimum value for the total effective modal mass. The proposed method employs enough number of modes to ensure that the defined total effective modal mass participates in all increments of the pushover loading. An adaptive demand curve is also developed for assessment of the seismic demand. The efficiency and robustness of the proposed method are demonstrated by conducting a parametric study. The analysis includes 18 four-span integral bridges with various heights of piers. The inelastic response history analysis is employed as reference solution in this study. Numerical results indicate excellent accuracy of the proposed method in assessment of the seismic response. For most bridges investigated in this study, the difference between the estimated response of the proposed method and the inelastic response history analysis is less than 25% for displacements and 10% for internal forces. This indicates a very good accuracy compared to available pushover procedures in the literature. The proposed method is therefore recommended to be applied to the seismic performance evaluation of integral bridges for engineering applications.

Reliability Evaluation of Bridges Based on Nonprobabilistic Response Surface Limit Method

Directory of Open Access Journals (Sweden)

Xuyong Chen

2017-01-01

Full Text Available Due to many uncertainties in nonprobabilistic reliability assessment of bridges, the limit state function is generally unknown. The traditional nonprobabilistic response surface method is a lengthy and oscillating iteration process and leads to difficultly solving the nonprobabilistic reliability index. This article proposes a nonprobabilistic response surface limit method based on the interval model. The intention of this method is to solve the upper and lower limits of the nonprobabilistic reliability index and to narrow the range of the nonprobabilistic reliability index. If the range of the reliability index reduces to an acceptable accuracy, the solution will be considered convergent, and the nonprobabilistic reliability index will be obtained. The case study indicates that using the proposed method can avoid oscillating iteration process, make iteration process stable and convergent, reduce iteration steps significantly, and improve computational efficiency and precision significantly compared with the traditional nonprobabilistic response surface method. Finally, the nonprobabilistic reliability evaluation process of bridge will be built through evaluating the reliability of one PC continuous rigid frame bridge with three spans using the proposed method, which appears to be more simple and reliable when lack of samples and parameters in the bridge nonprobabilistic reliability evaluation is present.

Parametric Analyses of Dynamic Characteristic of the Cable-Stayed Pedestrian Bridge

Directory of Open Access Journals (Sweden)

Pańtak Marek

2017-12-01

Full Text Available The paper presents characteristics of the structural system and results of dynamic field tests and numerical parametric analyses of three-span, two-pylon, cable-stayed pedestrian bridge with steel-concrete composite deck and spans of 25.5 + 60.0 + 25.5 m. The footbridge is characterized by increased dynamic susceptibility of the elements of the suspension system observed during the everyday operation of the structure. The analyses have shown that the high amplitude vibrations of the pylon back-stay cables change the parameters of the structural system and consequently change the value of the natural vibration frequencies of the structure. In the paper, the selection methodology of parameters of the computational model which allows to correctly determine the natural vibration frequencies of the footbridge has been presented.

Golden Gate Bridge response: a study with low-amplitude data from three earthquakes

Science.gov (United States)

Çelebi, Mehmet

2012-01-01

The dynamic response of the Golden Gate Bridge, located north of San Francisco, CA, has been studied previously using ambient vibration data and finite element models. Since permanent seismic instrumentation was installed in 1993, only small earthquakes that originated at distances varying between ~11 to 122 km have been recorded. Nonetheless, these records prompted this study of the response of the bridge to low amplitude shaking caused by three earthquakes. Compared to previous ambient vibration studies, the earthquake response data reveal a slightly higher fundamental frequency (shorter-period) for vertical vibration of the bridge deck center span (~7.7–8.3 s versus 8.2–10.6 s), and a much higher fundamental frequency (shorter period) for the transverse direction of the deck (~11.24–16.3 s versus ~18.2 s). In this study, it is also shown that these two periods are dominant apparent periods representing interaction between tower, cable, and deck.

Identification of dynamic characteristics by field vibration test in Tsurumi Tsubasa bridge; Tsurumi Tsubasakyo no shindo jikken ni yoru doteki tokusei no dotei

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, H. [Saitama University, Saitama (Japan). Faculty of Engineering; Takano, H.; Ogasawara, M.; Shimosato, T. [Metropolitan Expressway Public Corp., Tokyo (Japan); Kato, M.; Okada, J. [NKK Corp., Tokyo (Japan)

1996-07-21

Field vibration test of the Tsurumi Tsubasa Bridge, a long span cable stayed bridge, has been conducted. Focusing on its dynamic characteristics, an identification method from test results and its validity were investigated. The natural frequency identified using mode circle and resonance curve from steady vibration test agreed with that identified by the peak method from free damping test. Accordingly, there was no difference due to identification methods, and both methods provided appropriate accuracy. The natural vibration mode obtained from the steady vibration test agreed with that obtained by the eigenvalue analysis. The dispersion of experimental values, which indicates the adaptation to mode circle method, became a scale indicating reliability of identified values. When the damping obtained by the half power method for the microtremors test is compared with that identified from the steady vibration test and free damping test, it is required to compare them at lower amplitude level region, considering that the amplitude level of microtremors test is very low. For the dynamic characteristics of the Tsurumi Tsubasa Bridge, it was found that it has lower natural frequency and higher modal damping compared with other cable stayed bridges with similar scale of span. 18 refs., 13 figs., 4 tabs.

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 subject to the Bridge-to-Bridge Act transmitting on the designated navigational frequency must conduct...

Damage Detection in Bridge Structure Using Vibration Data under Random Travelling Vehicle Loads

International Nuclear Information System (INIS)

Loh, C H; Hung, T Y; Chen, S F; Hsu, W T

2015-01-01

Due to the random nature of the road excitation and the inherent uncertainties in bridge-vehicle system, damage identification of bridge structure through continuous monitoring under operating situation become a challenge problem. Methods for system identification and damage detection of a continuous two-span concrete bridge structure in time domain is presented using interaction forces from random moving vehicles as excitation. The signals recorded in different locations of the instrumented bridge are mixed with signals from different internal and external (road roughness) vibration sources. The damage structure is also modelled as the stiffness reduction in one of the beam element. For the purpose of system identification and damage detection three different output-only modal analysis techniques are proposed: The covariance-driven stochastic subspace identification (SSI-COV), the blind source separation algorithms (called Second Order Blind Identification) and the multivariate AR model. The advantages and disadvantages of the three algorithms are discussed. Finally, the null-space damage index, subspace damage indices and mode shape slope change are used to detect and locate the damage. The proposed approaches has been tested in simulation and proved to be effective for structural health monitoring. (paper)

Investigation of aerodynamic stability by wind response observation during cantilever construction of the Ikara Ohashi bridge; Ikara Ohashi haridashi sekoji no kaze kansoku ni yoru taifu anteisei no kento

Energy Technology Data Exchange (ETDEWEB)

Ueno, K.; Mukai, H.; Takeda, T. [Kajima Corp., Tokyo (Japan)

1995-12-20

In order to ensure aerodynamic stability during cantilever construction of the Ikara Ohashi Bridge, wind response observation was carried out and discussions were given on the result. The Ikara Ohashi Bridge is a 5-span continuous PC cable-stayed bridge with the central span being a concrete bridge having a length of 260 m, which is the longest in Japan. The bridge was constructed using a method that main girders are extended from the central tower to the right and left sides while the girders are stayed by bracing cables. The bridge construction site is in an area which is often subjected to typhoons and gusts like seasonal winds in winter, hence a discussion on aerodynamic stability of the bridge especially during extension work was viewed as an important matter. In addition, the construction used two small-capacity cables spaced and bundled as the bracing material, which required verification on their aerodynamic stability. In order to identify vibration characteristics of the main girders and the central tower, wind response observation has been performed as soon as the construction was begun. As a result, the vibration characteristics of the main girders and the central tower were identified, and it was verified that vibration shape and dominant frequency can be evaluated properly by an intrinsic value analysis that uses a multi-material point frame model. Furthermore, effects of different vibration absorbing measures were compared, and the effective methods were adopted as the result. 4 refs., 12 figs.

Wind-induced cable vibrations and countermeasures of cables of PC cable-stayed bridge. PC syachokyo keburu no kaze ni yoru shindo to sono taisaku

Energy Technology Data Exchange (ETDEWEB)

Yoneda, M. (Kawada Industries Inc., Tokyo (Japan))

1994-05-01

In recent years, long span of cable-stayed bridges is remarkable. The wind-induced cable vibration called as line vibration and wake galloping was given as an important problem not only in the steel cable-stayed bridges but also in the PC cable-stayed bridges. The technical engineers in design of the cable-stayed bridges have many times to confront the problems on the vibration control of cables, it is considered that sufficient understand of the wind-induced vibration and countermeasures for cables of the PC cable-stayed bridges is necessary. Many reports on the countermeasure examples and trend of vibration control centred on cables of the cable-stayed bridges have been published. In this paper, the wind-induced vibration of cables in the cable-stayed bridges was reviewed, the examples of countermeasures of vibration control on cables in the PC cable-stayed bridges was mainly introduced. The remaining tasks and future prospects on vibration control of the PC cable-stayed bridges were described. 14 refs., 13 figs., 4 tabs.

Advance features in the SPAN and SPAN/XRF gamma ray and X ray spectrum analysis software

International Nuclear Information System (INIS)

Wang Liyu

1998-01-01

This paper describes the advanced techniques, integral peak background, experimental peak shape and complex peak shape, which have been used successfully in the software packages SPAN and SPAN/XRF to process gamma ray and X ray spectra from HPGe and Si(Li) detector. Main features of SPAN and SPAN/XRF are also described. The software runs on PC and has convenient graphical capabilities and a powerful user interface. (author)

Integration of computer imaging and sensor data for structural health monitoring of bridges

International Nuclear Information System (INIS)

Zaurin, R; Catbas, F N

2010-01-01

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

Design of bridges against large tectonic deformation

Science.gov (United States)

Anastasopoulos, I.; Gazetas, G.; Drosos, V.; Georgarakos, T.; Kourkoulis, R.

2008-12-01

The engineering community has devoted much effort to understanding the response of soil-structure systems to seismic ground motions, but little attention to the effects of an outcropping fault offset. The 1999 earthquakes of Turkey and Taiwan, offering a variety of case histories of structural damage due to faulting, have (re)fueled the interest on the subject. This paper presents a methodology for design of bridges against tectonic deformation. The problem is decoupled in two analysis steps: the first (at the local level) deals with the response of a single pier and its foundation to fault rupture propagating through the soil, and the superstructure is modeled in a simplified manner; and the second (at the global level) investigates detailed models of the superstructure subjected to the support (differential) displacements of Step 1. A parametric study investigates typical models of viaduct and overpass bridges, founded on piles or caissons. Fixed-head piled foundations are shown to be rather vulnerable to faulting-induced deformation. End-bearing piles in particular are unable to survive bedrock offsets exceeding 10 cm. Floating piles perform better, and if combined with hinged pile-to-cap connections, they could survive much larger offsets. Soil resilience is beneficial in reducing pile distress. Caisson foundations are almost invariably successful. Statically-indeterminate superstructures are quite vulnerable, while statically-determinate are insensitive (allowing differential displacements and rotations without suffering any distress). For large-span cantilever-construction bridges, where a statically determinate system is hardly an option, inserting resilient seismic isolation bearings is advantageous as long as ample seating can prevent the deck from falling off the supports. An actual application of the developed method is presented for a major bridge, demonstrating the feasibility of design against tectonic deformation.

Investigating extreme event loading on coastal bridges using wireless sensor technology

Science.gov (United States)

Gelineau, Douglas A.; Davis, Justin R.; Rice, Jennifer A.

2017-04-01

Coastal infrastructure, such as bridges, are susceptible to many forms of coastal hazards: particularly hurricane surge and wave loading. These two forms of loading can cause catastrophic damage to aging highway infrastructure. It is estimated that storm damage costs the United States about $50 Billion per year. In light of this, it is crucial that we understand the damaging forces placed on infrastructure during storm events so that we can develop safer and more resilient coastal structures. This paper presents the ongoing research to enable the efficient collection of extreme event loads acting on both the substructure and superstructure of low clearance, simple span, reinforced concrete bridges. Bridges of this type were commonly constructed during the 1950's and 60's and are particularly susceptible to deck unseating caused by hurricane surge and wave loading. The sensing technology used to capture this data must be ruggedized to survive in an extremely challenging environment, be designed to allow for redundancy in the event of sensors or other network components being lost in the storm, and be relatively low cost to allow for more bridges to be instrumented per storm event. The prototype system described in this paper includes wireless technology, rapid data transmission, and, for the sensors, self-contained power. While this specific application focuses on hurricane hazards, the framework can be extended to include other natural hazards.

FEATURES OF DESIGN OF TIED-ARCH BRIDGES WITH FLEXIBLE INCLINED SUSPENSION HANGERS

Directory of Open Access Journals (Sweden)

V. O. Samosvat

2017-10-01

Full Text Available Purpose. Investigation and analysis of the hanger arrangement and the structural stability of a Network arch bridge – a tied-arch bridge with inclined hangers that cross each other at least twice. It is also necessary to make a comparative analysis with other types of hanger arrangements. Methodology. The authors in their research investigated a large number of parameters to determine their influence in the force distribution in the arch. Eventually they determined optimal values for all parameters. These optimal values allowed developing a design guide that leads to optimal arch design. When solving this problem, the authors used three-dimensional finite element models and the objective was to determine the most suitable solution for a road bridge, with a span of 100 meters, consisting of two inclined steel arches, located on a road with two traffic lanes, subjected to medium traffic. The virtual prototype of the model is performed by finite element simulator Midas Civil. Findings. In this study, for the bridge deck, a concrete tie appears to be the best solution considering the structural behavior of network arches, but economic advantages caused by easier erection may lead to steel or a composite bridge deck as better alternatives. Design requirements and local conditions of each particular bridge project will decide the most economic deck design.Originality. To ensure passenger comfort and the stability and continuity of the track, deformations of bridges are constricted. A network arch is a stiff structure with small deflections and therefore suitable to comply with such demands even for high speed railway traffic.
A network arch bridge with a concrete tie usually saves more than half the steel required for tied arches with vertical hangers and concrete ties. Practical value. Following the study design advice given in this article leads to savings of about 60 % of structural steel compared with conventional tied arch bridges with

Myocardial Bridge

Science.gov (United States)

... Center > Myocardial Bridge Menu Topics Topics FAQs Myocardial Bridge En español Your heart is made of muscle, ... surface of the heart. What is a myocardial bridge? A myocardial bridge is a band of heart ...

Carbon paint anode for reinforced concrete bridges in coastal environments

Energy Technology Data Exchange (ETDEWEB)

Cramer, Stephen D.; Bullard, Sophie J.; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Russell, James H.; Cryer, C.B. (ODOT); Laylor, H.M. (ODOT)

2002-01-01

Solvent-based acrylic carbon paint anodes were installed on the north approach spans of the Yaquina Bay Bridge (Newport OR) in 1985. The anodes continue to perform satisfactorily after more than 15 years service. The anodes were inexpensive to apply and field repairs are easily made. Depolarization potentials are consistently above 100 mV with long-term current densities around 2 mA/m 2. Bond strength remains adequate, averaging 0.50 MPa (73 psi). Some deterioration of the anode-concrete interface has occurred in the form of cracks and about 4% of the bond strength measurements indicated low or no bond. Carbon anode consumption appears low. The dominant long-term anode reaction appears to be chlorine evolution, which results in limited further acidification of the anode-concrete interface. Chloride profiles were depressed compared to some other coastal bridges suggesting chloride extraction by the CP system. Further evidence of outward chloride migration was a flat chloride profile between the anode and the outer rebar.

Simulation of the Vacuum Assisted Resin Transfer Molding (VARTM) process and the development of light-weight composite bridging

Science.gov (United States)

Robinson, Marc J.

A continued desire for increased mobility in the aftermath of natural disasters, or on the battlefield, has lead to the need for improved light-weight bridging solutions. This research investigates the development of a carbon/epoxy composite bridging system to meet the needs for light-weight bridging. The research focuses on two main topics. The first topic is that of processing composite structures and the second is the design and testing of these structures. In recent years the Vacuum Assisted Resin Transfer Molding (VARTM) process has become recognized as a low-cost manufacturing alternative for large Fiber Reinforced Polymer (FRP) composite structures for civil, military, and aerospace applications. The success of the VARTM process (complete wet-out) is very sensitive to the resin injection strategy used and the proper placement of flow distribution materials and inlet and vacuum ports. Predicting the flow front pattern, the time required for infusing a part with resin, and the time required to bleed excess resin at the end of filling, is critical to ensure that the part will become completely impregnated and desired fiber volume fractions achieved prior to the resin gelling (initiation of cure). In order to eliminate costly trial and error experiments to determine the optimal infusion strategy, this research presents a simulation model which considers in-plane flow as well as flow through the thickness of the preform. In addition to resin filling, the current model is able to simulate the bleeding of resin at the end of filling to predict the required bleeding time to reach desired fiber volume fractions for the final part. In addition to processing, the second portion of the dissertation investigates the design and testing of composite bridge deck sections which also serve as short-span bridging for gaps up to 4 m in length. The research focuses on the design of a light-weight core material for bridge decking as well as proof loading of short-span bridge

Comparing Structural Identification Methodologies for Fatigue Life Prediction of a Highway Bridge

Directory of Open Access Journals (Sweden)

Sai G. S. Pai

2018-01-01

Full Text Available Accurate measurement-data interpretation leads to increased understanding of structural behavior and enhanced asset-management decision making. In this paper, four data-interpretation methodologies, residual minimization, traditional Bayesian model updating, modified Bayesian model updating (with an L∞-norm-based Gaussian likelihood function, and error-domain model falsification (EDMF, a method that rejects models that have unlikely differences between predictions and measurements, are compared. In the modified Bayesian model updating methodology, a correction is used in the likelihood function to account for the effect of a finite number of measurements on posterior probability–density functions. The application of these data-interpretation methodologies for condition assessment and fatigue life prediction is illustrated on a highway steel–concrete composite bridge having four spans with a total length of 219 m. A detailed 3D finite-element plate and beam model of the bridge and weigh-in-motion data are used to obtain the time–stress response at a fatigue critical location along the bridge span. The time–stress response, presented as a histogram, is compared to measured strain responses either to update prior knowledge of model parameters using residual minimization and Bayesian methodologies or to obtain candidate model instances using the EDMF methodology. It is concluded that the EDMF and modified Bayesian model updating methodologies provide robust prediction of fatigue life compared with residual minimization and traditional Bayesian model updating in the presence of correlated non-Gaussian uncertainty. EDMF has additional advantages due to ease of understanding and applicability for practicing engineers, thus enabling incremental asset-management decision making over long service lives. Finally, parallel implementations of EDMF using grid sampling have lower computations times than implementations using adaptive sampling.

Erection of the Meiko-Central bridge; Meiko chuo ohashi no kasetsu

Energy Technology Data Exchange (ETDEWEB)

Kaneda, S.; Nishikawa, K.; Nagai, Y.; Ishihara, S.; Tsunekawa, M.; Yoshino, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1997-10-20

This is a 1170m-long triple-span continuous steel cable-stayed bridge with the central span measuring 590m, built to traverse Nagoya Port as part of the Isewangan highway. The 190m-high main towers are A-shaped, and have an octagonal cross section to stay stable against winds. The joints were designed to be welded mainly on the spot so as not to affect the surrounding landscape, and in this welding process the achievement of prescribed accuracy was the important technological task. The main girder was a 37m-wide multi-chamber/single-box type, and the steel stabs were installed by on-site welding. Since the erection was carried out above the ship course, a method was used in which the main girder was hung over with the cable stretched long, which demanded constant prudence to assure accuracy throughout the work. The cable is a 17-stage 2-face multi-fan type, a semi-parallel wire strand coated with polyethylene and white fluoroethylene resin. As for accuracy management for erection, it was accomplished by adjusting the amount of shim introduced into each of the four cables every time one stage of cable was erected for the side span and central span. Every accuracy management requirement met the target value with an adequate margin. 6 refs., 10 figs., 4 tabs.

Codimension-two bifurcation of axial loaded beam bridge subjected to an infinite series of moving loads

International Nuclear Information System (INIS)

Yang Xin-Wei; Tian Rui-Lan; Li Hai-Tao

2013-01-01

A novel model is proposed which comprises of a beam bridge subjected to an axial load and an infinite series of moving loads. The moving loads, whose distance between the neighbouring ones is the length of the beam bridge, coupled with the axial force can lead the vibration of the beam bridge to codimension-two bifurcation. Of particular concern is a parameter regime where non-persistence set regions undergo a transition to persistence regions. The boundary of each stripe represents a bifurcation which can drive the system off a kind of dynamics and jump to another one, causing damage due to the resulting amplitude jumps. The Galerkin method, averaging method, invertible linear transformation, and near identity nonlinear transformations are used to obtain the universal unfolding for the codimension-two bifurcation of the mid-span deflection. The efficiency of the theoretical analysis obtained in this paper is verified via numerical simulations. (general)

CONSTRUCTION THE BRIDGE PIER AS PARAMETRIC OBJECT USING AUTODESK REVIT

Directory of Open Access Journals (Sweden)

K. I. Hladka

2017-08-01

Full Text Available Purpose. The work is aimed to solve the following tasks: 1 to investigate the possibilities of Autodesk Revit to create parametric objects; 2 to create an information model of the bridge pier with the possibility of changing the model size without changing geometry of the object; 3 to trace the complexity and feasibility of using parametric models when designing the elements of bridges. Methodology. The studies were carried out using spatial modeling in the Autodesk Revit system. The ratio of the parameters of the object was set, the relationship between individual geometric elements was determined and the changes that were made to the model with the change of the specified parameters were checked. Findings. Support model of two types has been created: for railway bridges and for road bridges. Both types of models change the dimensions and the number of constituent elements in accordance with the entered parameters. The performed work confirms the possibility of creating information parametric models of complex form and the expediency of using them in the design of bridges and not only. Originality. Creation of information models is a modern and relevant topic. But both in the literature and in Internet resources, parametrization is considered on the example of simple objects. The model proposed in the article consists of several dependent geometric bodies; therefore, it opens the topic of objects parameterization more fully and in detail, in comparison with the existing sources. As for the creation of parametric models of the bridge elements - such information is not found in the literature, that is, it is proposed for the first time. Practical value. Parametrization of spatial models allows significantly to accelerate and simplify the process of designing any objects due to the use of typical parametric models in many projects. Especially it concerns the design of bridges, since the standard elements for them, such as support or span are not

Design and fabrication of single-crystal GaN nano-bridge on homogeneous substrate for nanoindentation

Science.gov (United States)

Hung, Shang-Chao

2014-12-01

This study reports a simple method to design and fabricate a freestanding GaN nano-bridge over a homogeneous short column as supporting leg. Test samples were fabricated from MOCVD-grown single-crystal GaN films over sapphire substrate using a FIB milling to leave freestanding short spans. We also investigated the nanoindentation characteristics and the corresponding nanoscopic mechanism of the GaN nano-bridge and its short column with a conical indenter inside transmission electron microscopy. The stress-strain mechanical properties and Young's modulus have also been examined and calculated as 108 GPa ± 4.8 % by the strain energy method. The significant slope switch of the L- D curve corresponds to the transition from the single-point bending indentation to the surface stretching indentation and has been interpreted with the evolution of TEM images. This freestanding fabrication and test have key advantages to characterize nanoscale behavior of one-dimensional bridge structure and greater ease of sample preparation over other micro-fabrication techniques.

Determinantal spanning forests on planar graphs

OpenAIRE

Kenyon, Richard

2017-01-01

We generalize the uniform spanning tree to construct a family of determinantal measures on essential spanning forests on periodic planar graphs in which every component tree is bi-infinite. Like the uniform spanning tree, these measures arise naturally from the laplacian on the graph. More generally these results hold for the "massive" laplacian determinant which counts rooted spanning forests with weight $M$ per finite component. These measures typically have a form of conformal invariance, ...

A FULL-SCALE MEASUREMENT OF WIND ACTIONS AND EFFECTS ON A SEA-CROSSING BRIDGE

Directory of Open Access Journals (Sweden)

Yi Zhou

2017-10-01

Full Text Available Wind loading is critical for the large-span and light-weight structures, and field measurement is the most effective way to evaluate the wind resistance performance of a specific structure. This study investigates the wind characteristics and wind-induced vibration on a sea-crossing bridge in China, namely Donghai Bridge, based on up to six years of monitoring data. It is found that: (1 there exists obvious discrepancy between the measured wind field parameters and the values suggested by the design code; and the wind records at the bridge site is easily interfered by the bridge structure itself, which should be considered in interpreting the measurements and designing structural health monitoring systems (SHMS; (2 for strong winds with high non-stationarity, a shorter averaging time than 10-min is preferable to obtain more stable turbulent wind characteristics; (3 the root mean square (RMS of the wind-induced acceleration of the girder may increase in an approximately quadratic curve relationship with the mean wind speed; and (4 compared to traffic load, the wind dominates the girder’s lateral vibration amplitude, while the heavy-load traffic might exert more influence on the girder’s vertical and torsional vibrations than the high winds. This study provides field evidence for the wind-resistant design and evaluation of bridges in similar operational conditions.

Thermodynamics and life span estimation

International Nuclear Information System (INIS)

Kuddusi, Lütfullah

2015-01-01

In this study, the life span of people living in seven regions of Turkey is estimated by applying the first and second laws of thermodynamics to the human body. The people living in different regions of Turkey have different food habits. The first and second laws of thermodynamics are used to calculate the entropy generation rate per unit mass of a human due to the food habits. The lifetime entropy generation per unit mass of a human was previously found statistically. The two entropy generations, lifetime entropy generation and entropy generation rate, enable one to determine the life span of people living in seven regions of Turkey with different food habits. In order to estimate the life span, some statistics of Turkish Statistical Institute regarding the food habits of the people living in seven regions of Turkey are used. The life spans of people that live in Central Anatolia and Eastern Anatolia regions are the longest and shortest, respectively. Generally, the following inequality regarding the life span of people living in seven regions of Turkey is found: Eastern Anatolia < Southeast Anatolia < Black Sea < Mediterranean < Marmara < Aegean < Central Anatolia. - Highlights: • The first and second laws of thermodynamics are applied to the human body. • The entropy generation of a human due to his food habits is determined. • The life span of Turks is estimated by using the entropy generation method. • Food habits of a human have effect on his life span

Reading Ability and Memory Span: Long-Term Memory Contributions to Span for Good and Poor Readers.

Science.gov (United States)

McDougall, Sine J. P.; Donohoe, Rachael

2002-01-01

Investigates the extent to which differences in memory span for good and poor readers can be explained by differences in a long-term memory component to span as well as by differences in short-term memory processes. Discusses the nature of the interrelationships between memory span, reading and measures of phonological awareness. (SG)

Life Span Developmental Approach

Directory of Open Access Journals (Sweden)

Ali Eryilmaz

2011-03-01

Full Text Available The Life Span Developmental Approach examines development of individuals which occurs from birth to death. Life span developmental approach is a multi-disciplinary approach related with disciplines like psychology, psychiatry, sociology, anthropology and geriatrics that indicates the fact that development is not completed in adulthood, it continues during the life course. Development is a complex process that consists of dying and death. This approach carefully investigates the development of individuals with respect to developmental stages. This developmental approach suggests that scientific disciplines should not explain developmental facts only with age changes. Along with aging, cognitive, biological, and socioemotional development throughout life should also be considered to provide a reasonable and acceptable context, guideposts, and reasonable expectations for the person. There are three important subjects whom life span developmental approach deals with. These are nature vs nurture, continuity vs discontinuity, and change vs stability. Researchers using life span developmental approach gather and produce knowledge on these three most important domains of individual development with their unique scientific methodology.

A 2.5-dimensional method for the prediction of structure-borne low-frequency noise from concrete rail transit bridges.

Science.gov (United States)

Li, Qi; Song, Xiaodong; Wu, Dingjun

2014-05-01

Predicting structure-borne noise from bridges subjected to moving trains using the three-dimensional (3D) boundary element method (BEM) is a time consuming process. This paper presents a two-and-a-half dimensional (2.5D) BEM-based procedure for simulating bridge-borne low-frequency noise with higher efficiency, yet no loss of accuracy. The two-dimensional (2D) BEM of a bridge with a constant cross section along the track direction is adopted to calculate the spatial modal acoustic transfer vectors (MATVs) of the bridge using the space-wave number transforms of its 3D modal shapes. The MATVs calculated using the 2.5D method are then validated by those computed using the 3D BEM. The bridge-borne noise is finally obtained through the MATVs and modal coordinate responses of the bridge, considering time-varying vehicle-track-bridge dynamic interaction. The presented procedure is applied to predict the sound pressure radiating from a U-shaped concrete bridge, and the computed results are compared with those obtained from field tests on Shanghai rail transit line 8. The numerical results match well with the measured results in both time and frequency domains at near-field points. Nevertheless, the computed results are smaller than the measured ones for far-field points, mainly due to the sound radiation from adjacent spans neglected in the current model.

Full-scale measurements and system identification on Sutong cable-stayed bridge during Typhoon Fung-Wong.

Science.gov (United States)

Wang, Hao; Tao, Tianyou; Guo, Tong; Li, Jian; Li, Aiqun

2014-01-01

The structural health monitoring system (SHMS) provides an effective tool to conduct full-scale measurements on existing bridges for essential research on bridge wind engineering. In July 2008, Typhoon Fung-Wong lashed China and hit Sutong cable-stayed bridge (SCB) in China. During typhoon period, full-scale measurements were conducted to record the wind data and the structural vibration responses were collected by the SHMS installed on SCB. Based on the statistical method and the spectral analysis technique, the measured data are analyzed to obtain the typical parameters and characteristics. Furthermore, this paper analyzed the measured structural vibration responses and indicated the vibration characteristics of the stay cable and the deck, the relationship between structural vibrations and wind speed, the comparison of upstream and downstream cable vibrations, the effectiveness of cable dampers, and so forth. Considering the significance of damping ratio in vibration mitigation, the modal damping ratios of the SCB are identified based on the Hilbert-Huang transform (HHT) combined with the random decrement technique (RDT). The analysis results can be used to validate the current dynamic characteristic analysis methods, buffeting calculation methods, and wind tunnel test results of the long-span cable-stayed bridges.

Full-Scale Measurements and System Identification on Sutong Cable-Stayed Bridge during Typhoon Fung-Wong

Directory of Open Access Journals (Sweden)

Hao Wang

2014-01-01

Full Text Available The structural health monitoring system (SHMS provides an effective tool to conduct full-scale measurements on existing bridges for essential research on bridge wind engineering. In July 2008, Typhoon Fung-Wong lashed China and hit Sutong cable-stayed bridge (SCB in China. During typhoon period, full-scale measurements were conducted to record the wind data and the structural vibration responses were collected by the SHMS installed on SCB. Based on the statistical method and the spectral analysis technique, the measured data are analyzed to obtain the typical parameters and characteristics. Furthermore, this paper analyzed the measured structural vibration responses and indicated the vibration characteristics of the stay cable and the deck, the relationship between structural vibrations and wind speed, the comparison of upstream and downstream cable vibrations, the effectiveness of cable dampers, and so forth. Considering the significance of damping ratio in vibration mitigation, the modal damping ratios of the SCB are identified based on the Hilbert-Huang transform (HHT combined with the random decrement technique (RDT. The analysis results can be used to validate the current dynamic characteristic analysis methods, buffeting calculation methods, and wind tunnel test results of the long-span cable-stayed bridges.

Assessment of bridge abutment scour and sediment transport under various flow conditions

Science.gov (United States)

Gilja, Gordon; Valyrakis, Manousos; Michalis, Panagiotis; Bekić, Damir; Kuspilić, Neven; McKeogh, Eamon

2017-04-01

Safety of bridges over watercourses can be compromised by flow characteristics and bridge hydraulics. Scour process around bridge foundations can develop rapidly during low-recurrence interval floods when structural elements are exposed to increased flows. Variations in riverbed geometry, as a result of sediment removal and deposition processes, can increase flood-induced hazard at bridge sites with catastrophic failures and destructive consequences for civil infrastructure. The quantification of flood induced hazard on bridge safety generally involves coupled hydrodynamic and sediment transport models (i.e. 2D numerical or physical models) for a range of hydrological events covering both high and low flows. Modelled boundary conditions are usually estimated for their probability of occurrence using frequency analysis of long-term recordings at gauging stations. At smaller rivers gauging station records are scarce, especially in upper courses of rivers where weirs, drops and rapids are common elements of river bathymetry. As a result, boundary conditions that accurately represent flow patterns on modelled river reach cannot be often reliably acquired. Sediment transport process is also more complicated to describe due to its complexity and dependence to local flow field making scour hazard assessment a particularly challenging issue. This study investigates the influence of flow characteristics to the development of scour and sedimentation processes around bridge abutments of a single span masonry arch bridge in south Ireland. The impact of downstream weirs on bridge hydraulics through variation of downstream model domain type is also considered in this study. The numerical model is established based on detailed bathymetry data surveyed along a rectangular grid of 50cm spacing. Acquired data also consist of riverbed morphology and water level variations which are monitored continuously on bridge site. The obtained data are then used to compare and calibrate

Probability Based Evaluation of Vehicular Bridge Load using Weigh-in-Motion Data

Directory of Open Access Journals (Sweden)

Widi Nugraha

2016-02-01

Full Text Available Load and Resistance Factored Design (LRFD method for designing bridge in Indonesia have been implemented for more than 25 years. LRFD method treating loads and strengths variables as random variables with specific safety factors for different loads and strengths variables type. The nominal loads, load factors, reduction factors, and other criteria for bridge design code can be determined to meet the reliability criteria. Statistical data of weigh-in-motion (WIM vehicular loads measurement in Northern Java highway, Cikampek - Pamanukan, West Java (2011, used in as statistical loads variable. A 25 m simple span bridge with reinforced concrete T-girder is used as a model for structural analysis due to WIM measured and nominal vehicular load based on RSNI T-02-2005, with applied bending moment of girder as the output. The distribution fitting result of applied bending moment due to WIM measured vehicular loads is lognormal. The maximum bending moment due to RSNI T-02-2005 nominal vehicular load is 842.45 kN-m and has probability of exceedance of 5x10-5. It can be concluded, for this study, that the bridge designed using RSNI T-02-2005 is safely designed, since it has reliability index, β of 5.02, higher than target reliability, β ranging from 3.50 or 3.72.

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....

Ground penetrating radar utilization in exploring inadequate concrete covers in a new bridge deck

Directory of Open Access Journals (Sweden)

Md. Istiaque Hasan

2014-01-01

Full Text Available The reinforced concrete cast in place four span deck of a concrete bridge near Roanoke, Texas, was recently completed. Due to possible construction errors, it was suspected that the concrete covers in the deck did not conform to drawings and specifications. A full scale non-destructive evaluation of the concrete covers was carried out using ground penetrating radar (GPR equipment. Cover values were determined from the radargram generated from the scan. The estimated covers were plotted on contour maps. Migration data can substitute the drilling based ground truth data without compromising the concrete cover estimations, except for areas with very high cover values. Areas with high water content may result in inaccurate concrete dielectric constants. Based on the results, significant retrofitting of the bridge deck, such as additional overlay, was recommended.

Realistic modelling of the effects of asynchronous motion at the base of bridge piers

International Nuclear Information System (INIS)

Romanelli, F.; Panza, G.F.; Vaccari, F.

2002-11-01

Frequently long-span bridges provide deep valley crossings, which require special consideration due to the possibility of local amplification of the ground motion as a consequence of topographical irregularities and local soil conditions. This does in fact cause locally enhanced seismic input with the possibility for the bridge piers to respond asynchronously. This introduces special design requirements so that possible out-of-phase ground displacements and the associated large relative displacements of adjacent piers can be accommodated without excessive damage. Assessment of the local variability of the ground motion due to local lateral heterogeneities and to attenuation properties is thus crucial toward the realistic definition of the asynchronous motion at the base of the bridge piers. We illustrate the work done in the framework of a large international cooperation to assess the importance of non-synchronous seismic excitation of long structures. To accomplish this task we compute complete synthetic accelerograms using as input a set of parameters that describes, to the best of our knowledge, the geological structure and seismotectonic setting of the investigated area. (author)

Army ants dynamically adjust living bridges in response to a cost-benefit trade-off.

Science.gov (United States)

Reid, Chris R; Lutz, Matthew J; Powell, Scott; Kao, Albert B; Couzin, Iain D; Garnier, Simon

2015-12-08

The ability of individual animals to create functional structures by joining together is rare and confined to the social insects. Army ants (Eciton) form collective assemblages out of their own bodies to perform a variety of functions that benefit the entire colony. Here we examine ‟bridges" of linked individuals that are constructed to span gaps in the colony's foraging trail. How these living structures adjust themselves to varied and changing conditions remains poorly understood. Our field experiments show that the ants continuously modify their bridges, such that these structures lengthen, widen, and change position in response to traffic levels and environmental geometry. Ants initiate bridges where their path deviates from their incoming direction and move the bridges over time to create shortcuts over large gaps. The final position of the structure depended on the intensity of the traffic and the extent of path deviation and was influenced by a cost-benefit trade-off at the colony level, where the benefit of increased foraging trail efficiency was balanced by the cost of removing workers from the foraging pool to form the structure. To examine this trade-off, we quantified the geometric relationship between costs and benefits revealed by our experiments. We then constructed a model to determine the bridge location that maximized foraging rate, which qualitatively matched the observed movement of bridges. Our results highlight how animal self-assemblages can be dynamically modified in response to a group-level cost-benefit trade-off, without any individual unit's having information on global benefits or costs.

Numerical Analysis on Variation of Dynamic Response of Girder Bridges with Torsional Reinforcement Panels

Directory of Open Access Journals (Sweden)

Kang Jae-Yoon

2015-01-01

Full Text Available The dynamic flexural behaviour of the railway bridge is influenced by its torsional behaviour. Especially, in the case of girder railway bridges, the dynamic response tends to amplify when the natural frequency in flexure (1st vibration mode is close to that in torsion (2nd vibration mode. In order to prevent such situation, it is necessary to adopt a flexural-to-torsional natural frequency ratio larger than 120%. This study proposes a solution shifting the natural frequency in torsion to high frequency range and restraining torsion by installing concrete panels on the bottom flange of the girder so as to prevent the superposition of the responses in the girder bridge. The applicability of this solution is examined by finite element analysis of the shift of the torsional natural frequency and change in the dynamic response according to the installation of the concrete panels. The analytical results for a 30 m-span girder railway bridge indicate that installing the concrete panels increases the natural frequency in torsion by restraining the torsional behaviour and reduces also the overall dynamic response. It is seen that the installation of 100 mm-thick concrete panels along a section of 4 m at both extremities of the girder can reduce the dynamic response by more than 30%.

Numerical Simulation of Vertical Random Vibration of Train-Slab Track-Bridge Interaction System by PEM

Directory of Open Access Journals (Sweden)

Zhi-ping Zeng

2014-01-01

Full Text Available The paper describes the numerical simulation of the vertical random vibration of train-slab track-bridge interaction system by means of finite element method and pseudoexcitation method. Each vehicle is modeled as four-wheelset mass-spring-damper system with two-layer suspension systems. The rail, slab, and bridge girder are modeled by three-layer elastic Bernoulli-Euler beams connected with each other by spring and damper elements. The equations of motion for the entire system are derived according to energy principle. By regarding rail irregularity as a series of multipoint, different-phase random excitations, the random load vectors of the equations of motion are obtained by pseudoexcitation method. Taking a nine-span simply supported beam bridge traveled by a train consisting of 8 vehicles as an example, the vertical random vibration responses of the system are investigated. Firstly, the suitable number of discrete frequencies of rail irregularity is obtained by numerical experimentations. Secondly, the reliability and efficiency of pseudoexcitation method are verified through comparison with Monte Carlo method. Thirdly, the random vibration characteristics of train-slab track-bridge interaction system are analyzed by pseudoexcitation method. Finally, applying the 3σ rule for Gaussian stochastic process, the maximum responses of train-slab track-bridge interaction system with respect to various train speeds are studied.

Rating of Dynamic Coefficient for Simple Beam Bridge Design on High-Speed Railways

Science.gov (United States)

Diachenko, Leonid; Benin, Andrey; Smirnov, Vladimir; Diachenko, Anastasia

2018-06-01

The aim of the work is to improve the methodology for the dynamic computation of simple beam spans during the impact of high-speed trains. Mathematical simulation utilizing numerical and analytical methods of structural mechanics is used in the research. The article analyses parameters of the effect of high-speed trains on simple beam spanning bridge structures and suggests a technique of determining of the dynamic index to the live load. Reliability of the proposed methodology is confirmed by results of numerical simulation of high-speed train passage over spans with different speeds. The proposed algorithm of dynamic computation is based on a connection between maximum acceleration of the span in the resonance mode of vibrations and the main factors of stress-strain state. The methodology allows determining maximum and also minimum values of the main efforts in the construction that makes possible to perform endurance tests. It is noted that dynamic additions for the components of the stress-strain state (bending moments, transverse force and vertical deflections) are different. This condition determines the necessity for differentiated approach to evaluation of dynamic coefficients performing design verification of I and II groups of limiting state. The practical importance: the methodology of determining the dynamic coefficients allows making dynamic calculation and determining the main efforts in split beam spans without numerical simulation and direct dynamic analysis that significantly reduces the labour costs for design.

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...

Working memory and inhibitory control across the life span: Intrusion errors in the Reading Span Test.

Science.gov (United States)

Robert, Christelle; Borella, Erika; Fagot, Delphine; Lecerf, Thierry; de Ribaupierre, Anik

2009-04-01

The aim of this study was to examine to what extent inhibitory control and working memory capacity are related across the life span. Intrusion errors committed by children and younger and older adults were investigated in two versions of the Reading Span Test. In Experiment 1, a mixed Reading Span Test with items of various list lengths was administered. Older adults and children recalled fewer correct words and produced more intrusions than did young adults. Also, age-related differences were found in the type of intrusions committed. In Experiment 2, an adaptive Reading Span Test was administered, in which the list length of items was adapted to each individual's working memory capacity. Age groups differed neither on correct recall nor on the rate of intrusions, but they differed on the type of intrusions. Altogether, these findings indicate that the availability of attentional resources influences the efficiency of inhibition across the life span.

Demonstration Assessment of Light-Emitting Diode (LED) Roadway Lighting, I-35W Bridge, Minneapolis, Minnesota, Phase I Report

Energy Technology Data Exchange (ETDEWEB)

Kinzey, B. R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Myer, M. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2009-08-01

On the I-35W Bridge in Minneapolis, Minnesota, the GATEWAY program conducted a two-phase demonstration of LED roadway lighting on the main span, which is one of the country's oldest continuously operated exterior LED lighting installations. The Phase I report provides an overview of initial project results including lighting performance, economic performance, and potential energy savings.

Implementation of Bridge Management System on Interurban Bridge in Maluku Province

Directory of Open Access Journals (Sweden)

Erwin Marasabessy

2015-05-01

Full Text Available Bridges as transport infrastructures play a vital role in smoothing traffic flows. The success of a bridge in playing its role and serving its function depends on its management. The Directorate General of Highways of the Ministry of Public Work has used a system to manage bridges known as the Bridge Management System (BMS. The system allows a systematic plan and provides a uniform procedure for all bridge operation activities on the national and provincial level. Data from Implementation Agency of National Inter-Urban Roads of Area IX, Northern Maluku in 2011 indicates that the total length of national roads in Maluku Province is 15,238.01 M, with a total of 562 bridges. In Ambon Island, especially, there are 52 bridges totaling 1,176.25 m in length. The study was conducted at several inter-urban bridges in Maluku Province of Ambon Island: Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari and Wai Tua bridges. Assessment of bridge structure conditions was conducted visually to determine the conditions of the existing bridges comprehensively by referring to the Bridge Management System (BMS complemented with a computer-based Bridge Management Information System (BMIS. Condition scores for the five bridges—Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua, according to Bridge Management System, are 2, 1, 2, 1, and 2 respectively. The scores of the five bridges indicate that their physical condition can be categorized as good or with minor defects. Based on technical screening, the proposed treatment for Wai Batu Merah, Wai Ruhu, Wai Lawa, dan Wai Tua bridges is the rehabilitation of their sub-elements. As for the Wai Yari Bridge, the treatment will be maintained regularly. The defect repair costs are IDR 149,138,238.00, IDR 81,048,000.00, IDR 174,579,106.10, IDR 79,233,324.01 and IDR 238,323,258.60 for Wai Batu, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua Bridges, respectively.

Life Span Developmental Approach

OpenAIRE

Ali Eryilmaz

2011-01-01

The Life Span Developmental Approach examines development of individuals which occurs from birth to death. Life span developmental approach is a multi-disciplinary approach related with disciplines like psychology, psychiatry, sociology, anthropology and geriatrics that indicates the fact that development is not completed in adulthood, it continues during the life course. Development is a complex process that consists of dying and death. This approach carefully investigates the development of...

Steel bridges structural health monitoring based on operational modal analysis accommodating evaluation of uncertainty

Directory of Open Access Journals (Sweden)

Saeid Jahan

2017-11-01

Full Text Available Structural damage detection is based on that the dynamic response of structure will change because of damage. Hence, it is possible to estimate the location and severity of damage leads to changes in the dynamic response before and after the damage. In this study, the genetic fuzzy system has been used for bridge structural health monitoring. A key objective of using genetic algorithms is to automate the design of fuzzy systems. This method is used for damage detection of a single span railway bridge with steel girders and a concrete bridge. For studying damage detection, the numerical models of these two bridges are built with the measured dynamic characteristics. A three-dimensional finite element model and a single two-dimensional girders model of the bridge have been constructed to study usefulness of the genetic fuzzy system for damage detection and the effectiveness of modeling. After analysis to control the uncertainties, the measured frequencies are contaminated with some noise and the effect of that on the achievement of damage detection method is evaluated. The present study has shown that the natural frequency has appropriate sensitivity to different damage scenarios in the structure. In addition, the natural frequency in comparison with other modal parameters, is less affected by random noise. Increasing the number of measurement modes and using torsional modes, will lead to an accurate damage diagnosis even in symmetrical structures.

Long-term bridge performance high priority bridge performance issues.

Science.gov (United States)

2014-10-01

Bridge performance is a multifaceted issue involving performance of materials and protective systems, : performance of individual components of the bridge, and performance of the structural system as a whole. The : Long-Term Bridge Performance (LTBP)...

Deflection control system for prestressed concrete bridges by CCD camera. CCD camera ni yoru prestressed concrete kyo no tawami kanri system

Energy Technology Data Exchange (ETDEWEB)

Noda, Y.; Nakayama, Y.; Arai, T. (Kawada Construction Co. Ltd., Tokyo (Japan))

1994-03-15

For the long-span prestressed concrete bridge (continuous box girder and cable stayed bridge), the design and construction control becomes increasingly complicated as construction proceeds because of its cyclic works. This paper describes the method and operation of an automatic levelling module using CCD camera and the experimental results by this system. For this automatic levelling system, the altitude can be automatically measured by measuring the center location of gravity of the target on the bridge surface using CCD camera. The present deflection control system developed compares the measured value by the automatic levelling system with the design value obtained by the design calculation system, and manages them. From the real-time continuous measurement for the long term, in which the CCD camera was set on the bridge surface, it was found that the stable measurement accuracy can be obtained. Successful application of this system demonstrates that the system is an effective and efficient construction aid. 11 refs., 19 figs., 1 tab.

47 CFR 80.163 - Operator requirements of the Bridge-to-Bridge Act.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Operator requirements of the Bridge-to-Bridge... Requirements § 80.163 Operator requirements of the Bridge-to-Bridge Act. Each ship subject to the Bridge-to-Bridge Act must have on board a radio operator who holds a restricted radiotelephone operator permit or...

Bridge health monitoring metrics : updating the bridge deficiency algorithm.

Science.gov (United States)

2009-10-01

As part of its bridge management system, the Alabama Department of Transportation (ALDOT) must decide how best to spend its bridge replacement funds. In making these decisions, ALDOT managers currently use a deficiency algorithm to rank bridges that ...

47 CFR 80.309 - Watch required by the Bridge-to-Bridge Act.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Watch required by the Bridge-to-Bridge Act. 80... Safety Watches § 80.309 Watch required by the Bridge-to-Bridge Act. In addition to the watch requirement contained in § 80.148, all vessels subject to the Bridge-to-Bridge Act must keep a watch on the designated...

New Quality Control Algorithm Based on GNSS Sensing Data for a Bridge Health Monitoring System

Directory of Open Access Journals (Sweden)

Jae Kang Lee

2016-05-01

Full Text Available This research introduces an improvement plan for the reliability of Global Navigation Satellite System (GNSS positioning solutions. It should be considered the most suitable methodology in terms of the adjustment and positioning of GNSS in order to maximize the utilization of GNSS applications. Though various studies have been conducted with regards to Bridge Health Monitoring System (BHMS based on GNSS, the outliers which depend on the signal reception environment could not be considered until now. Since these outliers may be connected to GNSS data collected from major bridge members, which can reduce the reliability of a whole monitoring system through the delivery of false information, they should be detected and eliminated in the previous adjustment stage. In this investigation, the Detection, Identification, Adaptation (DIA technique was applied and implemented through an algorithm. Moreover, it can be directly applied to GNSS data collected from long span cable stayed bridges and most of outliers were efficiently detected and eliminated simultaneously. By these effects, the reliability of GNSS should be enormously improved. Improvement on GNSS positioning accuracy is directly linked to the safety of bridges itself, and at the same time, the reliability of monitoring systems in terms of the system operation can also be increased.

Field performance of timber bridges. 7, Connell Lake stress-laminated deck bridge

Science.gov (United States)

L. E. Hislop; M. A. Ritter

The Connell Lake bridge was constructed in early 1991 on the Tongass National Forest, Alaska, as a demonstration bridge under the Timber Bridge Initiative. The bridge is a stress-laminated deck structure with an approximate 36-ft length and 18-ft width and is the first known stress-laminated timber bridge constructed in Alaska. Performance of the bridge was monitored...

Seismic performance evaluation of an historical concrete deck arch bridge using survey and drawing of the damages, in situ tests, dynamic identification and pushover analysis

Science.gov (United States)

Bergamo, Otello; Russo, Eleonora; Lodolo, Fabio

2017-07-01

The paper describes the performance evaluation of a retrofit historical multi-span (RC) deck arch bridge analyzed with in situ tests, dynamic identification and FEM analysis. The peculiarity of this case study lies in the structural typology of "San Felice" bridge, an historical concrete arch bridge built in the early 20th century, a quite uncommon feature in Italy. The preservation and retrofit of historic cultural heritage and infrastructures has been carefully analyzed in the international codes governing seismic response. A complete survey of the bridge was carried out prior to sketching a drawing of the existing bridge. Subsequently, the study consists in four steps: material investigation and dynamic vibration tests, FEM analysis and calibration, retrofit assessment, pushover analysis. The aim is to define an innovative approach to calibrate the FEM analysis through modern experimental investigations capable of taking structural deterioration into account, and to offer an appropriate and cost-effective retrofitting strategy.

Repeated multibeam echosounder hydrographic surveys of 15 selected bridge crossings along the Missouri River from Niobrara to Rulo, Nebraska, during the flood of 2011

Science.gov (United States)

Dietsch, Benjamin J.; Densmore, Brenda K.; Strauch, Kellan R.

2014-01-01

In 2011, unprecedented flooding in the Missouri River prompted transportation agencies to increase the frequency of monitoring riverbed elevations near bridges that cross the Missouri River. Hydrographic surveys were completed in cooperation with the Nebraska Department of Roads, using a multibeam echosounder at 15 highway bridges spanning the Missouri River from Niobrara to Rulo, Nebraska during and after the extreme 2011 flood. Evidence of bed elevation change near bridge piers was documented. The greatest amount of bed elevation change during the 2011 flood documented for this study occurred at the Burt County Missouri River Bridge at Decatur, Nebraska, where scour of about 45 feet, from before flooding, occurred between a bridge abutment and pier. Of the remaining sites, highway bridges where bed elevation change near piers appeared to have exceeded 10 feet include the Abraham Lincoln Memorial Bridge at Blair, Nebr., Bellevue Bridge at Bellevue, Nebr., and Nebraska City Bridge at Nebraska City, Nebr. Hydrographic surveys at 14 of the 15 sites were completed in mid-July and again in early October or late-November 2011. Near three of the bridges, the bed elevation of locations surveyed in July increased by more than 10 feet, on average, by late October or early November 2011. Bed elevations increased between 1 and 10 feet, on average, near six bridges. Near the remaining four bridges, bed elevations decreased between 1 and 4 feet, on average, from July to late October or early November.

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

International Nuclear Information System (INIS)

Huffman, S.; Bagchi, A.; Mufti, A.; Neale, K.; Sargent, D.; Rivera, E.

2006-01-01

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

Classical and Modern Design Solutions in Conceptual Design of a Pedestrian Bridge over Vistula River in Cracow

Science.gov (United States)

Ryż, Karol; Pańtak, Marek

2017-10-01

In the paper the design concept of the steel pedestrian bridge over Vistula river in Cracow, Poland has been characterised. The footbridge was designed as a truss structure with steel pipes, Warren truss configuration, arched bottom chord and spans 15.5+120.0+15.5 m. Intensive tourist traffic around the Wawel Castle in Cracow, directed towards the historic Kazimierz district, Wawel Hill and the Old Town Market Place requires the creation of a bridge structure over the Vistula River that will meet both the communication and recreation functions. An additional aim was to design a structure which architectural form will not unduly and negatively interfere in the environment and will join the technical capabilities of the XXI century with the charm of nearby historic buildings.

Age Differences in Memory Span

Science.gov (United States)

Chi, Michelene T. H.

1977-01-01

Three experiments were conducted to determine processes underlying age differences in the level of recall in a memory-span task. Five-year-olds recalled fewer items than adults in memory-span tasks involving both familiar and unfamiliar faces, even though the use of rehearsal and recoding strategies was minimized for adults. (MS)

On the size of monotone span programs

NARCIS (Netherlands)

Nikov, V.S.; Nikova, S.I.; Preneel, B.; Blundo, C.; Cimato, S.

2005-01-01

Span programs provide a linear algebraic model of computation. Monotone span programs (MSP) correspond to linear secret sharing schemes. This paper studies the properties of monotone span programs related to their size. Using the results of van Dijk (connecting codes and MSPs) and a construction for

Assessment of modal-pushover-based scaling procedure for nonlinear response history analysis of ordinary standard bridges

Science.gov (United States)

Kalkan, E.; Kwong, N.

2012-01-01

The earthquake engineering profession is increasingly utilizing nonlinear response history analyses (RHA) to evaluate seismic performance of existing structures and proposed designs of new structures. One of the main ingredients of nonlinear RHA is a set of ground motion records representing the expected hazard environment for the structure. When recorded motions do not exist (as is the case in the central United States) or when high-intensity records are needed (as is the case in San Francisco and Los Angeles), ground motions from other tectonically similar regions need to be selected and scaled. The modal-pushover-based scaling (MPS) procedure was recently developed to determine scale factors for a small number of records such that the scaled records provide accurate and efficient estimates of “true” median structural responses. The adjective “accurate” refers to the discrepancy between the benchmark responses and those computed from the MPS procedure. The adjective “efficient” refers to the record-to-record variability of responses. In this paper, the accuracy and efficiency of the MPS procedure are evaluated by applying it to four types of existing Ordinary Standard bridges typical of reinforced concrete bridge construction in California. These bridges are the single-bent overpass, multi-span bridge, curved bridge, and skew bridge. As compared with benchmark analyses of unscaled records using a larger catalog of ground motions, it is demonstrated that the MPS procedure provided an accurate estimate of the engineering demand parameters (EDPs) accompanied by significantly reduced record-to-record variability of the EDPs. Thus, it is a useful tool for scaling ground motions as input to nonlinear RHAs of Ordinary Standard bridges.

London SPAN version 4 parameter file format

International Nuclear Information System (INIS)

2004-06-01

Powernext SA is a Multilateral Trading Facility in charge of managing the French power exchange through an optional and anonymous organised trading system. Powernext SA collaborates with the clearing organization LCH.Clearnet SA to secure and facilitate the transactions. The French Standard Portfolio Analysis of Risk (SPAN) is a system used by LCH.Clearnet to calculate the initial margins from and for its clearing members. SPAN is a computerized system which calculates the impact of several possible variations of rates and volatility on by-product portfolios. The initial margin call is equal to the maximum probable loss calculated by the system. This document contains details of the format of the London SPAN version 4 parameter file. This file contains all the parameters and risk arrays required to calculate SPAN margins. London SPAN Version 4 is an upgrade from Version 3, which is also known as LME SPAN. This document contains the full revised file specification, highlighting the changes from Version 3 to Version 4

METHOD OF THE DRIVE POWER DETERMINATION OF THE MECHANISMS OF THE BRIDGE CRANE MOVEMENT CONSIDERING THE ROLLING FRICTION

Directory of Open Access Journals (Sweden)

V. M. Bohomaz

2015-08-01

Full Text Available Purpose. The value of drive resistance to its movement is the main parameter at calculating the drive power of bridge crane. The value of the wheel rolling friction on the rails is one of the important parts of the resistance to movement. It is necessary to determine the dependence of static (dynamic quantities of resistance to the bridge crane movement on a straight section of the track from the position of the bogie in the span, and explore the influence of the wheel flanges resistance for wear. Methodology. Using the analytical dependences for determining the rolling friction coefficient, that depends on the size of the half-width of the contact between the wheel and rail, the improved method for calculating the required drive power of the crane was proposed. Findings. With the proposed method of power calculation the characteristic curve of the crane wheel loads, the coefficient of rolling friction of the wheels and the crane resistance to movement from the position of the bogie on span were built. In the result of graphs analysis it was found that the engine power, obtained by the proposed method is higher than the recommended by the existing standards. The more precise formula for determining the total coefficient of sliding friction that takes into account the friction of wheel flanges on the rail is given. The characteristic curves of such coefficient of friction and the total resistance to movement of the position of the crane bogie were built. Originality. The scientists proposed an improved method of determining the required engine power of bridge crane, which takes into account the effect of rolling friction of the wheels on the rails and the bogie in the span. The improved formula for determining the coefficient of friction that takes into account the friction wheel flanges of the rail was given. The characteristic curve of this coefficient of friction and the total resistance movement of crane from the position of the crane bogie

Measurement of Non-Stationary Characteristics of a Landfall Typhoon at the Jiangyin Bridge Site

Directory of Open Access Journals (Sweden)

Xuhui He

2017-09-01

Full Text Available The wind-sensitive long-span suspension bridge is a vital element in land transportation. Understanding the wind characteristics at the bridge site is thus of great significance to the wind- resistant analysis of such a flexible structure. In this study, a strong wind event from a landfall typhoon called Soudelor recorded at the Jiangyin Bridge site with the anemometer is taken as the research object. As inherent time-varying trends are frequently captured in typhoon events, the wind characteristics of Soudelor are analyzed in a non-stationary perspective. The time-varying mean is first extracted with the wavelet-based self-adaptive method. Then, the non-stationary turbulent wind characteristics, e.g.; turbulence intensity, gust factor, turbulence integral scale, and power spectral density, are investigated and compared with the results from the stationary analysis. The comparison highlights the importance of non-stationary considerations of typhoon events, and a transition from stationarity to non-stationarity for the analysis of wind effects. The analytical results could help enrich the database of non-stationary wind characteristics, and are expected to provide references for the wind-resistant analysis of engineering structures in similar areas.

Measurement of Non-Stationary Characteristics of a Landfall Typhoon at the Jiangyin Bridge Site.

Science.gov (United States)

He, Xuhui; Qin, Hongxi; Tao, Tianyou; Liu, Wenshuo; Wang, Hao

2017-09-22

The wind-sensitive long-span suspension bridge is a vital element in land transportation. Understanding the wind characteristics at the bridge site is thus of great significance to the wind- resistant analysis of such a flexible structure. In this study, a strong wind event from a landfall typhoon called Soudelor recorded at the Jiangyin Bridge site with the anemometer is taken as the research object. As inherent time-varying trends are frequently captured in typhoon events, the wind characteristics of Soudelor are analyzed in a non-stationary perspective. The time-varying mean is first extracted with the wavelet-based self-adaptive method. Then, the non-stationary turbulent wind characteristics, e.g.; turbulence intensity, gust factor, turbulence integral scale, and power spectral density, are investigated and compared with the results from the stationary analysis. The comparison highlights the importance of non-stationary considerations of typhoon events, and a transition from stationarity to non-stationarity for the analysis of wind effects. The analytical results could help enrich the database of non-stationary wind characteristics, and are expected to provide references for the wind-resistant analysis of engineering structures in similar areas.

Design and construction of Chichibu-park bridge. Chichibu Koenkyo (kasho) no sekkei to seko

Energy Technology Data Exchange (ETDEWEB)

Hasuike, H.; Azami, Y. (Saitama Prefectural Government Office, Saitama (Japan) New Structural Engineering, Ltd., Tokyo (Japan)); Yamamoto, T.

1994-01-31

The design and construction of the Chichibu-Park Bridge in Japan were outlined which is the symmetric 2-span continuous PC cable stayed road bridge with one main tower (530 m in total length, 392 m in main bridge length, 19 m in width) built over the Arakawa River. The double-suspended four-box main girder with wind noses was adopted because of its excellent torsional rigidity of area and wind proof stability, and the rigid-frame main girder was rigidly connected to the middle main tower. The main tower with an H-type hollow section was adopted considering its workability, and was assembled with its divided 18 blocks. Each side of the main girder was suspended at 30 points spaced at 6.0 m, and the tower ends of the diagonal cables were fixed to the partition inside the main tower taking a landscape into account. The thick stranded wires composed of fine PC steel stranded wires and covered with polyethylene were adopted as diagonal cables, and structural beams were used for both ends of the diagonal cables. Damping wires were also adopted to damp the diagonal cables. 9 refs., 12 figs., 6 tabs.

Improving resistance of high strength concrete (HSC) bridge beams to frost and defrosting salt attack by application of hydrophobic agent

Science.gov (United States)

Kolisko, Jiri; Balík, Lukáš; Kostelecka, Michaela; Pokorný, Petr

2017-09-01

HSC (High Strength Concrete) is increasingly used for bearing bridge structures nowadays. Bridge structures in the Czech Republic are exposed to severe conditions in winter time and durability of the concrete is therefore a crucial requirement. The high strength and low water absorption of HSC suggests that the material will have high durability. However, the situation may not be so straightforward. We carried out a study of the very poor durability of HSC concrete C70/85 used to produce prestresed beams 37.1 m in length to build a 6-span highway bridge. After the beams were cast, a production control test indicated some problems with the durability of the concrete. There was a danger that 42 of the beams would not be suitable for use. All participants in the bridge project finally decided, after extensive discussions, to attempt to improve the durability of the concrete by applying a hydrophobic agent. Paper will present the results of comparative tests of four hydrophobic agents in order to choose one for real application and describes this application on construction site.

EarthCube - Earth System Bridge: Spanning Scientific Communities with Interoperable Modeling Frameworks

Science.gov (United States)

Peckham, S. D.; DeLuca, C.; Gochis, D. J.; Arrigo, J.; Kelbert, A.; Choi, E.; Dunlap, R.

2014-12-01

In order to better understand and predict environmental hazards of weather/climate, ecology and deep earth processes, geoscientists develop and use physics-based computational models. These models are used widely both in academic and federal communities. Because of the large effort required to develop and test models, there is widespread interest in component-based modeling, which promotes model reuse and simplified coupling to tackle problems that often cross discipline boundaries. In component-based modeling, the goal is to make relatively small changes to models that make it easy to reuse them as "plug-and-play" components. Sophisticated modeling frameworks exist to rapidly couple these components to create new composite models. They allow component models to exchange variables while accommodating different programming languages, computational grids, time-stepping schemes, variable names and units. Modeling frameworks have arisen in many modeling communities. CSDMS (Community Surface Dynamics Modeling System) serves the academic earth surface process dynamics community, while ESMF (Earth System Modeling Framework) serves many federal Earth system modeling projects. Others exist in both the academic and federal domains and each satisfies design criteria that are determined by the community they serve. While they may use different interface standards or semantic mediation strategies, they share fundamental similarities. The purpose of the Earth System Bridge project is to develop mechanisms for interoperability between modeling frameworks, such as the ability to share a model or service component. This project has three main goals: (1) Develop a Framework Description Language (ES-FDL) that allows modeling frameworks to be described in a standard way so that their differences and similarities can be assessed. (2) Demonstrate that if a model is augmented with a framework-agnostic Basic Model Interface (BMI), then simple, universal adapters can go from BMI to a

Complex measurement system for long-term monitoring of prestressed railway bridges of the new Lehrter Bahnhof in Berlin

Science.gov (United States)

Habel, Wolfgang R.; Hofmann, Detlef; Kohlhoff, H.; Knapp, J.; Brandes, K.; Haenichen, H.; Inaudi, Daniele

2002-07-01

A new central railway station - Lehrter Bahnhof - is being built in Berlin. Because of construction activities in immediate vicinity and because of difficult soil conditions, different vertical displacements have to be expected. In order to avoid damage to the bridges and to a widely spanned glass roof which will be supported by two concrete bridges these two bridges have to be monitored with regard to their deformation performance right from the beginning of construction until commissioning as well as later on for several years. For this purpose, a monitoring concept has been developed and sensors with excellent long-term stability have been chosen. This paper describes the system for monitoring settlements and heaves by means of laser-based optics and hydrostatic leveling. Additionally, strain and inclination of the prestressed concrete bridges are redundantly monitored by embedded long-gage length fiber-optic strain sensors as well as resistive strain gages, and inclinometers. Measurements on-site are referenced by measurements on two test beams well-defined loaded under laboratory and field conditions. The paper also describes the measuring concept and the sensor techniques as well as installation of the sensor system and first results.

Bridges

NARCIS (Netherlands)

Zant, W.

2017-01-01

We estimate to what extent bridges in Mozambique lead to transport cost reductions and attribute these reductions to key determinants, in particular road distance, road quality and crossing borders. For identification we exploit the introduction of a road bridge over the Zambezi river, in August

Comparison on the heat requirements of a four-span greenhouse with a melting snow system and a single-span greenhouse

International Nuclear Information System (INIS)

Furuno, S.; Sase, S.; Ishii, M.

2004-01-01

The heat requirements were measured and compared between a four-span greenhouse with a melting snow system and a typical single-span greenhouse with no melting snow system. Generally, single-span greenhouses require no melting snow system because snow drops off naturally from the roofs by gravity. The results for the four-span greenhouse showed that the provided heat by a heater for melting snow increased with an increase in snowfall, and there was a high correlation between them. The heat requirement per unit floor area of the four-span greenhouse was slightly less than that of the single-span greenhouse. This suggests that the decrease in heat requirement for internal air because of the larger floor/surface area ratio of the four-span greenhouse was more than the increase in heat requirement for melting snow. The measured heat requirement of the four-span greenhouse with the melting snow system was equal to the estimated heat load based on a common calculation procedure. On the other hand, that of the single-span greenhouse was slightly smaller than the estimated heat load. These suggest that the estimated heat load based on the common calculation procedure was slightly overestimated and larger than the actual heat requirement excluding the heat for the melting snow in snowy area. This is likely due to the fact that the parameters in the common calculation procedure were determined under the condition of larger net radiation than that in snowy area

Linking crowding, visual span, and reading.

Science.gov (United States)

He, Yingchen; Legge, Gordon E

2017-09-01

The visual span is hypothesized to be a sensory bottleneck on reading speed with crowding thought to be the major sensory factor limiting the size of the visual span. This proposed linkage between crowding, visual span, and reading speed is challenged by the finding that training to read crowded letters reduced crowding but did not improve reading speed (Chung, 2007). Here, we examined two properties of letter-recognition training that may influence the transfer to improved reading: the spatial arrangement of training stimuli and the presence of flankers. Three groups of nine young adults were trained with different configurations of letter stimuli at 10° in the lower visual field: a flanked-local group (flanked letters localized at one position), a flanked-distributed group (flanked letters distributed across different horizontal locations), and an isolated-distributed group (isolated and distributed letters). We found that distributed training, but not the presence of flankers, appears to be necessary for the training benefit to transfer to increased reading speed. Localized training may have biased attention to one specific, small area in the visual field, thereby failing to improve reading. We conclude that the visual span represents a sensory bottleneck on reading, but there may also be an attentional bottleneck. Reducing the impact of crowding can enlarge the visual span and can potentially facilitate reading, but not when adverse attentional bias is present. Our results clarify the association between crowding, visual span, and reading.

Filament to filament bridging and its influence on developing high critical current density in multifilamentary Bi2Sr2CaCu2Ox round wires

International Nuclear Information System (INIS)

Shen, T; Jiang, J; Kametani, F; Trociewitz, U P; Larbalestier, D C; Schwartz, J; Hellstrom, E E

2010-01-01

Increasing the critical current density (J c ) of the multifilamentary round wire Ag/Bi 2 Sr 2 CaCu 2 O x (2212) requires understanding its complicated microstructure, in which extensive bridges between filaments are prominent. In this first through-process quench study of 2212 round wire, we determined how its microstructure develops during a standard partial-melt process and how filament bridging occurs. We found that filaments can bond together in the melt state. As 2212 starts to grow on subsequent cooling, we observed that two types of 2212 bridges form. One type, which we call Type-A bridges, forms within filaments that bonded in the melt; Type-A bridges are single grains that span multiple bonded filaments. The other type, called Type-B bridges, form between discrete filaments through 2212 outgrowths that penetrate into the Ag matrix and intersect with other 2212 outgrowths from adjacent filaments. We believe the ability of these two types of bridges to carry inter-filament current is intrinsically different: Type-A bridges are high- J c inter-filament paths whereas Type-B bridges contain high-angle grain boundaries and are typically weak linked. Slow cooling leads to more filament bonding, more Type-A bridges and a doubling of J c without changing the flux pinning. We suggest that Type-A bridges create a 3D current flow that is vital to developing high J c in multifilamentary 2212 round wire.

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.

The hepatic bridge.

Science.gov (United States)

Sugarbaker, Paul H

2018-07-01

The hepatic bridge forms a tunnel of liver parenchyma that may obscure peritoneal metastases associated with the round ligament. Visualization and then resection of nodules associated with this structure is necessary. The incidence of a hepatic bridge and the extent that it covered the round ligament was determined in consecutive patients. Extent of coverage of the round ligament by the hepatic bridge was determined: Class 1 indicates up to one-third of the round ligament obscured, Class 2 up to two-thirds and Class 3 more than two-thirds. In 102 patients in whom the round ligament of the liver could be completely visualized, 50 had a hepatic bridge. Class 1 was 22 (44%) of the bridges, Class 2 was 16 (32%) and Class 3 was 12 (24%). A hepatic bridge was more frequently present in 28 of 45 male patients (62%) vs. 22 of 57 female patients (38%). Approximately one-half of our patients having cytoreductive surgery for peritoneal metastases were observed to have a hepatic bridge. Up to 56% of these patients have Class 2 or 3 hepatic bridge and may require division of the hepatic bridge to completely visualize the contents of the tunnel created by this structure. Copyright © 2018 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

Structural condition assessment and service load performance of deteriorated prestressed concrete deck beam bridges

Science.gov (United States)

Fuentes, Juan Bolivar

Precast pretensioned deck beam bridges are a generic bridge type widely used by IDOT for new construction through the end of the 1970's and still widely used on county roads throughout Illinois. While these bridges were economical to build, IDOT discontinued their use because reflective cracks developed along the length of the longitudinal joints between beams. Three 30 years old deteriorated beams were removed from an existing bridge over Spoon River in Fulton County, IL and delivered to Newmark Civil Engineering Laboratory. The program consisted of a series of comprehensive, destructive and non-destructive, tests and evaluations of the three beams with emphasis on three major areas; (1) The Condition Assessment of the as-delivered beams. (2) The service load performance of the bridge sub-assemblage constructed from those beams. After a comprehensive inspection of the beams was completed, the beams were integrated together into a bridge subassembly that simulated a bridge lane. (3) Following the service load tests, the three beams were separated and tested individually to failure. The critical signs to be observed in existing structures that will lead the inspectors to conclude that a deck beam is being overloaded were are also studied. Several conclusions were found. Cracking of the longitudinal joint has little effect on the stiffness of the bridge if the transverse rod is snug. The presence of a snug transverse tie rod increases the strength of the longitudinal joint. After a longitudinal joint has fractured, reincorporating a snug transverse rod can significantly reestablish the stiffness of the longitudinal joint and reduce overloading of a deteriorated beam. Participation factors must be based on relative bending moments of one beam with respect to the total amount of bending moment produced by the applied load and not to the amount of total vertical displacement. The participation factors will vary along the span of the bridge deck and will depend on the

Algorithms for highway-speed acoustic impact-echo evaluation of concrete bridge decks

Science.gov (United States)

Mazzeo, Brian A.; Guthrie, W. Spencer

2018-04-01

A new acoustic impact-echo testing device has been developed for detecting and mapping delaminations in concrete bridge decks at highway speeds. The apparatus produces nearly continuous acoustic excitation of concrete bridge decks through rolling mats of chains that are placed around six wheels mounted to a hinged trailer. The wheels approximately span the width of a traffic lane, and the ability to remotely lower and raise the apparatus using a winch system allows continuous data collection without stationary traffic control or exposure of personnel to traffic. Microphones near the wheels are used to record the acoustic response of the bridge deck during testing. In conjunction with the development of this new apparatus, advances in the algorithms required for data analysis were needed. This paper describes the general framework of the algorithms developed for converting differential global positioning system data and multi-channel audio data into maps that can be used in support of engineering decisions about bridge deck maintenance, rehabilitation, and replacement (MR&R). Acquisition of position and audio data is coordinated on a laptop computer through a custom graphical user interface. All of the streams of data are synchronized with the universal computer time so that audio data can be associated with interpolated position information through data post-processing. The audio segments are individually processed according to particular detection algorithms that can adapt to variations in microphone sensitivity or particular chain excitations. Features that are greater than a predetermined threshold, which is held constant throughout the analysis, are then subjected to further analysis and included in a map that shows the results of the testing. Maps of data collected on a bridge deck using the new acoustic impact-echo testing device at different speeds ranging from approximately 10 km/h to 55 km/h indicate that the collected data are reasonably repeatable. Use

Bridge resource program.

Science.gov (United States)

2013-09-01

The mission of Rutgers Universitys Center for Advanced Infrastructure and Transportation (CAIT) Bridge Resource Program (BRP) is to provide bridge engineering support to the New Jersey Department of Transportation (NJDOT)s Bridge Engineering an...

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.

Laboratory and field testing of an accelerated bridge construction demonstration bridge : US Highway 6 bridge over Keg Creek.

Science.gov (United States)

2013-04-01

The US Highway 6 Bridge over Keg Creek outside of Council Bluffs, Iowa is a demonstration bridge site chosen to put into practice : newly-developed Accelerated Bridge Construction (ABC) concepts. One of these new concepts is the use of prefabricated ...

Detailed free span assessment for Mexilhao flow lines

Energy Technology Data Exchange (ETDEWEB)

Pereira, Antonio; Franco, Luciano; Eigbe, Uwa; BomfimSilva, Carlos [INTECSEA, Houston, TX (United States); Escudero, Carlos [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

2009-07-01

The subsea gas production system of Mexilhao Field SPS-35, Santos Basin, offshore Brazil, is composed basically of two rigid 12.75 inches production flow lines approximately 21 km long installed in a fairly rough seabed. During the basic design, the free span assessment was performed considering the maximum allowable free span length determined by the response model proposed by DNV-RP-F105. This approach resulted in a large number of predicted free span requiring corrections, leading to a higher capital cost for the project. In this sense, a detailed free span VIV fatigue assessment was proposed, considering multi-spans and multi-mode effects and also the post lay survey data. The assessment followed the DNV-RP-F105 recommendations for multi-spans and multi-mode effects, using Finite Element Analysis to determine the natural frequencies, mode shapes and corresponding stresses associated with the mode shapes. The assessment was performed in three stages, the first during the detailed design as part of the bottom roughness analysis using the expected residual pipelay tension. The second stage was performed after pipelay, considering the post-lay survey data, where the actual requirements for span correction were determined. Actual pipelay tension was used and seabed soil stiffness adjusted in the model to match the as-laid pipeline profile obtained from the survey data. The first and second stage assessments are seamlessly automated to speed up the evaluation process and allow for quick response in the field, which was important to keep the construction vessel time minimized. The third stage was performed once the corrections of the spans were made and the purpose was to confirm that the new pipeline configuration along the supported spans had sufficient fatigue life for the temporary and operational phases. For the assessment of all three stages, the probability of occurrence and directionality of the near bottom current was considered to improve prediction of the

Guardrails for Use on Historic Bridges: Volume 2—Bridge Deck Overhang Design

OpenAIRE

Frosch, Robert J.; Morel, Adam J.

2016-01-01

Bridges that are designated historic present a special challenge to bridge engineers whenever rehabilitation work or improvements are made to the bridges. Federal and state laws protect historically significant bridges, and railings on these bridges can be subject to protection because of the role they play in aesthetics. Unfortunately, original railings on historic bridges do not typically meet current crash-test requirements and typically do not meet current standards for railing height and...

Evaluation of aerodynamic stability and a trial study of construction-accuracy control by daytime measurement of Meiko West Bridge; Meiko Nishi Ohashi no taifusei kento to chukan keisoku kekka wo mochiita kasetsu seido kanri no shiko

Energy Technology Data Exchange (ETDEWEB)

Morimoto, C.; Shimodoi, H.; Isoe, A.; Sakai, Y.; Ochiai, M.; Watabe, T.; Ebihara, R. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1998-12-20

The new Meiko West Bridge was constructed very closely to the phase I line bridge which have been already in a service from 1985, and the distance of this world unique parallel cable-stayed bridges is 50m. The length, span and pylon height of these bridges are identical. By conducting wind tunnel experiments considering the aerodynamic interference of the close parallel bridges, the aerodynamic stability of the bridge had been confirmed during construction as well as complete state. After the construction was completed, the important wind characteristics of the parallel cable-stayed bridges were obtained from the site observation. Regarding cable vibrations, a common problem with cable-stayed bridges, a suitable vibration suppression method was applied based on the site observation. In general, the construction-accuracy control is performed by doing measurement at night However, to study the possibility of the accuracy-control by daytime measurement the measurement was conducted not only at night but also in the daytime. (author)

Dynamic assessment of bridge deck performance considering realistic bridge-traffic interaction

Science.gov (United States)

2017-09-01

Concrete bridge decks are directly exposed to daily traffic loads and may experience some surface cracking caused by excessive stress or fatigue accumulation, which requires repair or replacement. Among typical bridges in North America, bridge decks ...

Determining the Environmental Benefits of Ultra High Performance Concrete as a Bridge Construction Material

Science.gov (United States)

Lande Larsen, Ingrid; Granseth Aasbakken, Ida; O'Born, Reyn; Vertes, Katalin; Terje Thorstensen, Rein

2017-10-01

Ultra High Performance Concrete (UHPC) is a material that is attracting attention in the construction industry due to the high mechanical strength and durability, leading to structures having low maintenance requirements. The production of UHPC, however, has generally higher environmental impact than normal strength concrete due to the increased demand of cement required in the concrete mix. What is still not sufficiently investigated, is if the longer lifetime, slimmer construction and lower maintenance requirements lead to a net environmental benefit compared to standard concrete bridge design. This study utilizes life cycle assessment (LCA) to determine the lifetime impacts of two comparable highway crossing footbridges spanning 40 meters, designed respectively with UHPC and normal strength concrete. The results of the study show that UHPC is an effective material for reducing lifetime emissions from construction and maintenance of long lasting infrastructure, as the UHPC design outperforms the normal strength concrete bridge in most impact categories.

Bridge Programs in Illinois: Results of the 2010 Illinois Bridge Status Survey

Science.gov (United States)

Taylor, J. L.; Harmon, T.

2010-01-01

This report provides a summary of major results of the Illinois Bridge Status Survey, administered online between April and June 2010. The purpose of the survey was to understand the extent to which bridge programs are being implemented in Illinois, as well as to build an online directory of bridge programs. Bridge programs are an emerging…

Documentation for assessment of modal pushover-based scaling procedure for nonlinear response history analysis of "ordinary standard" bridges

Science.gov (United States)

Kalkan, Erol; Kwong, Neal S.

2010-01-01

The earthquake engineering profession is increasingly utilizing nonlinear response history analyses (RHA) to evaluate seismic performance of existing structures and proposed designs of new structures. One of the main ingredients of nonlinear RHA is a set of ground-motion records representing the expected hazard environment for the structure. When recorded motions do not exist (as is the case for the central United States), or when high-intensity records are needed (as is the case for San Francisco and Los Angeles), ground motions from other tectonically similar regions need to be selected and scaled. The modal-pushover-based scaling (MPS) procedure recently was developed to determine scale factors for a small number of records, such that the scaled records provide accurate and efficient estimates of 'true' median structural responses. The adjective 'accurate' refers to the discrepancy between the benchmark responses and those computed from the MPS procedure. The adjective 'efficient' refers to the record-to-record variability of responses. Herein, the accuracy and efficiency of the MPS procedure are evaluated by applying it to four types of existing 'ordinary standard' bridges typical of reinforced-concrete bridge construction in California. These bridges are the single-bent overpass, multi span bridge, curved-bridge, and skew-bridge. As compared to benchmark analyses of unscaled records using a larger catalog of ground motions, it is demonstrated that the MPS procedure provided an accurate estimate of the engineering demand parameters (EDPs) accompanied by significantly reduced record-to-record variability of the responses. Thus, the MPS procedure is a useful tool for scaling ground motions as input to nonlinear RHAs of 'ordinary standard' bridges.

L-fuzzy/span> fixed points theorems for L-fuzzy/span> mappings via βℱL-admissible pair.

Science.gov (United States)

Rashid, Maliha; Azam, Akbar; Mehmood, Nayyar

2014-01-01

We define the concept of βℱL-admissible for a pair of L-fuzzy/span> mappings and establish the existence of common L-fuzzy/span> fixed point theorem. Our result generalizes some useful results in the literature. We provide an example to support our result.

Drill pipe bridge plug

International Nuclear Information System (INIS)

Winslow, D.W.; Brisco, D.P.

1991-01-01

This patent describes a method of stopping flow of fluid up through a pipe bore of a pipe string in a well. It comprises: lowering a bridge plug apparatus on a work string into the pipe string to a position where the pipe bore is to be closed; communicating the pipe bore below a packer of the bridge plug apparatus through the bridge plug apparatus with a low pressure zone above the packer to permit the fluid to flow up through the bridge plug apparatus; engaging the bridge plug apparatus with an internal upset of the pipe string; while the fluid is flowing up through the bridge plug apparatus, pulling upward on the work string and the bridge plug apparatus and thereby sealing the packer against the pipe bore; isolating the pipe bore below the packer from the low pressure zone above the packer and thereby stopping flow of the fluid up through the pipe bore; disconnecting the work string from the bridge plug apparatus; and maintaining the bridge plug apparatus in engagement with the internal upset and sealed against the pipe bore due to an upward pressure differential applied to the bridge plug apparatus by the fluid contained therebelow

Sexual conflict, life span, and aging.

Science.gov (United States)

Adler, Margo I; Bonduriansky, Russell

2014-06-17

The potential for sexual conflict to influence the evolution of life span and aging has been recognized for more than a decade, and recent work also suggests that variation in life span and aging can influence sexually antagonistic coevolution. However, empirical exploration of these ideas is only beginning. Here, we provide an overview of the ideas and evidence linking inter- and intralocus sexual conflicts with life span and aging. We aim to clarify the conceptual basis of this research program, examine the current state of knowledge, and suggest key questions for further investigation. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

Damage Detection for Continuous Bridge Based on Static-Dynamic Condensation and Extended Kalman Filtering

Directory of Open Access Journals (Sweden)

Haoxiang He

2014-01-01

Full Text Available As an effective and classical method about physical parameter identification, extended Kalman filtering (EKF algorithm is widely used in structural damage identification, but the equations and solutions for the structure with bending deformation are not established based on EKF. The degrees of freedom about rotation can be eliminated by the static condensation method, and the dynamic condensation method considering Rayleigh damping is proposed in order to establish the equivalent and simplified modal based on complex finite element model such as continuous girder bridge. According to the requirement of bridge inspection and health monitoring, the online and convenient damage detection method based on EKF is presented. The impact excitation can be generated only on one location by one hammer actuator, and the signal in free vibration is analyzed. The deficiency that the complex excitation information is needed based on the traditional method is overcome. As a numerical example, a three-span continuous girder bridge is simulated, and the corresponding stiffness, the damage location and degree, and the damping parameter are identified accurately. It is verified that the method is suitable for the dynamic signal with high noise-signal ratio; the convergence speed is fast and this method is feasible for application.

Bridging Anticoagulation

Science.gov (United States)

... clinical centers in the United States, Canada, and Brazil. A more detailed description of the study is ... Your Personal Message Send Message Share on Social Media Bridging Anticoagulation The BRIDGE Study Investigators Circulation. 2012; ...

Vertical vibration control system for PC cable-stayed bridge during cantilever construction; Shuketa jogedo seishin sochi ni yoru haridashi sekoji no PC shachokyo no seishin

Energy Technology Data Exchange (ETDEWEB)

Oshio, M.; Nakano, R.; Niihara, Y.; Yano, K.; Takeda, T. [Kajima Corp., Tokyo (Japan)

1995-12-20

A PC cable-stayed bridge under extension construction having long span length may have long-cycle vibration generated because of wind. The vibration puts workers working on main girders into a state of seasick causing the workability to drop. Therefore, with an objective to reduce vibration occurring on the main girders during construction, discussions were given on application of an active type vertical vibration absorbing device. The vibration absorbing device is an active system that a weight is driven vertically by a hydraulic actuator. The device was developed with a target that damping ratio when a maximum extension is 120 m becomes three times that when no vibration is absorbed for a 5-span continuous PC cable-stayed bridge with a length of 675 m, a central span of 260 m, and a width of 11 m. A cage housing the weight is connected with the actuator at its top by using pins, and the weight is supported being suspended from the top of the actuator. Vibration is absorbed by utilizing reactive force generated when the weight is driven vertically by the hydraulic actuator. The hydraulic actuator contains a gas spring that supports the dead weight of the weight. Experiments have verified the effectiveness of the vertical vibration absorbing device. 4 refs., 12 figs., 3 tabs.

Spanning forests and the vector bundle Laplacian

OpenAIRE

Kenyon, Richard

2011-01-01

The classical matrix-tree theorem relates the determinant of the combinatorial Laplacian on a graph to the number of spanning trees. We generalize this result to Laplacians on one- and two-dimensional vector bundles, giving a combinatorial interpretation of their determinants in terms of so-called cycle rooted spanning forests (CRSFs). We construct natural measures on CRSFs for which the edges form a determinantal process. ¶ This theory gives a natural generalization of the spanning tre...

Hydraulic risk assessment of bridges using UAV photogrammetry

Science.gov (United States)

Hackl, Jürgen; Adey, Bryan T.; Woźniak, Michał; Schümperlin, Oliver

2017-04-01

investigated includes: the use of geo-referenced images, taken by an UAV, the exportation of these images into a photogrammetric software, the creation of a 3D mesh of the terrain from these images, the conversion of the 3D mesh to a computational mesh, the use of the computational mesh to build a hydrodynamic model, and the use of the hydrodynamic model to run flow simulations. The process was used to estimate the complex water flow near a single span concrete bridge in the Canton of Grisons, Switzerland. The hydraulic events (abutment scour and overflow) predicted by the developed model were compared with with historical observations from a recent flood event in the region. The hydraulic events predicted by the developed model correspond with historical observations, indicating that the topological information collected in this way is sufficiently accurate to be used to simulate complex flow situations, which can be used in bridge risk assessments. Hackl, J., Adey, B.T., Heitzler, M., and Iosifescu Enescu, I. (2015). "An Overarching Risk Assessment Process to Evaluate the Risks Associated with Infrastructure Networks due to Natural Hazards." International Journal of Performability Engineering, 11(2), 153-168. Adey, B.T., Hackl, J., Lam, J.C., van Gelder, P., Prak, P., van Erp, N., Heitzler, M., Iosifescu Enescu, I., and Hurni, L. (2016). "Ensuring acceptable levels of infrastructure related risks due to natural hazards with emphasis on conducting stress tests." 1st International Symposium on Infrastructure Asset Management (SIAM2016), K. Kobayashi, ed., Kyoto, Japan, 19-29 (Jan).

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....

Fabrication and erection of 'Chuo ohashi bridge' for Tokyo Metropolitan Government. Tokyoto kensetsukyoku 'Chuo ohashi' no seisaku oyobi kasetsu

Energy Technology Data Exchange (ETDEWEB)

1994-07-01

The present report outlines the superstructure of 'Chuo Ohashi Bridge' spanning the Sumida River, Tokyo Metropolis. Being 210.7m in length and 25.0m in breadth, that bridge is a cable-stayed bridge partially curved with a 220m radius curvature. Having a height of 76.8m, its main tower is shaped into an upside-down V with a curved top. Description of the points of which care was specially taken for the fabrication and construction in yard covers the cable anchorage of both girders and tower, assembly and welding, anti-shrinkage camber of girders, weld bevel preparation for the tower, tentative assembly, and accuracy control. Results of the wind tunnel test with a (1/50) scale model are as follows: stay cables were installed as measures against the vibration during the main tower erection. The main girders, main tower and cables were the order of superstructural erection. The cable tensioning was supervised mainly with its proper tension adjustment and subsidiarily for the configuration of bridge built. 2 refs., 10 figs., 1 tab.

Bridge Crack Detection Using Multi-Rotary Uav and Object-Base Image Analysis

Science.gov (United States)

Rau, J. Y.; Hsiao, K. W.; Jhan, J. P.; Wang, S. H.; Fang, W. C.; Wang, J. L.

2017-08-01

Bridge is an important infrastructure for human life. Thus, the bridge safety monitoring and maintaining is an important issue to the government. Conventionally, bridge inspection were conducted by human in-situ visual examination. This procedure sometimes require under bridge inspection vehicle or climbing under the bridge personally. Thus, its cost and risk is high as well as labor intensive and time consuming. Particularly, its documentation procedure is subjective without 3D spatial information. In order cope with these challenges, this paper propose the use of a multi-rotary UAV that equipped with a SONY A7r2 high resolution digital camera, 50 mm fixed focus length lens, 135 degrees up-down rotating gimbal. The target bridge contains three spans with a total of 60 meters long, 20 meters width and 8 meters height above the water level. In the end, we took about 10,000 images, but some of them were acquired by hand held method taken on the ground using a pole with 2-8 meters long. Those images were processed by Agisoft PhotoscanPro to obtain exterior and interior orientation parameters. A local coordinate system was defined by using 12 ground control points measured by a total station. After triangulation and camera self-calibration, the RMS of control points is less than 3 cm. A 3D CAD model that describe the bridge surface geometry was manually measured by PhotoscanPro. They were composed of planar polygons and will be used for searching related UAV images. Additionally, a photorealistic 3D model can be produced for 3D visualization. In order to detect cracks on the bridge surface, we utilize object-based image analysis (OBIA) technique to segment the image into objects. Later, we derive several object features, such as density, area/bounding box ratio, length/width ratio, length, etc. Then, we can setup a classification rule set to distinguish cracks. Further, we apply semi-global-matching (SGM) to obtain 3D crack information and based on image scale we

BRIDGE CRACK DETECTION USING MULTI-ROTARY UAV AND OBJECT-BASE IMAGE ANALYSIS

Directory of Open Access Journals (Sweden)

J. Y. Rau

2017-08-01

Full Text Available Bridge is an important infrastructure for human life. Thus, the bridge safety monitoring and maintaining is an important issue to the government. Conventionally, bridge inspection were conducted by human in-situ visual examination. This procedure sometimes require under bridge inspection vehicle or climbing under the bridge personally. Thus, its cost and risk is high as well as labor intensive and time consuming. Particularly, its documentation procedure is subjective without 3D spatial information. In order cope with these challenges, this paper propose the use of a multi-rotary UAV that equipped with a SONY A7r2 high resolution digital camera, 50 mm fixed focus length lens, 135 degrees up-down rotating gimbal. The target bridge contains three spans with a total of 60 meters long, 20 meters width and 8 meters height above the water level. In the end, we took about 10,000 images, but some of them were acquired by hand held method taken on the ground using a pole with 2–8 meters long. Those images were processed by Agisoft PhotoscanPro to obtain exterior and interior orientation parameters. A local coordinate system was defined by using 12 ground control points measured by a total station. After triangulation and camera self-calibration, the RMS of control points is less than 3 cm. A 3D CAD model that describe the bridge surface geometry was manually measured by PhotoscanPro. They were composed of planar polygons and will be used for searching related UAV images. Additionally, a photorealistic 3D model can be produced for 3D visualization. In order to detect cracks on the bridge surface, we utilize object-based image analysis (OBIA technique to segment the image into objects. Later, we derive several object features, such as density, area/bounding box ratio, length/width ratio, length, etc. Then, we can setup a classification rule set to distinguish cracks. Further, we apply semi-global-matching (SGM to obtain 3D crack information and based

A floating bridge disrupts seaward migration and increases mortality of steelhead smolts in Hood Canal, Washington state.

Directory of Open Access Journals (Sweden)

Megan Moore

Full Text Available Habitat modifications resulting from human transportation and power-generation infrastructure (e.g., roads, dams, bridges can impede movement and alter natural migration patterns of aquatic animal populations, which may negatively affect survival and population viability. Full or partial barriers are especially problematic for migratory species whose life histories hinge on habitat connectivity.The Hood Canal Bridge, a floating structure spanning the northern outlet of Hood Canal in Puget Sound, Washington, extends 3.6 meters underwater and forms a partial barrier for steelhead migrating from Hood Canal to the Pacific Ocean. We used acoustic telemetry to monitor migration behavior and mortality of steelhead smolts passing four receiver arrays and several single receivers within the Hood Canal, Puget Sound, and Strait of Juan de Fuca. Twenty-seven mortality events were detected within the vicinity of the Hood Canal Bridge, while only one mortality was recorded on the other 325 receivers deployed throughout the study area. Migrating steelhead smolts were detected at the Hood Canal Bridge array with greater frequency, on more receivers, and for longer durations than smolts migrating past three comparably configured arrays. Longer migration times and paths are likely to result in a higher density of smolts near the bridge in relation to other sites along the migration route, possibly inducing an aggregative predator response to steelhead smolts.This study provides strong evidence of substantial migration interference and increased mortality risk associated with the Hood Canal Bridge, and may partially explain low early marine survival rates observed in Hood Canal steelhead populations. Understanding where habitat modifications indirectly increase predation pressures on threatened populations helps inform potential approaches to mitigation.

A floating bridge disrupts seaward migration and increases mortality of steelhead smolts in Hood Canal, Washington state.

Science.gov (United States)

Moore, Megan; Berejikian, Barry A; Tezak, Eugene P

2013-01-01

Habitat modifications resulting from human transportation and power-generation infrastructure (e.g., roads, dams, bridges) can impede movement and alter natural migration patterns of aquatic animal populations, which may negatively affect survival and population viability. Full or partial barriers are especially problematic for migratory species whose life histories hinge on habitat connectivity. The Hood Canal Bridge, a floating structure spanning the northern outlet of Hood Canal in Puget Sound, Washington, extends 3.6 meters underwater and forms a partial barrier for steelhead migrating from Hood Canal to the Pacific Ocean. We used acoustic telemetry to monitor migration behavior and mortality of steelhead smolts passing four receiver arrays and several single receivers within the Hood Canal, Puget Sound, and Strait of Juan de Fuca. Twenty-seven mortality events were detected within the vicinity of the Hood Canal Bridge, while only one mortality was recorded on the other 325 receivers deployed throughout the study area. Migrating steelhead smolts were detected at the Hood Canal Bridge array with greater frequency, on more receivers, and for longer durations than smolts migrating past three comparably configured arrays. Longer migration times and paths are likely to result in a higher density of smolts near the bridge in relation to other sites along the migration route, possibly inducing an aggregative predator response to steelhead smolts. This study provides strong evidence of substantial migration interference and increased mortality risk associated with the Hood Canal Bridge, and may partially explain low early marine survival rates observed in Hood Canal steelhead populations. Understanding where habitat modifications indirectly increase predation pressures on threatened populations helps inform potential approaches to mitigation.

Span efficiency in hawkmoths.

Science.gov (United States)

Henningsson, Per; Bomphrey, Richard J

2013-07-06

Flight in animals is the result of aerodynamic forces generated as flight muscles drive the wings through air. Aerial performance is therefore limited by the efficiency with which momentum is imparted to the air, a property that can be measured using modern techniques. We measured the induced flow fields around six hawkmoth species flying tethered in a wind tunnel to assess span efficiency, ei, and from these measurements, determined the morphological and kinematic characters that predict efficient flight. The species were selected to represent a range in wingspan from 40 to 110 mm (2.75 times) and in mass from 0.2 to 1.5 g (7.5 times) but they were similar in their overall shape and their ecology. From high spatio-temporal resolution quantitative wake images, we extracted time-resolved downwash distributions behind the hawkmoths, calculating instantaneous values of ei throughout the wingbeat cycle as well as multi-wingbeat averages. Span efficiency correlated positively with normalized lift and negatively with advance ratio. Average span efficiencies for the moths ranged from 0.31 to 0.60 showing that the standard generic value of 0.83 used in previous studies of animal flight is not a suitable approximation of aerodynamic performance in insects.

Bridge deterioration models to support Indiana's bridge management system.

Science.gov (United States)

2016-02-01

An effective bridge management system that is equipped with reliable deterioration models enables agency engineers to carry out : monitoring and long-term programming of bridge repair actions. At the project level, deterioration models help the agenc...

Radiocarbon dating of the first Turkish bridge over the River Tisza

International Nuclear Information System (INIS)

Szanto, Zs.; Molnar, M.; Futo, I.; Svingor, E.; Rinyu, L.; Palcsu, L.; Morgos, A.

2004-01-01

centuries. In order to avoid humic acids, as well as lignin alpha-cellulose was extracted from the wood samples by bleaching with NaClO 2 solution under acidic condition. Alpha-cellulose was separated finally by washing the residue with NaOH and dried. Using alpha-cellulose for dating the estimation of the extent to which the formation of the wood predated the archaeological event of interest became more precise due to the fact that exchange with the reservoir ceases at cellulose formation. Dating alpha-cellulose two different time periods were obtained: the first period (1505- 1595 AD and 1612-1673 AD, respectively) coincides with the Turkish occupation period, while the second interval (1733-1813 AD) proved the existence of another bridge from the 18 th century. The dendrochronological data (1558-1565 AD) [3] confirmed the assumed calendar time span, the archaeological excavation revealing without doubt the proof of the first wooden bridge over the River Tisza. (author)

Non-stationary random vibration analysis of a 3D train-bridge system using the probability density evolution method

Science.gov (United States)

Yu, Zhi-wu; Mao, Jian-feng; Guo, Feng-qi; Guo, Wei

2016-03-01

Rail irregularity is one of the main sources causing train-bridge random vibration. A new random vibration theory for the coupled train-bridge systems is proposed in this paper. First, number theory method (NTM) with 2N-dimensional vectors for the stochastic harmonic function (SHF) of rail irregularity power spectrum density was adopted to determine the representative points of spatial frequencies and phases to generate the random rail irregularity samples, and the non-stationary rail irregularity samples were modulated with the slowly varying function. Second, the probability density evolution method (PDEM) was employed to calculate the random dynamic vibration of the three-dimensional (3D) train-bridge system by a program compiled on the MATLAB® software platform. Eventually, the Newmark-β integration method and double edge difference method of total variation diminishing (TVD) format were adopted to obtain the mean value curve, the standard deviation curve and the time-history probability density information of responses. A case study was presented in which the ICE-3 train travels on a three-span simply-supported high-speed railway bridge with excitation of random rail irregularity. The results showed that compared to the Monte Carlo simulation, the PDEM has higher computational efficiency for the same accuracy, i.e., an improvement by 1-2 orders of magnitude. Additionally, the influences of rail irregularity and train speed on the random vibration of the coupled train-bridge system were discussed.

Automatic Bridge Control System

OpenAIRE

M. Niraimathi; S.Sivakumar; R.Vigneshwaran; R.Vinothkumar; P.Babu

2012-01-01

Bridge vibration control is an important issue whose purpose is to extend the structural service life of bridges. Normally, the bridge is modeled as an elastic beam or plate subject to a moving vehicle. However, the moving truck on a bridge is a complicated problem that must still be researched. In this paper, wepropose a new method, to overcome the huge load in the bridge a load cell is used at the entry which will monitor the load continuously at both ends. To escape from the heavy water fl...

Malingering in Toxic Exposure. Classification Accuracy of Reliable Digit Span and WAIS-III Digit Span Scaled Scores

Science.gov (United States)

Greve, Kevin W.; Springer, Steven; Bianchini, Kevin J.; Black, F. William; Heinly, Matthew T.; Love, Jeffrey M.; Swift, Douglas A.; Ciota, Megan A.

2007-01-01

This study examined the sensitivity and false-positive error rate of reliable digit span (RDS) and the WAIS-III Digit Span (DS) scaled score in persons alleging toxic exposure and determined whether error rates differed from published rates in traumatic brain injury (TBI) and chronic pain (CP). Data were obtained from the files of 123 persons…

Horizontal gust response of `Tatara Bridge` under construction; `Tatara ohashi` kasetsuji no taifu anteisei

Energy Technology Data Exchange (ETDEWEB)

Matsuda, K.; Iwasaki, T.; Tokushige, M.; Toriumi, R. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

1999-03-01

Wind tunnel tests of a long-span cable-stayed bridge under construction were conducted with two types of turbulent boundary layer simulations. The level of agreement between the wind tunnel measurements and a wind buffeting analysis varied with the type of turbulent boundary layer. An investigation of this behavior found that the aerodynamic admittance used in the buffeting analysis was different from the measured aerodynamic admittance. Past research showed that buffeting analysis based on strip theory, which assumes a spanwise correlation between the fluctuating wind velocity and the fluctuating aerodynamic loads, does not always hold. (author)

Statistical analysis of modal properties of a cable-stayed bridge through long-term structural health monitoring with wireless smart sensor networks

Science.gov (United States)

Asadollahi, Parisa; Li, Jian

2016-04-01

Understanding the dynamic behavior of complex structures such as long-span bridges requires dense deployment of sensors. Traditional wired sensor systems are generally expensive and time-consuming to install due to cabling. With wireless communication and on-board computation capabilities, wireless smart sensor networks have the advantages of being low cost, easy to deploy and maintain and therefore facilitate dense instrumentation for structural health monitoring. A long-term monitoring project was recently carried out for a cable-stayed bridge in South Korea with a dense array of 113 smart sensors, which feature the world's largest wireless smart sensor network for civil structural monitoring. This paper presents a comprehensive statistical analysis of the modal properties including natural frequencies, damping ratios and mode shapes of the monitored cable-stayed bridge. Data analyzed in this paper is composed of structural vibration signals monitored during a 12-month period under ambient excitations. The correlation between environmental temperature and the modal frequencies is also investigated. The results showed the long-term statistical structural behavior of the bridge, which serves as the basis for Bayesian statistical updating for the numerical model.

Streambed scour evaluations and conditions at selected bridge sites in Alaska, 2013–15

Science.gov (United States)

Beebee, Robin A.; Dworsky, Karenth L.; Knopp, Schyler J.

2017-12-27

Streambed scour potential was evaluated at 52 river- and stream-spanning bridges in Alaska that lack a quantitative scour analysis or have unknown foundation details. All sites were evaluated for stream stability and long-term scour potential. Contraction scour and abutment scour were calculated for 52 bridges, and pier scour was calculated for 11 bridges that had piers. Vertical contraction (pressure flow) scour was calculated for sites 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 also was calculated for large recorded floods at 13 sites.Channel instability at 11 sites was related to human activities (in-channel mining, dredging, and channel relocation). Eight of the dredged sites are located on active unstable alluvial fans and were graded to protect infrastructure. The trend toward aggradation during major floods at these sites reduces confidence in scour estimates.Vertical contraction and pressure flow occurred during the 0.2-percent or smaller annual exceedance probability floods at eight sites. Contraction scour exceeded 5 feet (ft) at four sites, and total scour at piers (pier scour plus contraction scour) exceeded 5 ft at four sites. Debris accumulation increased calculated pier scour at six sites by an average of 2.4 ft. Total scour at abutments exceeded 5 ft at 10 sites. Scour estimates seemed excessive at two piers where equations did not account for channel armoring, and at four abutments where failure of the embankment and attendant channel widening would reduce scour.

Potential of TCPInSAR in Monitoring Linear Infrastructure with a Small Dataset of SAR Images: Application of the Donghai Bridge, China

Directory of Open Access Journals (Sweden)

Lei Zhang

2018-03-01

Full Text Available Reliably monitoring deformation associated with linear infrastructures, such as long-span bridges, is vitally important to assess their structural health. In this paper, we attempt to employ satellite interferometric synthetic aperture radar (InSAR to map the deformation of Donghai Bridge over a half of an annual cycle. The bridge, as the fourth longest cross-sea bridge in the world, located in the north of Hangzhou Bay, East China Sea where the featureless sea surface largely occupied the radar image raises challenges to accurately co-register the coherent points along the bridge. To tackle the issues due to co-registration and the limited number of synthetic aperture radar (SAR images, we adopt the termed temporarily-coherent point (TCP InSAR (TCPInSAR technique to process the radar images. TCPs that are not necessarily coherent during the whole observation period can be identified within every two SAR acquisitions during the co-registration procedure based on the statistics of azimuth and range offsets. In the process, co-registration is performed only using the offsets of these TCPs, leading to improved interferometric phases and the local Delaunay triangulation is used to construct point pairs to reduce the atmospheric artifacts along the bridge. With the TCPInSAR method the deformation rate along the bridge is estimated with no need of phase unwrapping. The achieved result reveals that the Donghai Bridge suffered a line-of-sight (LOS deformation rate up to −2.3 cm/year from January 2009 to July 2009 at the cable-stayed part, which is likely due to the thermal expansion of cables.

Signal Enhancement with Variable Span Linear Filters

DEFF Research Database (Denmark)

Benesty, Jacob; Christensen, Mads Græsbøll; Jensen, Jesper Rindom

This book introduces readers to the novel concept of variable span speech enhancement filters, and demonstrates how it can be used for effective noise reduction in various ways. Further, the book provides the accompanying Matlab code, allowing readers to easily implement the main ideas discussed....... Variable span filters combine the ideas of optimal linear filters with those of subspace methods, as they involve the joint diagonalization of the correlation matrices of the desired signal and the noise. The book shows how some well-known filter designs, e.g. the minimum distortion, maximum signal......-to-noise ratio, Wiener, and tradeoff filters (including their new generalizations) can be obtained using the variable span filter framework. It then illustrates how the variable span filters can be applied in various contexts, namely in single-channel STFT-based enhancement, in multichannel enhancement in both...

Existing Steel Railway Bridges Evaluation

Science.gov (United States)

Vičan, Josef; Gocál, Jozef; Odrobiňák, Jaroslav; Koteš, Peter

2016-12-01

The article describes general principles and basis of evaluation of existing railway bridges based on the concept of load-carrying capacity determination. Compared to the design of a new bridge, the modified reliability level for existing bridges evaluation should be considered due to implementation of the additional data related to bridge condition and behaviour obtained from regular inspections. Based on those data respecting the bridge remaining lifetime, a modification of partial safety factors for actions and materials could be respected in the bridge evaluation process. A great attention is also paid to the specific problems of determination of load-caring capacity of steel railway bridges in service. Recommendation for global analysis and methodology for existing steel bridge superstructure load-carrying capacity determination are described too.

Hydraulic modeling of flow impact on bridge structures: a case study on Citarum bridge

Science.gov (United States)

Siregar, R. I.

2018-02-01

Flood waves because of the rapid catchment response to high intense rainfall, breaches of flood defenses may induce huge impact forces on structures, causing structural damage or even failures. Overflowing stream that passes over the bridge, it means to discharge flood water level is smaller than the capacity of the river flow. In this study, the researches present the methodological approach of flood modeling on bridge structures. The amount of force that obtained because of the hydrostatic pressure received by the bridge at the time of the flood caused the bridge structure disrupted. This paper presents simulation of flow impact on bridge structures with some event flood conditions. Estimating the hydrostatic pressure developed new model components, to quantify the flow impact on structures. Flow parameters applied the model for analyzing, such as discharge, velocity, and water level or head that effect of bridge structures. The simulation will illustrate the capability of bridge structures with some event flood river and observe the behavior of the flow that occurred during the flood. Hydraulic flood modeling use HEC-RAS for simulation. This modeling will describe the impact on bridge structures. Based on the above modelling resulted, in 2008 has flood effect more than other years on the Citarum Bridge, because its flow overflow on the bridge.

Electrode spanning with partial tripolar stimulation mode in cochlear implants.

Science.gov (United States)