WorldWideScience

Sample records for bridge decks

  1. Fatigue assessment for deck plates in orthotropic bridge decks

    NARCIS (Netherlands)

    Maljaars, J.; Dooren, F. van; Kolstein, H.

    2012-01-01

    Since the 1960s, orthotropic deck plates of highway bridges have been built with large coldformed trapezoidal stiffeners supporting a deck plate with a thickness of approx. 12 mm. The maximum cross-beam spacing is approx. 4 m. A number of these bridge decks in The Netherlands suffer from fatigue cra

  2. Steel plate reinforcement of orthotropic bridge decks

    NARCIS (Netherlands)

    Teixeira de Freitas, S.

    2012-01-01

    The PhD research is focused on the reinforcement of fatigue cracked orthotropic steel bridge decks (OBD) by adding a second steel plate to the existing deck. The main idea is to stiffen the existing deck plate, which will reduce the stresses at the fatigue sensitive details and extend the fatigue li

  3. Gust loading on streamlined bridge decks

    DEFF Research Database (Denmark)

    Larose, Guy; Mann, Jakob

    1998-01-01

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

  4. Renovation techniques for fatigue cracked orthotropic steel bridge decks

    NARCIS (Netherlands)

    de Jong, F.B.P.

    2007-01-01

    This dissertation presents the research into renovation techniques for orthotropic steel bridge decks. These techniques are needed to solve fatigue problems in the decks of these bridges, as several fatigue cracks have been detected in the deck structure of these bridges the last decade. A well-know

  5. Ultrasonic Underside Inspection for Fatigue Cracks in the Deck Plate of a Steel Orthotropic Bridge Deck

    NARCIS (Netherlands)

    Bakker, M.C.M.; De Jong, F.B.P.

    2003-01-01

    Due to an unexpected increase of heavy traffic large fatigue cracks appeared through the deck plate of orthotropic steel bridge decks in the Netherlands. Visual inspection revealed that this particular type of crack initiates where a weld joins the deck plate, a rib and a girder. These critical poin

  6. Fatigue Performance of Bridge Deck Pavement Materials

    Institute of Scientific and Technical Information of China (English)

    WU Shaopeng; ZHANG Guang; HAN Jun; LIU Gang; ZHOU Jie

    2009-01-01

    Three beam samplesof bridge deck pavementwere prepared, with gradationtypes of AC-13, and AC-16 and combined AC-13+AC-16. Four-point bending test was adopted to investigate the fatigue performance of these beam samples. The experimental results indicate that the initial bending stiffness is related to the type of beam sample and testing temperature. Fatigue life of these samples decreases as the increase of the controlled strain level. The AC-13 beam sample exhibits better fatigue resistance and bigger limiting bending strain at the given strain level and temperature. Com-pared with single beam sample, the fatigue performance of combining beam sample is relatively poor.

  7. Development of a nondestructive evaluation method for FRP bridge decks

    Science.gov (United States)

    Brown, Jeff; Fox, Terra

    2010-05-01

    Open steel grids are typically used on bridges to minimize the weight of the bridge deck and wearing surface. These grids, however, require frequent maintenance and exhibit other durability concerns related to fatigue cracking and corrosion. Bridge decks constructed from composite materials, such as a Fiber-reinforced Polymer (FRP), are strong and lightweight; they also offer improved rideability, reduced noise levels, less maintenance, and are relatively easy to install compared to steel grids. This research is aimed at developing an inspection protocol for FRP bridge decks using Infrared thermography. The finite element method was used to simulate the heat transfer process and determine optimal heating and data acquisition parameters that will be used to inspect FRP bridge decks in the field. It was demonstrated that thermal imaging could successfully identify features of the FRP bridge deck to depths of 1.7 cm using a phase analysis process.

  8. Detection of Subsurface Defects in Concrete Bridge Deck Joints

    Directory of Open Access Journals (Sweden)

    Wonchang Choi

    2011-01-01

    Full Text Available Problem statement: The integrity of deck joints in highway bridges plays a major role to determine overall performance of bridge system. As the bridge maintenance program, the defects in deck joints have historically been detected by conventional non-destructive testing and evaluation methods such as visual inspection, chain-dragging and by the detecting sounds under the traffic. Future bridge maintenance challenges will demand the development of techniques and procedures to detect and monitor such defects before they become apparent. Approach: Two non-destructive methods; namely Ground Penetration Radar (GPR and Seismic Properties Analyzer (SPA were employed to assess the integrity of deck joins installed in North Carolina bridges. Results: The results obtained with the GPR and SPA allows to quantify the subsurface defects in bridge deck joints. Conclusion: The practical application and limitations of each method are discussed in this study.

  9. 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...

  10. Investigation of Aerodynamic Interference of Double Deck Bridges

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-01

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

  11. Behavior of FRP Link Slabs in Jointless Bridge Decks

    Directory of Open Access Journals (Sweden)

    Aziz Saber

    2012-01-01

    Full Text Available The paper investigated the use of fiberglass-reinforced plastic (FRP grid for reinforcement in link slabs for jointless bridge decks. The design concept of link slab was examined based on the ductility of the fiberglass-reinforced plastic grid to accommodate bridge deck deformations. The implementation of hybrid simulation assisted in combining the experimental results and the theoretical work. The numerical analyses and the experimental work investigated the behavior of the link slab and confirmed its feasibility. The results indicated that the technique would allow simultaneous achievement of structural need, lower flexural stiffness of the link slab approaching the behavior of a hinge, and sustainability need of the link slab. The outcome of the study supports the contention that jointless concrete bridge decks may be designed and constructed with fiberglass-reinforced plastic grid link slabs. This concept would also provide a solution to a number of deterioration problems associated with bridge deck joints and can be used during new construction of bridge decks. The federal highway administration provided funds to Louisiana Department of Transportation through the innovative bridge research and development program to implement the use of FRP grid as link slab.

  12. Multidisciplinary health monitoring of a steel bridge deck structure

    NARCIS (Netherlands)

    Pahlavan, L.; Pijpers, R.J.M.; Paulissen, J.H.; Hakkesteegt, H.C.; Jansen, T.H.

    2013-01-01

    Fatigue cracks in orthotropic bridge decks are an important cause for the necessary renovation of existing bridges. Parallel utilization of various technologies based on different physical sensing principles can potentially maximize the efficiency of structural health monitoring (SHM) systems for th

  13. Fatigue classification of welded joints in orthotropic steel bridge decks

    NARCIS (Netherlands)

    Kolstein, M.H.

    2007-01-01

    This dissertation presents the research into fatigue classifications of welded joints in orthotropic steel bridge decks. These classifications are needed to calculate the fatigue life of these joints and should be included in the design codes. For years bridge design was mainly based on static loadi

  14. Fabrication procedure effects on fatigue resistance of rib -to-deck welded joints of steel orthotropic bridge decks

    OpenAIRE

    Sim, Hyoung-Bo

    2010-01-01

    Orthotropic steel bridge decks have been widely used for long- and medium-span bridges due to excellent structural characteristics. However, orthotropic decks have experienced various fatigue problems, resulting from high cyclic stresses in conjunction with inadequate welding details. In particular, crack at rib-to-deck welded joints due to wheel load is a concern because inspection and repair of the back side of this weld for closed ribs is not practical due to lack of access. Fatigue resist...

  15. Service Life and Maintenance Modelling of Reinforced Concrete Bridge Decks

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Recent research in the area of assessment and maintenance of reinforced concrete bridge decks is presented in this paper. Three definitions of service lifetime are introduced and the difficult problem of assessing the service life is discussed. A stochastic modelling of corrosion and corrosion...

  16. Concrete bridge deck early problem detection and mitigation using robotics

    Science.gov (United States)

    Gucunski, Nenad; Yi, Jingang; Basily, Basily; Duong, Trung; Kim, Jinyoung; Balaguru, Perumalsamy; Parvardeh, Hooman; Maher, Ali; Najm, Husam

    2015-04-01

    More economical management of bridges can be achieved through early problem detection and mitigation. The paper describes development and implementation of two fully automated (robotic) systems for nondestructive evaluation (NDE) and minimally invasive rehabilitation of concrete bridge decks. The NDE system named RABIT was developed with the support from Federal Highway Administration (FHWA). It implements multiple NDE technologies, namely: electrical resistivity (ER), impact echo (IE), ground-penetrating radar (GPR), and ultrasonic surface waves (USW). In addition, the system utilizes advanced vision to substitute traditional visual inspection. The RABIT system collects data at significantly higher speeds than it is done using traditional NDE equipment. The associated platform for the enhanced interpretation of condition assessment in concrete bridge decks utilizes data integration, fusion, and deterioration and defect visualization. The interpretation and visualization platform specifically addresses data integration and fusion from the four NDE technologies. The data visualization platform facilitates an intuitive presentation of the main deterioration due to: corrosion, delamination, and concrete degradation, by integrating NDE survey results and high resolution deck surface imaging. The rehabilitation robotic system was developed with the support from National Institute of Standards and Technology-Technology Innovation Program (NIST-TIP). The system utilizes advanced robotics and novel materials to repair problems in concrete decks, primarily early stage delamination and internal cracking, using a minimally invasive approach. Since both systems use global positioning systems for navigation, some of the current efforts concentrate on their coordination for the most effective joint evaluation and rehabilitation.

  17. Tranverse Deck Reinforcement for Use in Tide Mill Bridge

    OpenAIRE

    Bajzek, Sasha N

    2013-01-01

    The objective of the research presented in this thesis was to study and optimize the transverse deck reinforcement for a skewed concrete bridge deck supported by Hybrid Composite Beams (HCB\\'s).  An HCB consists of a Glass Fiber Reinforced Polymer outer shell, a concrete arch, and high strength seven wire steel strands running along the bottom to tie the ends of the concrete arch together.  The remaining space within the shell is filled with foam.  The concrete arch does not need to be cast u...

  18. Performance of Bridge Decks and Girders with Lightweight Aggregate Concrete

    OpenAIRE

    Ramirez, J.A.; Olek, J.; Rolle, Eric Joseph; Manlone, Brian J.

    2000-01-01

    Structural lightweight concrete is a very versatile material and Haydite and Minergy lightweight aggregates can be utilized in the mixture development of concrete for use in girders and decks in bridges. More widespread use of lightweight aggregates (LWA) would result in savings in construction cost due to considerable dead load reduction. The materials phase of this research study evaluated the fresh concrete properties (slump, unit weight, and air content), the mechanical properties of ha...

  19. Flutter Derivatives Identification and Aerodynamic Performance of an Optimized Multibox Bridge Deck

    Directory of Open Access Journals (Sweden)

    Zhida Wang

    2016-01-01

    Full Text Available The bridge deck sections used for long-span suspension bridges have evolved through the years, from the compact box deck girders geometrical configurations to twin-box and three-box bridge decks sections. The latest generation of split and multiple-box bridge decks proved to have better aerodynamic behavior; thus further optimization methods are sought for such geometrical configurations. A new type of multibox bridge deck, consisting of four aerodynamically shaped deck boxes, two side decks for the traffic lanes and two middle decks for the railway traffic, connected between them by stabilizing beams, was tested in the wind tunnel for identifying the flutter derivatives and to verify the aerodynamic performance of the proposed multibox deck. Aerodynamic static force coefficients were measured for the multibox bridge deck model, scaled 1 : 80, for Reynolds numbers up to 5.1 × 105, under angles of attack between −8° and 8°. Iterative Least Squares (ILS method was employed for identifying the flutter derivatives of the multibox bridge deck model, based on the results obtained from the free vibration tests and based on the frequency analysis the critical flutter wind speed for the corresponding prototype of the multibox bridge was estimated at 188 m/s.

  20. Causes of Early Age Cracking on Concrete Bridge Deck Expansion Joint Repair Sections

    Directory of Open Access Journals (Sweden)

    Jared R. Wright

    2014-01-01

    Full Text Available Cracking of newly placed binary Portland cement-slag concrete adjacent to bridge deck expansion dam replacements has been observed on several newly rehabilitated sections of bridge decks. This paper investigates the causes of cracking by assessing the concrete mixtures specified for bridge deck rehabilitation projects, as well as reviewing the structural design of decks and the construction and curing methods implemented by the contractors. The work consists of (1 a comprehensive literature review of the causes of cracking on bridge decks, (2 a review of previous bridge deck rehabilitation projects that experienced early-age cracking along with construction observations of active deck rehabilitation projects, and (3 an experimental evaluation of the two most commonly used bridge deck concrete mixtures. Based on the literature review, the causes of concrete bridge deck cracking can be classified into three categories: concrete material properties, construction practices, and structural design factors. The most likely causes of the observed early-age cracking were found to be inadequate curing and failure to properly eliminate the risk of plastic shrinkage cracking. These results underscore the significance of proper moist curing methods for concrete bridge decks, including repair sections. This document also provides a blueprint for future researchers to investigate early-age cracking of concrete structures.

  1. Experimental study of aerodynamic interference effects on aerostatic coefficients of twin deck bridges

    Institute of Scientific and Technical Information of China (English)

    Zhiwen LIU; Zhengqing CHEN; Gao LIU; Xinpeng SHAO

    2009-01-01

    The aerodynamic interference effects on aero-static coefficients of twin deck bridges with large span were investigated in detail by means of wind tunnel test.The distances between the twin decks and wind attack angles were changed during the wind tunnel test to study the effects on aerodynamic interferences of aerostatic coefficients of twin decks. The research results have shown that the drag coefficients of the leeward deck are much smaller than that of a single leeward deck. The drag coefficients of a windward deck decrease slightly com-pared with that of a single deck. The lift and torque coefficients of windward and leeward decks are also affected slightly by the aerodynamic interference of twin decks. And the aerodynamic interference effects on lift and torque coefficients of twin decks can be neglected.

  2. Biaxial Behavior of Ultra-High Performance Concrete and Untreated UHPC Waffle Slab Bridge Deck Design and Testing

    OpenAIRE

    D'Alessandro, Kacie Caple

    2013-01-01

    Ultra-high performance concrete (UHPC) was evaluated as a potential material for future bridge deck designs. Material characterization tests took place to identify potential challenges in mixing, placing, and curing UHPC. Biaxial testing was performed to evaluate behavior of UHPC in combined tension and compression stress states. A UHPC bridge deck was designed to perform similarly to a conventional concrete bridge deck, and a single unit bridge deck section was tested to evaluate the desi...

  3. Static and fatigue investigation of second generation steel free bridge decks

    International Nuclear Information System (INIS)

    This paper outlines the static and fatigue behavior of two different cast-in-place second generation steel-free bridge decks, which are: hybrid carbon fiber reinforced polymer (CFRP); and glass fiber reinforced polymer (GFRP) and steel strap design. Although cast monolithically, the first deck slab was divided into three segments with different reinforcement configurations. All three segments were tested under a 222kN cyclic loading to investigate fatigue behavior. The second bridge deck comprised an internal panel and two cantilevers and was equipped with a civionics system. The internal panel static test that this paper deals with is useful in the development of fatigue theory derived from fatigue testing of the first bridge deck. Test results form the cyclic loading of the first bridge deck indicated that the cross-sectional area of the reinforcement used in the test bridge deck can be reduced by 40% based on the reinforcement provided in the deck under service loads. The hybrid system also reduced the development of longitudinal crack widths to approximately 0.4 mm under service conditions, compared to the cracks that occurred approximately halfway between adjacent bridge girders that were determined to be roughly 1 mm in several first generation steel-free bridge decks constructed in Canada. Civionics, also discussed in the paper, is a new term coined from Civil-Electronics, which is the application of electronics to civil structures. The Civionics Specifications (2004) developed by ISIS Canada researchers are a helpful design tool for engineers and contractors to develop civionics and structural health monitoring systems for civil infrastructure that will last the lifetime of a structure. The use of civionics for the second test bridge deck ensured the survival of 100% of the 63 internal sensors throughout the rigors of the construction and casting of the deck. (author)

  4. Implementation of a Non-Metallic Reinforced Bridge Deck, Volume 2: Thayer Road Bridge

    OpenAIRE

    Frosch, Robert J.; Pay, Ali Cihan

    2006-01-01

    The primary maintenance problem with bridges in Indiana has been deterioration of the concrete deck which is often related to corrosion of the reinforcing steel. While a corrosion protection system consisting of epoxy-coated reinforcement in combination with 2-1/2 in. of Class C concrete cover has been used in Indiana, research and experience have demonstrated that this system can be compromised. As an alternative solution to the corrosion problem in reinforced concrete, fiber reinforced poly...

  5. Comparative Study on Pavement Temperature Features of Bridge Deck and Road Pavement

    OpenAIRE

    Yueqin Hou; Nanxiang Zheng; Yiluo Zhang

    2013-01-01

    The objective of this study was to comparatively analyze the difference of pavement temperature of bride deck and road pavement. The asphalt pavement temperature of road pavement and bride deck were tested in Guozigou area of Xinjiang, China. And the air temperature, wind speed, humidness and sunlight radiation were collected. Further, the distribution features of asphalt pavement of bridge deck and road pavement were comparatively analyzed. At last, the predictive model of pavement temperatu...

  6. Proof Testing a Bridge Deck Design with Glass Fiber Reinforced Polymer Bars as Top Mat of Reinforcement

    OpenAIRE

    Jason K. Cawrse; Roberts-Wollmann, Carin L.

    2003-01-01

    The primary objective of this project was to test a full-scale prototype of a bridge deck design containing glass fiber reinforced polymer (GFRP) bars as the top mat of reinforcement. The test deck mimics the design of the deck of one span of the new bridge over Gills Creek on Rt. 668 in Franklin County, Virginia. The purpose of the tests was to verify the deck design and provide assurance that the deck will behave as expected. Aspects of the behavior of the bridge deck, such as failure load,...

  7. Field Application of Automated Power Arc Spraying System on Steel Bridge Deck

    Institute of Scientific and Technical Information of China (English)

    YI Chun-long; SUO Shuang-fu; SUN Zhi; PANG Xu-nan

    2004-01-01

    The effective corrosion protection coating and high productive coating equipment for steel bridge deck has been a challenge for bridge engineers for many years. An automated power arc spraying system was first designed and field applied to coating the deck of Wuhan Junshan Yangtze River Bridge in high efficiency. This steel bridge is a continuous orthotropic deck box girder cable-stayed bridge with 962 m in length and 38.8 m in width, whose width is the No. 1 in China. The whole orthotropic deck with over 35,000 m2surface area was arc-sprayed a protective coating of zinc on site, followed by a sealant and SMA paving material. The side face and bottom of box girders were arc-sprayed with aluminum in factory.Field application indicated that the newly designed automated power arc spraying system with fan nozzle and separate primary & secondary atomizing air had some advantages over the conventional arc spraying system, such as automated operation,big arc spray current, high spraying rate, big breadth of each coat, even and small atomized particles, high density and low porosity of sprayed coating, and high adhesive strength to the substrate.Working procedure of surface preparation and automated arc spraying on bridge deck were introduced, and the quality of sprayed coating is controlled strictly. Field tests proved that the application of this automated power arc spraying system is successful and suitable for coating the steel bridge deck.

  8. Optimum Design of Multilayer Asphalt Surfacing Systems for Orthotropic Steel Deck Bridges

    NARCIS (Netherlands)

    Li, J.

    2015-01-01

    Orthotropic steel decks are widely utilized in long span bridges, movable bridges and shorter span road and rail bridges due to their favourable properties. These properties are low deadweight, large plastic reserves in case of overload and aesthetic advantages. Nowadays, more than 1000 orthotropic

  9. Performance in Transverse Direction of Fiber‐Reinforced Polymer Bridge Decks

    OpenAIRE

    Brühwiler, Eugen; Yanes Armas, Sonia; de Castro San Roman, Julia; Keller, Thomas

    2015-01-01

    Pultruded glass fiber‐reinforced polymer (GFRP) bridge decks distribute punctual vehicular loads to the underlying superstructure and can also act as the upper chord of hybrid main girders. The deck’s structural performance in both cases is influenced by its transverse behavior. The static bending behavior in the transverse‐to‐pultrusion direction of two GFRP bridge deck systems with trapezoidal (DS) and triangular (AS) cell cross‐sectional geometry was experimentally studied. Different load ...

  10. Parameters Influencing the Corrosion Protection Service Life of Epoxy Coated Reinforcing Steel in Virginia Bridge Decks

    OpenAIRE

    Wheeler, Megan Caroline

    2003-01-01

    This study is an evaluation of epoxy coated reinforcing steel (ECR) and its ability to effectively provide corrosion protection in reinforced concrete highway bridge decks. An analysis was conducted on 10 bridge decks built in the state of Virginia between the years 1981 and 1995. A total of 141 cores containing either ECR or bare steel were evaluated. A chloride solution was applied to the surface on a weekly cycle (for a total duration of 3.06 years) and a nondestructive electrochemica...

  11. Corrosion Protection Service Life of Epoxy-Coated Reinforcing Steel in Virginia Bridge Decks

    OpenAIRE

    Brown, Michael C.; Weyers, Richard E.; Megan C. Wheeler

    2003-01-01

    The corrosion protection service life extension provided by epoxy-coated reinforcement (ECR) was determined by comparing ECR and bare steel bars from 10 Virginia bridge decks built between 1981 and 1995. The objective was to determine the corrosion protection service life time extension provided by ECR field specimens with various degrees of coating adhesion: disbonded, partially disbonded, and wholly bonded coatings. The size and length distributions of cracks in Virginia bridge decks were i...

  12. Crack mitigation in concrete bridge decks through experimental analysis and computer modeling

    Science.gov (United States)

    Richardson, Douglas M.

    Bridge deck cracking can cause deterioration of bridge decks, leading to a shorter life span and poor performance. Throughout the US, cracking has been identified as a problem, with transverse cracking along the deck at regular spacings being the most prominent type. This problem is usually caused by drying shrinkage within the concrete. The material properties, restraint, and distances without expansion joints all affect the crack pattern within the deck. This study will delve into the reasons that bridge decks crack, the strains that are associated with drying shrinkage, and possible methods for abating its effects. The research is divided into two parts, the first being laboratory experimentation, which was conducted through the use of two 7 ft. x 10 ft. experimental concrete bridge bays. Each bay was instrumented with strain and temperature gages throughout the deck and girders, which collected data for six months. The first deck was poured with a control concrete mix used currently in Illinois. The second deck was poured with a type K expansive concrete, which could battle the effects of shrinkage. For both decks, the results suggest a compressive strain throughout the rebar and along the top surface of the concrete, except for the locations where cracks are found (at these locations the strain slopes upward into tension). The strain in the type K deck, though, was notably less than that in the control deck and the onset of cracking was delayed by three weeks, giving the indication of an improvement over the current mix design. The second portion of the research was focused on using a finite element model to replicate the bridge bay and study the results. Equivalent temperature loading was used to apply the shrinkage loads recorded during the experimental portion of the research. The model was then expanded to encompass a full-scale bridge and in order to provide some insight into shrinkage strain in the real world. The end goal is to help alleviate cracking

  13. Analysis, prediction, and case studies of early-age cracking in bridge decks

    Science.gov (United States)

    ElSafty, Adel; Graeff, Matthew K.; El-Gharib, Georges; Abdel-Mohti, Ahmed; Mike Jackson, N.

    2016-06-01

    Early-age cracking can adversely affect strength, serviceability, and durability of concrete bridge decks. Early age is defined as the period after final setting, during which concrete properties change rapidly. Many factors can cause early-age bridge deck cracking including temperature change, hydration, plastic shrinkage, autogenous shrinkage, and drying shrinkage. The cracking may also increase the effect of freeze and thaw cycles and may lead to corrosion of reinforcement. This research paper presents an analysis of causes and factors affecting early-age cracking. It also provides a tool developed to predict the likelihood and initiation of early-age cracking of concrete bridge decks. Understanding the concrete properties is essential so that the developed tool can accurately model the mechanisms contributing to the cracking of concrete bridge decks. The user interface of the implemented computer Excel program enables the user to input the properties of the concrete being monitored. The research study and the developed spreadsheet were used to comprehensively investigate the issue of concrete deck cracking. The spreadsheet is designed to be a user-friendly calculation tool for concrete mixture proportioning, temperature prediction, thermal analysis, and tensile cracking prediction. The study also provides review and makes recommendations on the deck cracking based mainly on the Florida Department of Transportation specifications and Structures Design Guidelines, and Bridge Design Manuals of other states. The results were also compared with that of other commercially available software programs that predict early-age cracking in concrete slabs, concrete pavement, and reinforced concrete bridge decks. The outcome of this study can identify a set of recommendations to limit the deck cracking problem and maintain a longer service life of bridges.

  14. 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.

  15. Towards Sensor-Based Health Monitoring Systems for Bridge Decks: A Full-Depth Precast Deck Panels Case Study

    Directory of Open Access Journals (Sweden)

    Osama Y. Abudayyeh

    2010-01-01

    Full Text Available Traffic and variable loading conditions greatly influence the performance, durability, and safety of a bridge structure throughout its service life. Continuous monitoring can provide the basis for determining the deterioration rate and for estimating the remaining service life, thus assisting in making important decisions regarding bridge maintenance. This paper presents the design and implementation of a health monitoring system for condition assessment of full-depth precast concrete bridge deck, which was developed for the Parkview Bridge in Kalamazoo, Michigan. This system is composed of a remotely accessible on-site data acquisition system and a sensor network of vibrating wire strain gauges to monitor strain and temperature over given time increments. The system relies on the sensor network embedded in the bridge deck to gather static performance data under different loading conditions to provide condition assessment by collecting, storing, analyzing, and reporting relevant performance data over time. The paper presents a practical case study that mainly focuses on describing the initial steps in the development of the sensor network system, namely, the design (system architecture and data structures and construction along with examples of how the data is acquired, organized, presented, and analyzed, keeping in mind that the bridge is still early in its life-cycle and has not yet experienced any structural problems.

  16. To the question of reliability and durability ballastless deck of bridge

    Directory of Open Access Journals (Sweden)

    V.V. Prystynskaya

    2012-12-01

    Full Text Available The principal causes of operational defects in bridge ballastless deck plates are considered in the article. The drawbacks of these plates construction that prevent from achieving a higher level of bridge framework reliability and durability have been analysed.

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

    OpenAIRE

    Zhang, Huiying

    1999-01-01

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

  18. Stiffness and strength of fiber reinforced polymer composite bridge deck systems

    Science.gov (United States)

    Zhou, Aixi

    This research investigates two principal characteristics that are of primary importance in Fiber Reinforced Polymer (FRP) bridge deck applications: STIFFNESS and STRENGTH. The research was undertaken by investigating the stiffness and strength characteristics of the multi-cellular FRP bridge deck systems consisting of pultruded FRP shapes. A systematic analysis procedure was developed for the stiffness analysis of multi-cellular FRP deck systems. This procedure uses the Method of Elastic Equivalence to model the cellular deck as an equivalent orthotropic plate. The procedure provides a practical method to predict the equivalent orthotropic plate properties of cellular FRP decks. Analytical solutions for the bending analysis of single span decks were developed using classical laminated plate theory. The analysis procedures can be extended to analyze continuous FRP decks. It can also be further developed using higher order plate theories. Several failure modes of the cellular FRP deck systems were recorded and analyzed through laboratory and field tests and Finite Element Analysis (FEA). Two schemes of loading patches were used in the laboratory test: a steel patch made according to the ASSHTO's bridge testing specifications; and a tire patch made from a real truck tire reinforced with silicon rubber. The tire patch was specially designed to simulate service loading conditions by modifying real contact loading from a tire. Our research shows that the effects of the stiffness and contact conditions of loading patches are significant in the stiffness and strength testing of FRP decks. Due to the localization of load, a simulated tire patch yields larger deflection than the steel patch under the same loading level. The tire patch produces significantly different failure compared to the steel patch: a local bending mode with less damage for the tire patch; and a local punching-shear mode for the steel patch. A deck failure function method is proposed for predicting the

  19. Influence of Bridge Deck Concrete Parameters on the Reinforcing Steel Corrosion

    OpenAIRE

    Balakumaran, Soundar Sriram G.

    2010-01-01

    Chloride induced corrosion of steel in concrete is one of the major forms of deterioration mechanisms found in reinforced concrete bridges. Early age corrosion damage reduces the lifespan of the bridges, which results in heavy economic losses. Research has been conducted to identify economic solutions for significantly delaying and/or preventing corrosion damage. Considering the amount of steel reinforcement used in bridge decks, the influence of as constructed parameters including clear spac...

  20. On the aeroelastic transient behaviour of a streamlined bridge deck section in a wind tunnel

    Science.gov (United States)

    Manzoor, S.; Hémon, P.; Amandolese, X.

    2011-11-01

    The study deals with the transient behaviour of a two degrees of freedom bridge deck section in a wind tunnel under the effect of an initial excitation. Response of the bridge deck section subjected to an initial mechanical excitation and excitation by an upstream gust is investigated separately. Experiments are conducted with three different frequency ratios between the plunge and pitch degrees of freedom. This experimental study shows that transient growth of energy occurs for wind velocities below the onset of flutter, reaching a level higher than 5 times the level of the initial excitation. In high wind conditions, this means that statistical or spectral computation techniques might underestimate the motion amplitude reached by a flexible bridge deck. This emphasises the importance of using temporal techniques under such circumstances.

  1. Performance of a Bridge Deck with Glass Fiber Reinforced Polymer Bars as the Top Mat of Reinforcement

    OpenAIRE

    Kimberly A. Phillips; Matthew Harlan; Roberts-Wollmann, Carin L.; Cousins, Thomas E.

    2005-01-01

    The purpose of this research was to investigate the performance of glass fiber reinforced polymer (GFRP) bars as reinforcement for concrete decks. Today's rapid bridge deck deterioration is calling for a replacement for steel reinforcement. The advantages of GFRP such as its high tensile strength, light weight, and resistance to corrosion make it an attractive alternative to steel. The deck of one end-span of the Gills Creek Bridge was constructed with GFRP bars as the top mat and epoxy-coate...

  2. Performance of a Bridge Deck with Glass Fiber Reinforced Polymer (GFRP) Bars as the Top Mat of Reinforcement

    OpenAIRE

    Phillips, Kimberly Ann

    2004-01-01

    The purpose of this research was to investigate the effectiveness and durability of GFRP bars as reinforcement for concrete decks. Today's rapid bridge deck deterioration is calling for a replacement for steel reinforcement. The advantages of GFRP such as its high tensile strength, light weight, and resistance to corrosion make it an attractive alternative to steel. The first objective of this research was to perform live load testing on a bridge deck reinforced with GFRP in one span and...

  3. A Review of Buffeting Loading on Bridge Decks

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The strip assumption is the basis of current buffeting analysis. However, the strip assumption has limitation in describing the buffeting load on a line-like structure. The validity of strip assumption was presented and an empirical 3-D aerodynamic admittance was proposed to describe the lift on streamlined decks. The relations between the 3-D admittance and Sears function are depicted.

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

    Science.gov (United States)

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

    2011-04-01

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

  5. Advanced numerical study of the response of orthotropic steel deck bridge with two membrane layers system

    NARCIS (Netherlands)

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

    2012-01-01

    In the Netherlands an asphaltic surfacing structure for orthotropic steel bridge decks mostly consists of two structural layers. The upper layer consists of Porous Asphalt (PA) because of reasons related to noise hindrance. For the lower layer a choice between Mastic Asphalt (MA) or Guss Asphalt (GA

  6. Assessment of concrete bridge decks with alkali silica reactions

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  7. Evaluation of Fiber Optic Strain Measurement System for Monitoring FRP Bridge Decks

    Science.gov (United States)

    Klinkhachorn, P.; Lonkar, G. M.; Halabe, Udaya B.; GangaRao, H. V. S.

    2005-04-01

    The use of Fiber Optic sensors for structural monitoring applications has attained popularity among researchers and practitioners recently due to their immense advantages. This paper discusses a continuous structural monitoring technique using surface mounted and embedded fiber optic strain sensors to measure the strain in FRP bridge decks. An Extrinsic Fabry-Perot Interferometric (EFPI) strain sensor was selected for evaluation as it offers a good compromise between accuracy and cost considerations. This EFPI strain sensor, along with a conventional strain gauge, was surface mounted on a FRP bridge decks. The decks were then subjected to an accelerated aging test in an environmental chamber and the performance of both the strain sensors was recorded for a performance comparison. The results from the seven months of accelerated aging that is equivalent to 10 years of actual life show that the strain gauge sensor and the EFPI Fiber Optic sensor are still in working condition. The EFPI fiber optic sensor detects minute and sudden changes in strain more effectively than the strain gauge sensor. Placement in the environmental chamber did not affect the EFPI sensor's performance and is an indication of its applicability to field structural monitoring for lengthy periods of time. The second part is a preliminary work where a fiber optic sensor was embedded inside a FRP plate during the pultrusion process. This shows the feasibility of manufacturing FRP bridge decks with embedded fiber optic sensors.

  8. Experimental Evaluation and Implementation of Post-Tensioning in Concrete Bridge Decks

    OpenAIRE

    Ramirez, Julio A.; Aguilar, Gerardo

    2010-01-01

    A research program was conducted to evaluate the design recommendations for transverse post-tensioning of bridge decks developed in the FHWA/IN/JTRP/2002-26 (SPR-2409) report. The test specimen consisted of a 40x18 ft cast-in-place concrete deck on precast pretensioned girders. Thirty-two tests were carried out by applying different distributions of transverse post-tensioning force, in combination with a changing number of diaphragms, and two conditions of end-restraint at the supports. The t...

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

    OpenAIRE

    Miceli, Marybeth

    2000-01-01

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

  10. Research on the Anticorrosion Coating Under the Paved Layer for Highway Steel Box Bridge Deck

    Institute of Scientific and Technical Information of China (English)

    SHEN Cheng-jin; MING Tu-zhang; HU Guang-wei; OU Xue-mei; GEN Ou

    2006-01-01

    The corrosion of the anticorrosion coating and the defects of the asphalt concrete paved layer have been investigated on long-span steel box bridge decks. The anticorrosion coating lies in the middle of two entirely different materials: a highway steel box bridge deck and a paved layer, which is used as anticorrosion and waterproof coating for the steel bridge deck. For our study, electrochemical corrosion and pull strength experiments have been selected for the investigation of the corrosion properties of inorganic zinc rich coating, epoxy zinc rich coating and arc sprayed zinc coating. The adhesive strength between the coatings and the panel, and the effect of the coating corrosion on the shear properties of the paved layers including cast asphalt, thermal asphalt mortar, epoxy asphalt and modified asphalt concrete have been investigated. The results show that the adhesive strength between the coatings and the bridge panel is controlled by the method of pre-processing rust removal. Coating by sandblasting has stronger adhesive strength than coating by shot peening. The results also reveal that shear strength of the paved layer is affected by the corrosion product of zinc coating. The arc sprayed zinc coating has stronger shear strength than zinc rich coatings.

  11. Numerical simulations and experimental measurements of steel and ice impacts on concrete for acoustic interrogation of delaminations in bridge decks

    Energy Technology Data Exchange (ETDEWEB)

    Mazzeo, Brian A.; Patil, Anjali N.; Klis, Jeffrey M. [Brigham Young University, Department of Electrical and Computer Engineering, Provo, Utah, 84602 (United States); Hurd, Randy C.; Truscott, Tadd T. [Brigham Young University, Department of Mechanical Engineering, Provo, Utah, 84602 (United States); Guthrie, W. Spencer [Brigham Young University, Department of Civil and Environmental Engineering, Provo, Utah, 84602 (United States)

    2014-02-18

    Delaminations in bridge decks typically result from corrosion of the top mat of reinforcing steel, which leads to a localized separation of the concrete cover from the underlying concrete. Because delaminations cannot be detected using visual inspection, rapid, large-area interrogation methods are desired to characterize bridge decks without disruption to traffic, without the subjectivity inherent in existing methods, and with increased inspector safety. To this end, disposable impactors such as water droplets or ice chips can be dropped using automatic dispensers onto concrete surfaces to excite mechanical vibrations while acoustic responses can be recorded using air-coupled microphones. In this work, numerical simulations are used to characterize the flexural response of a model concrete bridge deck subject to both steel and ice impactors, and the results are compared with similar experiments performed in the laboratory on a partially delaminated concrete bridge deck slab. The simulations offer greater understanding of the kinetics of impacts and the responses of materials.

  12. An Automatic Impact-based Delamination Detection System for Concrete Bridge Decks

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Gang; Harichandran, Ronald S.; Ramuhalli, Pradeep

    2012-01-02

    Delamination of concrete bridge decks is a commonly observed distress in corrosive environments. In traditional acoustic inspection methods, delamination is assessed by the "hollowness" of the sound created by impacting the bridge deck with a hammer or bar or by dragging a chain where the signals are often contaminated by ambient traffic noise and the detection is highly subjective. In the proposed method, a modified version of independent component analysis (ICA) is used to filter the traffic noise. To eliminate subjectivity, Mel-frequency cepstral coefficients (MFCC) are used as features for detection and the delamination is detected by a radial basis function (RBF) neural network. Results from both experimental and field data suggest that the proposed methods id noise robust and has satisfactory performance. The methods can also detect the delamination of repair patches and concrete below the repair patches. The algorithms were incorporated into an automatic impact-bases delamination detection (AIDD) system for field application.

  13. Performance of streamlined bridge decks in relation to the aerodynamics of a flat plate

    DEFF Research Database (Denmark)

    Larose, Guy; Livesey, Flora M.

    1997-01-01

    The aerodynamics of three modern bridge decks are compared to the aerodynamics of a 16:1 flat plate. The comparisons are made on the basis of the analytical evaluation of the performance of each cross-section to the buffeting action of the wind. In general, the closed-box girders studied in this ......The aerodynamics of three modern bridge decks are compared to the aerodynamics of a 16:1 flat plate. The comparisons are made on the basis of the analytical evaluation of the performance of each cross-section to the buffeting action of the wind. In general, the closed-box girders studied...... in this paper showed buffeting responses similar to a flat plate with the exception of the multi-box girder which performed much better aerodynamically....

  14. Structural Performance of Light Weight Multicellular FRP Composite Bridge Deck Using Finite Element Analysis

    Institute of Scientific and Technical Information of China (English)

    Woraphot Prachasaree; Pongsak Sookmanee

    2012-01-01

    Fiber reinforced polymer (FRP) composite materials having advantages such as higher strength to weight than conventional engineering materials,non-corrosiveness and modularization,which should help engineers to obtain more efficient and cost effective structural materials and systems.Currently,FRP composites are becoming more popular in civil engineering applications.The objectives of this research are to study performance and behavior of light weight multi-cellular FRP composite bridge decks (both module and system levels) under various loading conditions through finite element modeling,and to validate analytical response of FRP composite bridge decks with data from laboratory evaluations.The relative deflection,equivalent flexural rigidity,failure load (mode) and load distribution factors (LDF) based on FE results have been compared with experimental data and discussed in detail.The finite element results showing good correlations with experimental data are presented in this work.

  15. Performance of Bridge Decks and Girders with Lightweight Aggregate Concrete, v. 2 of 2

    OpenAIRE

    Ramirez, J.A.; Olek, J.; Rolle, Eric Joseph; Malone, Brian Joseph

    2000-01-01

    Structural lightweight concrete is a very versatile material and Haydite and Minergy lightweight aggregates can be utilized in the mixture development of concrete for use in girders and decks in bridges. More widespread use of lightweight aggregates (LWA) would result in savings in construction cost due to considerable dead load reduction. The materials phase of this research study evaluated the fresh concrete properties (slump, unit weight, and air content), the mechanical properties of ...

  16. Simulation of flow around bluff bodies and bridge deck sections using CFD

    OpenAIRE

    Liaw, Kai

    2005-01-01

    This thesis focuses on the simulation of flow around bluff bodies and bridge deck sections, in which unsteady nature and vortex shedding of flow are commonly found, using computational fluid dynamics (CFD). Various turbulence models have been tested to develop understanding and proper modelling techniques for the flow around such bodies. Throughout the thesis, the turbulence models employed, mainly large eddy simulation (LES) and detached eddy simulation (DES), have been validated through...

  17. A Novel Method for Evaluating Fatigue Properties of Bonding Layers Used in Bridge Deck Pavement

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jie; WU Shaopeng; HAN Jun; LIU Gang; ZHANG Guang

    2009-01-01

    A new method was used to evaluate the fatigue properties of the bonding layer used in the bridge deck pavement. The shear fatigue test of three bonding layers was conducted on a dy-namic shear rheometer(DSR). The fatigue formulas were gained for these layers. The experimental results indicate that, at the same torque level or at the same frequency, neoprene latex asphalt bonding layer exhibits excellent fatigue performance when compared to other two bonding layers.

  18. Durability assessment of concrete bridge deck considering waterproof membrane and epoxy-coated reinforcement

    OpenAIRE

    Petr Konečný; Petr Lehner

    2016-01-01

    The effect of waterproof membrane and steel reinforcement protection on the concrete bridge deck is modeled. The attention is paid to the durability prediction related to steel reinforcement corrosion initiation based on the chloride penetration. Thus 2-D finite element chloride ingress model is applied. The transient finite element model serves to solve Fick's second diffusion law using the computer tool compatible with the Matlab environment. The model focuses on the transport of chloride i...

  19. Glass Fiber Reinforced Polymer Bars as the Top Mat Reinforcement for Bridge Decks

    OpenAIRE

    DeFreese, James Michael

    2001-01-01

    The primary objective of this research was to experimentally investigate material and bond properties of three different types of fiber reinforced polymer (FRP) bars, and determine their effect on the design of a bridge deck using FRP bars as the top mat of reinforcement. The properties evaluated include the tensile strength, modulus of elasticity, bond behavior, and maximum bond stress. The experimental program included 47 tensile tests and 42 beam end bond tests performed with FRP bars. ...

  20. Glass fiber reinforced polymer bars as top mat reinforcement for bridge decks

    OpenAIRE

    J.M. DeFreese; Roberts-Wollmann, Carin L.

    2002-01-01

    The objectives of this research were to characterize the material and bond properties of three commercially available GFRP (glass fiber reinforced polymer) reinforcing bars, and evaluate the effects of the material properties and the current ACI design recommendations (ACI 2001) on the design of a bridge deck with GFRP as top mat reinforcement. The tensile properties evaluated were ultimate tensile strength, tensile modulus of elasticity and ultimate rupture strain. Ultimate bond stress and l...

  1. Implementation of a Non-Metallic Reinforced Bridge Deck, Volume 1: Bond Behavior

    OpenAIRE

    Frosch, Robert J.; Pay, A. Cihan

    2006-01-01

    The primary maintenance problem with bridges in Indiana has been deterioration of the concrete deck which is often related to corrosion of the reinforcing steel. While a corrosion protection system consisting of epoxy-coated reinforcement in combination with 2-1/2 in. of Class C concrete cover has been used in Indiana, research and experience have demonstrated that this system can be compromised. As an alternative solution to the corrosion problem in reinforced concrete, fiber reinforced poly...

  2. Identification of Flutter Derivatives of Bridge Decks in Wind Tunnel Test by Stochastic Subspace Identification

    Directory of Open Access Journals (Sweden)

    T. Janesupasaeree

    2009-01-01

    Full Text Available Problem statement: Flutter derivatives are the essential parameters in the estimations of the flutter critical wind velocity and the responses of long-span cable supported bridges. These derivatives can be experimentally estimated from wind tunnel test results. Generally, wind tunnel test methods can be divided into free decay test and buffeting test. Compared with the free decay method, the buffeting test is simpler but its outputs appear random-like. This makes the flutter derivatives extraction from its outputs more difficult and then a more advanced system identification is required. Most of previous studies have used deterministic system identification techniques, in which buffeting forces and responses are considered as noises. These previous techniques were applicable only to the free decay method. They also confronted some difficulties in extracting flutter derivatives at high wind speeds and under turbulence flow cases where the buffeting responses dominate. Approach: In this study, the covariance-driven stochastic subspace identification technique (SSI-COV was presented to extract the flutter derivatives of bridge decks from the buffeting test results. An advantage of this method is that it considers the buffeting forces and responses as inputs rather than as noises. Numerical simulations and wind tunnel tests of a streamlined thin plate model conducted under smooth flow by the free decay and the buffeting tests were used to validate the applicability of the SSI-COV method. Then, wind tunnel tests of a two-edge girder blunt type of Industrial-Ring-Road Bridge deck (IRR were conducted under smooth and turbulence flow. Results: The identified flutter derivatives of the thin plate model by the SSI-COV technique agree well with those obtained theoretically. The results from the thin plate and the IRR Bridge deck validated the reliability and applicability of the SSI-COV technique to various experimental methods and conditions of wind flow

  3. Epoxy asphalt concrete paving on the deck of long-span steel bridges

    Institute of Scientific and Technical Information of China (English)

    HUANG Wei; QIAN Zhendong; CHEN Gang; YANG Jun

    2003-01-01

    It is the first systematic research in the world on the composition design of epoxy asphalt concrete as pav- ing material. Material characteristics and service perform- ance of mixture, fatigue resistance characteristics of epoxy asphalt concrete by the fatigue test of complex beam have also been described. This research indicates that epoxy asphalt concrete is a good type of paving material. Research results have been applied successfully in the paving of steel deck of the Second Nanjing Yangtze River Bridge (SNYRB). It provides a new paving type for long-span steel bridges of China and has a bright application prospect.

  4. Laboratory Tests of a Bridge Deck Prototype With Glass Fiber Reinforced Polymer Bars as the Top Mat of Reinforcement

    OpenAIRE

    Cawrse, Jason Kyle

    2002-01-01

    The primary objective of this project was to test a full-scale prototype of an actual bridge deck containing GFRP bars as the top mat of reinforcement. The purpose of the tests was to verify that the design would resist the loads for which it was designed and provide assurance that the deck would not unexpectedly fail due to the use of this new material. Behavior of the bridge and deck, such as failure load, failure mode, cracking load, crack widths, deflections, and internal stresses, were...

  5. Bridge deck repairs with polymer concrete patching materials

    Science.gov (United States)

    Edgecomb, W. C., Jr.

    1983-01-01

    The FHWA polymer concrete as formulated at Brookhaven National laboratory (BNL) was mixed, placed into spalls and finished on grade with steel trowels on more than a dozen bridges. This polymer concrete was a two-component system consisting of a liquid monomer component comprised of methyl methacrylate base, which contained a cross linking agent with promoters and an inhibitor, and a powder component which contained reactive polymers, blend of silica sands, initiator, and color pigments. These formed an impregnable material of approximately 8000 psi. Cure time for this project's cold weather formulation to obtain this strength was approximately 2 hours at 40 F.

  6. Combination of nondestructive evaluations for reliable assessment of bridge deck

    Directory of Open Access Journals (Sweden)

    Khalim A.R.

    2011-01-01

    Full Text Available Non-destructive evaluation (NDE has offered unprecedented utilize for bridge management body to monitor structural health. None of these evaluation methods can provide all the damage information (damage category, quantitative assessment alone which is required for necessary repair activity and condition rating of structure. In most of the cases, the response of one evaluation method implies the presence of a defect among the multiple defects to which the evaluation method is sensitive. This paper is concerned with the combination of different non-destructive testing to find out the type of damage with the most efficient way. The different response (positive or negative obtained from each combination and how it confirms the defect is shown through the mathematical set operation. Thus, this study would assist field investigator to ascertain the type of defect which subsequently aids to rate structure based on damage type.

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

    Science.gov (United States)

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

    2016-03-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Li Hongtao; Zhang Chenchen; Hu Jing; Qian Zhendong

    2011-01-01

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

  9. Biaxial Behavior of Ultra-High Performance Concrete and Untreated UHPC Waffle Slab Bridge Deck Design and Testing

    Science.gov (United States)

    D'Alessandro, Kacie Caple

    Ultra-high performance concrete (UHPC) was evaluated as a potential material for future bridge deck designs. Material characterization tests took place to identify potential challenges in mixing, placing, and curing UHPC. Biaxial testing was performed to evaluate behavior of UHPC in combined tension and compression stress states. A UHPC bridge deck was designed to perform similarly to a conventional concrete bridge deck, and a single unit bridge deck section was tested to evaluate the design methods used for untreated UHPC. Material tests identified challenges with placing UHPC. A specified compressive strength was determined for structural design using untreated UHPC, which was identified as a cost-effective alternative to steam treated UHPC. UHPC was tested in biaxial tension-compression stress states. A biaxial test method was developed for UHPC to directly apply tension and compression. The influence of both curing method and fiber orientation were evaluated. The failure envelope developed for untreated UHPC with random fiber orientation was suggested as a conservative estimate for future analysis of UHPC. Digital image correlation was also evaluated as a means to estimate surface strains of UHPC, and recommendations are provided to improve consistency in future tests using DIC methods. A preliminary bridge deck design was completed for untreated UHPC and using established material models. Prestressing steel was used as primary reinforcement in the transverse direction. Preliminary testing was used to evaluate three different placement scenarios, and results showed that fiber settling was a potential placement problem resulting in reduced tensile strength. The UHPC bridge deck was redesigned to incorporate preliminary test results, and two single unit bridge deck sections were tested to evaluate the incorporated design methods for both upside down and right-side up placement techniques. Test results showed that the applied design methods would be conservative

  10. 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.

  11. Structural behaviour and design criteria of under-deck cable-stayed bridges subjected to seismic action

    OpenAIRE

    Cámara Casado, Alfredo; Ruiz Teran, Ana M.; Stafford, Peter J.

    2012-01-01

    SUMMARY: Under-deck cable-stayed bridges are very effective structural systems for which the strong contribution of the stay cables under live loading allows for the design of very slender decks for persistent and transient loading scenarios. Their behaviour when subjected to seismic excitation is investigated herein and a set of design criteria are presented that relate to the type and arrangement of bearings, the number and configuration of struts, and the transverse distribution of stay ca...

  12. Continuation of Field and Laboratory Tests of a Proposed Bridge Deck Panel Fabricated from Pultruded Fiber-Reinforced Polymer Components

    OpenAIRE

    Coleman, Jason Thomas

    2002-01-01

    This thesis presents research completed on the experimental performance of two 6 3/4 in thick bridge deck panels fabricated by the Stongwell Corporation of Bristol, Virginia. The panels are made of off-the-shelf, pultruded glass fiber-reinforced polymer elements, bonded and mechanically fastened together. The testing involved laboratory stiffness tests performed on one deck panel which afterwards, was placed in a field test site at the I-81 Troutville Weigh Station facility. The daily truc...

  13. Extension of semi-analytical approach to determine natural frequencies and mode shapes of multi-span orthotropic bridge deck

    OpenAIRE

    Rezaiguia, Abdelouahab; Fisli, Y.; Ellagoune, S.; et al

    2012-01-01

    This paper extends a single equation, semi-analytical approach for three-span bridges to multispan ones for the rapid and precise determination of natural frequencies and natural mode shapes of an orthotropic, multi-span plate. This method can be used to study the dynamic interaction between bridges and vehicles. It is based on the modal superposition method taking into account intermodal coupling to determine natural frequencies and mode shapes of a bridge deck. In this paper, a four- and a ...

  14. Typical Structure of Bridge Deck Asphalt Pavement of Cement Concrete Bridge%水泥混凝土桥沥青铺装典型结构研究

    Institute of Scientific and Technical Information of China (English)

    何德云; 熊欣; 董强

    2011-01-01

    Vehicle's safety and comfort has been directly affected by the quality of bridge deck pavement, and the quality of bridge deck pavement has been directly affected by the composite structure of bridge deck pavement. Through the interlayer cohesive tests with 7 sorts of materials, temperature stability and fatigue bending tests with 3 composite structures, the performance sequence of interlayer cohesive materials and asphalt composite structures have been confirmed. On the basis of the test results, the typical structure of bridge deck pavement has been proposed, which offers references for the design and construction of bridge deck pavement.%桥面铺装的质量直接影响着行车的安全性和舒适性,桥面铺装的结构组合又直接决定了桥面铺装的质量.通过对7种桥面铺装层材料的层间黏结性能试验、3种桥面铺装组合结构的温度稳定性试验和复合小梁弯曲疲劳试验,确定了桥面铺装层间黏结材料和沥青铺装结构的性能排序,在此基础上提出了桥面铺装的典型结构型式,可为桥面铺装设计和施工提供参考.

  15. Assessment of a Bridge WIM System on Integral Concrete Bridges and on Steel Orthotropic Decks

    OpenAIRE

    Ieng, Sio Song; SCHMIDT, Franziska; ROMBONI, Frédéric; Jacob, Bernard

    2011-01-01

    Bridge-Weigh-In-Motion uses bridges as a scale to weigh vehicles. Practically, this is done by measuring the strains in that bridge, and relating them to the weight and dimensions of a truck called “calibration trucks” whose shape and axle weights are well known. This article summarizes different B-WIM experiments the institute IFSTTAR (formerly called LCPC) realized and the lessons drawn from this experience. First, the system has been tested on frame-type bridges with integral s...

  16. Detection of Through-Deck Type Fatigue Cracks in Steel Bridges by Self-Reference Lock-in Thermography

    Directory of Open Access Journals (Sweden)

    Tamakoshi T.

    2010-06-01

    Full Text Available A new remote nondestructive inspection technique, based on thermoelastic temperature measurement by infrared thermography, is developed for detection and evaluation of fatigue cracks propagating from welded joints in steel bridges. Fatigue cracks are detected from localized high thermoelastic temperature change at crack tips due to stress singularity under variable loading from traffics on the bridge. Selfreference lock-in data processing technique is developed for the improvement of signal/noise ratio in the crack detection process. The technique makes it possible to perform correlation processing without an external reference signal. It is very difficult to detect through-deck type fatigue cracks in steel decks by the conventional NDT technique, since they are not open to the inspection. In this paper, self-reference lock-in thermography is applied for detection of through-deck type fatigue cracks. Experiments are carried out to steel deck sample, which simulates an actual steel bridge, during crack propagation test. It is found that significant stress concentration zone can be observed near the crack front, which enabled us to detect through-deck type fatigue cracks and to estimate its size.

  17. The Impact of Traffic-Induced Bridge Vibration on Rapid Repairing High-Performance Concrete for Bridge Deck Pavement Repairs

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2014-01-01

    Full Text Available Based on forced vibration tests for high-performance concrete (HPC, the influence of bridge vibration induced by traveling vehicle on compressive strength and durability of HPC has been studied. It is concluded that 1 d and 2 d compressive strength of HPC decreased significantly, and the maximum reduction rate is 9.1%, while 28 d compressive strength of HPC had a slight lower with a 3% maximal drop under the action of two simple harmonic vibrations with 2 Hz, 3 mm amplitude, and 4 Hz, 3 mm amplitude. Moreover, the vibration had a slight effect on the compressive strength of HPC when the simple harmonic vibration had 4 Hz and 1 mm amplitude; it is indicated that the amplitude exerts a more prominent influence on the earlier compressive strength with the comparison of the frequency. In addition, the impact of simple harmonic vibration on durability of HPC can be ignored; this shows the self-healing function of concrete resulting from later hydration reaction. Thus, the research achievements mentioned above can contribute to learning the laws by which bridge vibration affects the properties of concrete and provide technical support for the design and construction of the bridge deck pavement maintenance.

  18. Structural Aspects of Railway Truss Bridges Affecting Transverse Shear Forces in Steel-Concrete Composite Decks

    Science.gov (United States)

    Siekierski, Wojciech

    2015-03-01

    At the steel-concrete interface, the horizontal shear forces that are transverse to cross beams occur due to joint action of the steel-concrete composite deck and the truss girders. Numerical analysis showed that values of the forces are big in comparison to the longitudinal shear forces. In both cases extreme force values occur near side edges of a slab. The paper studies possibilities of reduction of these shear forces by structural alterations of the following: rigidity of a concrete slab, arrangement of a wind bracing, arrangement of concrete slab expansion joints. An existing railway truss bridge span has been analysed. Numerical analysis shows that it is possible to reduce the values of shear forces transverse to cross beams. It may reach 20% near the side edges of slabs and 23% in the centre of slab width.

  19. Electrokinetic nanoparticle treatment for corrosion remediation on simulated reinforced bridge deck

    Energy Technology Data Exchange (ETDEWEB)

    Kupwade-Patil, Kunal, E-mail: kunalk@latech.edu; Cardenas, Henry E., E-mail: cardenas@latech.edu [Louisiana Tech University, College of Engineering and Science (United States)

    2013-09-15

    ASTM G109 specimens were used in this work as these simulate the configuration of the bridge deck and subjected to elevated chloride levels. Nanoparticles which were 24 nm in size were driven directly through the concrete matrix and to the reinforcement using an electric field. The intent was to use the nanoparticles as pore blocking agents that could prevent chlorides from re-entering and accessing the rebar. Electrochemical, microstructure, and pore structure characterization was conducted on the electrokinetic nanoparticle (EN) treated and control specimens. At the end of post saltwater exposure period EN-treated specimens exhibited lower corrosion current densities, chloride contents below the threshold limit for new construction and 22 % reduction in porosity as compared to the controls. EN treatment was successful in mitigating reinforcement corrosion in concrete.

  20. The Dynamic Properties of the Bridge Deck Model Reinforced With FRP Bars

    Directory of Open Access Journals (Sweden)

    Markiewicz Barbara

    2015-01-01

    Full Text Available Significant application of composites can be observed in numerous fields over the last decades. Composite materials mainly used in the aeronautics industry are gaining more and more application in various areas such as the construction of bridges. The article presents a set of dynamic research carried out on a plate made of lightweight concrete reinforced with composite rods. The tested plate with dimensions 514 × 190 × 18 cm was a model of the actual bridge deck. A multi-channel signal recorder with specialized software was used for performing the measurements and estimating modal parameters of the plate. Dynamic response of the plate on a modal hammer impact was measured with numerous of piezoelectric acceleration sensors. A range of FEM models was created, started with 1-D beam model. Next, 2-D plate and 3-D volume, more complex models were developed. Only in the 3-D model the composite rods were modeled. The basic frequencies and mode shapes obtained for physical model were compared with those for numerical models. There were significant differences. The conducted analysis indicated more complicated than theoretical boundary conditions of the tested plate.

  1. Multi-mode traffic-induced vibrations in composite ladder-deck bridges under heavy moving vehicles

    Science.gov (United States)

    Camara, A.; Ruiz-Teran, A. M.

    2015-10-01

    Composite (steel-concrete) ladder-decks represent one of the most common solutions in road bridges nowadays. In these structures the Serviceability Limit State (SLS) of vibrations is traditionally ignored or roughly addressed by means of simple static deflection-based approaches, inherently assuming that the vibrations are controlled by the fundamental longitudinal mode. This work demonstrates that a wide range of high-order vibrational modes, involving the transverse flexure of the slab between longitudinal girders, govern the accelerations recorded in the deck and inside the vehicles. In addition, a new methodology for analysing the Vehicle-Bridge Interaction is proposed, including the approaching platforms, the transition slabs, and the bridge joints. The results suggest that the riding comfort for vehicle users is specially affected by direct effects on the wheels, like the road roughness and possible construction misalignments at the bridge joints, as well as low-frequency vibrations coming from the deck in short or slender bridges. The filtering effects resulting from the average of the response in time and in space when calculating the root mean square acceleration are also explored, and new design parameters are provided. In addition, several structural features (such as the depth and spacing of the longitudinal and transverse steel beams, the thickness of the concrete slab, and the stiffness of the cantilever cross beams at the diaphragm sections) have been studied, and a set of new design criteria has been established. It has been demonstrated that the transverse flexibility of the deck (specially influenced by the support conditions and the slab thickness) is critically important for the users' (pedestrians and vehicle passengers) comfort, as it controls the aforementioned high-order vibrational modes which govern the dynamic response.

  2. Field Test of a Bridge Deck with Glass Fiber Reinforced Polymer Bars as the Top Mat of Reinforcement

    OpenAIRE

    Harlan, Matthew

    2004-01-01

    The primary objective of this research project was to perform live load tests on a bridge deck with GFRP reinforcement in the field under service conditions. The strains and deflections in the span reinforced with GFRP in the top mat were recorded under a series of truck crossings, and these were compared to the span reinforced with all steel bars under identical loading conditions, as well as design values and other test results. Transverse strains in the GFRP bars, girder distribution fac...

  3. Application of Noise Cancelling and Damage Detection Algorithms in NDE of Concrete Bridge Decks Using Impact Signals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Gang; Harichandran, Ronald S.; Ramuhalli, Pradeep

    2011-09-13

    Delamination is a commonly observed distress in concrete bridge decks. Among all the delamination detection methods, acoustic methods have the advantages of being fast and inexpensive. In traditional acoustic inspection methods, the inspector drags a chain along or hammers on the bridge deck and detects delamination from the 'hollowness' of the sounds. The signals are often contaminated by ambient traffic noise and the detection of delamination is highly subjective. This paper describes the performance of an impact-bases acoustic NDE method where the traffic noise was filtered by employing a noise cancelling algorithm and where subjectivity was eliminated by introducing feature extraction and pattern recognition algorithms. Different algorithms were compared and the best one was selected in each category. The comparison showed that the modified independent component analysis (ICA) algorithm was most effective in cancelling the traffic noise and features consisting of mel-frequency cepstral coefficients (MFCCs) had the best performance in terms of repeatability and separabillty. The condition of the bridge deck was then detected by a radial basis function (RBF) neural network. The performance of the system was evaluated using both experimental and field data. The results show that the selected algorithms increase the noise robustness of acoustic methods and perform satisfactorily if the training data is representative.

  4. Modeling of Multi-Layered Protection Systems for Chloride Penetration in Concrete Bridge Decks

    Science.gov (United States)

    Harajli, Ali A.

    Modeling of Multi-Layered Protection Systems for Chloride Penetration in Concrete Bridge Decks. This paper covers the development of a new methodology for predicting the chloride concentration and corrosion initiation times for a multi-layer protection overlay system. The first topic will be presenting an innovative method to predict the chloride concentrations using different diffusion coefficients for each protective layer. The new method covers the cases where the applied surface chloride concentrations are either a constant or linear functions with time. The second topic will implement the results from field data about the chloride variations due to the presence of applied topical layers for comparison with the theoretical models. This section will also apply damage factors that are time-dependent to simulate external factors such as traffic loading or vibrations. The third topic will investigate the sensitivity of the single and multi-layer systems due to diffusivity parameter changes. The fourth topic will analyze the random variation of the diffusivity values to predict the mean and standard deviation of chloride concentrations. The diffusivity values are selected from published values by NIST and are based on certain water cement (w/c) ratios.

  5. Experimental evaluation of the buckling phenomena in the new joint design for upper deck structure of a bridge

    Directory of Open Access Journals (Sweden)

    Solazzi L.

    2010-06-01

    Full Text Available This paper is concerned with the experimental mechanical analysis of a new design of a joint for a main components of a upper deck of a road bridge. These components are subject to the compression state stress induced by the weight and the load acting on the road. Each upper deck of a bridge (positioned on each side of the bridge is composed by four tubular structures that must be joint each together. The joint must to take in to account many aspects, for example that the length of each component is not the same (because, obviously, there is a mechanical tolerance. This phenomena induce different compression stress on each component and so is very important non only the critical buckling load but also the post buckling behaviour of the structure. It is very important that if a single tubular structure reaches the critical load of instability, it still has load capacity . This is to avoid that, in the case where a column reaches the instability, the entire load acting on a column increase the load on the remaining three. For this purpose many different geometrical solutions have been designed (elaborated by fem analyses and successively tested experimentally. This work reports the main experimental results on the best joint solution and how this increase the load capacity and the displacement respect to the solution without this flange.

  6. Development and construction of low-cracking high-performance concrete (LC-HPC) bridge decks: Free shrinkage tests, restrained ring tests, construction experience, and crack survey results

    Science.gov (United States)

    Yuan, Jiqiu

    2011-12-01

    The development, construction, and evaluation of low-cracking high-performance concrete (LC-HPC) bridge decks are described based on laboratory test results and experiences gained during the construction of 13 LC-HPC bridge decks in Kansas, along with another deck bid under the LC-HPC specifications but for which the owner did not enforce the specification. This study is divided into four parts covering (1) an evaluation of the free shrinkage properties of LC-HPC candidate mixtures, (2) an investigation of the relationship between the evaporable water content in the cement paste and the free shrinkage of concrete, (3) a study of the restrained shrinkage performance of concrete using restrained ring tests, and (4) a description of the construction and preliminary evaluation of LC-HPC and control bridge decks constructed in Kansas. The first portion of the study involves evaluating the effects of the duration of curing, fly ash, and a shrinkage reducing admixture (SRA) on the free-shrinkage characteristics of concrete mixtures. The results indicate that an increase of curing period reduces free shrinkage. With 7 days of curing, concretes containing fly ash as a partial replacement for cement exhibit higher free shrinkage than concretes with 100% portland cement. When the curing period is increased to 14, 28, and 56 days, the adverse effect of adding fly ash on free shrinkage is minimized and finally reversed. The addition of an SRA significantly reduces free shrinkage for both the 100% portland cement mixture and the mixture containing fly ash. The second portion of the study investigates the relationship between the evaporable water content in the cement paste and the free shrinkage of concrete. A linear relationship between free shrinkage and evaporable water content in the cement paste is observed. For a given mixture, specimens cured for a longer period contain less evaporable water and exhibit lower free shrinkage and less weight loss in the free shrinkage

  7. Post-stressed constant depth beam concrete road and railway bridge voided decks morphology; Morfologia de tableros aligerados de canto constante postesados para puentes carreteros y ferroviarios

    Energy Technology Data Exchange (ETDEWEB)

    Yepes, V.; Alcala, J.; Diaz, J.; Gonzalez-Vidosa, F.

    2011-07-01

    In the work a study to statistically characterise 82 prestressed concrete bridge decks of real flyovers of constant depth are treated. The main objective of the study is to find design formulae with the least number of data so as to improve the preliminary design of this type of structures. The study performs an exploratory analysis and a multivariate analysis of the geometrical variables, the amount of materials and the cost for voided decks. The regression models have allowed predicting the depth of the deck as function of the span and the external void. The depth is the variable that better explains (51,9%) the cost per unit surface of the deck in road bridges, while for railway decks this variable only explains in the order of 23,4%, what implies more independent variables. The main spans and the total length in the case of the railway deck are enough to find the preliminary design of the slab with reasonable accuracy for the economic assessment of the design. (Author) 17 refs.

  8. Flexible concrete link slabs used as expansion joints in bridge decks

    DEFF Research Database (Denmark)

    Lárusson, Lárus Helgi; Fischer, Gregor

    2011-01-01

    reinforcement serves as a flexible concrete element between the adjacent deck segments. The use of an Engineered Cementitious Composite (ECC) material instead of conventional concrete significantly reduces crack widths under service conditions and prevents deterioration of the link slab in the tension...... joints are currently unresolved. In the proposed system described in this paper, a ductile cement-based composite section reinforced with Glass Fiber Reinforced Polymers (GFRP) replaces the damaged expansion joint. The combination of this ductile concrete together with corrosion resistant GFRP...

  9. Bridge deck surface temperature monitoring by infrared thermography and inner structure identification using PPT and PCT analysis methods

    Science.gov (United States)

    Dumoulin, Jean

    2013-04-01

    One of the objectives of ISTIMES project was to evaluate the potentialities offered by the integration of different electromagnetic techniques able to perform non-invasive diagnostics for surveillance and monitoring of transport infrastructures. Among the EM methods investigated, we focused our research and development efforts on uncooled infrared camera techniques due to their promising potential level of dissemination linked to their relative low cost on the market. On the other hand, works were also carried out to identify well adapted implementation protocols and key limits of Pulse Phase Thermography (PPT) and Principal Component Thermography (PCT) processing methods to analyse thermal image sequence and retrieve information about the inner structure. So the first part of this research works addresses infrared thermography measurement when it is used in quantitative mode (not in laboratory conditions) and not in qualitative mode (vision applied to survey). In such context, it requires to process in real time thermal radiative corrections on raw data acquired to take into account influences of natural environment evolution with time, thanks to additional measurements. But, camera sensor has to be enough smart to apply in real time calibration law and radiometric corrections in a varying atmosphere. So, a complete measurement system was studied and developed [1] with low cost infrared cameras available on the market. In the system developed, infrared camera is coupled with other sensors to feed simplified radiative models running, in real time, on GPU available on small PC. The whole measurement system was implemented on the "Musmeci" bridge located in Potenza (Italy). No traffic interruption was required during the mounting of our measurement system. The infrared camera was fixed on top of a mast at 6 m elevation from the surface of the bridge deck. A small weather station was added on the same mast at 1 m under the camera. A GPS antenna was also fixed at the

  10. Construction Techniques for ERS of Steel Deck Surfacing Layer of Mingzhou Bridge%明州大桥钢桥面铺装层ERS施工技术

    Institute of Scientific and Technical Information of China (English)

    杨崇国; 刘小勇

    2012-01-01

    为了解决钢桥面板与铺装层间防水、抗滑移、高温稳定等问题,宁波明州大桥主桥钢桥面板铺装层采用树脂沥青组合体系(ERS)桥面铺装技术,桥面铺装结构组成为40 mm高粘改性沥青(SMA-13)+改性沥青防水粘结层+25 mm环氧沥青混凝土(RA05)+环氧粘结碎石层(EBCL).通过对钢桥面板喷砂除锈,达到Sa2.5级;按比例混和EBCL胶料,分2层涂刷,同时洒布碎石;摊铺RA05混合料,并用胶轮压路机碾压,在其固化后洒布防水粘结层;摊铺SMA-13沥青混凝土层,采用钢轮+胶轮+钢轮的组合方式碾压,确保了ERS施工质量,桥面铺装效果良好.%To cope with the problems of the waterproof, slip resistance and high temperature stability of deck surfacing layer with steel deck plate, the deck surfacing technique of epoxy resin asphalt system (ERS) was applied to the steel deck surfacing layer of the main bridge of the Mingzhou Bridge in Ningbo. The structure of the surfacing layer of the bridge comprised 40 mm high viscosity modified asphalt (stone mastic asphalt, SMA-13) +waterproof binding layer of the modified asphalt+25 mm epoxy resin asphalt concrete (RA05)+epoxy bond crushed stone layer (EBCL). After the steel deck plates of the bridge were sand blasted to the rust removal level of Sa2. 5, the binder for the EBCL was blended according to its proportion and was then brushed onto the deck plates in two layers. At the same time, the crushed stones were spread, the RA05 was laid and compacted by the rubber wheel road roller. When these surfacing materials were set, the SMA-13 was laid and was compacted by the combined way of the steel wheel + rubber wheel+steel wheel. With the technique, the construction quality of the ERS was guaranteed and the sound effect of the deck surfacing of the bridge was achieved.

  11. EXPERIMENTAL STUDIES OF WALL GIRDERS IN DIFFERENT TYPES OF BRIDGE DECK

    Directory of Open Access Journals (Sweden)

    O. L. Zakora

    2010-03-01

    Full Text Available The results of experimental studies of wall girders under live load are given in the paper. These studies were conducted in several stages with different types of the bridge floor.

  12. MECHANICAL ANALYSIS OF PAVEMENT ON GFRP BRIDGE DECK%GFRP桥面铺装力学性能研究

    Institute of Scientific and Technical Information of China (English)

    朱坤宁; 万水

    2011-01-01

    GFRP桥面铺装是GFRP桥面板组合梁桥行车体系的重要组成部分.本文采用有限元分析软件对车辆荷载作用下GFRP桥面铺装层的应力分布情况进行了分析,得到了计算铺装层最大拉应力的控制荷位,并计算了在此荷位下GFRP桥面铺装层中的应力水平.研究了GFRP桥面铺装层中的应力、应变分布规律.根据分析结果,提出了大广高速6号跨线桥及类似GFRP桥面铺装的设计指标.%Pavement on GFRP bridge deck is an important part in vehicle system. The distribution of stress in the pavement is analysed with FEM software. The controlling load position is found and the stress in the pavement is computed under the load position. The distribution of the stress and strain in the asphalt concrete surfacing is stud ied. Based on analysis results, the design indexes of the No. 6 flyover bridge of Daguang Highway are proposed.

  13. 桥面铺装与小箱梁的共同作用试验%Experiment of Coaction of Bridge Deck Pavement and Small Box Girder

    Institute of Scientific and Technical Information of China (English)

    钱寅泉; 周正茂; 袁桂芳; 王素娟

    2012-01-01

    Load tests on a single small box girder and a bridge were carried out to evaluate the effects of deck pavement by comparing the deflections of the girders before and after the pavement surfaced. The comprehensive elastic modulus was obtained from the test before pavement surfaced, and the coaction degree of the bridge deck pavement and the girders was obtained by comparing the flexural inertia moment corresponding to the deflection in the test after pavement surfaced with the theoretical flexural inertia moment corresponding to the supposed thickness of the pavement in work. The results from these tests show that (1) the rough interface could greatly improve the coaction degree of bridge deck pavement with girders, which could reach 100% ; (2) in general cases, the extent of the coaction of bridge deck pavement with girders could reach 70% , and for a pavement with thickness of 8 cm, the thickness of the pavement in coaction could be taken as 60% or 3 cm in thickness could be substracted from the pavement in design; (3 ) the pavement could improve the uniformity of the transverse load distribution. Load tests on a single small box girder and a bridge were carried out to evaluate the effects of deck pavement by comparing the deflections of the girders before and after the pavement surfaced. The comprehensive elastic modulus was obtained from the test before pavement surfaced, and the coaction degree of the bridge deck pavement and the girders was obtained by comparing the flexural inertia moment corresponding to the deflection in the test after pavement surfaced with the theoretical flexural inertia moment corresponding to the supposed thickness of the pavement in work. The results from these tests show that (1) the rough interface could greatly improve the coaction degree of bridge deck pavement with girders, which could reach 100% ; (2) in general cases, the extent of the coaction of bridge deck pavement with girders could reach 70% , and for a pavement with

  14. 华南地区浇筑式钢桥面铺装MA性能研究%PERFORMANCE STUDY ON CASTING-TYPE STEEL BRIDGE DECK MIXTURE MA

    Institute of Scientific and Technical Information of China (English)

    万涛涛

    2012-01-01

    浇筑式桥面铺装方案MA是当前钢桥面铺装应用较为广泛的一种铺装方案,然而该铺装方案在我国华南地区应用状况却不是很好.由于目前仍然没有标准的MA混合料设计规范,而MA由于其较小的孔隙率都具有较好的水稳定性.通过大量调查发现MA混凝土在我国华南地区应用的主要破坏形式是车辙和疲劳开裂.通过硬度值、马歇尔试验和车辙试验研究了MA的高温性能,采用四点弯曲试验研究了MA混合料的疲劳性能,结果表明通过调整MA混合料的级配可以改善MA的高温性能和疲劳性能,最后通过试验路段得到验证.%Casting type steel bridge deck pavement scheme MA is a wide range used plan Of the current steel bridge deck pavement, yet its application situation in China is not very well. According to the investigation of our country's steel bridge deck applications, the study found the main damage forms of south china steel bridge deck pavement is the rutting and fatigue cracking. Research the high temperature performance of MA through the hardness value test, Marshall test and rutting test. Research the fatigue performance of MA through four points bending test. The results show that by adjusting the MA mixture graded can improve the performance of high temperature and fatigue performance of MA.

  15. Development of a pedestrian bridge with GFRP profiles and fibre reinforced self-compacting concrete deck

    OpenAIRE

    Barros, Joaquim A. O.; Mendes, Pedro J. D.; Sena-Cruz, José; Taheri, Mahsa

    2011-01-01

    In recent years, the number of pedestrian bridges built from composites materials has notably increased. The combination of fiber reinforced polymers (FRP) profiles with fiber reinforced concrete (FRC) elements is being adopted in this type of structures, since the ductility, high post-cracking tensile strength, compressive stiffness and strength of FRC can be combined with the benefits derived from the use of FRP’s profiles to obtain high performance structural systems. In the...

  16. 钢主梁拱桥组合桥面系力学性能分析%MECHANICAL BEHAVIOR ANALYSIS OF COMPOSITE DECK FLOOR OF ARCH BRIDGE WITH STEEL GIRDER

    Institute of Scientific and Technical Information of China (English)

    苏庆田; 李杰; 董冰

    2012-01-01

    钢-混凝土组合结构桥面系近几年开始在拱桥结构中使用,拱桥中组合桥面系受力复杂,其力学性能受钢与混凝土是否连接、是否张拉系杆以及混凝土的浇注顺序等影响.该文采用空间有限元模型,开展了钢主梁拱桥组合桥面系的力学性能研究.研究表明:在钢主梁拱桥结构中混凝土桥面板与钢主梁是否结合对桥面系的整体受力影响甚微,只对桥面系局部位置的混凝土桥面板应力分布有所影响;拱桥中是否安装系杆对桥面系的受力影响较大,而且桥面系的受力与系杆张拉力有密切关系;对于组合桥面系的拱桥采用一次浇筑混凝土桥面板施工方法的桥面系受力要明显优于采用分段浇筑混凝土桥面板的方法.%A steel-concrete composite deck has been used in acrh bridges recently. The mechanism of a composite deck is complex, and was affected by the factors of setting connections between concrete decks and steel girder or not, setting tied bars or not, different deck concrete casting sequences etc. In this paper, mechanical behaviors of a composite deck floor of an arch bridge with steel girders are analyzed by a spatial finite element model. The research results show that whether setting connections between concrete decks and a steel girder or not slightly affects the total mechanical behavior of a deck floor but influents the local stress of the deck; whether setting tied bar affects the deck floor mechanical property greatly and the deck floor stress depends on the tension force of tied bars heavily; as to arch bridge with a composite deck floor, the mechanical behavior of deck floors with casting deck concrete by one time is superior to that of deck floors with casting deck concrete by several times.

  17. 钢筋混凝土桥面板疲劳寿命评估%Fatigue life estimation for reinforced concrete bridge deck

    Institute of Scientific and Technical Information of China (English)

    王春生; 吴全友; 缪文辉

    2013-01-01

    In order to ensure the service safety, it is necessary to evaluate the fatigue life of concrete bridge decks. The fatigue life estimation and prediction models for concrete bridge decks were proposed based on the theory of cumulative fatigue damage, wheel loading test data and the correlation coefficient of actual bridge deck fatigue life and tested fatigue life. Based on the fatigue life estimation model of concrete bridge decks, the effects of the different standard fatigue vehicles in BS5400, Eurocode, AASHTO design codes and truck overload were evaluated. The results show that the technical parameters of the different standard fatigue vehicles have obvious effect on the fatigue life, so a special fatigue vehicle model for concrete bridge decks should be developed; wheel live load spectrum value of BS5400 is the preferred choice under no traffic detection data; the fatigue life of concrete bridge decks decreases greatly at truck overload of 20% , and the fatigue life is less than 10 years at truck overload of 40%. So the trucks with 20% overload must be strictly prohibited to pass the operation concrete bridges. 4 tabs, 4 figs, 17 refs.%为确保桥梁使用安全,对混凝土桥面板进行疲劳寿命评估十分迫切.基于疲劳损伤累积理论和混凝土桥面板车轮移动疲劳加载下试验数据,并引入模型相关系数,用来考虑桥面板实际寿命和试验寿命的差异,建立了混凝土桥面板疲劳寿命预测模型,对混凝土桥面板的疲劳寿命进行评估.分析比较了采用英国BS5400、欧洲规范Eurocode和美国AASHTO规范中标准疲劳车评价混凝土桥面板疲劳寿命的差异性,以及车辆超载对桥面板使用寿命的影响.计算结果表明:疲劳标准车技术参数对混凝土桥面板的疲劳寿命影响较大,应研发适用于桥面板疲劳分析的车辆荷载模型;在没有实桥调查数据情况下,建议优先采用BS5400规定的车轮活载频谱值;当车辆超载20%以上

  18. Fatigue behaviour of an orthotropic steel bridge deck: Benefits of an Ultra-High Performance Fibre Reinforced Concrete topping layer

    OpenAIRE

    Gomes, Fernanda; Marchand, Pierre; RENAUD, Jean Claude; MASSOTTE, Cyril; ESTIVIN, Marc; BILLO, Joël; BAZIN, Céline; LAPEYRERE, Romain; LAUVIN, Ludovic; BARIN, FX; SIEGERT, Dominique; Toutlemonde, François

    2011-01-01

    A large-scale experimental program has been carried out at the LCPC structures laboratory to assess the influence of topping layer on the behaviour of orthotropic decks and their resistance to fatigue phenomenon. These tests have been carried out within the frame of a joint R& D project called Orthoplus, in partnership with Eiffage Company, Arcadis engineering office and the Sétra (French Highways technical authority). This project aims at improving the design rules for orthotropic deck and d...

  19. The influence of rainfall on the static characteristics of bridge deck sections%降雨对桥梁主梁静力特性的影响

    Institute of Scientific and Technical Information of China (English)

    辛大波; 王亮; 李惠; 欧进萍

    2012-01-01

    The three influencing factors of wind-rain-induced static forces were analyzed aiming at the phenomenon of simultaneous actions of wind and rain for long-span bridge decks, based on the analysis of static load on the bridge deck section. The test method of the increment of wind-rain-induced static forces in joint wind and rain comparing to wind-induced static forces in single wind is given. The wind-rain-induced static characteristics test was carried out in the surroundings of simultaneous actions of wind and rain built in the atmospheric boundary layer wind tunnel, taking a twin-separated box girder as research object. The influencing rule of rainfall on the wind-induced static forces of bridge deck sections was obtained. Experimental results display the effect of impact force of rain on the wind-induced drag force of bridge deck sections is dominant in the large negative angle of attack of circumstances. The effect of change of flow field and water film on the surface of bridges on the wind-induced drag force of bridge deck sections is dominant in the small negative and positive angle of attack of circumstances. The gravity of raindrops, impact force of rain, change of flow field and water film on the surface of bridges all have certain contribution on the wind-induced lift force of bridge deck sections. The change of flow field and water film on the surface of bridges play the most important role on the wind-induced pitching moment of bridge deck sections, followed by the gravity of raindrops, finally is the impact force of rain. The result shows that the effect of rainfall on the wind-induced static forces of bridge deck sections is mainly depended on the change of flow field and water film on the surface of bridges.%针对大跨桥梁主梁风雨联合作用现象,从静力学角度出发,分析风雨联合作用下桥梁主梁荷载的三个组成成分——风雨致静力三组分,以及桥梁主梁风雨致静力相对于纯

  20. 钢桥面组合铺装结构性能研究%Research on Structural Performances of Combined Pavement on Steel Bridge Deck

    Institute of Scientific and Technical Information of China (English)

    伍朝晖; 张峰; 郝增恒

    2011-01-01

    通过对包括沥青混凝土的3种组合铺装结构高温稳定性能、低温弯曲性能、疲劳性能以及防水材料性能的综合研究,对比环氧沥青与浇筑式组合结构、与双层环氧铺装结构的性能差异,通过试验验证不同类型的组合铺装结构作为钢桥面铺装的技术性能,提出组合铺装结构作为钢桥面铺装的建议.%Based on a comprehensive research on performance of high-temperature stability, performance of low-temperature bending, fatigue performance and performance of water-proof materials of three combined pavement structures including asphalt concrete, and comparison of performance deviations between epoxy asphalt & casting combined structure and double-layer epoxy pavement structure, this paper verifies technical properties of different types of combined pavement structures on steel bridge deck via test, and puts forward suggestions of combined pavement structures adopted for steel bridge deck.

  1. Live-Load Testing and Finite-Element Analysis of a Steel Cantilever Deck Arched Pratt Truss Bridge for the Long-Term Bridge Performance Program

    OpenAIRE

    Laurendeau, Matthew P.

    2011-01-01

    The Long Term Bridge Performance (LTBP) program is an organization within the Federal Highway Administration that inspects, tests, analyzes, and observes, for an extended period of time, a variety of bridge types throughout the United States. Part of the program includes periodic testing of select bridges of a span of 20 years. The Kettle River Bridge located outside of Sandstone, Minnesota was selected for study due to its unique design. The Kettle River Bridge is a historical steel can...

  2. Analysis on cracking of deck pavement on Jiangyin Bridge%江阴大桥桥面铺装裂缝分析

    Institute of Scientific and Technical Information of China (English)

    程刚; 陈先华; 王晓

    2005-01-01

    通过对江阴大桥浇注式沥青铺装4年的现场调查与跟踪,研究了浇注式沥青铺装的开裂原因.根据裂缝长度与宽度对其进行了总结以得到裂缝的发展规律.为评估交通荷载对铺装层的影响,同时进行了包括交通量、轴重、车速等调查.对现场取回的试样分别进行了拉拔试验与疲劳试验以评估铺装层的真实状况.结果表明:铺装层的疲劳抗力与高温稳定性不足、层间粘结层较弱、低速超载的大交通等是导致铺装层开裂的主要原因.%Based on four-year field inspection and investigation on deck pavement of mastic asphalt on Jiangyin Bridge, cracking causes of mastic asphalt are studied. Cracks of deck pavement are summarized on crack length and width to get a clear view of their propagations. Traffic surveys including traffic volume, axle load and vehicle speed were also conducted to assess their influences. Samples taken on-site were tested with pulling-out test and fatigue test to benchmark their properties. According to the inspection and tests results, it is concluded that the cracks are induced by rutting and fatigue. Lack of fatigue resistance, not well bonded to the steel deck and insufficient high temperature stability are supposed to be the main reasons as well as high density of low speed, excessively overloaded trucks.

  3. On application of steel fiber concrete in bridge deck pavement%钢纤维混凝土在桥面铺装中的运用

    Institute of Scientific and Technical Information of China (English)

    白建珍

    2012-01-01

    简要介绍了钢纤维混凝土的一些技术特性和要求,从配合比设计、现场拌合、施工控制等方面入手阐述了钢纤维混凝土与普通混凝土的区别,以促进钢纤维混凝土在桥面铺装中的运用。%The paper briefly introduces the technical features and requirements of the steel fiber concrete, illustrates the differences between the steel fiber concrete and common concrete from the design of the mix proportion, the mixing on the spot, and the construction control, so as to enhance the application of the steel fiber concrete in the bridge deck pavement.

  4. 环氧沥青混凝土复合铺装结构疲劳试验研究%Research on the Fatigue Property of Multilayered Pavement on Concrete Bridge Deck

    Institute of Scientific and Technical Information of China (English)

    陈团结; 钱振东

    2012-01-01

    水泥混凝土桥面铺装整体结构的疲劳特性是决定铺装层使用寿命的关键.通过对双层沥青铺装层结构的复合梁以及“水泥混凝土板十双层沥青混合料铺装”三层复合结构的疲劳试验,对水泥混凝土桥面铺装层复合结构的疲劳性能进行了研究,同时考虑了层间防水粘结层的影响.结果表明当微应变为700×10-6时,“环氧沥青混凝土+SMA”结构的疲劳寿命是其他类型铺装结构的1.4倍;“水泥混凝土板十环氧沥青混凝土+SMA”三层复合结构的疲劳寿命是其他类型铺装结构的2.1倍.结论表明“环氧沥青+SMA”复合铺装结构适宜于水泥混凝土桥面铺装.%It is key for life-span of deck pavement that if the fatigue property of the whole deck pavement structure is better or not. The facts showed that when some materials with good fatigue properties were adopted, but the life of deck pavement was not prolonged at all. Here some experiments on double-layered asphalt deck pavement and "concrete deck + double-layered asphalt deck pavement" were done, along with some researches on the fatigue property of multi-layered deck pavement, considering the influence of adhesion layer. Some conclusions have been arrived that when the micro strain equals to 700 × 10-6, the fatigue life of the beam combined with epoxy asphalt concrete and SMA is 1. 4 times than other deck pavement structures; the fatigue life of the triple-layered deck pavement combined with concrete deck, epoxy asphalt concrete and SMA is 2. 1 times than other type of deck pavement. That indicates that deck pavement combined with epoxy asphalt concrete and SMA is suitable for concrete bridges.

  5. 上承式拱梁组合桥设计%Design of combined deck type arch bridge

    Institute of Scientific and Technical Information of China (English)

    严国香

    2012-01-01

    结合某桥的工程地理位置及沿河景观要求,对该桥的结构设计特点、构造与施工要点等进行了简要介绍,目前该桥运营情况良好,并取得了一定的经济、社会效益,为同类型桥梁施工积累宝贵经验。%This paper synthesized the engineering geographic location and river landscape requirements of a bridge,simply introduced the structure design features,structure and construction key points of this bridge,present the bridge was operating in good condition,and achieved certain economic,social effect,accumulated valuable experience for the same type bridge construction.

  6. 正交异性钢桥面板足尺疲劳试验%Fatigue Test on Full-scale Orthotropic Steel Bridge Deck

    Institute of Scientific and Technical Information of China (English)

    王春生; 付炳宁; 张芹; 冯亚成

    2013-01-01

    Based on an orthotropic steel deck of a long-span cable-stayed bridge, a full-scale fatigue test was carried out for researching the fatigue behavior of critical details in steel bridge decks. The load cycle had reached 10. 2 million when the fatigue test was completed. The results show that fatigue cracks are found at the rib-to-deck details and also at weld toe of rib-to-diaphragm which expand along rib web; due to the welding residual stress, cracks are found in the compressive zone of rib-to-diaphragm; however, none is found in the cutout of diaphragm; based on the stress change criterion, the fatigue detail of rib-to-diaphragm satisfies the category D of AASHTO Specification and the category 63 of Eurocode while the fatigue detail of rib-to-deck is more than the category D of AASHTO Specification and the category 71 of Eurocode; if fatigue crack observation rule is adopted, the fatigue detail of rib-to-diaphragm is higher than the category D of AASHTO Specification and the category 80 of Eurocode.%以某大跨径斜拉桥采用的正交异性钢桥面板为工程背景,进行钢桥面板疲劳性能试验研究,足尺疲劳试验循环次数累积达到1 020万次.试验结果表明:加劲肋与盖板连接部位出现了纵向疲劳裂纹;加劲肋与横隔板连接的焊缝端部出现了在焊趾处萌生并沿加劲肋腹板扩展的疲劳裂纹;受焊接残余应力影响,处于疲劳荷载压应力区的腹板与横隔板连接焊缝端部也萌生了疲劳裂纹;横隔板挖孔部位无疲劳裂纹;若以测点应力发生变化为疲劳失效判据,则加劲肋与横隔板连接端部的疲劳细节高于AASHTO中D类和Eurocode的63类细节等级,加劲肋与盖板连接的疲劳细节高于AASHTO中D类和Eurocode的71类细节等级;若以出现疲劳裂纹为疲劳失效判据,则其疲劳细节高于AASHTO规范中D类和Eurocode的80类细节等级.

  7. 采用GFRP配筋解决混凝土碳化对桥梁面板的负面影响%THE SOLUTION FOR ADVERSE IMPACT OF CARBONATION ON CONCRETE BRIDGE DECK SLABS BT USING GFRP REINFORCEMENT

    Institute of Scientific and Technical Information of China (English)

    郑愚; 秦怀泉; 李春红

    2009-01-01

    As crucial structural components in bridge structures, bridge deck slabs played an important role in integral structural behaviours and transportation. However, with the increasing of ages in services, the durability of reinforced concrete bridge deck slabs was influenced significantly by carbonation. Recently, because of high strength, light weight and strong corrosion-resistance, glass fiber polymer reinforcement bars (GFRP bars) were accepted by civil engineers. Due to the existence of compressive membrane action, it was shown that the structural behaviours of GFRP reinforced concrete bridge deck slabs with same reinforcement percentage were similar as those of steel reinforced concrete bridge deck slabs in nonlinear finite element analysis. Based on numerical analysis results, GFRP is available to be used as replacement of steel reinforcement. According the analysis of mechanism of concrete carbonation and material properties of GFRP, it was found that the durability of GFRP reinforced concrete bridge deck slabs was enhanced after the occurrence of carbonation in concrete structures, because carbonation reduced the permeability and porosity of concrete.%桥梁面板是桥梁结构的主要构件,对结构的整体性能和交通运输起着至关重要的作用.然而随着使用年限的增加,混凝土碳化将对钢筋混凝土桥梁面板的耐久性能产生较大的影响.近年来,玻璃纤维增强复合筋材(GFRP Bars)因具有高强、轻质、耐腐蚀等性能而逐渐被工程界认可.非线性有限元分析结果表明,由于压缩薄膜效应的存在使得同样配筋率的GFRP筋混凝土桥梁面板与钢筋混凝土桥梁面板的工作性能相似,证实了GFRP筋代替钢筋的可行性.在分析混凝土的碳化机理和GFRP的材料属性后发现,由于碳化使混凝土的渗透性和孔隙率降低,在碳化发生以后GFRP筋混凝土桥梁面的耐久性能不仅没有下降反而有所提高.

  8. 采用GFRP配筋解决混凝土碳化对桥梁面板的负面影响%THE SOLUTION FOR ADVERSE IMPACT OF CARBONATION ON CONCRETE BRIDGE DECK SLABS BY USING GFRP REINFORCEMENT

    Institute of Scientific and Technical Information of China (English)

    郑愚; 秦怀泉; 李春红

    2011-01-01

    As crucial structural components in bridge structures, bridge deck slabs played an important role in integral structural behaviours and transportation. However, with the increasing of ages in services, the durability of reinforced concrete bridge deck slabs was influenced significantly by carbonation. Recently, because of high strength, light weight and strong corrosion-resistance, glass fiber polymer reinforcement bars ( GFRP bars) were accepted by civil engineers. Due to the existence of compressive membrane action, it was shown that the structural be haviours of GFRP reinforced concrete bridge deck slabs with same reinforcement percentage were similar as those of steel reinforced concrete bridge deck slabs in nonlinear finite element analysis. Based on numerical analysis results, GFRP is available to be used as replacement of steel reinforcement. According the analysis of mechanism of concrete carbonation and material properties of GFRP, it was found that the durability of GFRP reinforced concrete bridge deck slabs was enhanced after the occurrence of carbonation in concrete structures, because carbonation reduced the permeability and porosity of concrete.%桥梁面板是桥梁结构的主要构件,对结构的整体性能和交通运输起着至关重要的作用.然而随着使用年限的增加,混凝土碳化将对钢筋混凝土桥梁面板的耐久性能产生较大的影响.近年来,玻璃纤维增强复合筋材( GFRP Bars)因具有高强、轻质、耐腐蚀等性能而逐渐被工程界认可.非线性有限元分析的结果表明,由于压缩薄膜效应的存在使得同样配筋率的GFRP筋混凝土桥梁面板与钢筋混凝土桥梁面板的工作性能相似,证实了GFRP筋代替钢筋的可行性.在分析混凝土的碳化机理和GFRP的材料属性后发现,由于碳化使混凝土的渗透性和孔隙率降低,在碳化发生以后GFRP筋混凝土桥梁面的耐久性能不仅没有下降反而有所提高.

  9. Effect of cable-stayed bridge's relative height of deck on viscous damper's seismic reduction behavior%斜拉桥面相对高度对粘滞阻尼器减震效果影响研究

    Institute of Scientific and Technical Information of China (English)

    张文学; 黄荐; 王景景

    2015-01-01

    由于地震响应特性对斜拉桥结构影响较大,在塔梁之间合理设置粘滞阻尼器可改善斜拉桥抗震性能。而目前研究多针对具体工程未考虑斜拉桥面相对高度对粘滞阻尼器减震效果影响。以某斜拉桥为模型,通过改变其下塔柱高度改变斜拉桥面相对高度,并系统分析桥面相对高度对斜拉桥粘滞阻尼器减震效果影响。研究表明,桥面相对高度对粘滞阻尼器最优参数及最优减震效果均有较大影响。%Studies show that proper elastic viscous damper between the tower and girder can improve the seismic behavior of cable-stayed bridge.However,conclusions at present are mostly drawn from some specific engineering projects without considering the influence of different relative height of deck on viscous damper's shock reduction effect.By changing the height of lower towers to alter the relative height of deck,the influence of relative height of deck on tower-girder viscous damper's shock reduction effect was analysed based on a certain cable-stayed bridge model.According to the study,it is shown that the relative height of deck of cable-stayed bridge has an outstanding influence on the damper's optimal parameters and the optimum shock reduction effect.

  10. Key Technology and Test Analysis of the Hoisting Construction of the Main Municipal Bridge Deck Beam%市政主桥桥面吊装施工关键技术及检测分析

    Institute of Scientific and Technical Information of China (English)

    钟志良

    2016-01-01

    Based on the construction project of hoisting of the main bridge deck beam of a municipal bridge in Guangdong Province, this paper introduces the key technical problems and solutions of this project in process of bridge deck hoisting construction in detail. It emphasizes that the hoisting of municipal bridge must adjust measures to local conditions and use innovative construction technology, roundly consider the inland river navigation, field condition, equipment layout and mechanical usage and other elements to implement the high-quality and efficient hoisting construction of the main bridge deck beam of this project. The test results show that the indicators meet the design requirements and make remarkable construction benefit.%以广东省某市政桥梁主桥桥面吊装施工项目为基础,详细介绍了该项目桥面吊装施工过程中遇到的关键技术难题及解决方案,强调市政桥梁吊装必须因地制宜,敢于应用创新的施工工艺,将内河通航、现场条件、设备布局和机械使用等要素统筹考量,实现该项目主桥吊装优质高效施工,检测结果显示各项指标达到设计要求,取得了显著的建设效益。

  11. Aerodynamic interaction between road deck and rail deck of separate-type highway-railway bridges and its effect on train running performance%分离式公铁双层桥面相互气动干扰及对列车走行性的影响

    Institute of Scientific and Technical Information of China (English)

    李永乐; 姜孝伟; 苏洋; 李龙安; 廖海黎

    2016-01-01

    There exists aerodynamic interaction between road deck and rail deck of highway-railway bridges under cross wind.In order to investigate the effect of different height intervals between two decks on train running performance, a separate-type highway-railway concrete box girder bridge was taken as an engineering example.The numerical simulation with CFD and the coupled vibration analysis of a wind-vehicle-bridge system were performed to determine train aerodynamic characteristics and to obtain its dynamic response.The results showed that the height interval between two decks has a major influence on train aerodynamic characteristics and its dynamic response;reducing the height interval leads to increase in the train lift coefficient and its vertical acceleration,and the wheel load reduction ratio increases as well;the effect of height intervals between two decks should receive more attention when selecting the optimal height interval in the design of highway-railway bridges.%横向风作用下公铁两用双层桥的上、下桥面间存在相互的气动干扰,为研究公铁两用组合桥间隔高度对列车走行性的影响,针对某分离式公铁两用混凝土箱梁桥,采用计算流体动力学(CFD)数值模拟和风-车-桥耦合振动研究的方法,分析了上、下桥面间隔高度对列车气动特性和车辆动力响应的影响。分析结果表明,公铁两用组合桥间隔高度对列车的气动特性和动力响应影响显著,间隔高度减小,列车升力系数和竖向加速度显著增大,轮重减载率也随之增大。公铁两用组合桥的设计应考虑间隔高度对列车的影响,以选择合理的间隔高度。

  12. Experimental study on wind-rain-induced and vortex-induced vibration in bridge deck sections of long-span bridges%大跨度桥梁主梁风雨致涡激振动试验研究

    Institute of Scientific and Technical Information of China (English)

    辛大波; 张明晶; 王亮; 欧进萍; 李惠

    2011-01-01

    针对风雨联合作用下的大跨桥梁风雨致涡激振动问题,以某一分离式双箱主梁桥梁及其闭口主梁型式桥梁为研究对象,通过在大气边界层风洞中搭建风雨联合作用试验系统,完成风雨联合作用下大跨桥梁节段模型涡激振动试验. 试验结果显示:不同雨强下,开口节段模型涡激振动的起振风速及锁定风速基本一致,但最大振动幅值有一定差别.不同雨强下,闭口节段模型随机振动的振动时程有一定差别,且随着风速增大,振动幅值增大.开口节段模型风雨联合作用下的位移幅值大于单一风作用下的位移幅值,最大增量可达1/4.得出结论:降雨增大了桥梁主梁涡激振动幅值;闭口节段模型相对开口节段模型在抵抗涡激振动方面性能更优良.%The vortex-induced vibration test in bridge deck sections of long-span bridges was carried out by considering vortex-induced vibration characteristics under the simultaneous actions of wind and rain, taking a separated twin-box girder bridge and its closed form as research objects. A system of simultaneous actions of wind and rain built in an atmospheric boundary layer wind tunnel was also utilized. Experimental results display that the wind speed at the start of oscillation and the wind speed of the lock-in region for the slotted section model show no difference in various rainfall intensities, but the maximal amplitudes of vortex-excited resonance display some differences. The time histories of stochastic vibration for the closed section model have some differences in various rainfall intensities, and the amplitude of vibration increases with rising wind speed. The displacement amplitude under the simultaneous actions of wind and rain is larger than the displacement amplitude under a single wind load; the highest increment reaches one quarter. Experimental results also show that the amplitude of vortex-induced vibration in bridge deck sections is increased by

  13. The Maintenance Measures of Steel Deck Pavement of Zhoushan Sea-crossing Bridge%舟山跨海大桥钢桥面铺装养护措施

    Institute of Scientific and Technical Information of China (English)

    竺海钢; 曾田; 贺才松

    2015-01-01

    Based on the construction environment and operational requirements of steel deck pavement of Zhoushan Sea-crossing Bridge,the types and causes of steel deck pavement disease are analyzed,and the conservation measures of steel deck epoxy asphalt pavement are proposed.By comparing the construction effects of two rehabilitation programs of double layer epoxy gravel concrete structure and ER structure,the construction feasibility and maintenance rationality of double layer epoxy gravel concrete structure are verified.%基于舟山跨海大桥的施工环境和钢桥面铺装的使用要求,并对钢桥面铺装病害类型及成因进行分析,提出了环氧沥青钢桥面铺装养护措施.通过采用双层环氧碎石混凝土结构和ER结构两种修复方案进行施工对比,验证了双层环氧碎石混凝土结构的施工可行性和维修合理性.

  14. The Maintenance Measures of Steel Deck Pavement of Zhoushan Sea-crossing Bridge%舟山跨海大桥钢桥面铺装养护措施

    Institute of Scientific and Technical Information of China (English)

    竺海钢; 曾田; 贺才松

    2015-01-01

    Based on the construction environment and operational requirements of steel deck pavement of Zhoushan Sea-crossing Bridge,the types and causes of steel deck pavement disease are analyzed,and the conservation measures of steel deck epoxy asphalt pavement are proposed.By comparing the construction effects of two rehabilitation programs of double layer epoxy gravel concrete structure and ER structure,the construction feasibility and maintenance rationality of double layer epoxy gravel concrete structure are verified.%基于舟山跨海大桥的施工环境和钢桥面铺装的使用要求,并对钢桥面铺装病害类型及成因进行分析,提出了环氧沥青钢桥面铺装养护措施。通过采用双层环氧碎石混凝土结构和ER结构两种修复方案进行施工对比,验证了双层环氧碎石混凝土结构的施工可行性和维修合理性。

  15. Optimizing rib width to height and rib spacing to deck plate thickness ratios in orthotropic decks

    Directory of Open Access Journals (Sweden)

    Abdullah Fettahoglu

    2016-12-01

    Full Text Available Orthotropic decks are composed of deck plate, ribs, and cross-beams and are frequently used in industry to span long distances, due to their light structures and load carrying capacities. Trapezoidal ribs are broadly preferred as longitudinal stiffeners in design of orthotropic decks. They supply the required stiffness to the orthotropic deck in traffic direction. Trapezoidal ribs are chosen in industrial applications because of their high torsional and buckling rigidity, less material and welding needs. Rib width, height, spacing, thickness of deck plate are important parameters for designing of orthotropic decks. In the scope of this study, rib width to height and rib spacing to deck plate thickness ratios are assessed by means of the stresses developed under different ratios of these parameters. For this purpose a FE-model of orthotropic bridge is generated, which encompasses the entire bridge geometry and conforms to recommendations given in Eurocode 3 Part 2. Afterwards necessary FE-analyses are performed to reveal the stresses developed under different rib width to height and rib spacing to deck plate thickness ratios. Based on the results obtained in this study, recommendations regarding these ratios are provided for orthotropic steel decks occupying trapezoidal ribs.

  16. GFRP-花旗松胶合木夹芯桥面板受弯性能试验与结构设计%Experiment on Bending Capacity and Structural Design of GFRP-pseudotsuga Taxifolia Glulam Bridge Deck

    Institute of Scientific and Technical Information of China (English)

    方海; 韩娟; 刘伟庆; 祝露

    2014-01-01

    采用花旗松胶合木作为芯材,玻璃纤维增强复合材料(GFRP)作为面层制备夹芯结构桥面板,在对花旗松胶合木芯材和 GFRP 开展基本力学性能试验研究的基础上,开展了 GFRP-花旗松胶合木夹芯梁的受弯性能试验,得出了其荷载-跨中挠度曲线与 GFRP 荷载-跨中应变曲线,并对抗弯刚度测试值与理论计算值进行了对比;针对某 GFRP-花旗松胶合木桥面板,提出了完整的结构设计流程,给出了桥面板的合理设计参数。研究结果表明:GFRP-花旗松胶合木桥面板应用于钢梁-复合材料桥面板组合桥梁结构较为可行。%The bridge panel of sandwich structure was manufactured by using pseudotsuga taxifolia glulam as core materials and glass fiber reinforced polymer (GFRP) as surface course . The bending experiment of GFRP-pseudotsuga taxifolia glulam beam was carried out based on basic mechanical property of pseudotsuga taxifolia glulam core materials and GFRP .From the bending experiment ,the load-midspan deflection curve and GFRP load-midspan strain curve were got ,and the test value was compared with theoretical value of bending stiffness .It brought up a whole structured design process of a sandwich structure bridge deck , and gave the design parameter of bridge deck .The study results show that using GFRP-pseudotsuga taxifolia glulam bridge deck into girder-composite bridge panel is feasible .

  17. GFRP-花旗松胶合木夹芯桥面板受弯性能试验与结构设计%Experiment on Bending Capacity and Structural Design of GFRP-pseudotsuga Taxifolia Glulam Bridge Deck

    Institute of Scientific and Technical Information of China (English)

    方海; 韩娟; 刘伟庆; 祝露

    2014-01-01

    The bridge panel of sandwich structure was manufactured by using pseudotsuga taxifolia glulam as core materials and glass fiber reinforced polymer (GFRP) as surface course . The bending experiment of GFRP-pseudotsuga taxifolia glulam beam was carried out based on basic mechanical property of pseudotsuga taxifolia glulam core materials and GFRP .From the bending experiment ,the load-midspan deflection curve and GFRP load-midspan strain curve were got ,and the test value was compared with theoretical value of bending stiffness .It brought up a whole structured design process of a sandwich structure bridge deck , and gave the design parameter of bridge deck .The study results show that using GFRP-pseudotsuga taxifolia glulam bridge deck into girder-composite bridge panel is feasible .%采用花旗松胶合木作为芯材,玻璃纤维增强复合材料(GFRP)作为面层制备夹芯结构桥面板,在对花旗松胶合木芯材和 GFRP 开展基本力学性能试验研究的基础上,开展了 GFRP-花旗松胶合木夹芯梁的受弯性能试验,得出了其荷载-跨中挠度曲线与 GFRP 荷载-跨中应变曲线,并对抗弯刚度测试值与理论计算值进行了对比;针对某 GFRP-花旗松胶合木桥面板,提出了完整的结构设计流程,给出了桥面板的合理设计参数。研究结果表明:GFRP-花旗松胶合木桥面板应用于钢梁-复合材料桥面板组合桥梁结构较为可行。

  18. 双层桥箱内壁车辆碰撞混凝土损伤仿真研究%Simulation Study on Concrete Damage of the Inner Box Collision of the Double Decked Continuous Box Girder Bridge

    Institute of Scientific and Technical Information of China (English)

    沈正峰; 方金苗; 郑净

    2014-01-01

    Double-decked continuous box bridge is a new structure system and how to evaluate the structure damage caused by vehicle collision inner box has a great significance to the wide application of the new structure .This paper researches all conditions of structure damages caused by vehicle collision inner box by means of computerized simulation .The study finds out the concrete injured parts and its degree ,analysis the sensitive factor of concrete damage ,which provides suggestions for the design of double-decked bridge .%双层连续箱梁桥是一种新型结构体系,如何评价车辆撞击箱梁内部造成的结构损伤对于这种新型结构的广泛运用具有重要意义。通过计算机仿真技术研究各种工况下车辆对箱梁桥内壁撞击引起的结构损伤情况,得出混凝土损伤部位以及程度,分析影响混凝土损伤的敏感因子,为双层桥结构设计提供参考。

  19. 结合梁桥面系异形钢箱拱肋系杆拱桥设计%Design of Special-shaped Steel Box Arch Rib Bowstring Arched Bridge of Bonding Beam Deck System

    Institute of Scientific and Technical Information of China (English)

    李文勃

    2009-01-01

    The main bridge of Putian Chenggang Avenue Bridge crossing Molan River is the special-shaped bowstring arched bridge of 2-span simple-supported double-rib half-through steel box arch rib bonding beam deck system. The single span is 72 m long and the bridge is 47.5 m wide with city-Class A load and double-direction of 8 lanes. Taking the preliminary design and construction drawing design of this bridge as the basis, the article introduces the scheme study of bridge type, structural design of main bridge and analysis of structural calculation of the special-shaped bowstring arched bridge, and analyzes some technical characteristics of this bridge. The design method of the main bridge inclined crossed with the curve river, the design thinks of bonding beam in the arched bridge, the temporary constructed supporting point for improving the structural bearing, and the design method of special arch rib modeling can be referred for the design of the similar bridges.%莆田城港大道跨木兰溪大桥主桥是两跨简支的双肋下承式钢箱拱肋结合梁桥面系的异形系杆拱桥,单跨跨径72m,桥宽47.5m,城一A级荷载,双向8车道.该文以该桥的初步设计和施工图设计为基础,介绍了异形系杆拱桥的桥型方案研究、主桥结构设计、结构计算分析等内容,并分析了该桥的一些技术特点.该桥的弯曲河道斜交主桥设计方法、结合梁在拱桥中的设计思想、结合梁横梁设置临时支点改善结构受力、独特拱肋造型的设计方法等内容,可供类似桥梁设计时参考.

  20. EXPERIMENTAL STUDY OF COMPRESSIVE MEMBRANE ACTION IN THE CONCRETE BRIDGE DECK SLABS REINFORCED WITH GFRP BARS%GFRP筋混凝土桥面板内压缩薄膜效应的试验研究

    Institute of Scientific and Technical Information of China (English)

    潘云锋; 郑愚; 钟永刚

    2013-01-01

    With the consideration of compressive membrane action (CMA) in the structural design of concrete bridge deck slabs reinforced with GFRP bars, the reinforcement percentages and construction costs could be decreased. Therefore, a series of one-third scaled experimental tests of GFRP reinforced concrete bridge deck slabs under static patch loads was carried out. In the experimental study, the influences from some structural variables were .investigated, which included widths of supporting beams, reinforcing materials and reinforcement percentages. In this study, some structural parameters, such as loading capacity, stress&strain relationship, cracking patterns, were measured and observed in the different stages. The structural behaviours of GFRP reinforced concrete bridge deck slabs were discussed, including displacements of supporting beams, cracking patterns and failure mechanism. The results were used to study the effects of CMA and influenced from this structural phenomenon on structures. In this study, it was found that the increase in lateral restraint stiffness could enhance load-carrying capacities significantly. However, the effects of reinforcement percentages were not obvious. Furthermore, current design standards underestimate the load-carrying capacities without consideration of CMA.%结合压缩薄膜效应对GFRP筋混凝土桥面板进行结构设计,有效降低了桥面板的配筋率,降低了结构的建造成本.以支撑梁宽度、筋材种类、配筋率为参数,对1∶3比例缩小的梁板式桥面板进行静力加载试验,测量各个结构模型在整个加载过程中各阶段的承载力、应变、变形等数据,考察其基本力学性能.分析研究桥面板在轮胎荷载下,支撑梁变形、桥面板的裂缝扩展和破坏形态,清晰揭示压缩薄膜效应在整个受力过程中的变化以及对结构性能的影响.

  1. The application of pouring asphalt steel deck pavement construction method in suspension bridge%浇筑式沥青钢桥面铺装工法在悬索桥中的应用

    Institute of Scientific and Technical Information of China (English)

    李逢源

    2014-01-01

    This paper compared and analyzed the thermoset materials,asphalt materials,composite materials three kinds of steel deck pavement schemes,combining with the pavement case of Nanjing Yangtze River four bridge,mainly discussed the pavement method of composite pouring asphalt steel deck,the practice proved that the method ensured the back resistance and fatigue resistance of pavement structure,not only im-proved the construction quality,also shorten the construction period.%对热固性材料、沥青类材料、组合类材料三类钢桥面铺装方案进行了对比分析,结合南京长江四桥的铺装案例,主要对复合浇筑式沥青钢桥面的铺装工法进行了论述,实践证明该工法确保了铺装结构的追随性与抗疲劳性,既提高了施工质量,又缩短了工期。

  2. Critical wind velocities for several kinds of typical vehicle running on a cable-stayed bridge deck%几种典型车辆在斜拉桥桥面行驶的临界风速研究

    Institute of Scientific and Technical Information of China (English)

    马麟; 韩万水; 刘健新; 李加武

    2011-01-01

    The critical wind velocity and running velocity were studied for three kinds of typical vehicle running on a cable-stayed bridge deck under action of strong side wind. The effects of the bridge's side buffeting and the following coordinate features of the vehicle's moving equations on the vehicle side deviation relative to the bridge deck were analyzed, the calculation formulas of its relative side slipping and velocity were obtained. Based on previous studies, a wind-vehicle-bridge coupling vibration system including vehicle side deviation and driver's behavior was studied, and the corresponding simulation code was improved and tested. A cable-stayed bridge was taken as an example, critical wind velocities of three kinds of typical automobile running on the bridge deck were obtained. Results showed that the critical wind velocity is not significantly influenced by controlling objectives of driver behavior; the accident types of different vehicles are possibly different; for box-type truck, its critical wind velocity of side slipping is always lower than that of overturning; but for cars like Santana and Jia-bao, overturning accident plays a controlling role when running velocity is high, while side slipping accident does when running velocity is low.%研究强侧风作用下三种典型汽车在斜拉桥桥面行驶时的临界风速和车速.分析汽车运动方程的随动坐标特性和桥梁的侧向抖振对汽车相对桥面侧偏的影响,得到侧偏位移及速率的计算式,在以往基础上,研究了考虑车辆侧偏和驾驶员行为的风-车-桥空间耦合振动系统,完善了仿真分析程序的功能.以某斜拉桥为实例,分析三种典型车辆在桥面行使的临界风速.分析结果表明:采用控制重心还是前轮侧滑的驾驶员模型不显著影响桥面汽车临界风速的大小;不同类型汽车的事故原因可能不同,对于箱式货车,侧滑事故起控制作用,对于桑塔纳和一汽佳宝,车速高时,侧倾

  3. Mechanics Analysis on Rigid-flexible Composite Pavement Structure of Fabricated Steel Box Girder Bridge Deck%装配式钢箱梁桥面刚柔复合铺装结构力学分析

    Institute of Scientific and Technical Information of China (English)

    吴国雄; 程菓; 伍成忱

    2016-01-01

    选择钢箱梁刚柔复合桥面铺装体系为研究对象,建立正交异形板以及铺装层的三维有限元模型,探索车轮荷载作用下刚柔复合铺装层及其与钢桥面板界面上力学响应的分布规律。分析表明,刚柔复合铺装结构整体刚度较好,铺装层受力的局部效应减弱;纵向拉应力为刚柔复合铺装中拉应力的主要控制指标;正交异性板的刚度突变位置易出现最大应力值。研究结果可对钢桥面铺装设计提供理论依据。%This paper chooses rigid-flexible composite steel box girder bridge deck as the research object, establishes a three-dimensional finite element model of orthotropic plate and pavement to explore the distribution rule of the mechanical response from the rigid-flexible composite pavement and the bridge deck interface under wheel loads. The analysis shows that the overall stiffness of the rigid-flexible composite pavement structure is good, and the local effects of pavement force weakens; longitudinal tensile stress is the main control indicator of the tensile stress in the rigid-flexible pavement com-posite; the stiffness mutation of orthotropic plate is prone to the maximum stress. The results provide a theoretical basis for pavement design.

  4. 准流线型桥梁断面涡激共振的雷诺数效应%Reynolds number effect on vortex resonance of streamline-like bridge deck section

    Institute of Scientific and Technical Information of China (English)

    崔欣; 李加武; 陈飞; 刘健新

    2011-01-01

    为了研究准流线型桥梁断面涡激共振的雷诺数效应,通过改变模型尺度实现雷诺数的改变,并在模型表面布置测压点,进行风洞试验.测量了大、小2种模型风速与振幅的关系及各测点的风压时程,分析了振动频谱、扭矩系数时程及各测点脉动压力频谱随雷诺数的变化规律,揭示了扭转涡激振动的雷诺数效应.研究结果表明,脉动压力频谱的雷诺数效应引起了扭矩系数时程的雷诺数效应,从而引发振动频谱的雷诺数效应,最终导致了流线型桥梁断面扭转涡激振动的雷诺数效应.%In order to study the Reynolds number effect on vortex resonance of streamline-like bridge deck section, Reynolds number was changed by adjusting scale of model, and pressure taps were set on the surface of model. Amplitude and wind pressure time history of two models were recorded. Reynolds number effect on vibration frequency spectrum, moment coefficient time history and fluctuation pressure frequency spectrum were studied. Intrinsic reasons of Reynolds number effect on vortex was revealed. The investigation indicates that Reynolds number effect on pressure spectrum cause the Reynolds number effect on moment coefficient time history and cause Reynolds number effect on vibration frequency spectum, lead to Reynolds number effect on vortex resonance of streamline-like bridge deck section. 1 tab, 9 figs, 11 refs.

  5. Applications of IES for Local Accurate Detection in Reinforced Concrete Bridge Deck%IES冲击回波仪在钢筋混凝土桥面局部精确检测的应用分析

    Institute of Scientific and Technical Information of China (English)

    张志清; 刘晓姗; 丛铖东; 汪怡然

    2012-01-01

    为了克服电磁波检测仪受磁场干扰的影响,探询钢筋混凝土桥面局部精确检测的可行方法,从IES冲击回波仪的检测原理出发,分析了目前无损检测技术各自的适用性,研究了IES在钢筋混凝土桥面局部精确检测中应用的可行性.IES能够弥补其他无损检测方法的局限和不足,不受被检对象磁场干扰,可以进行单面测试,形成2D或3D图像,直接对反射信号进行分析,对桥面铺装层内部缺陷、脱层、钢筋网保护层厚度不足及钢筋网下沉现象进行精确判定,是1种良好的无损检测方法.%To overcome the magnetic field interference of electromagnetic wave detector, this paper attempts to seek a viable method for local accurate detection of reinforced bridge deck. From the detection principle of the Impact Echo Scanning (IES) , the paper analyzes the application of the current non-destructive testing technology and studies the application feasibility of IES in the local accurate detection of reinforced concrete bridge deck. It is found out that the IES can compensate for the limitations and shortcomings of other NDT methods. It can be tested single-sided and can not be disturbed by the magnetic field of detected objects. Moreover, it can analyze the reflected signal directly and form 2D and 3D images. Furthermore, it is able to accurately determine the deck cracks, internal delamination, subsidence of steel mesh and the insufficiency of cover. IES method is a good non-destructive testing method.

  6. A-DECK Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The technical objectives of A-DECK are: 1)Flight Weight including rideshare payloads will be less than 500 Kg. 2)First fundamental frequency of integrated A-DECK...

  7. 钢管混凝土拱桥桥面铺装动力学特性研究%Research on Dynamics Characteristics of Deck Pavement of Concrete-Filled Steel Tube Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    杨咏梅; 庄月明

    2011-01-01

    首先,建立了千岛湖钢管混凝土拱桥的3D有限元模型.通过有限元计算,得到了该钢管混凝土拱桥前8阶的自振频率和自振振型.同时,计算了该钢管混凝土拱桥的水平自振基频与竖向自振基频.接着,选用移动恒载研究车辆荷载作用下的钢管混凝土拱桥桥面铺装结构动力学特性.计算得到该钢管混凝土拱桥的共振速度并分析了桥梁共振响应的可能性.计算了不同车速下跨中节点的竖向最大位移与纵向拉应力,并进一步计算了冲击系数,提出了钢管混凝土拱桥的荷载冲击系数参考值.最后,考虑施工荷载,计算了梁底最大拉应力与最大剪应力,分析了Dynapac CC522型振动压路机施工时对桥梁结构的影响.%First of all, finite element 3D model of the concrete-filled steel tube arch bridge above Qian-dao Lake is established. By calculation of finite element method, the initial eight stages auto-oscillation frequency and mode of the concrete-filled steel tube arch bridge are acquired. Meanwhile, horizontal and vertical auto-oscillation fundamental frequency of the concrete-filled steel tube arch bridge is calculated. Secondly, moving constant load is used to research the dynamics characteristics of deck pavement of the concrete-filled steel tube arch bridge. Resonance velocity of the concrete-filled steel tube arch bridge above Qiandao Lake is computed to analyze the probability of bridge resonance. The maximum vertical displacement and longitudinal tensile stress of mid-span node under different vehicle speeds are calculated. Furthermore, impact coefficient reference value of the concrete-filled steel tube arch bridge is put forward. Finally, considering construction loads, the maximum tensile stress and shearing stress of beam bottom are calculated to analyze the influence of construction exploiting "Dynapac CC522" vibratory roller.

  8. 浙闽木拱桥类型学研究——以桥板苗系统为视角%Typological study on timber arch bridges in Zhe-Min provinces:with focus on bridge-deck-beam-system

    Institute of Scientific and Technical Information of China (English)

    刘妍

    2011-01-01

    The timber arch bridge in Zhejiang (Zhe) and Fujian (Min) provinces is a unique beamweaving-arch structure, and has a close genetic relationship with the Rainbow Bridge in the famous Song-dynasty painting the scene of the upriver at pure brightness festival ". By a study of typological analysis focusing on the timber structure, it is pointed out in this paper that there is an important distinction between the timber arch bridge in Zhe-Min provinces and the Rainbow Bridge over the Bian River. Throughout the development of the former, the bridge-deck-beam-system has hold a significant role, and should be seen as the third system aside from the first and second systems, viz. the tri-segment arch, and the penta-segment arch. The signification in the bridgedeck-beam-system of timber arch bridge in Zhe-Min provinces includes: functionally, it provides a gentle-sloped floor for the bridge-deck; structurally, it shares the load of the arch, and serves the structural stability; typologically, the method of the combination of the bridge-deck-beam-system and the arch system provides an important factor of depicting the development of the typology of timber bridges. And an essential character of the evolvement of the structure of timber bridges is structure addition and simplification. The simplification and stabilization are the main motivation in the evolvement of timber arch bridges.%浙闽木拱桥独特的编梁拱形结构与汴水虹桥有着密切的关系.对木拱桥结构的类型学分析结果表明,浙闽木拱桥与汴水虹桥的一个重要区别在于,在浙闽木拱桥的发展历程中,桥板苗系统自始至终占有重要的地位,可视作三节苗、五节苗体系之外的第三套体系.浙闽木拱桥桥板苗系统的重要性体现在使用功能上,可保证桥面的平缓;在结构上有效地分担了拱架荷载,并保证结构的稳定;在类型学上,桥板苗系统与编织拱系统的结合方式的多样做法,是探讨木拱桥类型学

  9. 大跨钢桁拱钢-混组合桥面板极限承载力试验%Experiment on Ultimate Bearing Capacity of Steel and Concrete Composite Deck Slab of Long Span Steel Truss Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    卢彭真; 赵人达; 任剑

    2012-01-01

    To assess the ultimate bearing capacity of the steel-concrete composite deck slab subject to highway load, ultimate bearing capacity tests were carried out. According to Saint Venant Principle, by taking the part steel-concrete deck slab in column area with positive and negative bending moments as finite element models of the actual bridge, the study focused on the ultimate bearing capacity of the steel-concrete deck slab in column area with positive and negative bending moments for 2 composite deck slab specimens (model A and model B). The results show that tensile failure has occurred in the concrete slab of model A. The upper and lower flange plates of I beam, web plate and longitudinal reinforcement have not yielded under ultimate load, but steel bottom plate, PBL and lateral reinforcement have yielded before failure. The failure load of model A is 1 750 kN. As for model B, concrete slab has compression failure, PBL has yielded before failure, and the failure load of model B is 2 200 kN. Research results provide reference for design calculation of the ultimate bearing capacity of steel-concrete composite deck slab.%为评估钢一混组合桥面板结构在公路荷栽作用下的极限承载力,对其进行极限承载力性能试验研究。根据圣维南原理,选取正负双向弯矩受力的立柱区部分桥面板作为实桥的有限元分析模型,并试验制作了2个等尺模型试件A和B,用于考察钢一混组合桥面板正负双向弯矩区的极限承载力性能。试验结果表明:模型A混凝土板被拉坏,工.字钢上下翼缘板、腹板以及纵向钢筋始终未屈服,PBL、钢底板以及横向钢筋均在破坏之前屈服,模型A的破坏荷载为1750kN;模型B混凝土板被压坏,PBL在破坏之前屈服,模型B的破坏荷载为2200kN。研究结果可为钢一混组合桥面板极限承栽能力设计计算提供参考。

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  11. Design of Experimental Suspended Footbridge with Deck Made of UHPC

    Directory of Open Access Journals (Sweden)

    Blank Marek

    2016-01-01

    Full Text Available This paper deals with the static and dynamic design of experimental footbridge for pedestrians and cyclists in the municipality Lužec nad Vltavou in Czech Republic, Europe. This work aims to familiarize the reader with calculations carried out and the results obtained, describing the static and dynamic properties of proposed footbridge. The construction of footbridge is designed as a suspended 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 tons. 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. The utilization of the excellent properties of UHPC allows to design a very thin and lightweight construction of the deck, which could not be achieved with the use of normal concrete.

  12. Comparison of Stresses of Fatigue-sensitive Regions in Orthotropic Deck of Steel Box Girder for Highway and Railway Bridges%钢箱梁用于公、铁桥梁时正交异性板疲劳敏感部位应力比较

    Institute of Scientific and Technical Information of China (English)

    高立强; 蒲黔辉; 施洲

    2011-01-01

    The scheme of steel box girder used in the design of Yongjiang Railway Cable-stayed Bridge of Ningbo city is the first case in railway bridges in China. For railway bridges, the transverse position of steel rails is stable, and bridge deck pavement is different from that of highway bridges. In order to study the difference of orthotropic deck used in railway bridge and highway bridge, railway bridge and highway bridge deck pavements were installed on the deck separately. With the finite element method, the transverse and longitudinal influence lines of the stresses in the fatigue-sensitive regions with different bridge deck pavements were calculated. The reason why the stress in each fatigue-sensitive region was studied, and the characteristics of steel box girder orthotropic deck for railway bridge and highway bridge were analyzed. With the representative railway and highway vehicles as the loads, the stresses of steel box girder orthotropic deck in some fatigue-sensitive regions were calculated. The results of analysis and calculation show that (1 ) The dispersion of asphalt concrete deck pavement for highway bridge is weak, while that of railway bridge deck pavement is strong. Compared with highway bridge, the values of influence lines of the stresses in the fatigue-sensitive regions are smaller, and the lengths of influence lines are longer for railway bridge. (2) Under theload of normal railway vehicle, the largest stresses of rib-to-diaphragm joint and edge of cutout in diaphragm are similar to that under the load of normal highway vehicle. (3) In comparison with railway bridge, fatigue cracks are likely to emerge at the rib-to-deck joint for highway bridge orthotropic deck.%宁波甬江铁路斜拉桥在设计中采用钢箱梁方案,在铁路桥中为国内首例.铁路桥梁钢轨横向位置固定,桥面铺装也与公路桥梁不同,为研究钢箱粱正交异性板用于铁路桥梁和公路桥梁的区别,在桥面板上分别设置铁路与公路铺

  13. 混凝土桥面双层SMA铺装高温性能研究%Research on High-temperature Performance of Double-layer SMA Pavement on Concrete Bridge Deck

    Institute of Scientific and Technical Information of China (English)

    杨通明

    2014-01-01

    At present the asphalt layer paved on cement concrete bridge deck adopts the same structure as the general pavement. In accordance with foreign applications, this paper lays down 5 double-layer SMA structures in different combination modes and inspects the high -temperature resistant deformation performance of each type of mixtures via Schellenberg Binder Drain Down Test, Cantabro Test and rutting test. On this basis the paper analyzes the high-temperature resistant deformation performance of double-layer SMA structures in 5 different combination modes via APA test and rutting test, the results show that the integral capability of double-layer SMA structures resistant to deformation is mostly dependent on combination modes of structures; the integral deformation resistant capability of combination between the mixture on upper surface course with less strong deformation resistant capability and the mixture on lower surface course with strong deformation resistant capability may be superior to the combination of double-layer mixtures with strong deformation resistant capability; therefore, the combination of pavement layer structures of SMA13+SMA9. 5 or SMA9. 5+SMA13 are recommended for concrete bridge deck.%当前水泥混凝土桥面铺装沥青层一般采用与路面相同的结构。根据国外应用情况,拟定不同组合方式的5种双层SMA结构,通过谢伦堡析漏试验、肯塔堡飞散试验以及车辙试验来检验每种类型混合料的抗高温变形性能。在此基础上,通过APA试验和车辙试验分析5种不同组合方式的双层SMA结构抗高温变形性能,结果显示:双层SMA结构整体抗变形能力更大程度上依赖于结构组合方式;上面层抗变形能力稍差的混合料与下面层抗变形能力较强的混合料组合的整体抗变形能力可能优于双层抗变形能力较强的混合料组合;故推荐混凝土桥面采用SMA13+SMA9.5或SMA9.5+SMA13铺装层结构组合。

  14. 带有挑臂的双层钢桁悬索桥颤振性能风洞试验%Wind tunnel test for flutter stability of double-deck truss girder suspension bridge with cantilever beam

    Institute of Scientific and Technical Information of China (English)

    向活跃; 李永乐; 武兵

    2014-01-01

    为了提高加劲梁的颤振性能,针对某三塔两跨公铁两用悬索桥进行了节段模型风洞试验,探讨了多种气动措施对加劲梁颤振临界风速的影响。结果显示,在三种风攻角下,常规气动措施如增加上下桥面板中央稳定板、铁路道板及检修道开槽等措施降低了加劲梁的颤振临界风速,封闭铁路挑臂并给合上桥面板上、下中央稳定板后,加劲梁在三种风攻角下的颤振性能均大幅提高,使颤振临界风速满足要求。相关结论可为类似桥梁断面的颤振优化提供借鉴。%To improve the flutter stability of stiffened girder, the sectional model wind tunnel tests of a long span highway-railway suspension bridge with two main spans and three towers were carried out. A variety of aerodynamic measures on the flutter stability were explored. The results indicate that conventional aerodynamic measures such as the upper and lower central stabilizer, slotting rail road board and railway maintenance road reduce the critical flutter wind speed in three attack angle cases, while the flutter stability is increased significantly after closing the railway cantilever and u-sing the upper and lower central stabilizer in upper deck, which meets the requirement of standard. The conclusions can provide some references for similar bridge cross-section in the optimization of flutter stability.

  15. 南京长江第四大桥钢桥面铺装疲劳性能试验研究%Study on fatigue performance of steel deck pavement for the Fourth Nanjing Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    詹俞; 李国芬; 王宏畅

    2013-01-01

      结合南京长江第四大桥钢桥面铺装实体工程,开展铺装层混合料20℃疲劳性能试验。为了使试验结果能够更真实地反映主桥铺装的实际情况,直接采用主桥铺装使用的混合料成型试件,其中,带钢板复合梁试件为施工现场摊铺、碾压成型。室内试验对铺装结构单层采用劈裂疲劳试验,选择0.2、0.3、0.4、0.5、0.6这5个等级的应力水平,对组合结构采用带钢板复合梁疲劳试验,荷载水平为6 kN、7 kN、8 kN,并通过回归分析得到疲劳方程。%Based on the steel deck pavement of the Fourth Nanjing Yangtze River Bridge,this paper car-ried out fatigue performance tests of the pavement at 20℃. In order to make the results reflecting the actual situa-tion of pavement more realistically,we used main bridge pavement’s mixes for molding specimens;molding and rolling composite beam with steel was at the construction site. The splitting fatigue tests and five stress levels of 0.2,0.3,0.4,0.5,0.6 were used to study the fatigue property of each layer;in addition,the fatigue tests of composite beams with steel plates and three load levels of 6 kN,7 kN,8 kN were chosen to study the fatigue property of the composite structure. Finally,the fatigue equation by regression analysis was got.

  16. Combined Plate-Beam Element Method for Local Vibration Computation of Orthotropic Steel Bridge Deck%正交异性钢桥面板局部振动计算的组合板梁单元法

    Institute of Scientific and Technical Information of China (English)

    马牛静; 王荣辉

    2011-01-01

    Proposed in this paper is a combined plate-beam element method to calculate the local vibration of the orthotropic steel bridge deck with trapezoid stiffened ribs, which is used in the long-span steel bridge. In this method, the top plate and the trapezoid stiffened rib are respectively taken as the flat shell element and the plate-beam element, and the corresponding displacement model is established according to the deformation coordination relationship between the plate and the rib. Moreover, the stiffness matrix of the combined plate-beam element is obtained based on the energy-variation principle, and the consistent mass matrix and the consistent load matrix are obtained based on the shape function of each sub-element. Then, the finite dynamic equilibrium equations are obtained. Finally, a calculation program of dynamic finite element is presented for the combined plate-beam element, and the first 10 consequent natural frequencies are compared with those of the shell finite element, finding that the latters accord well with the formers. Thus, the proposed method proves to be feasible and efficient.%针对大跨度钢桥中采用梯形加劲肋的正交异性钢桥面板,提出一种计算钢桥面板局部振动的组合板梁单元法.其中顶板用平板壳单元分析,梯形加劲肋视为板梁单元,两者的位移模式根据板与肋的变形协调关系建立.组合板梁单元的刚度矩阵通过能量变分原理得到,利用各子单元的形函数可以求得组合板梁单元的一致质量矩阵与一致荷载列阵,进而得到相应的有限元动力平衡方程组.最后编制了组合板梁单元的有限元动力计算程序,将其前10阶自振频率与板壳有限元计算结果进行比较,验证了该方法的可行性与高效性.

  17. Study on fatigue performance of steel deck pavement for the Fourth Nanjing Yangtze River Bridge%南京长江第四大桥钢桥面铺装疲劳性能试验研究

    Institute of Scientific and Technical Information of China (English)

    詹俞; 李国芬; 王宏畅

    2013-01-01

      结合南京长江第四大桥钢桥面铺装实体工程,开展铺装层混合料20℃疲劳性能试验。为了使试验结果能够更真实地反映主桥铺装的实际情况,直接采用主桥铺装使用的混合料成型试件,其中,带钢板复合梁试件为施工现场摊铺、碾压成型。室内试验对铺装结构单层采用劈裂疲劳试验,选择0.2、0.3、0.4、0.5、0.6这5个等级的应力水平,对组合结构采用带钢板复合梁疲劳试验,荷载水平为6 kN、7 kN、8 kN,并通过回归分析得到疲劳方程。%Based on the steel deck pavement of the Fourth Nanjing Yangtze River Bridge,this paper car-ried out fatigue performance tests of the pavement at 20℃. In order to make the results reflecting the actual situa-tion of pavement more realistically,we used main bridge pavement’s mixes for molding specimens;molding and rolling composite beam with steel was at the construction site. The splitting fatigue tests and five stress levels of 0.2,0.3,0.4,0.5,0.6 were used to study the fatigue property of each layer;in addition,the fatigue tests of composite beams with steel plates and three load levels of 6 kN,7 kN,8 kN were chosen to study the fatigue property of the composite structure. Finally,the fatigue equation by regression analysis was got.

  18. The Application of Deck-shuttering Beams on Qing-Gao Super Large Bridge of Xiang-Gui Railway%上承式移动模架制梁在湘桂铁路青高特大桥的应用

    Institute of Scientific and Technical Information of China (English)

    熊文章

    2012-01-01

    The Qing-Gao super large bridge of Xiang-Gui railway uses the live simply-supported beam.Because of the influence of abutment,construction sites,address status and other factors,deck-shuttering beams are the optimal selection.But the difficulties of deck-shuttering construction technique are deck mobile formwork carrier installations which include the static load testing of movable rack installation,internal model installation,steel bar installation,concrete construction,via,such mobile formwork construction technique.This practice has proved that deck-shuttering beams in bridge construction over complex terrain have promotional value.%湘桂铁路青高特大桥采用现场简支梁制备,因受到相邻墩台、施工场地、地址状况等因素影响,采用上承式移动模架制梁是最优选择。而上承式移动模架施工技术的难点在于,上承式移动模架的安装,其中包括移动模架静载试验、内模安装、钢筋安装、混凝土施工、过孔等移动模架施工技术。工程实践证明,上承式移动模架制梁在复杂地形桥梁施工中具有推广价值。

  19. Boeing flight deck design philosophy

    Science.gov (United States)

    Stoll, Harty

    1990-01-01

    Information relative to Boeing flight deck design philosophy is given in viewgraph form. Flight deck design rules, design considerations, functions allocated to the crew, redundancy and automation concerns, and examples of accident data that were reviewed are listed.

  20. Integral Abutment and Jointless Bridges

    OpenAIRE

    Cristian-Claudiu Comisu

    2005-01-01

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

  1. State-of-the-art of long-span bridge engineering in China

    Institute of Scientific and Technical Information of China (English)

    XIANG Haifan; GE Yaojun

    2007-01-01

    This paper introduces the state-of-the-art of long-span bridge engineering in China with emphases on recent long-span bridge projects,bridge deck configuration and material,design codes of long-span bridges and improvement of aerodynamic performance.The recent long-span bridge projects include thirty-eight completed suspension bridges,cable-stayed and arch bridges with a main span over 400 m,and eighteen major bridges are under construction.The bridge deck configuration and material,with prestressed concrete decks,steel-concrete composite decks and steel box decks together with several popular cross-sections,are presented.The third part briefly outlines four design codes,including static and dynamic design for highway long-span bridges,and the recent engineering experiences gained from several aerodynamic vibration control projects of long-span bridges are shared in the last part.

  2. 水泥混凝土桥梁长寿命桥面铺装层复合结构疲劳特性%Fatigue Performance of Composite Structure for Perpetual Pavement on Cement Concrete Bridge Deck

    Institute of Scientific and Technical Information of China (English)

    钱振东; 王江洋; 王亚奇

    2012-01-01

    In order concrete bridge, to design the perpetual pavement with excellent fatigue behavior for the cement based on the characteristics required for perpetual road pavement, three composite structures were tested with four-point flexural bending test to investigate fatigue properties based on the Weibull distribution theory. The double-logarithm fatigue equations for perpetual pavement were established. The results show that the fatigue lives of three composite structures follow the double-parameter Weibull distribution. With the failure probability of 0.1, the fatigue performance of composite structure, when the lower layer is AC while the lower layer uses epoxy asphalt mixture (EAM) as a substitute for stone mastic asphalt (SMA), is improved significantly. In addition, the fatigue performance of composite structure, when the lower layer is EAM while the upper layer uses SMA as a substitute for asphalt concrete (AC), is improved more. The combination structure of EAM and SMA has the best fatigue performance, and totally satisfies the structure design feature requirement for perpetual pavement. The research results provide a reliable foundation for the further study of the perpetual bridge deck pavement.%为了构建疲劳性能优异的水泥混凝土桥梁长寿命铺装结构,借鉴长寿命沥青路面设计的基本思路,选取3种铺装复合结构方案,采用应变控制的四点弯曲疲劳试验,并基于Weibull分布理论对复合结构的疲劳特性进行分析,建立长寿命桥面铺装复合结构双对数疲劳预估方程。研究结果表明:3种铺装复合结构的疲劳寿命均服从双参数Weibull分布;在失效概率为0.1时,复合结构上面层同为AC,下面层采用环氧沥青混合料(EAM)代替SMA后,其疲劳性能得到提高,复合结构下面层同为EAM,上面层采用SMA代替AC后,疲劳性能得到再次提高;"EAM+SMA"的组合具有较好的抗疲劳性能,同时满足长寿命桥面铺装的结构最优设

  3. Influence Analvsis of Compressive Membrane Action on Serviceability of GFRP Reinforced Concrete Bridge Deck Slabs Under Transportation Loads%交通荷载作用下压缩薄膜效应对GFRP筋混凝土桥梁面板工作性能的影响分析

    Institute of Scientific and Technical Information of China (English)

    郑愚; 潘云峰; 于国友

    2011-01-01

    为了研究采用玻璃纤维增强筋作为配筋材料的混凝土桥梁面板的工作性能,结合板内的压缩薄膜效应对该结构类型在交通衙载作用下的工作性能进行了非线性有限元分析.通过对已建的GFRP筋混凝土桥梁结构、现行GFRP筋桥梁面板设计规范和数值模拟结果的比较分析,可以发现由于压缩薄膜效应的作用,实际的桥梁面板中所需的配筋率要远低于规范的计算结果.基于所建立的非线性有限元模型与试验结果有着良好的吻合,对结合了压缩薄膜效应进行设计的GFRP筋混凝土桥梁结构的工作性能进行了分析.分析结果表明,该非金属桥梁结构在交通荷载作用下有着良好的工作性能.%In the investigation of structural behaviours of concrete bridge deck slabs reinforced with Glass Fiber-Polymer Bars (GFRP Bars)under transportation loads, nonlinear finite element analysis (NLFEA) on this structural type are carried out with consideration of compressive membrane action (CMA). In the study on existing GFRP reinforced concrete bridge deck slabs,current design standard and numerical results, it is found that the real required reinforcement percentage is lower than that predicted by design methods. Based on the good correlation between NLFEA and experimental tests, the serviceability of a GFRP reinforced concrete bridge deck slabs with consideration of CMA is investigated. The good structural behaviours are observed in the analysis of this non-metallic bridges under transportation loads.

  4. 典型箱梁断面双竖向涡振区的成因分析%Investigation into formation of two lock-in districts of vertical vortex-induced vibration of a box bridge deck section

    Institute of Scientific and Technical Information of China (English)

    管青海; 李加武; 刘健新

    2013-01-01

    The formation of two lock-in districts of vertical vortex-induced vibration of a box bridge deck section was investigated via the amplitude response and surface pressure time-histories obtained by synchronizing vibration and surface pressure measurement in the uniform flow wind tunnel test.The relationship between amplitude and wind velocity,means and standard deviations of surface pressure coefficient,correlation coefficient between local lift force and total lift force,contribution of the local lift force to vertical vortex-induced vibration were studied.The results show that the lock-in district of high wind speed vertical vortex response is wider than that of low wind speed vertical vortex response,and the amplitude of high wind speed vertical vortex response is larger than that of low wind speed vertical vortex response.It is considered that the cause of two vertical vortex shedding response results from two different vortex shedding with a respective Strouhal number of 0.145 and 0.082.Vortex-induced forces of low wind vertical vortex response come mainly from the airflow fluctuation at 2 guard rails's area of the middle upper surface and back pressure zone of the lower surface,vortex vortex-induced forces of high wind vertical vortex response come mainly from the airflow fluctuation at the downstream zone of the upper surface and back pressure zone of the lower surface,and the vortex shedding at their upper surface are significantly different.The research results have general applicability for some typical blunt box girder sections,and the research methods can provide a reference for similar studies.1 tab,9 figs,15 refs.%为研究箱梁断面产生双竖向涡振区的原因,通过同步测振和测压均匀风场风洞试验,基于涡振区的振幅响应与表面压力脉动时程,分析了2个竖向涡振区的振幅与风速关系、表面压力系数均值与均方差值、局部升力与总升力的相关性及局部升力对竖向涡振的贡献.分

  5. New Concept for Durable Concrete Bridges

    OpenAIRE

    Damek, Marek

    2015-01-01

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

  6. Technology for long cable erection of a thousand-meter scale cable-stayed bridge

    Institute of Scientific and Technical Information of China (English)

    Rao Huarong; Deng Huibin

    2009-01-01

    In the background of the construction of Sutong Yangtze River Bridge (short as Sutong Bridge), the cable construction method and techniques of a thousand-meter scale cable-stayed bridge are introduced. Some key construction techniques, such as outspreading cable on deck, installing cable at pylon, pulling and fixing cable at the attachment with decks and cable PE sheath protection are discussed.

  7. 多箱渡槽槽身静风三分力系数风洞试验研究%A wind tunnel test study on aerostatic coefficients of large scale multi-box aqueduct bridge deck

    Institute of Scientific and Technical Information of China (English)

    李遇春; 邸庆霜; 张文杰; 张婷婷

    2012-01-01

    A wind tunnel test for the six scaled multi-box aqueduct decks (including 3 two-box and 3 three-box models) was conducted. The cases with full and without water, and with different wind attack an- gles are considered respectively. The drag, lift and pitching moment coefficients of multi-box aqueduct decks were obtained by the test result analyses. The surface pressure distributions and the aerostatic coeffi- cients of the test models were displayed and discussed. The results show that: (1) The wind flow field around multi-box aqueduct deck is similar to that of blunt body; (2) The drag force is the most important wind load among the three static loads; (3) The drag coefficient decreases with the increasing of width/ height ratio of aqueduct decks in the whole tendency.%对6个多箱式渡槽槽身刚性测压模型进行了风洞试验研究,分别模拟了满槽、空槽以及不同风攻角的试验工况。根据试验结果得到了槽身模型的静风三分力(阻力、升力和扭矩)系数,讨论了模型风压分布以及三分力系数的变化规律。试验结果表明:(1)多箱式渡槽槽身绕流更趋近于钝体绕流;(2)槽身风荷载主要表现为风阻力;(3)阻力系数在总体趋势上随着槽截面宽高比的增加而减小。试验结果可为多箱渡槽的抗风研究与设计提供初步的参考。

  8. Analysis of an Orthotropic Deck Stiffened with a Cement-Based Overlay

    DEFF Research Database (Denmark)

    Walter, Rasmus; Olesen, John Forbes; Stang, Henrik;

    2007-01-01

    decks. A solution might be to enhance the stiffness of the traditional orthotropic bridge deck by using a cement-based overlay. In this paper, an orthotropic steel bridge deck stiffened with a cement-based overlay is analyzed. The analysis is based on nonlinear fracture mechanics, and utilizes...... the finite-element method. The stiffness of the steel deck reinforced with an overlay depends highly on the composite action. The composite action is closely related to cracking of the overlay and interfacial cracking between the overlay and underlying steel plate (debonding). As an example, a real size...... can influence the cracking behavior of the cement-based overlay system. Both mechanical and environmental loading have to be considered, and effects such as shrinkage, temperature gradients, and traffic loading are taken into account. The performance of four overlay materials are investigated in terms...

  9. Collision Between Platform Deck and Service Vessel Wheelhouse

    OpenAIRE

    Sætre, Jan Børge Mork

    2013-01-01

    Collisions between ships and oshore structures are rarely occurring events, butpose a constant threat to the safety at sea. Observed trends in recent years hasshow that the size of both oshore structures and servicing vessels is increasing,making it possible for an oshore structure deck or module to pass above thebow and hit the superstructure and bridge of the vessel. An accident like thiscould have severe consequences.The superstructure of ships is typically considerably less stiened than t...

  10. Seafloor Surficial Sediments (Deck 41)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Geophysical Data Center (NGDC) "Deck41" database contains surficial sediment descriptions for over 36,000 seafloor samples worldwide. The file was...

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

    Science.gov (United States)

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

    2014-04-01

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

  12. Similarities and differences in bare concrete deck deterioration curves from multi NDE technology surveys

    Science.gov (United States)

    Kim, Jinyoung; Gucunski, Nenad; Dinh, Kien

    2016-04-01

    Reinforced concrete decks are in most cases the fastest deteriorating components of a bridge due to the multitude of influencing factors: direct traffic loading and environmental effects, maintenance activities (salting), etc. Among many deterioration types, corrosion-induced deterioration is the most common problem in reinforced concrete decks. The study concentrates on the condition assessment of bridge decks using complementary NDE techniques. The assessment has three main components: assessment of corrosive environment and corrosion processes, and assessment with respect to the deck delamination. The study concentrates on a complementary use of five NDE techniques: impact echo (IE) to detect and characterize delamination, ground penetrating radar (GPR) to describe the corrosive environment and detect delamination, and electrical resistivity (ER) to estimate the corrosion rate by measuring concrete resistivity. The ability of the NDE methods to objectively characterize deterioration progression is illustrated by the results from NDE surveys of 10 bridges of different ages in New Jersey during a period of one year. The deterioration progression is illustrated by condition maps and condition indices. As demonstrated in the paper, multiple deterioration models are developed utilizing the proposed methodology, which shows high potential for development of more realistic deterioration and life cycle cost models for bridge decks.

  13. Bridge Pressure Flow Scour at Clear Water Threshold Condition

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  14. Modified Geometry of Transition Slabs for Integral Bridges

    OpenAIRE

    Dreier, Damien

    2010-01-01

    Over the past decades, an increasing number of integral bridges have been built. This type of bridge offers various advantages in comparison with standard bridges equipped with expansion joints and bearings. In particular, integral bridges require less maintenance since they require less mechanical elements. Transition slabs, which are used in integral bridges, are directly connected to the bridge deck and therefore they are subjected to large displacements caused by creep, shrinkage and temp...

  15. Progressive collapse susceptibility of a long span suspension bridge

    DEFF Research Database (Denmark)

    Olmati, Pierluigi; Giuliani, Luisa

    2013-01-01

    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...... ones may lead to subsequent failures. In suspension bridges, which are characterized by a relatively low continuity of the system, the damage of the deck may favor a collapse standstill, in case of an early detachment of the deck collapsing section. In the paper, a long span suspension bridge is taken...

  16. Duality and the Deck effect

    CERN Document Server

    Törnqvist, N A

    1972-01-01

    As shown by Deck, the double-peripheral model for three-particle final states gives a substantial low-mass enhancement over phase space in two-body subchannels. With the advent of duality it was conjectured that the Deck effect and a true resonance are just different manifestations of the same phenomena. Thus the presence of a Deck enhancement could be interpreted as evidence for the existence of the A/sub 1/ resonance. The conjecture has been subject to criticism of two different kinds. These two points are clarified by constructing a counter example to the conjecture of Chew and Pignotti, using the five-point amplitude (B/sub 5/) of the generalized Veneziano model. (8 refs).

  17. Parametric modelling of nonstationary platform deck motions

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.

    -sense-stationary processes. Then the time series are modelled by the maximum entropy method which is formulated here for spectral estimation of platform deck displacements. The lower order maximum entropy spectra of nonstationary platform deck displacements are compared...

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

    Directory of Open Access Journals (Sweden)

    Eon-Kyoung Kim

    2014-01-01

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

  19. 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...

  20. Active aerodynamic stabilisation of long suspension bridges

    DEFF Research Database (Denmark)

    Nissen, Henrik Ditlev; Sørensen, Paul Haase; Jannerup, Ole Erik

    2004-01-01

    The paper describes the addition of actively controlled appendages (flaps) attached along the length of the bridge deck to dampen wind-induced oscillations in long suppension bridges. A novel approach using control systems methods for the analysis of dynamic stability is presented. In order to ma...

  1. Super-Light Prefabricated Deck Element Integrated in Traditional Concrete Prefabricated Element Construction

    DEFF Research Database (Denmark)

    Christensen, Jacob Ellehauge; Hertz, Kristian Dahl

    the super-light slab element are element size, which have greatly reduced the total number of elements the pedestrian bridges consist of. The application also demonstrated the ability to control the path that the forces will take in the element. The deck elements are for example fully prepared at the...

  2. State-of-art of asphalt surfacings on long-spanned orthotropic steel deck in China

    NARCIS (Netherlands)

    Chen, X.; Liu, X.; Qian, Z.; Lei, Z.

    2012-01-01

    Reliable and durable asphalt surfacing systems still remain to be desired for the long-spanned orthotropic steel bridges as the nationally and internationally reports on distresses in deck pavement. Based on ten-year research works, this paper has presented a brief review and discussion of the Chine

  3. Bending Moments Distribution at the Main Structural Elements of Skew Deck-Slab and Their Implementation on Cost Effectiveness

    Directory of Open Access Journals (Sweden)

    Maher Kakish

    2007-01-01

    Full Text Available The distribution of bending moments in T-beam deck slab varies from one T-beam to another. The design of T-beams should be based on the actual bending moments each beam is subjected to for the purpose of achieving economy especially in bridge deck slab, extended over big area. The saving in some cases is substantial due to reducing the quantities of steel and concrete.

  4. Dynamic Bridge Response for a Bridge-friendly Truck

    Directory of Open Access Journals (Sweden)

    V. Šmilauer

    2004-01-01

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

  5. RECONSTRUCTION AND REINFORCEMENT OF BRIDGE ACROSS THE RIVER. SYLVA IN KUNGUR, RUSSIA

    Directory of Open Access Journals (Sweden)

    R. Ye. Heizn

    2010-04-01

    Full Text Available Sylva Bridge at Kungur city is one of the oldest road bridges in Perm region, the West Urals, Russia. Its erection was begun in 1912 and was interrupted with the First World War and the further events in Russia. The bridge was opened only in 1931. For 75 years of bridge operation the most part of bridge constructions has been acquired plural damages, both mechanical and corrosion. After the bridge inspection in 2003 and according to the calculations of its capacity, the decision on reconstruction of the bridge was accepted. The purpose of rehabilitation was to replace the timber deck by steel orthotropic deck with asphalt pavement. A new deck was to be engaged in combined action with the existing metal structures with the help of socles with high-strength bolts. Due to this, the bridge carrying capacity was increased as required by the present standards. In 2006, after tests, the bridge was opened for traffic.

  6. 基于黏弹性力学分析和线性累积疲劳损伤理论的钢桥面铺装疲劳寿命预估%Fatigue Life Prediction of Steel Bridge Deck Pavement Based on Viscoelastic Mechanical Analysis and Linear Fatigue Cumulative Damage Law

    Institute of Scientific and Technical Information of China (English)

    赵国云; 闫东波; 磨炼同

    2013-01-01

    -10℃ ,0℃ and 15t: fatigue life of Stone mastic asphalt concrete(SMA) and Epoxy asphalt concret(EAC) are tested to obtain fatigue curves and equations. Dynamic mechanical tests for SMA,GAC, EAC, Eliminator waterproof adhesive layer and modified asphalt emulsion (MAE) are performed with DSR, Q800-TMA and UTM-25 hydraulic servo system to obtain viscoelastic mechanical parameters. Maximum transversal tensile strain of four kinds of deck pavement structures under load and temperature coupling influence are got by means of finite element simulation based on the project of Jiujiang Changjiang River Highway Bridge considering with local traffic and climate characteristics, Prediction of lifetime of four deck pavement structures are made according to the linear cumulative damage law. The results indicate that EAC pavement structure fatigue life is longer than GAC pavement structure,and the later structure is suited for the situation of north climate characteristics in China. Meanwhile,the application of Eliminator waterproof adhesive layer in double EAC concrete pavement structure could increase fatigue life remarkablely.%对常用于钢桥面铺装表层的SMA沥青混凝土和环氧沥青混凝土进行-10℃、0℃和15℃四点弯曲疲劳试验,得出疲劳曲线和疲劳方程;使用动态剪切流变仪(DSR)、Q800动态热机械分析仪(TMA)和UTM-25伺服液压系统对SMA沥青混凝土、浇注式沥青混凝土、环氧沥青混凝土、Eliminator防水黏结层、环氧沥青和改性乳化沥青等常用钢桥面铺装材料进行动态力学试验,获取黏弹性力学参数,并进行有限元数值模拟,得出荷载温度耦合作用下铺装表面最大横向弯拉应变.计算江西九江长江公路大桥不同温度区域下的交通量,根据线性累积疲劳损伤理论预估钢桥面铺装的使用寿命.结果表明:环氧沥青混凝土铺装结构疲劳寿命预测结果优于浇注式沥青混凝土铺装结构,后者更适合于北方

  7. Experimental Research and Fnite Element Analysis on Steel Bridge Deck in CFRP Reinforced SFRC Pavements%CFRP 增强钢纤维混凝土钢桥面铺装力学性能试验与数值模拟

    Institute of Scientific and Technical Information of China (English)

    徐欣; 方海; 徐超; 刘伟庆; 庄勇

    2015-01-01

    由于我国日益增加的交通量,很多正交异性钢桥面铺装和正交异性钢板在服役期内都出现了很多病害。碳纤维(CFRP)具有轻质、高强、耐腐蚀等优越性,钢纤维混凝土具有沥青混凝土没有的刚度和普通混凝土没有的抗裂性能。对于将这两种材料用于钢桥面铺装中形成的组合桥面板,取涡河大桥主桥钢箱梁的一段正交异性钢板,分别对“无铺装”,“沥青混凝土铺装”,“钢纤维混凝土铺装”3种模型进行有限元模拟,比较正交异性钢板的应力、挠度、铺装层的纵向拉应力和横向拉应力,找出最不利荷载工况及变化规律。通过计算比较“沥青混凝土铺装”、“钢纤维混凝土铺装”和“CFRP -钢纤维混凝土铺装”3种铺装层的纵向和横向拉应力,得出 CFRP 网格筋对铺装层表面拉应力的控制作用。结果表明低弹模铺装时横向拉应力为控制应力,而高弹模铺装时纵向拉应力为控制应力,正交异性钢板应力最大部位发生在横隔板开孔附近,碳纤维网格筋可以有效地降低铺装面层的横向和纵向拉应力。%Most orthotropic steel deck pavements and orthotropic steel plates appeared many seri-ous diseases in the service period because of the increasing traffic in our country.Carbon Fibre Reinforced Polymer(CFRP)has the superiority of light weight,high strength,corrosion resistance and so on.The stiff-ness of bitulith concrete is small and normal concrete crack resistance is poor.But the steel fiber rein-forced concrete has great stiffness and good crack resistance.This paper proposed a new composite deck combined with CFRP and SFRC.An orthotropic plate of Guohe Bridge is calculated as a case.The Stress and deflection of Orthotropic steel plate,the longitudinal tensile stress and transverse tensile stress of pavement have been calculated in three models,including “without pavement”,“with bitumen

  8. 46 CFR 177.900 - Deck rails.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Deck rails. 177.900 Section 177.900 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.900 Deck rails. (a) Except as otherwise provided in this section, rails...

  9. Commander Brand sleeps on aft flight deck

    Science.gov (United States)

    1982-01-01

    Commander Brand, with hands folded in front of his chest, sleeps on aft flight deck. Brand's head is just above aft flight deck floor with his back to onorbit station panels. The back and feet of a second crewmember appear next to Brand.

  10. Parametric Study on Dynamic Response of Fiber Reinforced Polymer Composite Bridges

    Directory of Open Access Journals (Sweden)

    Woraphot Prachasaree

    2015-01-01

    Full Text Available Because of high strength and stiffness to low self-weight ratio and ease of field installation, fiber reinforced polymer (FRP composite materials are gaining popularity as the materials of choice to replace deteriorated concrete bridge decks. FRP bridge deck systems with lower damping compared to conventional bridge decks can lead to higher amplitudes of vibration causing dynamically active bridge deck leading serviceability problems. The FRP bridge models with different bridge configurations and loading patterns were simulated using finite element method. The dynamic response results under varying FRP deck system parameters were discussed and compared with standard specifications of bridge deck designs under dynamic loads. In addition, the dynamic load allowance equation as a function of natural frequency, span length, and vehicle speed was proposed in this study. The proposed dynamic load allowance related to the first flexural frequency was presented herein. The upper and lower bounds’ limits were established to provide design guidance in selecting suitable dynamic load allowance for FRP bridge systems.

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  12. Review on antibacterial characteristics of bridge engineering biomaterials.

    Science.gov (United States)

    Zhao, Qing-Qing; Chen, Meng-Yao; He, Rui-Lin; Zhang, Zhong-Feng; Ashraf, Muhammad Aqeel

    2016-01-01

    This review summarizes the research on timber construction materials used in bridge construction. It focuses on the application of antiseptic treatments and the use of timber engineering materials in decks and bridges. This review also provides an overview on the future research and prospects of engineered timber materials. PMID:26858558

  13. Damage identification of RC bridge decks under fatigue loading

    OpenAIRE

    Zanuy, C.; Maya-Duque, L. F.; Gallego, J. M.; de la Fuente, P.

    2014-01-01

    The complex nature of structural phenomena still requires the comparison between numerical models and the real structural performance. Accordingly, many civil structures are monitored to detect structural damage and provide updated data for numerical models. Monitoring usually relies on the change of dynamic properties (experimental modal analysis). Regarding concrete structures, existing works have typically focused on the progressive decrease of natural frequencies under gradually increasin...

  14. Damage identification of RC bridge decks under fatigue loading

    Directory of Open Access Journals (Sweden)

    Zanuy, C.

    2014-12-01

    Full Text Available The complex nature of structural phenomena still requires the comparison between numerical models and the real structural performance. Accordingly, many civil structures are monitored to detect structural damage and provide updated data for numerical models. Monitoring usually relies on the change of dynamic properties (experimental modal analysis. Regarding concrete structures, existing works have typically focused on the progressive decrease of natural frequencies under gradually increasing loads. In this paper, high-cycle fatigue effects are analyzed. An experimental campaign on specimens reproducing the top slab of concrete girders has been carried out, including fatigue tests and a reference static test. Impact-excitation tests were done at different stages to extract dynamic properties. Output-only models (only based on the structural response to an external excitation that is not measured were used as identification techniques. The evolution of dynamic properties was correlated with damage development, with emphasis on the fatigue process stages: crack formation, cyclic reduction of tension-stiffening and brittle fracture of the reinforcement.La naturaleza compleja de muchos fenómenos estructurales requiere que los modelos numéricos necesiten ser verificados con el comportamiento estructural real. Por ello, muchas estructuras son monitorizadas, tanto para detectar posibles daños estructurales como para proporcionar datos a incluir en los modelos. A menudo, la monitorización se basa en el cambio de las propiedades dinámicas mediante técnicas de análisis modal experimental. Con respecto al hormigón estructural, la mayoría de los trabajos existentes se ha centrado en el cambio de las frecuencias propias con cargas monótonamente crecientes. En este artículo se analizan los efectos de la fatiga. Se ha llevado a cabo una campaña experimental sobre piezas que reproducen la losa superior de tableros de puentes, realizándose ensayos de fatiga y uno estático de referencia. Las propiedades dinámicas se han ido extrayendo mediante técnicas de output-only a partir de ensayos de excitación mediante impacto. El cambio de las propiedades dinámicas se ha correlacionado con las etapas del proceso de fatiga: formación de fisuras, reducción de tension-stiffening y rotura frágil de la armadura.

  15. Research on Working Procedure of Lag Pouring of Wet-joint in Bridge Deck Concrete Slab on Composite Girder of Cable-stayed Bridge%叠合梁斜拉桥混凝土桥面板滞后浇筑湿接缝的工序研究

    Institute of Scientific and Technical Information of China (English)

    胡俊; 曾一峰; 贾俊峰

    2016-01-01

    Construction procedure is complicated for cable-stayed bridge using composite beam. Final state of bridge depends on construction greatly. In the article,a large span cable-stayed bridge was studied. The bridge 3D finite element model was established to analyze the effect of working procedure during construction and at completion. Three working procedures were studied: no lag pouring,one lag pouring and twice lag pouring of wet-joint of concrete slab. The analysis results indicate that tensile stress in concrete slab is small for one/twice lag pouring. But, as lag times increase,compression stress in steel girders increases significantly. One lag pouring is best for structure stress in the construction process and operation stage,and the construction period is short.%叠合梁斜拉桥施工工序繁多,最终的成桥状态与施工过程密切相关.以一大跨度叠合梁斜拉桥为对象,采用空间有限元软件建立精细化力学模型,对比分析了混凝土桥面板湿接缝不滞后、滞后1次及滞后2次这3种施工工序对桥梁结构在施工过程及成桥的受力影响.结果表明,滞后1次及滞后2次的工序下桥面板几乎不出现拉应力,而随着桥面板滞后次数的增加,钢主梁的压应力显著增大,选择桥面板滞后1次的施工工序,结构在施工过程中及成桥运营阶段的受力最佳,同时工期也较短.

  16. Flight Deck I-Glasses Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Flight Deck i-Glasses is a color, stereoscopic 3-D display mounted on consumer style eye glass frames that will enhance operator performance and multi-modal...

  17. 33 CFR 155.790 - Deck lighting.

    Science.gov (United States)

    2010-07-01

    ...) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS Transfer Personnel... horizontal plane 3 feet above the deck the illumination must measure at least: (1) 5.0 foot candles...

  18. Deck41 Surficial Seafloor Sediment Description Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Deck41 is a digital summary of surficial sediment composition for 36,401 seafloor samples worldwide. Data include collecting source, ship, cruise, sample id,...

  19. A strange bridge by Leonardo

    CERN Document Server

    Huylebrouck, Dirk

    2013-01-01

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

  20. Is deck B a disadvantageous deck in the Iowa Gambling Task?

    Directory of Open Access Journals (Sweden)

    Chiu Yao-Chu

    2007-03-01

    Full Text Available Abstract Background The Iowa gambling task is a popular test for examining monetary decision behavior under uncertainty. According to Dunn et al. review article, the difficult-to-explain phenomenon of "prominent deck B" was revealed, namely that normal decision makers prefer bad final-outcome deck B to good final-outcome decks C or D. This phenomenon was demonstrated especially clearly by Wilder et al. and Toplak et al. The "prominent deck B" phenomenon is inconsistent with the basic assumption in the IGT; however, most IGT-related studies utilized the "summation" of bad decks A and B when presenting their data, thereby avoiding the problems associated with deck B. Methods To verify the "prominent deck B" phenomenon, this study launched a two-stage simple version IGT, namely, an AACC and BBDD version, which possesses a balanced gain-loss structure between advantageous and disadvantageous decks and facilitates monitoring of participant preferences after the first 100 trials. Results The experimental results suggested that the "prominent deck B" phenomenon exists in the IGT. Moreover, participants cannot suppress their preference for deck B under the uncertain condition, even during the second stage of the game. Although this result is incongruent with the basic assumption in IGT, an increasing number of studies are finding similar results. The results of the AACC and BBDD versions can be congruent with the decision literatures in terms of gain-loss frequency. Conclusion Based on the experimental findings, participants can apply the "gain-stay, loss-shift" strategy to overcome situations involving uncertainty. This investigation found that the largest loss in the IGT did not inspire decision makers to avoid choosing bad deck B.

  1. Abutments influence in the dynamic response of bridges

    OpenAIRE

    Martínez Cutillas, Antonio; Gómez Lera, Sagrario; Alarcón Álvarez, Enrique

    1996-01-01

    A simplified analytical model of a short span bridge is proposed. The inertial interaction effects of pier foundations and abutments has been included in order to evaluate the response sensitivities to different soil-structure interaction variables. The modification of natural frequency and damping properties is shown for typical short span bridges of the integral deck-abutment type for longitudinal vibrations or general bridges for the transverse ones.

  2. COUPLING VIBRATION OF VEHICLE-BRIDGE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    陈炎; 黄小清; 马友发

    2004-01-01

    By applying the sinusoidal wave mode to simulate the rugged surface of bridge deck,accounting for vehicle-bridge interaction and using Euler-Bernoulli beam theory, a coupling vibration model of vehicle-bridge system was developed. The model was solved by mode analyzing method and Runge-Kutta method, and the dynamic response and the resonance curve of the bridge were obtained. It is found that there are two resonance regions, one represents the main resonance while the other the minor resonance, in the resonance curve. The influence due to the rugged surface, the vibration mode of bridge, and the interaction between vehicle and bridge on vibration of the system were discussed. Numerical results show that the influence due to these parameters is so significant that the effect of roughness of the bridge deck and the mode shape of the bridge can't be ignored and the vehicle velocity should be kept away from the critical speed of the vehicle.

  3. Air-Decking Technique in Bench Blasting

    Institute of Scientific and Technical Information of China (English)

    ZHU Hong-bing; LU Wen-bo; WU Liang

    2006-01-01

    The mechanism and the design parameters of blasting with air-decking are studied. The theory of detonation waves is used to investigate the processes of the one-dimensional plane detonation wave within a borehole. The interaction of the rarefaction wave with an interface and reflection on a rigid wall is also analyzed. The same courses of the shock wave are also investigated. This decides the distribution of the pressure of the explosion products changing with time along the borehole. Based on the above theoretical analysis, two conditions should be met for a reasonable range of values of the air-decking ratio in blasting rock. First, the rarefaction wave from the contact interface between detonation products and air reaches the bottom earlier than that of the reflected shock wave from the end of the stemming. Second,the reflected shock wave reaches the contact interface between the detonation products and air earlier than that of the reflected rarefaction wave from the bottom of the borehole. Finally, the reasonable value of the air-decking ratio must be decided theoretically in air-decking blasting. For different explosives, the reasonable range of air-decking ratio varies from 0.15 to 0.4. This result is well consistent with what was obtained by previous researchers.

  4. Experimental investigation of multilayer surfacing system on orthotropic steel bridge with the five-point bending test

    NARCIS (Netherlands)

    Tzimiris, G.; Liu, X.; Scarpas, A.; Li, J.; Hofman, R.; Voskuilen, J.

    2013-01-01

    Due to lightweight and flexibility, orthotropic steel deck bridges become popular the last decades but several problems were reported in relation to asphalt surfacing materials such as rutting, cracking, loss of bond between the surfacing system and steel deck. In the Netherlands a surfacing structu

  5. Innovative configurations for long-span suspension bridges

    OpenAIRE

    Bartoli, G.; P. D’Asdia; S. Febo; C. Mannini; S. Noè; L. Procino

    2009-01-01

    This paper reports the results of a piece of research about long-span suspension bridges with multiple-box girder steel deck characterized by low drag coefficient and high aeroelastic stability. For this type of bridges, by increasing the span length, the contribution to the stiffness of the suspension cables becomes dominant with respect to that of the deck, so that the ratio of the frequency of the first torsional mode to the frequency of the first vertical bending mode approaches unity, wh...

  6. Predicting the static bending behavior of pallets with panel decks

    OpenAIRE

    Mackes, Kurt H.

    1998-01-01

    With increased use of pallets constructed utilizing structural panel decks, there is a need for a standardized, reliability-based design system, PDS-PANEL, to assist in the design and manufacture of panel-deck pallets. The primary objective of this research was to develop finite element models which predict the static bending behavior of pallets with at least one panel deck. stringer and block pallets were modeled using plate elements to simulate deck behavior and were...

  7. Generalized fragility curves for bearing-supported skew bridges, for arbitrary angle of incidence of the seismic action

    OpenAIRE

    Moschonas, I. F.; Kappos, A. J.

    2011-01-01

    In a previous work by the authors and their co-workers an analytical methodology for the derivation of seismic fragility curves for bridges was proposed. Bridges were classified into three main categories according to their seismic energy dissipation mechanism: bridges with yielding piers of the column type, bridges with bearings and non-yielding piers of the wall type, and bridges with bearings and yielding piers of the column type. Then, damage states were defined using deck displacement at...

  8. 14 CFR 125.315 - Admission to flight deck.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Admission to flight deck. 125.315 Section...,000 POUNDS OR MORE; AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT Flight Operations § 125.315 Admission to flight deck. (a) No person may admit any person to the flight deck of an airplane unless...

  9. Super-light concrete decks for building floor slabs

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl; Castberg, Niels Andreas; Christensen, Jacob

    2014-01-01

    This paper presents investigations carried out at the Technical University of Denmark (DTU) on a prototype series for a super-lightweight prestressed concrete deck element called the SL-Deck. The intention behind making a new prefabricated deck element is to improve performance with respect...

  10. Standard plans for southern pine bridges. Forest Service general technical report

    Energy Technology Data Exchange (ETDEWEB)

    Hilbrich Lee, P.D.; Ritter, M.A.; Triche, M.

    1995-09-01

    This publication contains standardized designs and details for three timber bridge superstructure types, including stress-laminated sawn lumber bridges, stress laminated glued laminated timber (glulam) bridges, and longitudinal sawn lumber stringer bridges with transverse plank decks. Each set of plans encompasses numerous span length and width combinations, design loadings for AASHTO HS 20-44 and HS 25-44 vehicles, and two options for live-load deflection criteria.

  11. Experimental investigation of soil - structure interaction for transition slabs of integral bridges

    OpenAIRE

    BURDET, Olivier; Einpaul, Jürgen; Muttoni, Aurelio

    2015-01-01

    This paper presents the results of an experimental test series on the soil-structure-pavement interaction in the vicinity of the transition slab at the end of an integral bridge. The main function of transition slabs is to ease the transition between the bridge deck and the embankment in case of differential settlements. Additionally, in the case of integral bridges, they can solve the problem of moderate imposed longitudinal deformations at the bridge...

  12. Rapid-to-deploy wireless monitoring systems for static and dynamic load testing of bridges: validation on the Grove Street Bridge

    Science.gov (United States)

    Hou, Tsung-Chin; Lynch, Jerome P.

    2006-03-01

    Bridge management officials have expressed a keen interest in the use of low-cost and easy-to-install wireless sensors to record bridge responses during short-term load testing. To illustrate the suitability of wireless sensors for short-term monitoring of highway bridges, a wireless monitoring system is installed upon the Grove Street Bridge to monitor structural responses during static and dynamic load testing. Specifically, load testing of the Grove Street Bridge is conducted after its construction to validate the behavior of a novel jointless bridge deck constructed from a high-performance fiber reinforced cementitious composite (HPFRCC) material. A heterogeneous array of sensing transducers are installed in the bridge including metal foil strain gages, accelerometers and linear variable differential transducers (LVDTs). First, the acceleration response of the bridge is monitored by the wireless system during routine traffic loading. Modal parameters (modal frequencies and mode shapes) are calculated by the wireless sensors so that an analytical model of the bridge constructed in a standard commercial finite element package can be updated off-line. Next, the bridge is closed to traffic and trucks of known weight are parked on the bridge to induce static deformations. The installation strategy of the wireless monitoring system during static load testing is optimized to monitor the strain and rotation response of the HPFRCC deck. The measured static response of the deck is compared to that predicted by the updated analytical model.

  13. Social psychology on the flight deck

    Science.gov (United States)

    Helmreich, R. L.

    1980-01-01

    Social psychological and personality factors that can influence resource management on the flight deck are discussed. It is argued that personality and situational factors intersect to determine crew responses and that assessment of performance under full crew and mission conditions can provide the most valuable information about relevant factors. The possibility of training procedures to improve performance on these dimensions is discussed.

  14. 75 FR 4584 - Wire Decking From China

    Science.gov (United States)

    2010-01-28

    ... to the extent permitted by section 201.8 of the Commission's rules, as amended, 67 FR 68036 (November..., 67 FR 68168, 68173 (November 8, 2002). Additional written submissions to the Commission, including... COMMISSION Wire Decking From China AGENCY: United States International Trade Commission. ACTION:...

  15. The Potential of Roof Deck Play Spaces.

    Science.gov (United States)

    Canada Mortgage and Housing Corp., Ottawa (Ontario).

    This report, the fifteenth in a series of twenty completed by the Children's Environments Advisory Service for the International Year of the Child, 1979, presents a guide for planning play spaces on roof decks in high density family housing projects where on-grade land is too scarce or too expensive for development as communal recreation space.…

  16. Deck Yourself with Flu Protection Song

    Centers for Disease Control (CDC) Podcasts

    2009-12-22

    This song (sung to the tune of Deck the Halls) describes actions you can take to protect yourself and others from the flu. Sing along!  Created: 12/22/2009 by National Center for Preparedness, Detection, and Control of Infectious Diseases (NCPDCID), Division of Global Migration and Quarantine (DGMQ).   Date Released: 12/22/2009.

  17. 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...

  18. 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...... 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......-tensioning cables, the rise to span ratio, the height of the filling, and the height of the Super-Light Decks. We find that Pearl-Chain Bridges can be adjusted to resist specific moment loads by changing the normal force in the arch cross section by altering the above parameters. It is also found that the negative...

  19. Effects of fundamental factors on coupled vibration of wind-rail vehicle-bridge system for long-span cable-stayed bridge

    Institute of Scientific and Technical Information of China (English)

    张明金; 李永乐; 汪斌

    2016-01-01

    In a wind-vehicle-bridge (WVB) system, there are various interactions among wind, vehicle and bridge. The mechanism for coupling vibration of wind-vehicle-bridge systems is explored to demonstrate the effects of fundamental factors, such as mean wind, fluctuating wind, buffeting, rail irregularities, light rail vehicle vibration and bridge stiffness. A long cable-stayed bridge which carries light rail traffic is regarded as a numerical example. Firstly, a finite element model is built for the long cable-stayed bridge. The deck can generally be idealized as three-dimensional spine beam while cables are modeled as truss elements. Vehicles are modeled as mass-spring-damper systems. Rail irregularities and wind fluctuation are simulated in time domain by spectrum representation method. Then, aerodynamic loads on vehicle and bridge deck are measured by section model wind tunnel tests. Eight vertical and torsional flutter derivatives of bridge deck are identified by weighting ensemble least-square method. Finally, dynamic responses of the WVB system are analyzed in a series of cases. The results show that the accelerations of the vehicle are excited by the fluctuating wind and the track irregularity to a great extent. The transverse forces of wheel axles mainly depend on the track irregularity. The displacements of the bridge are predominantly determined by the mean wind and restricted by its stiffness. And the accelerations of the bridge are enlarged after adding the fluctuating wind.

  20. Simplified modelling of bridge abutments-soil interaction under seismic effects

    OpenAIRE

    Martínez Cutillas, Antonio; Alarcón Álvarez, Enrique

    1995-01-01

    A simplified model is proposed to show the importance that the dynamic soil-abutment interaction can have in the global behavior of bridges submitted to seismic loading. The modification of natural frequency and damping properties is shown in graphic form for typical short span bridges of the integral deck-abutment type for longitudinal vibrations or general ones for transverse vibrations.

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

    Directory of Open Access Journals (Sweden)

    Flaga Kazimierz

    2015-03-01

    Full Text Available 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.

  2. Wind-Tunnel Tests of a Bridge Model with Active Vibration Control

    DEFF Research Database (Denmark)

    Hansen, H. I.; Thoft-Christensen, Palle; Mendes, P. A.;

    The application of active control systems to reduce wind vibrations in bridges is a new area of research. This paper presents the results that were obtained on a set of wind tunnel tests of a bridge model equipped with active movable flaps. Based on the monitored position and motion of the deck...

  3. Computational fluid dynamic analysis of flutter characteristics for self-anchored suspension bridges

    Institute of Scientific and Technical Information of China (English)

    Zhiwen ZHU; Zhaoxiang WANG; Zhengqing CHEN

    2008-01-01

    This paper outlines the essentials and proce-dures of computational fluid dynamics (CFD) simulation applicable to evaluating flutter derivatives of bridge decks. An arbitrary Lagrangian-Eulerian (ALE) description of the flow around the moving rigid box girder combined with the finite volume discretization and multi-grid algorithm is pre-sented. The proposed methods are employed to identify flutter derivatives of the bridge deck of the Sanchaji Self-anchored Suspension Bridge. The results agree well with ones from wind tunnel tests. It demonstrates accuracy and efficiency of the present method.

  4. Bridges analysis, design, structural health monitoring, and rehabilitation

    CERN Document Server

    Bakht, Baidar

    2015-01-01

    This book offers a valuable guide for practicing bridge engineers and graduate students in structural engineering; its main purpose is to present the latest concepts in bridge engineering in fairly easy-to-follow terms. The book provides details of easy-to-use computer programs for: ·      Analysing slab-on-girder bridges for live load distribution. ·      Analysing slab and other solid bridge components for live load distribution. ·      Analysing and designing concrete deck slab overhangs of girder bridges under vehicular loads. ·      Determining the failure loads of concrete deck slabs of girder bridges under concentrated wheel loads. In addition, the book includes extensive chapters dealing with the design of wood bridges and soil-steel bridges. Further, a unique chapter on structural health monitoring (SHM) will help bridge engineers determine the actual load carrying capacities of bridges, as opposed to their perceived analytical capacities. The chapter addressing structures...

  5. Aerodynamic stability of cable-stayed-suspension hybrid bridges

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-jun; SUN Bing-nan

    2005-01-01

    Three-dimensional nonlinear aerodynamic stability analysis was applied to study the aerodynamic stability of a cable-stayed-suspension (CSS) hybrid bridge with main span of 1400 meters, and the effects of some design parameters (such as the cable sag, length of suspension portion, cable plane arrangement, subsidiary piers in side spans, the deck form, etc.) on the aerodynamic stability of the bridge are analytically investigated. The key design parameters, which significantly influence the aerodynamic stability of CSS hybrid bridges, are pointed out, and based on the wind stability the favorable structural system of CSS hybrid bridges is discussed.

  6. Geodetic Measurement of Longitudinal Displacements of the Railway Bridge

    Directory of Open Access Journals (Sweden)

    Jaroslav Braun

    2014-06-01

    Full Text Available The paper deals with geodetic measurements of mutual longitudinal displacements ofconstruction of the railway bridge and rails on the bridge in Klášterec nad Oh í.Construction of the bridge is made of steel with a concrete deck, which carries the stonesuperstructure and rails. The bridge is about 100 meters long and expected deformationsare in millimetres. The method of geodetic network with the expected standard deviationsof coordinates about 0.2 mm was chosen. The deformation of the structure was determinedto be 4 mm, the deformation of the rails was determined to be 1 mm, both as a result ofepoch comparison.

  7. Measurement of Prestressing Force in Pretensioned UHPC Deck Using a Fiber Optic FBG Sensor Embedded in a 7-Wire Strand

    Directory of Open Access Journals (Sweden)

    Jae-min Kim

    2016-01-01

    Full Text Available This paper presents the results of the performance test and long-term monitoring of the prestressing force inside concrete performed on a pretensioned Ultra-High Performance Concrete (UHPC deck. The force is measured by applying a 7-wire strand embedded with an FBG (Fiber Bragg Grating sensor. The performance test was conducted on a 3.7 m × 1.8 m pretensioned deck specimen through wheel loading tests to verify the applicability of the measurement method. In addition, a 12.3 m long and 4.8 m wide bridge with a pretensioned UHPC deck was erected and long-term monitoring was conducted over three years to verify the applicability of the method to real bridges. The effectiveness of the measurement method of the prestressing force inside concrete is verified, and the long-term monitoring data are used to investigate various temperature compensation methods. The results show that the proposed method enables effective measurement of small changes in the prestressing force inside the concrete. These changes are caused by the external forces acting on the bridge in service and provide sufficient durability for long-term sensing. The analysis of the prestressing force obtained through long-term monitoring reveals the necessity of conducting temperature compensation for the consistency of the data acquired using the FBG sensor. Moreover, the selection of the thermal expansion coefficient appears also to be of critical importance for temperature compensation.

  8. Nondestructive evaluation techniques for enhanced bridge inspection

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-10-01

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

  9. 46 CFR 178.450 - Calculation of drainage area for cockpit and well deck vessels.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Calculation of drainage area for cockpit and well deck....450 Calculation of drainage area for cockpit and well deck vessels. (a) The drainage area required on... cockpit deck; DR=total deck area of the cockpit or well deck in the after 2/3 of the vessel length...

  10. A Proposal for 4000m-span Cable-stayed Suspension Bridge

    Directory of Open Access Journals (Sweden)

    Haijun Wang

    2013-06-01

    Full Text Available This study proposed a compound bridge of suspension bridges and cable-stayed bridges with 4000 m super-long-span over the Tsugaru Strait, Japan. Near to the main towers, cable-stayed bridges and prestressed concrete decks are proposed. It is helpful to enhance rigidity and endure the great axial compression force. In the center of the span, suspension bridges and steel box decks are stiffened by trusses, it can reduce self-weigh and the space between girders, thus contribute to aero-elastic stability. RCFT main tower, RC shell pier and RCFT jacket foundation can enhance rigidity and reduce self-weigh. As a result, the live-dead load ratio of proposal is 0.05 and it is equivalent to 2500m-span suspension bridge.

  11. Fatigue monitoring and analysis of orthotropic steel deck considering traffic volume and ambient temperature

    Institute of Scientific and Technical Information of China (English)

    SONG; YongSheng; DING; YouLiang

    2013-01-01

    Fatigue has gradually become a serious issue for orthotropic steel deck used for long-span bridges. Two fatigue effects, namely number of stress cycles and equivalent stress amplitude, were introduced as investigated parameters in this paper. Investigation was focused on their relationships with traffic volume and ambient temperature by using 7-months fatigue monitoring data of an actual bridge. A fatigue analytical model considering temperature-induced changes in material property of asphalt pavement was established for verifying these relationships. The analysis results revealed that the number of stress cycles and equivalent stress amplitude showed a linear correlation with the traffic volume and ambient temperature, respectively, and that the rib-to-deck welded joint was much more sensitive to the traffic volume and ambient temperature than the rib-to-rib welded joint. The applicability of the code-recommended model for fatigue vehicle loading was also discussed, which revealed that the deterministic vehicle loading model requires improvement to account for significant randomness of the actual traffic conditions.

  12. 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.

  13. 46 CFR 11.403 - Structure of deck officer endorsements.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Structure of deck officer endorsements. 11.403 Section 11.403 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN REQUIREMENTS FOR OFFICER ENDORSEMENTS Professional Requirements for Deck Officers § 11.403 Structure of...

  14. 29 CFR 1915.165 - Ship's deck machinery.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Ship's deck machinery. 1915.165 Section 1915.165 Labor... (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT Ship's Machinery and Piping Systems § 1915.165 Ship's deck machinery. (a) Before work is performed on the anchor windlass or any...

  15. Impact coefficient and reliability of mid-span continuous beam bridge under action of extra heavy vehicle with low speed

    Institute of Scientific and Technical Information of China (English)

    刘波; 王有志; 胡朋; 袁泉

    2015-01-01

    To analyze the dynamic response and reliability of a continuous beam bridge under the action of an extra heavy vehicle, a vehicle–bridge coupled vibration model was established based on the virtual work principle and vehicle–bridge displacement compatibility equation, which can accurately simulate the dynamic characteristics of the vehicle and bridge. Results show that deck roughness has an important function in the effect of the vehicle on the bridge. When an extra heavy vehicle passes through the continuous beam bridge at a low speed of 5 km/h, the impact coefficient reaches a high value, which should not be disregarded in bridge safety assessments. Considering that no specific law exists between the impact coefficient and vehicle speed, vehicle speed should not be unduly limited and deck roughness repairing should be paid considerable attention. Deck roughness has a significant influence on the reliability index, which decreases as deck roughness increases. For the continuous beam bridge in this work, the reliability index of each control section is greater than the minimum reliability index. No reinforcement measures are required for over-sized transport.

  16. Passive Control System for Mitigation of Longitudinal Buffeting Responses of a Six-Tower Cable-Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Fangfang Geng

    2016-01-01

    Full Text Available This paper presents an investigation of mitigation of longitudinal buffeting responses of the Jiashao Bridge, the longest multispan cable-stayed bridge in the world. A time-domain procedure for analyzing buffeting responses of the bridge is implemented in ANSYS with the aeroelastic effect included. The characteristics of longitudinal buffeting responses of the six-tower cable-stayed bridge are studied in some detail, focusing on the effects of insufficient longitudinal stiffness of central towers and partially longitudinal constraints between the bridge deck and part of bridge towers. The effectiveness of viscous fluid dampers on the mitigation of longitudinal buffeting responses of the bridge is further investigated and a multiobjective optimization design method that uses a nondominating sort genetic algorithm II (NSGA-II is used to optimize parameters of the viscous fluid dampers. The results of the parametric investigations show that, by appropriate use of viscous fluid dampers, the top displacements of central towers and base forces of bridge towers longitudinally restricted with the bridge deck can be reduced significantly, with hampering the significant gain achieved in the base forces of bridge towers longitudinally unrestricted with the bridge deck. And the optimized parameters for the viscous fluid dampers can be determined from Pareto-optimal fronts using the NSGA-II that can satisfy the desired performance requirements.

  17. The Damage Analysis of Usu Bridge under Seismic Load

    Directory of Open Access Journals (Sweden)

    Jian-Hui Gao

    2014-02-01

    Full Text Available In order to obtain the dynamic response of Usu bridge the compression damage model of concrete materials and the finite element method are used in this study. The frequency and the main vibration mode of Usu bridge are calculated. The damage distribution and the location of maximum damage of concrete structures under the four kinds of seismic load are obtained. The results show that the maximum damage of bridge deck occurs in close to support position, the maximum compression damage of the main tower occurs in the upper tower root place. Therefore, in the construction and maintenance process note the influence of seismic load of in these positions.

  18. Investigation of Influence Factors of Wind-Induced Buffeting Response of a Six-Tower Cable-Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Zhi-Qiang Zhang

    2016-01-01

    Full Text Available This paper presents an investigation of the wind-induced buffeting responses of the Jiashao Bridge, the longest multispan cable-stayed bridge in the world. A three-dimensional finite element model for the Jiashao Bridge is established using the commercial software package ANSYS and a 3D fluctuating wind field is simulated for both bridge deck and towers. A time-domain procedure for analyzing buffeting responses of the bridge is implemented in ANSYS with the aeroelastic effect included. The characteristics of buffeting responses of the six-tower cable-stayed bridge are studied in some detail, focusing on the effects including the difference in the longitudinal stiffness between the side towers and central towers, partially longitudinal constraints between the bridge deck and part of bridge towers, self-excited aerodynamic forces, and the rigid hinge installed in the middle of the bridge deck. The analytical results can provide valuable references for wind-resistant design of multispan cable-stayed bridges in the future.

  19. 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.

  20. Critical traffic loading for the design of prestressed concrete bridge

    International Nuclear Information System (INIS)

    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

  1. Retrofit of existing railway bridges of short to medium spans for high-speed traffic using viscoelastic dampers

    OpenAIRE

    MOLINER CABEDO, EMMANUELA; Museros Romero, Pedro; MARTÍNEZ RODRIGO, MARÍA DE LOS DOLORES

    2012-01-01

    This paper presents a study on the energy-absorbing capacities of viscoelastic dampers (VEDs) for reducing the resonant vibrations of simply supported high-speed railway bridges of short to medium span. The proposed solution is based on retrofitting the bridge with a set of discrete VEDs connected to the slab and to an auxiliary structure, placed underneath the bridge deck and resting on the abutments. In this investigation attention is focused on mitigating flexural vibrations; therefore, bo...

  2. 14 CFR 121.547 - Admission to flight deck.

    Science.gov (United States)

    2010-01-01

    ... REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Flight Operations § 121.547 Admission to flight deck... holder. However, the certificate holder may not admit employees of traffic, sales, or other...

  3. Influence of maximum decking charge on intensity of blasting vibration

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on the character of short-time non-stationary random signal, the relationship between the maximum decking charge and energy distribution of blasting vibration signals was investigated by means of the wavelet packet method. Firstly, the characteristics of wavelet transform and wavelet packet analysis were described. Secondly, the blasting vibration signals were analyzed by wavelet packet based on software MATLAB, and the change of energy distribution curve at different frequency bands were obtained. Finally, the law of energy distribution of blasting vibration signals changing with the maximum decking charge was analyzed. The results show that with the increase of decking charge, the ratio of the energy of high frequency to total energy decreases, the dominant frequency bands of blasting vibration signals tend towards low frequency and blasting vibration does not depend on the maximum decking charge.

  4. Bridge aerodynamics and aeroelasticity: A comparison of modeling schemes

    Science.gov (United States)

    Wu, Teng; Kareem, Ahsan

    2013-11-01

    Accurate modeling of wind-induced loads on bridge decks is critical to ensure the functionality and survivability of long-span bridges. Over the last few decades, several schemes have emerged to model bridge behavior under winds from an aerodynamic/aeroelastic perspective. A majority of these schemes rely on the quasi-steady (QS) theory. This paper systematically compares and assesses the efficacy of five analytical models available in the literature with a new model presented herein. These models include: QS theory-based model, corrected QS theory-based model, linearized QS theory-based model, semi-empirical linear model, hybrid model, and the proposed modified hybrid model. The ability of these models to capture fluid memory and nonlinear effects either individually or collectively is examined. In addition, their ability to include the effects of turbulence in the approach flow on the bridge behavior is assessed. All models are compared in a consistent manner by utilizing the time domain approach. The underlying role of each model in capturing the physics of bridge behavior under winds is highlighted and the influence of incoming turbulence and its interaction with the bridge deck is examined. A discussion is included that focuses on a number of critical parameters pivotal to the effectiveness of corresponding models.

  5. Probabilistic Corrosion Service Life Model of Concrete Bridge Exposed to Chloride Deicer Salts

    Directory of Open Access Journals (Sweden)

    Cristian-Claudiu Comisu

    2005-01-01

    Full Text Available A model to determine the time till first repair and subsequent rehabilitation of concrete bridge decks exposed to chloride deicer salts that recognizes and incorporates the statistical nature of factors affecting the corrosion process, consists of the following serial phases: diffusion to the depth of the steel that would precipitate first maintenance actions; corrosion of the steel at the first maintenance depth until cracking and spalling occurs; continuous spalling until a damage level is reached which is defined as the end of functional service life for the deck of concrete bridge. The model expands on an existing deterministic model using statistical computing techniques, including resampling techniques such as the parametric and simple bootstrap. Emphasis was placed on the diffusion portion of the diffusion-cracking model, but advances can be readily included for the time for corrosion deterioration after corrosion initiation. The diffusion phase is described by Fick’s law and the boundary conditions define the solution form. The time till cracking model depends upon some factors as concrete strength properties, cover depth and corrosion rate. Corrosion rate has a significant influence on the time to cracking which typically occurs in three to seven years after initiation. Service life model that predict the time to first repair and rehabilitation of concrete bridge decks provide a useful tool for comparing the effectiveness measures and provide bridge engineers with a useful planning tool. A service life model for the corrosion of concrete bridge deck in chloride laden environments is proposed. The aim of this paper is to enhance the awareness among the engineering community to use the model to determine the time till first repair and subsequent rehabilitation of concrete bridge decks exposed to chloride deicer salts in Romania.

  6. Multiobjective Optimal Control of Longitudinal Seismic Response of a Multitower Cable-Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Geng Fangfang

    2016-01-01

    Full Text Available The dynamic behavior of a multitower cable-stayed bridge with the application of partially longitudinal constraint system using viscous fluid dampers under real earthquake ground motions is presented. The study is based on the dynamic finite element model of the Jiashao Bridge, a six-tower cable-stayed bridge in China. The prime aim of the study is to investigate the effectiveness of viscous fluid dampers on the longitudinal seismic responses of the bridge and put forth a multiobjective optimization design method to determine the optimized parameters of the viscous fluid dampers. The results of the investigations show that the control objective of the multitower cable-stayed bridge with the partially longitudinal constraint system is to yield maximum reductions in the base forces of bridge towers longitudinally restricted with the bridge deck, with slight increases in the base forces of bridge towers longitudinally unrestricted with the bridge deck. To this end, a multiobjective optimization design method that uses a nondominating sort genetic algorithm II (NSGA-II is used to optimize parameters of the viscous fluid dampers. The effectiveness of the proposed optimization design method is demonstrated for the multitower cable-stayed bridge with the partially longitudinal constraint system, which reveals that a design engineer can choose a set of proper parameters of the viscous fluid dampers from Pareto optimal fronts that can satisfy the desired performance requirements.

  7. Running safety analysis of a train on the Tsing Ma Bridge under turbulent winds

    Institute of Scientific and Technical Information of China (English)

    Guo Weiwei; Xia He; Xu Youlin

    2010-01-01

    The dynamic responses of the Tsing Ma suspension bridge and the running behaviors of trains on the bridge under turbulent wind actions are analyzed by a three-dimensional wind-train-bridge interaction model. This model consists of a spatial finite element bridge model, a train model composed of eight 4-axle identical coaches of 27 degrees-of-freedom, and a turbulent wind model. The fluctuating wind forces, including the buffeting forces and the self-excited forces, act on the bridge only, since the train runs inside the bridge deck. The dynamic responses of the bridge are calculated and some results are compared with data measured from Typhoon York. The runnability of the train passing through the Tsing Ma suspension bridge at different speeds is researched under turbulent winds with different wind velocities. Then, the threshold curve of wind velocity for ensuring the running safety of the train in the bridge deck is proposed, from which the allowable train speed at different wind velocities can be determined. The numerical results show that rail traffic on the Tsing Ma suspension bridge should be closed as the mean wind velocity reaches 30 m/s.

  8. Dynamic Analysis of Horizontally Curved Thin-Walled Box-Girder Bridge due to Moving Vehicle

    Directory of Open Access Journals (Sweden)

    K. Nallasivam

    2007-01-01

    Full Text Available The impact on curved box-girder bridges due to vehicle moving across rough bridge deck have been analyzed using bridge-vehicle coupled dynamics. The bridge deck unevenness has been assumed to be a homogeneous random process in space specified by a PSD function. The analysis incorporates the effect of centrifugal forces due to vehicle moving on curved bridge. The curved box-girder bridge has been numerically modeled using computationally efficient thin-walled box-beam finite elements which take into account the torsional warping, distortion and distortional warping, that are important features of thin-walled box girders. Rigid vehicle with longitudinal and transverse input to the wheels giving rise to heave-pitch-roll degrees of freedom has been considered. The theoretical bridge model used in simulation study has been validated by a free vibration experiment using impact excitation. The impact factors for several response parameters such as bending moment, shear force, torsional moment, torsional bi-moment, distortional moment, distortional bi-moment and vertical deflections have been obtained for various bridge-vehicle parameters. Both constant velocity and forward acceleration of the vehicle have been considered to examine impact factor. The results highlighted that the impact factors of a curved box girder bridge corresponding to torsion, distortion and their corresponding bimoments have been observed to be generally very high, while those of the other responses are also relatively higher than that of corresponding straight box girder bridge.

  9. Bridge Management Systems

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

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

  10. Programmevaluierung Bridge

    OpenAIRE

    Warta, Katharina; Good, Barbara; Geyer, Anton

    2009-01-01

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

  11. On estimating the aerodynamic admittance of bridge sections by a mesh-free vortex method

    DEFF Research Database (Denmark)

    Hejlesen, Mads Mølholm; Rasmussen, Johannes Tophøj; Larsen, Allan;

    2015-01-01

    A stochastic method of generating a synthetic turbulent flow field is combined with a 2D mesh-free vortex method to simulate the effect of an oncoming turbulent flow on a bridge deck cross-section within the atmospheric boundary layer. The mesh-free vortex method is found to be capable of preserv...

  12. Analysis of five-point bending test for multilayer surfacing system on orthotropic steel bridge

    NARCIS (Netherlands)

    Li, J.; Scarpas, A.; Tzimiris, G.; Kasbergen, C.; Hofman, R.; Voskuilen, J.

    2013-01-01

    The French five-point bending test (5PBT) provides a laboratory scale test that allows studying the fatigue resistance of surfacing systems on orthotropic steel deck bridges (OSDB). The surfacing structure for OSDB in the Netherlands consists mostly of multilayer system: top porous asphalt layer, gu

  13. Wind-induced vibration control of bridges using liquid column damper

    Institute of Scientific and Technical Information of China (English)

    薛素铎; 高赞明; 徐幼麟

    2002-01-01

    The potential application of tuned liquid column damper (TLCD) for suppressing wind-induced vibration of long span bridges is explored in this paper. By installing the TLCD in the bridge deck, a mathematical model for the bridge-TLCD system is established. The governing equations of the system are developed by considering all three displacement components of thc deck in vertical, lateral, and torsional vibrations, in which the interactions between the bridge deck, the TLCD, the aeroelastic forces, and the aerodynamic forces are fully reflected. Both buffeting and flutter analyses are carried out. The buffeting analysis is performed through random vibration approach, and a critical flutter condition is identified from flutter analysis. A numerical example is presented to demonstrate the control effectiveness of the damper and it is shown that the TLCD can be an effective device for suppressing wind-induced vibration of long span bridges, either for reducing the buffeting response or increasing the critical flutter wind velocity of the bridge.

  14. Structure-borne noise of railway composite bridge: Numerical simulation and experimental validation

    Science.gov (United States)

    Li, Xiaozhen; Liu, Quanmin; Pei, Shiling; Song, Lizhong; Zhang, Xun

    2015-09-01

    In order to investigate the characteristics of the noise from steel-concrete composite bridges under high-speed train loading, a model used to predict the bridge-borne noise is established and validated through a field experiment. The numerical model for noise prediction is developed based on the combination of spatial train-track-bridge coupled vibration theory and Statistical Energy Analysis (SEA). Firstly, train-track-bridge coupled vibration is adopted to obtain the velocity time history of the bridge deck vibration. Then, the velocity time history is transferred into frequency domain through FFT to serve as the vibratory energy of SEA deck subsystems. Finally, the transmission of the vibratory energy is obtained by solving the energy balance equations of SEA, and the sound radiation is computed using the vibro-acoustic theory. The numerically computed noise level is verified by a field measurement. It is determined that the dominant frequency of steel-concrete composite bridge-borne noise is 20-1000 Hz. The noise from the bottom flange of steel longitudinal girder is less than other components in the whole frequency bands, while the noise from web of steel longitudinal girder is dominant in high frequency range above 315 Hz. The noise from concrete deck dominates in low-frequency domain ranges from 80 Hz to 160 Hz.

  15. National Bridge Inventory (NBI) Bridges

    Data.gov (United States)

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

  16. 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.

  17. Seismic Response Analysis of Continuous Multispan Bridges with Partial Isolation

    Directory of Open Access Journals (Sweden)

    E. Tubaldi

    2015-01-01

    Full Text Available Partially isolated bridges are a particular class of bridges in which isolation bearings are placed only between the piers top and the deck whereas seismic stoppers restrain the transverse motion of the deck at the abutments. This paper proposes an analytical formulation for the seismic analysis of these bridges, modelled as beams with intermediate viscoelastic restraints whose properties describe the pier-isolator behaviour. Different techniques are developed for solving the seismic problem. The first technique employs the complex mode superposition method and provides an exact benchmark solution to the problem at hand. The two other simplified techniques are based on an approximation of the displacement field and are useful for preliminary assessment and design purposes. A realistic bridge is considered as case study and its seismic response under a set of ground motion records is analyzed. First, the complex mode superposition method is applied to study the characteristic features of the dynamic and seismic response of the system. A parametric analysis is carried out to evaluate the influence of support stiffness and damping on the seismic performance. Then, a comparison is made between the exact solution and the approximate solutions in order to evaluate the accuracy and suitability of the simplified analysis techniques for evaluating the seismic response of partially isolated bridges.

  18. Tacoma Bridge Failure-- a Physical Model

    CERN Document Server

    Green, D; Green, Daniel; Unruh, William G.

    2004-01-01

    The cause of the collapse of the Tacoma Narrows Bridge has been a topic of much debate and confusion since the day it fell. Many mischaracterizations of the observed phenomena have limited the widespread understanding of the problem. Nevertheless, there has always been an abundance of evidence in favour of a negative damping model. Negative damping, or positive feedback, is responsible for many large amplitude oscillations observed in many applications. In this paper, we will explain some well-known examples of positive feedback. We will then present a feedback model, derived from fundamental physics, capable of explaining a number of features observed in the instabilities of many bridge decks. This model is supported by computational, experimental and historical data.

  19. Truck-based mobile wireless sensor networks for the experimental observation of vehicle–bridge interaction

    International Nuclear Information System (INIS)

    Heavy vehicles driving over a bridge create a complex dynamic phenomenon known as vehicle–bridge interaction. In recent years, interest in vehicle–bridge interaction has grown because a deeper understanding of the phenomena can lead to improvements in bridge design methods while enhancing the accuracy of structural health monitoring techniques. The mobility of wireless sensors can be leveraged to directly monitor the dynamic coupling between the moving vehicle and the bridge. In this study, a mobile wireless sensor network is proposed for installation on a heavy truck to capture the vertical acceleration, horizontal acceleration and gyroscopic pitching of the truck as it crosses a bridge. The vehicle-based wireless monitoring system is designed to interact with a static, permanent wireless monitoring system installed on the bridge. Specifically, the mobile wireless sensors time-synchronize with the bridge's wireless sensors before transferring the vehicle response data. Vertical acceleration and gyroscopic pitching measurements of the vehicle are combined with bridge accelerations to create a time-synchronized vehicle–bridge response dataset. In addition to observing the vehicle vibrations, Kalman filtering is adopted to accurately track the vehicle position using the measured horizontal acceleration of the vehicle and positioning information derived from piezoelectric strip sensors installed on the bridge deck as part of the bridge monitoring system. Using the Geumdang Bridge (Korea), extensive field testing of the proposed vehicle–bridge wireless monitoring system is conducted. Experimental results verify the reliability of the wireless system and the accuracy of the vehicle positioning algorithm

  20. Truck-based mobile wireless sensor networks for the experimental observation of vehicle-bridge interaction

    Science.gov (United States)

    Kim, Junhee; Lynch, Jerome P.; Lee, Jong-Jae; Lee, Chang-Geun

    2011-06-01

    Heavy vehicles driving over a bridge create a complex dynamic phenomenon known as vehicle-bridge interaction. In recent years, interest in vehicle-bridge interaction has grown because a deeper understanding of the phenomena can lead to improvements in bridge design methods while enhancing the accuracy of structural health monitoring techniques. The mobility of wireless sensors can be leveraged to directly monitor the dynamic coupling between the moving vehicle and the bridge. In this study, a mobile wireless sensor network is proposed for installation on a heavy truck to capture the vertical acceleration, horizontal acceleration and gyroscopic pitching of the truck as it crosses a bridge. The vehicle-based wireless monitoring system is designed to interact with a static, permanent wireless monitoring system installed on the bridge. Specifically, the mobile wireless sensors time-synchronize with the bridge's wireless sensors before transferring the vehicle response data. Vertical acceleration and gyroscopic pitching measurements of the vehicle are combined with bridge accelerations to create a time-synchronized vehicle-bridge response dataset. In addition to observing the vehicle vibrations, Kalman filtering is adopted to accurately track the vehicle position using the measured horizontal acceleration of the vehicle and positioning information derived from piezoelectric strip sensors installed on the bridge deck as part of the bridge monitoring system. Using the Geumdang Bridge (Korea), extensive field testing of the proposed vehicle-bridge wireless monitoring system is conducted. Experimental results verify the reliability of the wireless system and the accuracy of the vehicle positioning algorithm.

  1. Seismic Performance of Multi-Span RC Railway Bridges

    DEFF Research Database (Denmark)

    Georgakis, Christos; Barrau, Xavier

    2008-01-01

    and fragility curves in relation to PGA. The cost comparisons clearly show that particular bridge types perform better than others economically for specific ground types and expected seismic intensities, even though in some cases they may be expected to suffer larger damages during their lifetime....... with Lead Rubber Bearing (LRB) supports and the laterally fixed continuous deck (CRB) with LRBs. In this paper, the seismic performance of these four types is examined for varying ground types and seismic intensities. For the purposes of comparison, all of the bridges have five spans with identical span...... to increase the performance and reduce the overall bridge cost. Finally, an evaluation of the lifetime bridge costs are made assuming current prices, including costs relating to the damage associated with the expected seismic events. This is accomplished through the use of approximated damage states...

  2. Building Bridges

    DEFF Research Database (Denmark)

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

  3. Fatigue Reliability of Deck Structures Subjected to Correlated Crack Growth

    Institute of Scientific and Technical Information of China (English)

    G.Q. Feng; Y. Garbatov; C. Guedes Soares

    2013-01-01

    The objective of this work is to analyse fatigue reliability of deck structures subjected to correlated crack growth. The stress intensity factors of the correlated cracks are obtained by finite element analysis and based on which the geometry correction functions are derived. The Monte Carlo simulations are applied to predict the statistical descriptors of correlated cracks based on the Paris-Erdogan equation. A probabilistic model of crack growth as a function of time is used to analyse the fatigue reliability of deck structures accounting for the crack propagation correlation. A deck structure is modelled as a series system of stiffened panels, where a stiffened panel is regarded as a parallel system composed of plates and are longitudinal. It has been proven that the method developed here can be conveniently applied to perform the fatigue reliability assessment of structures subjected to correlated crack growth.

  4. Vibration Transmission from Deck to Hull via a Bulkhead

    Science.gov (United States)

    Leung, R. C. N.

    1998-06-01

    Machines on board a ship are mounted on decks, which are supported by bulkheads from the hull. This paper studies the vibration transmission characteristics along the transmission path of deck-bulkhead-hull. The model used in this study consists of two infinite parallel plates, representing a deck and a hull, connected by a single bulkhead. The excitation force is applied on the top plate, in the plane of the bulkhead. Thus, only in-plane waves exist in the bulkhead. The two infinite plates are assumed to have pure bending waves only. The analyses show that at low frequencies the two parallel plates are strongly coupled. At frequencies above the first resonance of the bulkhead due to shear waves, the two plates become uncoupled. The top plate, which the excitation is acted upon, exhibits the behaviour of a single infinite plate. The bottom plate, however, can be treated as a series of independent beam elements running perpendicular to the bulkhead.

  5. 紧水滩大桥桥型方案设计%The Bridge Type Design Scheme of Jinshuitan Bridge

    Institute of Scientific and Technical Information of China (English)

    杨成峰; 邱白

    2014-01-01

    This paper introduces the design scheme of bridge type of Jinshuitan Bridge, compares the three kinds of schemes of the deck concrete arch bridge, prestressed concrete T beams and prestressed concrete continuous rigid frame bridge, and gi-ves the relevant conclusions and recommendations. Its design experience can be used for reference in the professional design personnel.%本文介绍了紧水滩大桥的桥型方案设计,比较了上承式混凝土拱桥、预应力砼 T 梁及预应力砼连续刚构等三种桥型方案,并给出相关结论和建议。其设计经验可供专业设计人员参考。

  6. Building Bridges

    DEFF Research Database (Denmark)

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

  7. 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.

  8. 46 CFR 69.173 - Tonnage assignments for vessels with only one deck.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Tonnage assignments for vessels with only one deck. 69... with only one deck. A vessel without a second deck is assigned only one gross and one net tonnage. In calculating the gross tonnage, only the exemptions in § 69.169 (a) through (d) are allowed. Markings...

  9. Research on Construction Technology of GFRP-steel Composite Bridge%GFRP-钢组合结构桥梁施工技术研究

    Institute of Scientific and Technical Information of China (English)

    朱坤宁; 万水

    2011-01-01

    纤维增强复合材料(FRP)桥面板是近年来在桥梁工程中应用的一种新型桥面板结构.大广高速6号立交桥为我国第一座GFRP桥面板组合结构公路桥.介绍了GFRP-钢组合结构桥梁的施工技术,包括GFRP拉挤型材的黏结,GFRP桥面板的吊装与黏结和螺栓连接件的安装工艺.解决了GFRP桥面板间的连接问题和GFRP板与承重梁间的连接问题,施工方法满足工程要求.%Fiber reinforced polymer bridge deck is an innovated structural element applied to bridge engineering recently. The No. 6 bridge overpass of Daqing-Guangzhou highway is the first GFRP-steel composite highway bridge in China. Combing with the actual project, main construction processes are introduced including the gluing of GFRP profiles, lifting and bonding of GFRP bridge deck and the installation of bolt connector. The connection problems among GFRP bridge decks are solved, as well as the connection problems between the GFRP deck and the steel girder. The construction method can meet requirements of the project.

  10. 33 CFR 157.168 - Crew member: Main deck watch.

    Science.gov (United States)

    2010-07-01

    ... (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels Cow Operations § 157.168 Crew member: Main deck watch. During COW operations, the master shall ensure that at least one member of the crew with...

  11. Astronaut Kevin Chilton displays map of Scandinavia on flight deck

    Science.gov (United States)

    1994-01-01

    Astronaut Kevin P. Chilton, pilot, displays a map of Scandinavia on the Space Shuttle Endeavour's flight deck. Large scale maps such as this were used by the crew to locate specific sites of interest to the Space Radar Laboratory scientists. The crew then photographed the sites at the same time as the radar in the payload bay imaged them.

  12. Experiments and theory on deck and girder crushing

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup; Ocakli, Hasan

    1999-01-01

    This paper is concerned with theoretical and experimental analysis of deep plastic collapse of a deck or deep girder subjected to an in-plane, concentrated load. A theory is derived which is valid until initition of fracture in the structure. The presented experimental results show load-deflectio...

  13. Experimental Study of Properties of Pervious Concrete used for Bridge Superstructure

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard; Hertz, Kristian Dahl

    2014-01-01

    -Chain Bridges are a new patented bridge technology consisting of a number of Super-Light Deck elements, which are post-tensioned to create an arch bridge used for example for highways. The present study investigates how pervious concrete can be applied as a stabilizing filling materi-al between the arch...... substructure and the wearing course. One pervious concrete mixture contain-ing air entrainment is designed and tested. The tests include investigations of compaction meth-ods, compressive strength, stiffness, frost resistance and permeability....

  14. Study on longitudinal wind load calculation method of cables for cable-stayed bridge

    Institute of Scientific and Technical Information of China (English)

    Pei Minshan; Zhang Xigang; Zhu Bin; Hou Bin; Liu Changpeng

    2009-01-01

    Along with the expanding of span of cable-stayed bridge, wind load becomes a more and more important controlling factor for bridge the design. A very large proportion of the wind load acting on cables has exceeded that acting on deck. There was not any detailed prescript in Chinese code for calculation of longitudinal wind load on cables due to lack of theoretical research and experiment, and conservative simplified calculation was adopted during design, which leads to conservative and uneconomical design of structures. To resolve this problem, cable force experiment was carried out during the design of Sutong Bridge. By comparing with international research results, the calculation formula of longitudinal wind drag coefficient for cables was advanced to fill the blank of bridge wind resistant code of China, and has already been adopted in the Highway Bridge Wind Resistant Design Code (JTG/T D60-01-2004) with great significance for bridge engineering.

  15. Fiber reinforced polymer composites for bridge structures

    Directory of Open Access Journals (Sweden)

    Alexandra CANTORIU

    2013-12-01

    Full Text Available Rapid advances in construction materials technology have led to the emergence of new materials with special properties, aiming at safety, economy and functionality of bridges structures. A class of structural materials which was originally developed many years ago, but recently caught the attention of engineers involved in the construction of bridges is fiber reinforced polymer composites. This paper provides an overview of fiber reinforced polymer composites used in bridge structures including types, properties, applications and future trends. The results of this study have revealed that this class of materials presents outstanding properties such as high specific strength, high fatigue and environmental resistance, lightweight, stiffness, magnetic transparency, highly cost-effective, and quick assembly, but in the same time high initial costs, lack of data on long-term field performance, low fire resistance. Fiber reinforced polymer composites were widely used in construction of different bridge structures such as: deck and tower, I-beams, tendons, cable stands and proved to be materials for future in this field.

  16. Fracture Mechanics Prediction of Fatigue Life of Aluminum Highway Bridges

    DEFF Research Database (Denmark)

    Rom, Søren; Agerskov, Henning

    2015-01-01

    Fracture mechanics prediction of the fatigue life of aluminum highway bridges under random loading is studied. The fatigue life of welded joints has been determined from fracture mechanics analyses and the results obtained have been compared with results from experimental investigations....... The fatigue life of welded plate specimens has been investigated. Both the fracture mechanics analyses and the fatigue tests have been carried out using load histories, which correspond to one week's traffic loading, determined by means of strain gauge measurements on the deck structure of the Farø Bridges...... against fatigue in aluminum bridges, may give results which are unconservative. Furthermore, it was in both investigations found that the validity of the results obtained from Miner's rule will depend on the distribution of the load history in tension and compression....

  17. Modeling of cable vibration effects of cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The analysis of dynamic responses of cable-stayed bridges subjected to wind and earthquake loads generallyconsiders only the motions of the bridge deck and pylons. The influence of the stay cable vibration on the responses of the bridgeis either ignored or considered by approximate procedures. The transverse vibration of the stay cables, which can be significant insome cases, are usually neglected in previous research. In the present study, a new three-node cable element has been developed tomodel the transverse motions of the cables. The interactions between the cable behavior and the other parts of the bridgesuperstructure are considered by the concept of dynamic stiffness. The nonlinear effect of the cable caused by its self-weight isincluded in the formulation. Numerical examples are presented to demonstrate the accuracy and efficiency of the proposed model.The impact of cable vibration behavior on the dynamic characteristics of cable-stayed bridges is discussed.

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

    OpenAIRE

    Sotelino, Elisa D.; Teng, Ming-Hung

    2002-01-01

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

  19. Robotics and Automation for Flight Deck Aircraft Servicing

    Energy Technology Data Exchange (ETDEWEB)

    Chesser, J.B.; Draper, J.V.; Pin, F.G.

    1999-03-01

    One of the missions of the Future Aircraft Carriers Program is to investigate methods that would improve aircraft turnaround servicing activities on carrier decks. The major objectives and criteria for evaluating alternative aircraft servicing methods are to reduce workload requirements, turnaround times (TAT), and life-cycle costs (LCC). Technologies in the field of Robotics and Automation (R and A) have the potential to significantly contribute to these objectives. The objective of this study was to investigate aircraft servicing functions on carrier decks which would offer the potentially most significant payoff if improved by various R and A technologies. Improvement in this case means reducing workload, time and LCC. This objective was accomplished using a ''bottom-up'' formalized approach as described in the following.

  20. Snap loads and torsional oscillations of the original Tacoma Narrows Bridge

    Science.gov (United States)

    Plaut, R. H.

    2008-01-01

    In 1940, the original Tacoma Narrows Bridge was completed on June 10 and opened to traffic on July 1. On November 7, the deck collapsed. Before that day, significant vertical oscillations had occurred, but no torsion. The bridge as built was stable with respect to torsional motion under the winds of November 7 and previous winds with higher speeds. However, snap loads in the diagonal ties attached to the north midspan cable band helped to loosen the band, and the frictional resistance between the band and the north suspension cable passing through it was overcome. The cable began to slip through the band. For this new structural system, with longitudinal motion of the north cable, the wind speed was higher than the critical speed for torsional flutter, and torsional motion was initiated. Approximately 700 cycles of torsional oscillations occurred during the hour prior to the collapse. In the present study, the snap loads on the cable band are discussed first. Then a continuum model of the central span (deck, cables, and hangers) is formulated. The longitudinal motions of the cables are included, so that the slippage can be incorporated. Known information from the observed steady-state torsional motion is utilized with assumed forms of the vertical cable displacements, and the governing equations provide the horizontal cable displacements, the dynamic tensions in the cables, the vertical and torsional motions of the deck, and the resultant lift force and pitching moment (including damping) acting on the deck during its final hour.

  1. RESEARCH ON KEY TECHNOLOGY IN CONSTRUCTING FRP-STEEL COMPOSITE BRIDGE%FRP-钢组合结构桥梁建造关键技术研究

    Institute of Scientific and Technical Information of China (English)

    朱坤宁; 万水

    2011-01-01

    对FRP-钢组合结构公路桥研制过程中的关键技术进行了研究,通过GFRP桥面板的设计与加工、有限元分析和试验研究,研制出适用于我国公路桥梁用的重型FRP桥面板.将GFRP桥面板与波形腹板H型钢梁组合起来,建成我国第一座FRP-钢组合结构公路桥.对GFRP-钢组合结构公路桥梁结构进行成桥荷载试验.试验结果表明,FRP-钢组合结构桥梁处于安全受力状态,满足设计荷载下的使用要求.%The construction technology of FRP-steel composite bridge is researched through the development process. The FRP bridge deck that used in bridge structure is developed through the design and fabricate, as well as the finite element analysis and experimental research of GFRP bridge deck. And the first FRP-steel composite bridge in China is built with GFRP bridge deck and steel H girder with corrugated web. Load test of the composite bridge is made, and the result shows that the structure is in a safe state and meets the requirements under the design load.

  2. RESEARCH ON KEY TECHNOLOGY IN CONSTRUCTING FRP-STEEL COMPOSITE BRIDGE%FRP-钢组合结构桥梁建造关键技术研究

    Institute of Scientific and Technical Information of China (English)

    朱坤宁; 万水

    2011-01-01

    The construction technology of FRP-steel composite bridge is researched through the development process. The FRP bridge deck that used in bridge structure is developed through the design and fabricate, as well as the finite element analysis and experimental research of GFRP bridge deck. And the first FRP-steel composite bridge in China is built with GFRP bridge deck and steel H girder with corrugated web. Load test of the composite bridge is made, and the result shows that the structure is in a safe state and meets the requirements under the design load.%对FRP-钢组合结构公路桥研制过程中的关键技术进行了研究,通过GFRP桥面板的设计与加工、有限元分析和试验研究,研制出适用于我国公路桥梁用的重型FRP桥面板.将GFRP桥面板与波形腹板H型钢梁组合起来,建成我国第一座FRP-钢组合结构公路桥.对GFRP-钢组合结构公路桥梁结构进行成桥荷载试验.试验结果表明,FRP-钢组合结构桥梁处于安全受力状态,满足设计荷载下的使用要求.

  3. Finite-element (FE modelling of bridge dynamics from exposure to moving load

    Directory of Open Access Journals (Sweden)

    G.M. Kadisov

    2013-12-01

    Full Text Available Solutions to the problem of cable-stayed bridge dynamics are received and analysed on the basis of two modelling options. According to the first one space-time finite-elements are used. The first three bridge vibration modes are shown to study cable-stayed bridge fluctuations when exposed to the vertical force moving at a constant speed and compile charts of time history strains in fixed sections of a deck. According to the second option a suspended superstructure is represented by a fold with absolutely rigid transverse membranes in joints of cables, a bridge tower is represented by a beam. Natural modes of the bridge are received by a solution of homogeneous system equations of the mixed method. Nodal lines of a fold for the first four natural modes are shown. The comparative description of applicability of the above-mentioned methods of solving problems of dynamics affected by moving load is given.

  4. DEM simulation of particle flow on a single deck banana screen

    Institute of Scientific and Technical Information of China (English)

    Liu Chusheng; Wang Hong; Zhao Yuemin; Zhao Lala; Dong Hailin

    2013-01-01

    A mathematical study of particle flow on a banana screen deck using the discrete element method (DEM) was presented in this paper.The motion characteristics and penetrating mechanisms of particles on the screen deck were studied.Effects of geometric parameters of screen deck on banana screening process were also investigated.The results show that when the values of inclination of discharge and increment of screen deck inclination are 10° and 5° respectively,the banana screening process get a good screening performance in the simulation.The relationship between screen deck length and screening efficiency was further confirmed.The conclusion that the screening efficiency will not significantly increase when the deck lengthL ≥430 mm (L/B ≥3.5) was obtained,which can provide theoretical basis for the optimization of banana screen.

  5. In-service performance and behavior characterization of the hybrid composite bridge system - a case study

    CERN Document Server

    Civitillo, John M; Gheitasi, Amir; Saliba, Mark; Kassner, Bernard L

    2014-01-01

    The Hybrid Composite Beam (HCB) system is an innovative structural technology that has been recently used in bridge construction within the U.S. transportation network. In this system, the superstructure consists of a conventional reinforced concrete deck supported by Hybrid Composite Beams. Each beam is comprised of a glassfiber reinforced polymer (FRP) box shell containing a tied parabolic concrete arch. Inclined stirrups provide shear integrity and enforce composite action between the HCBs and the concrete deck. This paper focuses on evaluating the in-service performance of a newly constructed HCB bridge superstructure located on Route 205 in Colonial Beach, Virginia. A live load test was conducted using tandem axle dump trucks under both quasi-static and dynamic conditions. Results obtained from the experimental investigation were used to determine three key behavior characteristics. Dynamic amplification and lateral load distribution were found to be reasonable in comparison to the assumed design values....

  6. The Feasibilty of Recycling CCA Treated Wood From Spent Residential Decks

    OpenAIRE

    Bailey, David Samuel

    2003-01-01

    The amount of CCA treated wood being removed from spent residential decks is increasing at a tremendous rate. While most spent CCA treated wood is being disposed in landfills, further useful and environmentally beneficial alternatives have to be met. This research estimated the percentage of recoverable lumber from spent CCA decks that can be recycled into other usable products. Six residential decks were removed from service, by either demolition or deconstruction procedures. It was found...

  7. Stress analysis of deck pavement of continuous steel box girder%连续钢箱梁桥面铺装层结构应力分析

    Institute of Scientific and Technical Information of China (English)

    李国芬; 曹牧; 王宏畅; 朱华平

    2013-01-01

      正交异性钢桥面的构造复杂,用理论算法对铺装层进行力学计算,较难得到精确的计算结果。本文利用有限元通用软件对曲线钢箱梁桥浇筑式沥青铺装层进行受力分析,将正交异性钢桥面板、铺装层作为整体,建立有限元模型,研究铺装层受力变形特点。根据钢桥面铺装层常出现的病害,并结合超载及刹车产生的水平荷载对铺装层受力的影响,提出相应的桥面铺装层破坏的综合控制指标。%The geometric structure of steel deck plates is complex. So it is difficult to get precise results in the mechanics calculation of deck pavement with traditional methods. This paper adopts the finite element meth-od for the mechanics analysis of the composite guss asphalt surfacing layer of curved steel box girder bridges. By taking the orthotropic steel deck and the pavement as a whole,a reasonable finite element model which estab-lished can be used to study the stress and deformation features of the surfacing layer. According to the common diseases in steel deck pavements and the effect of the overload and the horizontal load in braking to the pave-ment,this paper puts forward the comprehensive control indicators for pavement failures.

  8. Numerical Hybrid Simulation Modeling Verification for a Curved 3-Pier Bridge (Investigation of Combined Actions on Reinforced Concrete Bridge Piers (CABER Project

    Directory of Open Access Journals (Sweden)

    Adel Abdelnaby

    2013-06-01

    Full Text Available Reinforced concrete bridge piers are subjected to complex loading conditions under earthquake ground motions. Bridge geometric irregularities and asymmetries result in combined actions imposed on the piers as a combination of displacements and rotations in all six degrees of freedom at the pier-deck juncture. Existing analytical tools have proven their inadequacy in representing the actual behavior of piers under these combined actions, particularly in their inelastic range. The objective of this investigation is to develop a fundamental understanding of the effects of these combined actions on the performance of RC piers and the resulting system response. This paper describes a part of the CABER project that verifies the numerical hybrid simulation of the curved bridge. In this part two models were introduced, a whole model and a sub-structured hybrid model. The whole model was established using the Zeus-NL analysis platform, which is capable of performing inelastic nonlinear response history analysis of the whole curved bridge. The hybrid model was divided into three modules which comprised the deck, left and right piers, and the middle pier of the bridge. The three modules were modeled by Zeus-NL as a static analysis module interface. The simulation coordinator (SimCor software was utilized to communicate between these modules using a Pseudo-Dynamic time integration scheme. Results obtained from both models were compared and conclusions were drawn.

  9. Applicability of URANS and DES Simulations of Flow Past Rectangular Cylinders and Bridge Sections

    OpenAIRE

    Claudio Mannini

    2015-01-01

    This paper discusses the results of computational fluid dynamics simulations carried out for rectangular cylinders with various side ratios of interest for many civil engineering structures. A bridge deck of common cross-section geometry was also considered. Unsteady Reynolds-averaged Navier-Stokes (URANS) equations were solved in conjunction with either an eddy-viscosity or a linearized explicit algebraic Reynolds stress model. The analysis showed that for the case studies considered the 2-D...

  10. Ambient Vibration Test on Reinforced Concrete Bridges

    Directory of Open Access Journals (Sweden)

    Idris Nurul Shazwin

    2016-01-01

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

  11. Construction and control technology of the main bridge superstructure of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Hong; Luo Chenbin; Zhang Yongtao; You Xinpeng

    2009-01-01

    The Sutong Yangtze River Bridge (short as Sutong Bridge) is now the largest span cable-stayed bridge in the world. The construction of the superstructure of the middle bridge covered several stages including erection of the big block girders for the side span, assistant span and tower area, erection of standard girders and closure of the middle span. The big block girders were hoisted by a floating crane, and the standard girders were hoisted by a double crane system on the deck. The pushing assistant method was adopted for the middle span closure construction. Furthermore, key technologies and innovative methods used in the processes of girder erection and cable assemblage in all stages were expatiated systematically. An all-stage self- adaptive geometry control method was used in the construction process. By accurately controlling the unstressed dimensions and shape of all structural components in each step, and realization that the control system and the controlled system adapt to each other, the goal was to make control of the final line shape and inner force of the bridge structure achievable. Two solutions, including GPS based and total station based dynamic geometry monitoring systems, were used to resolve the measure problem under the wide-range of wind-induced vibrations in the long cantilever state. Finally, research on the wind-induced vibration of the superstructure during the construction period was executed. Buffeting response analysis to the longest single and double cantilever states were carried out. The analysis and evaluation of wind resistance safety of the main girders under the longest single cantilever state was made, and corresponding wind resistance measures were suggested. The as-built geometric error and cable force error were controlled in a required design range, and this whole technological achievement can be a benchmark for construction of other large span cable-stayed bridges in the future.

  12. Studies on Technical Development of Railway Steel-Concrete Composite Cirider Bridges in China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Steel-concrete composite girder bridge boasts the advantages of strong rigidity,low noise and low construction height.Along with the large-scale construction of passengerdedicated lines (PDL) and high-speed lines (HSL),tests and researches on steel-concrete composite girder bridges have been conducted with the main types of which including steel plate girder-concrete composite girder bridge,deck steel truss girder-concrete composite girder bridge,through steel truss girder-concrete composite girder bridge and through type tied arch composite girder bridge.Based on the application and researches on steel-concrete composite technology and in combination with the engineering construction of railway bridges,the construction of HSL and PDL and upgrading of existing lines for speed-up in China,this paper analyzes the main structural forms of through steel truss girder-concrete composite girder bridges with different spans and structure systems,carries out studies on the force acted upon these bridges and the related theory and methods for design and computation,and puts forward the solutions required in relation to the key technologies for further development of railway steel-concrete composite girder bridges.

  13. On maintenance strategies of roads and bridges%谈公路桥梁养护对策

    Institute of Scientific and Technical Information of China (English)

    赵文峰

    2015-01-01

    The paper analyzes the meaning and aims of the road and bridge maintenance,illustrates factual maintenance measures of bridges and roads from the bridge beam maintenance,bridge pier maintenance,and deck maintenance,so as to prolong the life of roads and bridges and re-duce the times and cost of the roads and bridge maintenance by the maintenance measures.%分析了公路桥梁养护的意义及目的,从桥梁梁板养护、桥梁墩台养护、桥面铺装养护三方面,阐述了公路桥梁的具体养护措施,以延长公路桥梁的使用年限,减少公路桥梁修复的次数与成本。

  14. Analysis on Adhesively-Bonded Joints of FRP-steel Composite Bridge under Combined Loading: Arcan Test Study and Numerical Modeling

    NARCIS (Netherlands)

    Jiang, X.; Qiang, X.; Kolstein, M.H.; Bijlaard, F.S.K.

    2016-01-01

    The research presented in this paper is an experimental study and numerical analysis on mechanical behavior of the adhesively-bonded joint between FRP sandwich bridge deck and steel girder. Generally, there are three typical stress states in the adhesively-bonded joint: shear stress, tensile stress,

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

    Science.gov (United States)

    Celebi, 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.

  16. Parametrically excited oscillation of stay cable and its control in cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    孙炳楠; 汪至刚; 高赞明; 倪一清

    2003-01-01

    This paper presents a nonlinear dynamic model for simulation and analysis of a kind of parametrically excited vibration of stay cable caused by support motion in cable-stayed bridges. The sag, inclination angle of the stay cable are considered in the model, based on which, the oscillation mechanism and dynamic response characteristics of this kind of vibration are analyzed through numerical calculation. It is noted that parametrically excited oscillation of a stay cable with certain sag, inclination angle and initial static tension force may occur in cable-stayed bridges due to deck vibration under the condition that the natural frequency of a cable approaches to about half of the first model frequency of the bridge deck system. A new vibration control system installed on the cable anchorage is proposed as a possible damping system to suppress the cable parametric oscillation. The numerical calculation results showed that with the use of this damping system, the cable oscillation due to the vibration of the deck and/or towers will be considerably reduced.

  17. Flight Deck Weather Avoidance Decision Support: Implementation and Evaluation

    Science.gov (United States)

    Wu, Shu-Chieh; Luna, Rocio; Johnson, Walter W.

    2013-01-01

    Weather related disruptions account for seventy percent of the delays in the National Airspace System (NAS). A key component in the weather plan of the Next Generation of Air Transportation System (NextGen) is to assimilate observed weather information and probabilistic forecasts into the decision process of flight crews and air traffic controllers. In this research we explore supporting flight crew weather decision making through the development of a flight deck predicted weather display system that utilizes weather predictions generated by ground-based radar. This system integrates and presents this weather information, together with in-flight trajectory modification tools, within a cockpit display of traffic information (CDTI) prototype. that the CDTI features 2D and perspective 3D visualization models of weather. The weather forecast products that we implemented were the Corridor Integrated Weather System (CIWS) and the Convective Weather Avoidance Model (CWAM), both developed by MIT Lincoln Lab. We evaluated the use of CIWS and CWAM for flight deck weather avoidance in two part-task experiments. Experiment 1 compared pilots' en route weather avoidance performance in four weather information conditions that differed in the type and amount of predicted forecast (CIWS current weather only, CIWS current and historical weather, CIWS current and forecast weather, CIWS current and forecast weather and CWAM predictions). Experiment 2 compared the use of perspective 3D and 21/2D presentations of weather for flight deck weather avoidance. Results showed that pilots could take advantage of longer range predicted weather forecasts in performing en route weather avoidance but more research will be needed to determine what combinations of information are optimal and how best to present them.

  18. Identification of aeroelastic forces on bridge cables from full-scale measurements

    DEFF Research Database (Denmark)

    Acampora, Antonio; Macdonald, J.H.G.; Georgakis, Christos

    2011-01-01

    Despite much research in recent years, large amplitude vibrations of inclined cables continue to be of concern for cable-stayed bridges. Various mechanisms have been suggested for their excitation, including rain-wind excitation, dry inclined cable galloping, high reduced velocity vortex shedding...... Bridge. The system records wind conditions and weather conditions, as well as accelerations of certain cables and a few locations on the deck and tower. Using state-of-the-art methods of output-only system identification, the vibration modes of the cables have been identified. From these modes...

  19. Nonlinear Analysis of Cable Vibration of a Multispan Cable-Stayed Bridge under Transverse Excitation

    OpenAIRE

    Kun Lin; Dujian Zou; Minghai Wei

    2014-01-01

    The nonlinear vibrations of cable in a multispan cable-stayed bridge subjected to transverse excitation are investigated. The MECS (multielements cable system) model, where multielements per cable stay are used, is built up and used to analyze the model properties of the multispan cable-stayed bridges. Then, a simplified two-degrees-of-freedom (2-DOFs) model, where the tower or the deck is reduced to a beam, is proposed to analyze the nonlinear dynamic behaviors of the beam and cable. The res...

  20. Lyapunov-Based Control for Suppression of Wind-Induced Galloping in Suspension Bridges

    Directory of Open Access Journals (Sweden)

    Naif B. Almutairi

    2011-01-01

    Full Text Available This paper investigates the suppression of galloping in a suspension bridge due to wind loads. The galloping phenomenon can be destructive due to the high-amplitude oscillations of the structure. Two controllers are proposed to generate the control force needed to suppress the vertical galloping in the suspended cables and in the bridge deck. SIMULINK software is used to simulate the controlled system. The simulation results indicate that the proposed controllers work well. In addition, the performance of the system with the proposed controllers is compared to the performance of the system controlled with a tuned mass damper.

  1. Design of bridges against large tectonic deformation

    Institute of Scientific and Technical Information of China (English)

    I.Anastasopoulost; G.Gazetas; V.Drosos; T.Georgarakos; R.Kourkoulis

    2008-01-01

    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.

  2. STS-38 Mission Specialist (MS) Springer uses camera on OV-104 aft flight deck

    Science.gov (United States)

    1990-01-01

    STS-38 Mission Specialist (MS) Robert C. Springer, holding HASSELBLAD camera, positions himself under aft flight deck overhead window W7 before recording the Earth's surface below. Behind Springer are Atlantis', Orbiter Vehicle (OV) 104's, onorbit station and aft flight deck viewing windows.

  3. 46 CFR 116.1120 - Drainage of cockpit vessels, well deck vessels, and open boats.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Drainage of cockpit vessels, well deck vessels, and open boats. 116.1120 Section 116.1120 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL... Drainage of cockpit vessels, well deck vessels, and open boats. Drainage of cockpit vessels, well...

  4. 46 CFR 108.137 - Bulkhead and deck separations of accommodation spaces.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Bulkhead and deck separations of accommodation spaces. 108.137 Section 108.137 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Structural Fire Protection § 108.137 Bulkhead and deck separations...

  5. 上承式悬索桥结构介绍及内力分析%On the Introduction and Analysis of Internal Force of Suspension Bridge Structure

    Institute of Scientific and Technical Information of China (English)

    何钰龙; 申杨凡; 李兴正

    2013-01-01

      本文对一种新式公路桥,人行桥即上承式悬带桥进行了结构介绍。同时,通过桥梁计算软件“桥梁博士”对所拟定的桥梁进行了内力分析,得到了上承式悬带桥的内力特性。%In this paper, a new type of highway bridge, the pedestrian bridge on the bearing type of suspension bridge str-ucture is introduced. Dr. At the same time, through bridge calc-ulation software “bridge doctor”on the bridge's internal force analysis, obtained the deck type hanging bridge's internal force characteristics.

  6. Hygrothermal Performance of West Coast Wood Deck Roofing System

    Energy Technology Data Exchange (ETDEWEB)

    Pallin, Simon B [ORNL; Kehrer, Manfred [ORNL; Desjarlais, Andre Omer [ORNL

    2014-02-01

    Simulations of roofing assemblies are necessary in order to understand and adequately predict actual the hygrothermal performance. At the request of GAF, simulations have been setup to verify the difference in performance between white and black roofing membrane colors in relation to critical moisture accumulation for traditional low slope wood deck roofing systems typically deployed in various western U.S. Climate Zones. The performance of these roof assemblies has been simulated in the hygrothermal calculation tool of WUFI, from which the result was evaluated based on a defined criterion for moisture safety. The criterion was defined as the maximum accepted water content for wood materials and the highest acceptable moisture accumulation rate in relation to the risk of rot. Based on the criterion, the roof assemblies were certified as being either safe, risky or assumed to fail. The roof assemblies were simulated in different western climates, with varying insulation thicknesses, two different types of wooden decking, applied with varying interior moisture load and with either a high or low solar absorptivity at the roof surface (black or white surface color). The results show that the performance of the studied roof assemblies differs with regard to all of the varying parameters, especially the climate and the indoor moisture load.

  7. Community-based benchmarking of the CMIP DECK experiments

    Science.gov (United States)

    Gleckler, P. J.

    2015-12-01

    A diversity of community-based efforts are independently developing "diagnostic packages" with little or no coordination between them. A short list of examples include NCAR's Climate Variability Diagnostics Package (CVDP), ORNL's International Land Model Benchmarking (ILAMB), LBNL's Toolkit for Extreme Climate Analysis (TECA), PCMDI's Metrics Package (PMP), the EU EMBRACE ESMValTool, the WGNE MJO diagnostics package, and CFMIP diagnostics. The full value of these efforts cannot be realized without some coordination. As a first step, a WCRP effort has initiated a catalog to document candidate packages that could potentially be applied in a "repeat-use" fashion to all simulations contributed to the CMIP DECK (Diagnostic, Evaluation and Characterization of Klima) experiments. Some coordination of community-based diagnostics has the additional potential to improve how CMIP modeling groups analyze their simulations during model-development. The fact that most modeling groups now maintain a "CMIP compliant" data stream means that in principal without much effort they could readily adopt a set of well organized diagnostic capabilities specifically designed to operate on CMIP DECK experiments. Ultimately, a detailed listing of and access to analysis codes that are demonstrated to work "out of the box" with CMIP data could enable model developers (and others) to select those codes they wish to implement in-house, potentially enabling more systematic evaluation during the model development process.

  8. Seismic Retrofitting of an Existing Steel Railway Bridge by Fluid Viscous Dampers

    Science.gov (United States)

    Gangopadhyay, Avijit; Ghosh, Aparna Dey

    2016-06-01

    There are over a lakh of bridges in the Indian Railways, many of which have become seismically deficient, either through aging or due to inadequate seismic design considerations. The extensive damage of bridges all over the world in recent earthquakes has propelled significant advancement in earthquake protection and retrofitting of bridges. Amongst various passive control systems that are reliable as well as cost-effective, Fluid Viscous Dampers (FVDs) are proving to be successful in bridge vibration control. Orificed FVDs, commercially available as Taylor Devices, have already been successfully installed in several bridges worldwide. However, there has been no such application or study related to Indian railway bridges. In this paper, an existing thirty years' old railway bridge in Jharkhand, India, has been analyzed in SAP2000v14 considering reduced stiffness and found deficient when subjected to spectrum-compatible accelerograms. Subsequent retrofitting of the bridge superstructure with FVDs has been carried out and the results indicate substantial reductions in the responses of the bridge deck.

  9. Real-time seismic monitoring of the integrated cape girardeau bridge array and recorded earthquake response

    Science.gov (United States)

    Celebi, M.

    2006-01-01

    This paper introduces the state of the art, real-time and broad-band seismic monitoring network implemented for the 1206 m [3956 ft] long, cable-stayed Bill Emerson Memorial Bridge in Cape Girardeau (MO), a new Mississippi River crossing, approximately 80 km from the epicentral region of the 1811-1812 New Madrid earthquakes. The bridge was designed for a strong earthquake (magnitude 7.5 or greater) during the design life of the bridge. The monitoring network comprises a total of 84 channels of accelerometers deployed on the superstructure, pier foundations and at surface and downhole free-field arrays of the bridge. The paper also presents the high quality response data obtained from the network. Such data is aimed to be used by the owner, researchers and engineers to assess the performance of the bridge, to check design parameters, including the comparison of dynamic characteristics with actual response, and to better design future similar bridges. Preliminary analyses of ambient and low amplitude small earthquake data reveal specific response characteristics of the bridge and the free-field. There is evidence of coherent tower, cable, deck interaction that sometimes results in amplified ambient motions. Motions at the lowest tri-axial downhole accelerometers on both MO and IL sides are practically free from any feedback from the bridge. Motions at the mid-level and surface downhole accelerometers are influenced significantly by feedback due to amplified ambient motions of the bridge. Copyright ASCE 2006.

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

    Directory of Open Access Journals (Sweden)

    Kittisak Kuntiyawichai

    2014-01-01

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

  11. Fatigue in Steel Highway Bridges under Random Loading

    DEFF Research Database (Denmark)

    Agerskov, Henning; Nielsen, J.A.; Vejrum, Tina

    1997-01-01

    welded plate test specimens have been carried through. The materials that have been used are either conventional structural steel with a yield stress of ~ 400-410 MPa or high-strength steel with a yield stress of ~ 810-840 MPa.The fatigue tests have been carried out using load histories, which correspond......In the present investigation, fatigue damage accumulation in steel highway bridges under random loading is studied. The fatigue life of welded joints has been determined both experimentally and from a fracture mechanics analysis.In the experimental part of the investigation, fatigue test series on...... to one week's traffic loading, determined by means of strain gage measurements on the orthotropic steel deck structure of the Farø Bridges in Denmark.The test series which have been carried through show a significant difference between constant amplitude and variable amplitude fatigue test results...

  12. Fatigue in Steel Highway Bridges under Random Loading

    DEFF Research Database (Denmark)

    Agerskov, Henning; Nielsen, Jette Andkjær

    1999-01-01

    have been carried through. The materials that have been used are either conventional structural steel with a yield stress of f(y) similar to 400-410 MPa or high-strength steel with a yield stress of f(y) similar to 810-840 MPa. The fatigue tests have been carried out using load histories, which......Fatigue damage accumulation in steel highway bridges under random loading is studied. The fatigue life of welded joints has been determined both experimentally and from a fracture mechanics analysis. In the experimental part of the investigation, fatigue test series on welded plate test specimens...... correspond to one week's traffic loading, determined by means of strain gauge measurements on the orthotropic steel deck structure of the Faro Bridges in Denmark. The test series carried through show a significant difference between constant amplitude and variable amplitude fatigue test results. Both the...

  13. Aspects regarding analysis of the work deck from a support vessel

    Science.gov (United States)

    Axinte, T.; Nutu, C.; Stanca, C.; Cupsa, O.; Carp, A.

    2016-08-01

    The authors are presenting an analysis of the work deck only for the support vessel, a ship having in its structure among others: deck cranes and helicopter deck. The work deck is one of the most important parts of the support vessel's hull. We are starting the paper by presenting the role and the importance of the support vessel's type, by using an original execution drawing carried out using the Unigraphics NX 8.0 Software from Siemens.. Further on we can determine the shear, normal and the von Mises stresses pertaining to the work deck by using the finite element method. After determination of these stresses we can assess fatigue life, strength safety factor and fatigue safety factor. In order to determine the fatigue, the loading pattern only with the full unit cycle will be used. As for determining the safety factor only the ultimate strength stress criterion with the stress type von Mises from failure theories, will be used.

  14. Investigation of Flow Behavior around Corotating Blades in a Double-Spindle Lawn Mower Deck

    Directory of Open Access Journals (Sweden)

    Chon W.

    2005-01-01

    Full Text Available When the airflow patterns inside a lawn mower deck are understood, the deck can be redesigned to be efficient and have an increased cutting ability. To learn more, a combination of computational and experimental studies was performed to investigate the effects of blade and housing designs on a flow pattern inside a 1.1m wide corotating double-spindle lawn mower deck with side discharge. For the experimental portion of the study, air velocities inside the deck were measured using a laser Doppler velocimetry (LDV system. A high-speed video camera was used to observe the flow pattern. Furthermore, noise levels were measured using a sound level meter. For the computational fluid dynamics (CFD work, several arbitrary radial sections of a two-dimensional blade were selected to study flow computations. A three-dimensional, full deck model was also developed for realistic flow analysis. The computational results were then compared with the experimental results.

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

    Directory of Open Access Journals (Sweden)

    Ladislaus Lwambuka

    2014-01-01

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

  16. Hydroelastic responses of cross deck panel to slamming; Slamming ni taisuru cross deck panel no dansei oto ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Toyama, Y. [Mitsui Engineering and Shipbuilding Co. Ltd., Tokyo (Japan)

    1998-06-01

    An analysis and a study were performed on deformation and stress response occurring in a structure when a high-speed catamaran ship is subjected to wave slamming on the lower face of the cross deck. The study proposed a method to analyze response to water slamming, which can consider elastic effects by utilizing solution of potential flow around a flat plate having perpendicular speed distribution of a triangle form. A dynamic response simulation was performed by using this method on a problem that a flat cross deck slams wave crests of parabolic shape. As a result, the following points were made clear: the maximum bending and bending moment at the center of a span of the panel show a trend of becoming proportional to the drop speed as the curvature radius on the water surface increases, where the proportion constant shows a trend of not depending on the curvature radius of the water surface; the peak value of impact pressure is thought not to give large effect directly to the dynamic response; and the reason for the maximum bending at the span center becoming proportional to the drop speed can be explained by reduction in magnification of the dynamic response. 10 refs., 14 figs., 1 tab.

  17. 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....

  18. Eye Tracking Metrics for Workload Estimation in Flight Deck Operation

    Science.gov (United States)

    Ellis, Kyle; Schnell, Thomas

    2010-01-01

    Flight decks of the future are being enhanced through improved avionics that adapt to both aircraft and operator state. Eye tracking allows for non-invasive analysis of pilot eye movements, from which a set of metrics can be derived to effectively and reliably characterize workload. This research identifies eye tracking metrics that correlate to aircraft automation conditions, and identifies the correlation of pilot workload to the same automation conditions. Saccade length was used as an indirect index of pilot workload: Pilots in the fully automated condition were observed to have on average, larger saccadic movements in contrast to the guidance and manual flight conditions. The data set itself also provides a general model of human eye movement behavior and so ostensibly visual attention distribution in the cockpit for approach to land tasks with various levels of automation, by means of the same metrics used for workload algorithm development.

  19. Heat Storage Performance of the Prefabricated Hollow Core Concrete Deck Element with Integrated Microencapsulated Phase Change Material

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2012-01-01

    many emerging buildings. The new concrete deck with microencapsulated PCM is the standard deck on which one more layer with PCM concrete was added and at the same time the latent heat storage was introduced to the construction. The challenge to simulate the performance of the new deck with PCM concrete......The paper presents the numerically calculated dynamic heat storage capacity of the prefabricated hollow core concrete deck element with and without microencapsulated phase change material (PCM). The reference deck is the ordinary deck made of standard concrete material and that is broadly used in...... or the building with such a deck is that the thermal properties of such a new material are not yet well defined. The results presented in the paper include models in which PCM concrete material properties such as thermal conductivity and specific heat capacity were theoretically calculated using...

  20. Taizhou Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

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

  1. Fluid-structure interaction analysis of a deck structure during a HCDA. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Kulak, R.F.

    1979-01-01

    Presented is an assessment of the structural integrity of the deck structure of a pool-type LMFBR during a Hypothetical Core Disruptive Accident (HCDA). During this accident the sodium above the core is propelled upward until it impacts against the deck structure. This hydrodynamic loading could produce (1) significant structural damage and (2) sodium leak paths. A finite-element model is used to study the deck dynamics during slug impact. By using the symmetry of the system, a sector model which accounts for the salient features of the system is developed. The main radial I-beam, component support I-beam and bottom annular plate are modeled using triangular plate elements. The concrete fill is modeled using hexahedral continuum elements. Using the above finite-element model the dynamics of the deck during a HCDA are investigated.

  2. ASSESSING CHILDREN'S EXPOSURES TO THE WOOD PRESERVATIVE CCA (CHROMATED COPPER ARSENATE) ON TREATED PLAYSETS AND DECKS

    Science.gov (United States)

    Concerns have been raised regarding the safety of young children contacting arsenic and chromium residues while playing on and around Chromated Copper Arsenate (CCA) treated wood playground structures and decks. Although CCA registrants voluntarily canceled treated wood for re...

  3. Flight Deck of the Future: Virtual Windows and e-textile iGear Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Flight Deck of the Future (F.F) will integrate interdisciplinary talent to design innovative, integrated human interfaces for the next generation of human...

  4. Numerical Analysis of Heat Storage and Heat Conductivity in the Concrete Hollow Core Deck Element

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund;

    2011-01-01

    In order to minimize energy used for cooling and heating, one of the passive solutions is to efficiently utilize heat storage of a building construction. Presently, heat storage calculations in whole building simulation programs are based on 1D heat transfer models. This paper investigates to what...... the overall heat transfer and heat storage in the hollow-core decks. The presented results allow comparison between detailed results from 2D-COMSOL simulations and simple 1D calculations from the whole building simulation tool such as BSim program and moreover, it is possible to validate the calculation...... method in BSim for the concrete deck element with air voids. Finally, this paper presents a comparison of the calculated heat conductivity of the hollow-core concrete deck and the measured heat conductivity for the same deck by using hot box apparatus....

  5. STS-33 MS Carter operates translation hand control (THC) on aft flight deck

    Science.gov (United States)

    1989-01-01

    STS-33 Mission Specialist (MS) Manley L. Carter, Jr operates translation hand control (THC) at the aft flight deck onorbit station while peering out overhead window W7. Carter's communications kit assembly headset microphone extends across his face.

  6. Application of Close Range Photogrammetry to Deck Measurement in Recreational Ships

    OpenAIRE

    Celestino Ordóñez; Belén Riveiro; Pedro Arias; Julia Armesto

    2009-01-01

    In this article, we present results that demonstrate the utility of close range photogrammetry in the measurement of decks in recreational craft as an alternate measurement system to the one based on direct acquisition of coordinates. The areas of deck covered with teakwood for aesthetic or security reasons were measured. Both methods were compared in terms of precision of measurements, time consumption, equipment cost, and ease of manipulation and equipment transportation. Based on the resul...

  7. Concrete bridge prioritization system

    OpenAIRE

    Kesselring, Debbie Anne

    1995-01-01

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

  8. Influence of central buckle on suspension bridge dynamic characteristics and driving comfort

    Institute of Scientific and Technical Information of China (English)

    王达; 邓扬; 刘扬

    2015-01-01

    The central buckle, which is often used in a suspension bridge, can improve bridges’ performance in the actual operation condition. The influence of the central buckle on natural vibration characteristics and bridge-deck driving comfort of a long-span suspension bridge is studied by using a case study of Siduhe Suspension Bridge in China. Based on the finite element software ANSYS and independently complied program, the influence of the central buckle on the structure force-applied characteristics of a long-span suspension bridge has been explored. The results show that the huge increases of natural frequencies can result in the presence of central buckles because of the increases of bending and torsional rigidities. The central buckle basically makes the stiffening girders and cables within the triangular area covered as a relatively approximate rigid area. Hence, the central buckle can reduce the torsional displacement of the main girder. However, the increases of bending and torsional rigidities have little influence on the impact factor, which is obtained by using vehicle-bridge coupled vibration analysis. This means that the central buckle has little effect on the comfort indices. In addition, it is found that the central buckle can enhance the bridge deck’s driving stability due to the decrease of the torsional displacements of the main girder.

  9. Aerodynamic problems of cable-stayed bridges spanning over one thousand meters

    Institute of Scientific and Technical Information of China (English)

    Chen Airong; Ma Rujin; Wang Dalei

    2009-01-01

    Tbe elongating of cable-stayed bridge brings a series of aerodynamic problems. First of all, geometric nonlin-ear effect of extreme long cable is much more significant for cable-stayed bridge spanning over one thousand meters. Lat-eral static wind load will generate additional displacement of long cables, which causes the decrease of supporting rigidi-ty of the whole bridge and the change of dynamic properties. Wind load, being the controlling load in the design of ca-hie-stayed bridge, is a critical problem and needs to be solved. Meanwhile, research on suitable system between pylon and deck indicates fixed-fixed connection system is an effective way for improvement performance of cable-stayed bridges under longitudinal wind load. In order to obtain aerodynamic parameters of cable-stayed bridge spanning over one thou-sand meters, identification method for flutter derivatives of full bridge aero-elastic model is developed in this paper. Furthermore, vortex induced vibration and Reynolds number effect are detailed discussed.

  10. 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....

  11. Bridging the Gap

    OpenAIRE

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

    2015-01-01

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

  12. Semiconductor bridge (SCB) detonator

    Science.gov (United States)

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

    1999-01-01

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

  13. Theoretical and Experimental Studies of Wave Impact underneath Decks of Offshore Platforms

    Energy Technology Data Exchange (ETDEWEB)

    Baarholm, Rolf Jarle

    2001-07-01

    The main objective of this thesis has been to study the phenomenon of water impact underneath the decks of offshore platforms due to propagating waves. The emphasis has been on the impact loads. Two theoretical methods based on two-dimensional potential theory have been developed, a Wagner based method (WBM) and a nonlinear boundary element method (BEM). A procedure to account for three-dimensional effects is suggested. The deck is assumed to be rigid. Initial studies of the importance of hydroelasticity for wave loads on an existing deck structure have been performed. For a given design wave, the local structural responses were found to behave quasi-static. Global structural response has not been studied. In the Wagner based method gravity is neglected and a linear spatial distribution of the relative impact velocity along the deck is assumed. The resulting boundary value problem is solved analytically for each time step. A numerical scheme for stepping the wetted deck area in time is presented. The nonlinear boundary element method includes gravity, and the exact impact velocity is considered. The incident wave velocity potential is given a priori, and a boundary value problem for the perturbation velocity potential associated with the impact is defined. The boundary value problem is solved for each time step by applying Green's second identity. The exact boundary conditions are imposed on the exact boundaries. A Kutta condition is introduced as the fluid flow reaches the downstream end of the deck. At present, the BEM is only applicable for fixed platform decks. To validate the theories, experiments have been carried out in a wave flume. The experiments were performed in two-dimensional flow condition with a fixed horizontal deck at different vertical levels above the mean free surface. The vertical force on the deck and the wetting of the deck were the primary parameters measured. Only regular propagating waves were applied. When a wave hits the deck, the

  14. Damage analysis and seismic retrofitting of a continuous prestressed reinforced concrete bridge

    Directory of Open Access Journals (Sweden)

    Nicola Caterino

    2014-12-01

    Full Text Available The seismic analysis and retrofit of prestressed reinforced concrete bridge is discussed by considering a real case of a viaduct still in use. The unique features of this bridge make this type of bridge particularly interesting, either structurally or architecturally. The paper begins with the analysis of certain particular structural deficiencies that emerged during the viaduct operation. The results of the analysis indicate that the structural performance can be enhanced by only modifying the support devices. The primary structural components are not required to be involved in the retrofitting process. Using the modern seismic code, the upgrading of the viaduct performance is obtained by replacing the old bearing devices on the piers and existing viscous dampers connected abutments to the deck with new modernised ones.

  15. Identification of aeroelastic forces on twin bridge cables from full-scale measurements in skew winds

    DEFF Research Database (Denmark)

    Acampora, Antonio; Macdonald, J.H.G.; Georgakis, Christos T.;

    2012-01-01

    Despite much research in recent years, large amplitude vibrations of inclined bridge cables continue to be of concern. Various mechanisms for the excitation have been suggested, including rain-wind excitation, dry inclined cable galloping, high reduced-velocity vortex shedding and excitation from...... the deck and/or towers. Since 2010, the Technical University of Denmark has been monitoring the vibrations of the twin inclined cables of the Øresund Bridge. From the acquired data, Georgakis and Acampora [1] showed that the cable aerodynamic damping can be determined for wind orthogonal to the twin cables...... of this paper is to identify the aeroelastic forces for in-plane and out-of-plane vibrations of bridge cables in dry conditions as in [2], but now for skewed winds. To achieve this, an output-only system identification employing the Eigenvalue Realisation Algorithm (ERA) [3] has been applied to selected...

  16. Structural assessment of roof decking using visual inspection methods

    International Nuclear Information System (INIS)

    The Hanford Site has approximately 1,100 buildings, some of which date back to the early 1940s. The roof on these buildings provides a weather resisting cover as well as the load resisting structure. Past experience has been that these roof structures may have structural modifications, the weather resisting membrane may have been replaced several times, and the members may experience some type of material degradation. This material degradation has progressed to cause the collapse of some roof deck members. The intent of the Hanford Site Central Engineering roof assessment effort is to provide an expedient structural assessment of the large number of buildings at the Hanford Site. This assessment is made by qualified structural inspectors following the open-quotes Preliminary Assessment close-quote procedures given in the American Society of Civil Engineers (ASCE) Standard ASCE 11-90. This roof assessment effort does not provide a total qualification of the roof for the design or in-place loads. This inspection does provide a reasonable estimate of the roof loading capacity to determine if personnel access restrictions are needed. A document search and a visual walkdown inspection provide the initial screening to identify modifications and components having questionable structural integrity. The structural assessment consists of baseline dead and live load stress calculations of all roofing components based on original design material strengths. The results of these assessments are documented in a final report which is retrievable form that future inspections will have comparative information

  17. Principles of Bridge Reliability

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Nowak, Andrzej S.

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

  18. The floating water bridge

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Ali Fadhil Naser

    2013-10-01

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

  20. Performance-based seismic assessment of skewed bridges with and without considering soil-structure interaction effects for various site classes

    Science.gov (United States)

    Ghotbi, Abdoulreza

    This study aims to investigate the behavior of skewed and straight highway overpass bridges both with and without taking into account the effects of Soil-Structure Interaction (SSI) due to near-fault ground motions. Both deterministic (i.e., pushover and nonlinear dynamic analyses) and probabilistic approaches were utilized. A set of response sensitivity analyses was performed considering various skew angles, column elements, and soil properties for bridge considered both as fixed-base and SSI models. It has been observed that as the skew angle increased, the bridge responded more severely to the ground motion. For instance, the deck rotation and shear-keys displacement increased with an increase in the skew angle. A modal pushover analysis was also performed in conjunction with the nonlinear dynamic analysis. It has been found that combining the bridge responses for various modes of vibration resulted in a relatively accurate seismic response compared to the nonlinear dynamic analysis while saving time and analysis cost, to a great extent. A probabilistic analysis was also performed considering record-to-record variability in ground motion, and a set of probabilistic seismic demand and fragility plots was generated. The effects of change in the skew angle and also SSI were studied to see various bridge responses. The damage probability increased especially with respect to deck rotation as the skew angle increased. The SSI had a decreasing effect on the overall response of the bridge with pile foundation.

  1. Cognitive models of pilot categorization and prioritization of flight-deck information

    Science.gov (United States)

    Jonsson, Jon E.; Ricks, Wendell R.

    1995-01-01

    In the past decade, automated systems on modern commercial flight decks have increased dramatically. Pilots now regularly interact and share tasks with these systems. This interaction has led human factors research to direct more attention to the pilot's cognitive processing and mental model of the information flow occurring on the flight deck. The experiment reported herein investigated how pilots mentally represent and process information typically available during flight. Fifty-two commercial pilots participated in tasks that required them to provide similarity ratings for pairs of flight-deck information and to prioritize this information under two contextual conditions. Pilots processed the information along three cognitive dimensions. These dimensions included the flight function and the flight action that the information supported and how frequently pilots refer to the information. Pilots classified the information as aviation, navigation, communications, or systems administration information. Prioritization results indicated a high degree of consensus among pilots, while scaling results revealed two dimensions along which information is prioritized. Pilot cognitive workload for flight-deck tasks and the potential for using these findings to operationalize cognitive metrics are evaluated. Such measures may be useful additions for flight-deck human performance evaluation.

  2. Formulation of Equations of Motion for a Simply Supported Bridge under a Moving Railway Freight Vehicle

    Directory of Open Access Journals (Sweden)

    Ping Lou

    2007-01-01

    Full Text Available Based on energy approach, the equations of motion in matrix form for the railway freight vehicle-bridge interaction system are derived, in which the dynamic contact forces between vehicle and bridge are considered as internal forces. The freight vehicle is modelled as a multi-rigid-body system, which comprises one car body, two bogie frames and four wheelsets. The bogie frame is linked with the car body through spring-dashpot suspension systems, and the bogie frame is rigidly linked with wheelsets. The bridge deck, together with railway track resting on bridge, is modelled as a simply supported Bernoulli-Euler beam and its deflection is described by superimposing modes. The direct time integration method is applied to obtain the dynamic response of the vehicle-bridge interaction system at each time step. A computer program has been developed for analyzing this system. The correctness of the proposed procedure is confirmed by one numerical example. The effect of different beam mode numbers and various surface irregularities of beam on the dynamic responses of the vehicle-bridge interaction system are investigated.

  3. Intelligent control for braking-induced longitudinal vibration responses of floating-type railway bridges

    International Nuclear Information System (INIS)

    This paper presents an intelligent control method and its engineering application in the control of braking-induced longitudinal vibration of floating-type railway bridges. Equations of motion for the controlled floating-type railway bridges have been established based on the analysis of the longitudinal vibration responses of floating-type railway bridges to train braking and axle-loads of moving trains. For engineering applications of the developed theory, a full-scale 500 kN smart magnetorheologic (MR) damper has been designed, fabricated and used to carry out experiments on the intelligent control of braking-induced longitudinal vibration. The procedure for using the developed intelligent method in conjunction with the full-scale 500 kN MR dampers has been proposed and used to control the longitudinal vibration responses of the deck of floating-type railway bridges induced by train braking and axle-loads of moving trains. This procedure has been applied to the longitudinal vibration control of the Tian Xingzhou highway and railway cable-stayed bridge over the Yangtze River in China. The simulated results have shown that the intelligent control system using the smart MR dampers can effectively control the longitudinal response of the floating-type railway bridge under excitations of braking and axle-loads of moving trains

  4. Research on the special lifting devices for steel box girders of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Chen Ming; Wu Qihe; Luo Chengbin; Zhou Hanfa

    2009-01-01

    Sutong Bridge is a cable-stayed bridge with a steel box girder and a main span of 1 088 m. The steel box girder of main span includes five portions: back span large unit, large block of pylon, standard girder, back span closure girder and middle span closure girder. Each back span large unit is fabricated by welding several deck segments together in factory, and is erected by floating crane. As navigational clearance of the main bridge is high, the traditional truss lifting device can' t satisfy the requirement of domestic lifting cranes for this kind of lifting height and weight. Hence, a kind of lighter lifting device for the erection of back span large units was accepted for this bridge. In this paper, the design and use of this lifting device is introduced.The upper structure used lifting gantry to install the standard girder segment by cantilever method. Because the bridge's navigation clearance is high, and the girder segment is wide and heavy, the meteorology and hydrology condition of the bridge district is abominable, and the requirements of long cable girder side pull-in, structure and performance propose high request to the lifting gantry. In this paper, the design and use key point of long cable pull-in angle adjustment device integrate into lifting gantry is introduced.

  5. Torsional and longitudinal vibration of suspension bridge subject to aerodynamic forces

    Directory of Open Access Journals (Sweden)

    Ahmed N. U.

    1998-01-01

    Full Text Available In this paper we consider a dynamic model of suspension bridge governed by a pair of coupled partial differential equations which describe both torsional and longitudinal vibration of the road bed. The vertical and torsional motions are coupled through a nonlinear operation with the nonlinearity arising from loss of tension in the vertical cables supporting the decks. We study the impact of wind forces on the stability of motion of this system both in the absence and presence of viscous and structural damping. The results are illustrated by numerical simulation.

  6. Bridge technology report

    CERN Document Server

    2013-01-01

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

  7. Analysis on Adhesively-Bonded Joints of FRP-steel Composite Bridge under Combined Loading: Arcan Test Study and Numerical Modeling

    OpenAIRE

    Xu Jiang; Xuhong Qiang; Henk Kolstein; Frans Bijlaard

    2016-01-01

    The research presented in this paper is an experimental study and numerical analysis on mechanical behavior of the adhesively-bonded joint between FRP sandwich bridge deck and steel girder. Generally, there are three typical stress states in the adhesively-bonded joint: shear stress, tensile stress, and combination of both. To realize these stress states in the adhesively-bonded joint during tests, a specific loading device is developed with the capacity of providing six different loading ang...

  8. 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.

  9. Thermal and thermal stress analysis of a pool type LMFBR deck structure

    International Nuclear Information System (INIS)

    The thermal capabilities of the ANSYS code were used to construct a thermal model of a pool type LMFBR system. This model included the primary tank of hot sodium covered by the concrete deck. Included in the geometry were the pump, heat exchanger, and control rod penetrations, and the metallic insulation underneath the concrete. The model included radiation and conduction of heat from the hot sodium to the concrete deck, and the cooling of the concrete via water pipes embedded in it. Thermal stresses are calculated within the code for the various plate and shell steel elements used in the code to represent different parts of the structure. This study provides a basis for studying the effect of insulation and coolant in the design of the deck structure

  10. Bridged Race Population Estimates

    Data.gov (United States)

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

  11. Long Span Bridges in Scandinavia

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1998-01-01

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

  12. Performance-based seismic assessment of skewed bridges with and without considering soil-foundation interaction effects for various site classes

    Science.gov (United States)

    Ghotbi, Abdoul R.

    2014-09-01

    The seismic behavior of skewed bridges has not been well studied compared to straight bridges. Skewed bridges have shown extensive damage, especially due to deck rotation, shear keys failure, abutment unseating and column-bent drift. This research, therefore, aims to study the behavior of skewed and straight highway overpass bridges both with and without taking into account the effects of Soil-Structure Interaction (SSI) due to near-fault ground motions. Due to several sources of uncertainty associated with the ground motions, soil and structure, a probabilistic approach is needed. Thus, a probabilistic methodology similar to the one developed by the Pacific Earthquake Engineering Research Center (PEER) has been utilized to assess the probability of damage due to various levels of shaking using appropriate intensity measures with minimum dispersions. The probabilistic analyses were performed for various bridge configurations and site conditions, including sand ranging from loose to dense and clay ranging from soft to stiff, in order to evaluate the effects. The results proved a considerable susceptibility of skewed bridges to deck rotation and shear keys displacement. It was also found that SSI had a decreasing effect on the damage probability for various demands compared to the fixed-base model without including SSI. However, deck rotation for all types of the soil and also abutment unseating for very loose sand and soft clay showed an increase in damage probability compared to the fixed-base model. The damage probability for various demands has also been found to decrease with an increase of soil strength for both sandy and clayey sites. With respect to the variations in the skew angle, an increase in skew angle has had an increasing effect on the amplitude of the seismic response for various demands. Deck rotation has been very sensitive to the increase in the skew angle; therefore, as the skew angle increased, the deck rotation responded accordingly

  13. Structural evaluation of a prestressed concrete bridge under an alkali-silica reaction; Evaluacion estructural de un puente de hormigon pretensado afectado por una reaccion alcali-silice

    Energy Technology Data Exchange (ETDEWEB)

    Carpintero Garcia, I.; Bermudez Adriozola, B.

    2010-07-01

    The Central Laboratory of Structures and Materials (CEDEX) was commissioned by the National Department of Highways to evaluate the safety conditions of one bridge built on 1997, which is part of the net of the Spanish National Highways. Even at the first inspection many cracks were detected in the concrete deck, associated with expansion concrete processes. This examination revealed that concrete deterioration was not associated with any reinforcement corrosion process; in fact, there were no symptoms of this pathology all along the bridge. for that reason the internal chemical reactions were considered as the most probable cause for the expansion of concrete, as no symptoms of deterioration due to external attack were found. In order to check the origin of concrete expansion, some tests were carried out on concrete samples drilled on the decks. Results of these tests show that there had been internal reactions in concrete mass which explains its expansion and the appearance of those cracks observed. Further more, some other activities were also carried out on site to estimate the importance of the structural damages, as topographic levelling and dynamic testing of the decks. Also the mechanical properties of concrete probes were tested at laboratory. This article shows the main results obtained on the study carried on to determine the cause and significance of the structural damages of the bridge. (Author) 3 refs.

  14. 三塔悬索桥施工过程静风稳定性分析%Aerostatic Stability Analysis of Three-tower Suspension Bridge During Construction

    Institute of Scientific and Technical Information of China (English)

    郭辉; 孙华卿

    2011-01-01

    By taking a three-tower suspension bridge--Taizhou Highway Bridge over Yangtze River with main span of 1 080 m as example, by using 3D structural nonlinear aerostatic analysis, the influence of deck erection sequence on the aerostatic stability during the whole construction process is revealed, and the favorable deck erection sequence is also proposed with respect to the aerostatic stability.The resuhs show that good aerostatic stability can be obtained for threetower suspension bridges as the deck erection starts simultaneously from the pylons to the midpoints of main spans.%以在建主跨为1080m的三塔双跨悬索桥——泰州长江公路大桥为工程背景,采用三维非线性空气静力稳定性分析方法,分析不同的主梁架设顺序对三塔悬索桥施工阶段空气静力稳定性的影响,确定具有良好抗风稳定件的施工方案。结果表明:三塔悬索桥主梁拼装采用从桥塔处至跨中施工时,可以获得较好的空气静力稳定性。

  15. STS-31 crewmembers during simulation on the flight deck of JSC's FB-SMS

    Science.gov (United States)

    1988-01-01

    On the flight deck of JSC's fixed based (FB) shuttle mission simulator (SMS), Mission Specialist (MS) Steven A. Hawley (left), on aft flight deck, looks over the shoulders of Commander Loren J. Shriver, seated at the commanders station (left) and Pilot Charles F. Bolden, seated at the pilots station and partially blocked by the seat's headrest (right). The three astronauts recently named to the STS-31 mission aboard Discovery, Orbiter Vehicle (OV) 103, go through a procedures checkout in the FB-SMS. The training simulation took place in JSC's Mission Simulation and Training Facility Bldg 5.

  16. SIMPLIFIED CFD MODAL AND AERODYNAMIC CHARACTERISTICS OF INVERTED TRAPEZOIDAL PLATE-TRUSS DECK%倒梯形板桁主梁CFD简化模型及气动特性研究

    Institute of Scientific and Technical Information of China (English)

    李永乐; 安伟胜; 蔡宪棠; 何庭国

    2011-01-01

    板桁主梁以其良好的整体性和合理的受力性能广泛应用于铁路桥梁建设中,随着桥梁跨径的增大,其抗风性能已逐渐成为控制桥梁设计的关键因素之一.基于桁架受风面积等效,并考虑上流、下流构件间相互的气动干扰,提出了一种简化的CFD分析模型,该模型偏安全地忽略了腹杆和上弦杆、下弦杆连接处相互的气动作用,将三维板桁主梁等效为二维平面结构,从而降低建模难度和减小计算工作量.基于该简化CFD分析模型,对倒梯形板桁主梁的静力气动力系数、涡振性能、颤振导数进行了计算分析,并对比了桥上车辆存在对板桁主梁的气动特性的影响.研究结果表明,倒梯形板桁主梁的涡振性能对雷诺数较为敏感,桥上车辆的存在显著改变了板桁主梁的气动特性.%With its good properties of integrity and reasonable mechanics, the plate-truss deck is gradually widely used in the construction of railway bridges. But its wind-resistant capability becomes one of the important factors controlling the bridge design with the increasing of a bridge span. A simplified CFD modal was presented by the basis of the equivalent trusses area acted by wind. The modal fully consider the aerodynamic interference between the structural members at windward and leeward sides. The modal neglects the aerodynamic interference at the junction of top chords, bottom chords and web members. The three-dimensional plate-truss deck is simplified into a two-dimensional cross section, which can reduce the modeling difficulty and calculation work. The static aerodynamic coefficients, vortex-vibration performance and flutter derivatives of the inverted trapezoidal plate-truss deck are simulated. The influence of train existing on the deck is investigated. The research results show that vortex vibration performance of the inverted trapezoidal plate-truss deck is more sensitive to the Reynolds number, and the existence of

  17. 钢桥面铺装的拉应力分析%Tensile Stress Analysis of Steel Bridge Deck Surface

    Institute of Scientific and Technical Information of China (English)

    王辉; 刘涌

    2002-01-01

    针对典型的钢桥桥面铺装体系,采用SAP有限元软件,分析了铺装层内的拉应力的变化规律.分析表明,铺装层内的最大横向拉应力远远大于最大纵向拉应力,最大横向拉应力通常出现在梯形加劲肋肋顶的铺装层表面;铺装层的模量也对拉应力影响很大.

  18. Dynamic Heat Storage and Cooling Capacity of a Concrete Deck with PCM and Thermally Activated Building System

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2012-01-01

    the performance of the new deck with PCM concrete is the thermal properties of such a new material, as the PCM concrete is yet to be well defined. The results presented in the paper include models in which the PCM concrete material properties, such as thermal conductivity, and specific heat capacity were first......This paper presents a heat storage and cooling concept that utilizes a phase change material (PCM) and a thermally activated building system (TABS) implemented in a hollow core concrete deck. Numerical calculations of the dynamic heat storage capacity of the hollow core concrete deck element...... with and without microencapsulated PCM are presented. The new concrete deck with microencapsulated PCM is the standard deck on which an additional layer of the PCM concrete was added and, at the same time, the latent heat storage was introduced to the construction. The challenge of numerically simulating...

  19. STS-38 MS Springer on OV-104's flight deck with Navy banner and Marine decal

    Science.gov (United States)

    1990-01-01

    STS-38 Mission Specialist (MS) Robert C. Springer stretches out in front of the forward flight deck control panels onboard Atlantis, Orbiter Vehicle (OV) 104. Springer poses with a 'Semper Fi United States Marines' decal and a U.S. Naval Academy banner. A HASSELBLAD camera freefloats in front of his chest.

  20. STS-26 crew on fixed based (FB) shuttle mission simulator (SMS) flight deck

    Science.gov (United States)

    1988-01-01

    STS-26 Discovery, Orbiter Vehicle (OV) 103, Commander Frederick H. Hauck (left) and Pilot Richard O. Covey review checklists in their respective stations on the foward flight deck. The STS-26 crew is training in the fixed base (FB) shuttle mission simulator (SMS) located in JSC Mission Simulation and Training Facility Bldg 5.

  1. STS-39 MS Veach monitors AFP-675 panel on OV-103's aft flight deck

    Science.gov (United States)

    1991-01-01

    STS-39 Mission Specialist (MS) Charles L. Veach analyzes data displayed on Air Force Program 675 (APF-675) command and monitor panel on the aft flight deck payload station aboard Discovery, Orbiter Vehicle (OV) 103. Just above Veach's head, Panel A3 closed circuit television (CCTV) screen A2 glows. At Veach's right is a portable laptop computer attached to panel L10.

  2. Stacked Deck: An Effective, School-Based Program for the Prevention of Problem Gambling

    Science.gov (United States)

    Williams, Robert J.; Wood, Robert T.; Currie, Shawn R.

    2010-01-01

    School-based prevention programs are an important component of problem gambling prevention, but empirically effective programs are lacking. Stacked Deck is a set of 5-6 interactive lessons that teach about the history of gambling; the true odds and "house edge"; gambling fallacies; signs, risk factors, and causes of problem gambling; and skills…

  3. STS-54 MS3 Helms talks to radio station from OV-105's aft flight deck

    Science.gov (United States)

    1993-01-01

    STS-54 Mission Specialist (MS3) Susan J. Helms, holding microphone, participates in an interview with a radio station on the Continental United States (CONUS) from the aft flight deck of the Earth-orbiting Endeavour, Orbiter Vehicle (OV) 105. Behind Helms are Pilot Donald R. McMonagle (left) and MS2 Gregory J. Harbaugh.

  4. 49 CFR 176.74 - On deck stowage of break-bulk hazardous materials.

    Science.gov (United States)

    2010-10-01

    .... (a) Packages containing hazardous materials must be secured by enclosing in boxes, cribs or cradles... 49 Transportation 2 2010-10-01 2010-10-01 false On deck stowage of break-bulk hazardous materials... HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS...

  5. 75 FR 32902 - Wire Decking from the People's Republic of China: Final Affirmative Countervailing Duty...

    Science.gov (United States)

    2010-06-10

    ... Equipment Manufacture Co., 437.11% Ltd Nanjing Jiangrui International Logistics Co......... 437.11% Nanjing... International China Ltd. (Dalian Branch)... 437.11% Shanghai Boracs Logistics Equipment Manufacturing 437.11% Co... International Trade Administration Wire Decking from the People's Republic of China: Final...

  6. 46 CFR 72.05-10 - Type, location, and construction of fire control bulkheads and decks.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Type, location, and construction of fire control bulkheads and decks. 72.05-10 Section 72.05-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS CONSTRUCTION AND ARRANGEMENT Structural Fire Protection § 72.05-10 Type, location, and construction of fire control...

  7. 46 CFR 108.133 - Hull superstructure, structural bulkheads, decks, and deckhouses.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Hull superstructure, structural bulkheads, decks, and deckhouses. 108.133 Section 108.133 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Structural Fire Protection § 108.133 Hull...

  8. 46 CFR 108.139 - Boundary bulkheads and decks of a space containing emergency power.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Boundary bulkheads and decks of a space containing emergency power. 108.139 Section 108.139 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Structural Fire Protection § 108.139 Boundary bulkheads and...

  9. 46 CFR 108.135 - Boundary bulkheads, decks of galleys, and combustible material lockers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Boundary bulkheads, decks of galleys, and combustible material lockers. 108.135 Section 108.135 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Structural Fire Protection § 108.135 Boundary...

  10. Human Factors of Flight-deck Automation: NASA/Industry Workshop

    Science.gov (United States)

    Boehm-Davis, D. A.; Curry, R. E.; Wiener, E. L.; Harrison, R. L.

    1981-01-01

    The scope of automation, the benefits of automation, and automation-induced problems were discussed at a workshop held to determine whether those functions previously performed manually on the flight deck of commercial aircraft should always be automated in view of various human factors. Issues which require research for resolution were identified. The research questions developed are presented.

  11. 46 CFR 32.56-30 - Category A machinery spaces: Bulkheads and decks-T/ALL.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Category A machinery spaces: Bulkheads and decks-T/ALL... EQUIPMENT, MACHINERY, AND HULL REQUIREMENTS Structural Fire Protection for Tank Ships With a Keel Laying Date On or After January 1, 1975 § 32.56-30 Category A machinery spaces: Bulkheads and decks—T/ALL....

  12. Aerodynamic stability of long span suspension bridges with low torsional natural frequencies

    DEFF Research Database (Denmark)

    Andersen, Michael Styrk; Johansson, Jens; Brandt, Anders;

    2016-01-01

    Classical flutter of suspended bridge decks can be avoided if the torsional frequencies are lower than the vertical. Wind tunnel tests of single boxes and twin box section models with torsional natural frequencies above and below the vertical frequency has been conducted. Flutter was avoided in all...... tests where the torsional frequency was lower than the vertical. But too low torsional stiffness caused large static displacements of the girder at medium–high wind speeds and steady state oscillations driven by a combination of torsional divergence and stalling behavior at the critical wind seed....... In order to design aerodynamically stable suspension bridges with low torsional natural frequencies it is suggested to increase the mass moment of inertia and provide adequate torsional stiffness by the main cables spacing....

  13. Field measurement on wind characteristic and buffeting response of the Runyang Suspension Bridge during typhoon Matsa

    Institute of Scientific and Technical Information of China (English)

    WANG Hao; LI AiQun; GUO Tong; XIE Jing

    2009-01-01

    Field measurement on wind characteristic and buffeting response of existing bridge is of great value to the development of bridge wind engineering, and the structural health monitoring system (SHMS) em-ployed in many long-span bridges provide a research basis for the field measurement. In order to pro-vide reliable basis for wind resistant evaluation of Runyang Suspension Bridge (RSB), two anemome-ters and 85 accelerometers were installed in the SliMS of RSB. In August 2005, Typhoon Matsa crossed over Jiangsu, the SHMS timely recorded the typhoon and structural vibration responses. In this paper by using the time-frequency technique and statistical theory, the recorded data were analyzed to obtain the strong wind characteristics, the buffeting response characteristics of the cable and deck, and the variation of buffeting response RMS versus wind speed. Results obtained in this study can be em-ployed to validate the credibility of current buffeting response analysis theory techniques, and provide reference values for wind resistant evaluation of other long-span bridges.

  14. Fatigue Performance Assessment of Composite Arch Bridge Suspenders Based on Actual Vehicle Loads

    Directory of Open Access Journals (Sweden)

    Bin Chen

    2015-01-01

    Full Text Available In the through arch bridges, the suspenders are the key components connecting the arch rib and the bridge deck in the middle, and their safety is an increasing focus in the field of bridge engineering. In this study, various vehicle traffic flow parameters are investigated based on the actual vehicle data acquired from the long-term structural health monitoring system of a composite arch bridge. The representative vehicle types and the probability density functions of several parameters are determined, including the gross vehicle weight, axle weight, time headway, and speed. A finite element model of the bridge structure is constructed to determine the influence line of the cable force for various suspenders. A simulated vehicle flow, generated using the Monte Carlo method, is applied on the influence lines of the target suspender to determine the stress process, and then the stress amplitude spectrum is obtained based on the statistical analysis of the stress process using the rainflow counting method. The fatigue performance levels of various suspenders are analyzed according to the Palmgren-Miner linear cumulative damage theory, which helps to manage the safety of the suspenders.

  15. Field measurement on wind characteristic and buffeting response of the Runyang Suspension Bridge during typhoon Matsa

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Field measurement on wind characteristic and buffeting response of existing bridge is of great value to the development of bridge wind engineering,and the structural health monitoring system(SHMS) em-ployed in many long-span bridges provide a research basis for the field measurement.In order to pro-vide reliable basis for wind resistant evaluation of Runyang Suspension Bridge(RSB),two anemome-ters and 85 accelerometers were installed in the SHMS of RSB.In August 2005,Typhoon Matsa crossed over Jiangsu,the SHMS timely recorded the typhoon and structural vibration responses.In this paper by using the time-frequency technique and statistical theory,the recorded data were analyzed to obtain the strong wind characteristics,the buffeting response characteristics of the cable and deck,and the variation of buffeting response RMS versus wind speed.Results obtained in this study can be em-ployed to validate the credibility of current buffeting response analysis theory techniques,and provide reference values for wind resistant evaluation of other long-span bridges.

  16. Temperature effects on the bridge structure during the all-day monitoring

    Directory of Open Access Journals (Sweden)

    Ondřej Michal

    2015-06-01

    Full Text Available In current time the large amount of pre-stressed bridge structures is used. Their horizontal and vertical displacements are well predicted, but for verification of theoretical results is necessary to measure real displacements of these structures depending on external conditions. Given by the complexity of the design and by the inhomogeneity of external influences (especially temperature of the atmosphere, insolation, wind speed, etc. cannot yet be reliably determined the changes of the construction caused by the immediate state of the environment and to distinguish them from irreversible (permanent deformation of the structure.In this paper the deflection line of the bridge of general Chábera over river Labe during the all-day monitoring will be analyzed. There is dense coverage of stabilized points enabling accurate approximation of the displacement of the bridge structure. The paper is focused especially on temperature effects on the bridge structure. The temperature changes cause the deformation of the construction not immediately, but with the time shift between change of temperature and structure deformation. Although the points are stabilized on both sides of the bridge deck, for the analysis of results were used only the points on the left side of the main span, where the biggest vertical displacements was detected. For testing of dependence of the time shift between the structure deformations and the structure temperature the Pearson coefficient of correlation was used.

  17. Istanbul Bridge Conference 2014

    CERN Document Server

    Gülkan, Polat; Mahmoud, Khaled

    2016-01-01

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

  18. Active Control of Suspension Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

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

  19. Full-scale measurements of dynamic response of suspension bridge subjected to environmental loads using GPS technology

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Nowadays, there are many larger and taller engineering structures than in the past. These structures are commonly designed to be more flexible. Thus, they are sensitive to severe wind gust and earthquake tremor. For the dynamic response prediction, finite element (FE) modal updating and structural health monitoring, the dynamic characteristics of a structure are becoming increasingly important. The aim of this paper is to show an emerging tool-the real time kinematic (RTK) global positioning system (GPS), which is used to measure and monitor the low-frequency vibration of Dalian BeiDa Bridge, a medium span suspension bridge. The modal analysis is firstly performed on the developed three-dimensional FE model according to the original blue prints of the bridge to provide the analytical frequencies and mode shapes. The field ambient vibration tests using the accelerometers on the bridge deck are conducted just prior to the use of the GPS system in order to validate the FE model. And then, the calibration test is done to assess the dynamic displacement measurement accuracy of the GPS in three orthogonal directions. The GPS signal properties, such as the amplitude, standard deviations (STD), power spectral density (PSD), and probability density functions (PDF), are studied in details. After that, a structural health monitoring system based on the GPS is devised and installed on the bridge to provide real-time measurement of deck movement. The output-only modal parameter identification is carried out by using the Periodogram method to investigate the responses of the bridge. The result shows that the spectral densities of the displacements measured by the GPS correspond well with the results by the FEM analysis and the accelerometer vibration test. It is concluded that the GPS method is reliable and useful to clarify the ambient vibration response behaviors of the flexible structures. The integration of the GPS and accelerometer methods results in a hybrid arrangement

  20. Experimental study on AR fiberglass connectors for bridges made of composite materials

    Directory of Open Access Journals (Sweden)

    Tolosana, N.

    2006-06-01

    Full Text Available One highly relevant aspect in composite material bridgedesing is the study of the shear connectors to be used.Composite material bridges most commonly comprise acomposite deck resting on steel or reinforced concrete girders.This article analyzes the connectors most frequentlyused in such bridges.It also reviews the connectors used in the King StormwaterChannel Bridge, whose fibreglass deck is supported bygirders made of concrete-filled carbon fibre girders.The paper advances proposals for several types of connectorsand discusses the results of push-out test run ona number of prototypes with different geometries.The results are analyzed to identify the optimum model forthe “Autovia del Cantabrico” Overpass, with its 46-m span,carbon fibre girders and AR glass shear connectors.Un aspecto relevante dentro del proyecto de un puenterealizado en materiales compuestos es el estudio de losconectores. El caso mas frecuente de puente en materialescompuestos es aquel que presenta un tablero de materialescompuestos soportado por vigas metalicas o de hormigonarmado. En este trabajo se analizaran los tipos deconectores mas utilizados en este tipo de puentesSe analizaran tambien los conectores utilizados en elKing Stormwater Channel Bridge, donde ademas deltablero en fibra de vidrio, se fabricaron las vigas en fibrasde carbono rellenas de hormigon.En este articulo se propondran varios tipos de conectoresy se presentaran los resultados experimentales correspondientesal ensayo de “push-out” de varios prototipos condiferentes geometrias.Tras evaluar los resultados, se determinara el mas idoneopara su implantacion en el Paso Superior de la Autovia delCantabrico, de 46 metros de luz y que presenta las vigasen fibra de carbono y los conectores de vidrio AR.

  1. Damage Localization of Cable-Supported Bridges Using Modal Frequency Data and Probabilistic Neural Network

    Directory of Open Access Journals (Sweden)

    X. T. Zhou

    2014-01-01

    Full Text Available This paper presents an investigation on using the probabilistic neural network (PNN for damage localization in the suspension Tsing Ma Bridge (TMB and the cable-stayed Ting Kau Bridge (TKB from simulated noisy modal data. Because the PNN approach describes measurement data in a Bayesian probabilistic framework, it is promising for structural damage detection in noisy conditions. For locating damage on the TMB deck, the main span of the TMB is divided into a number of segments, and damage to the deck members in a segment is classified as one pattern class. The characteristic ensembles (training samples for each pattern class are obtained by computing the modal frequency change ratios from a 3D finite element model (FEM when incurring damage at different members of the same segment and then corrupting the analytical results with random noise. The testing samples for damage localization are obtained in a similar way except that damage is generated at locations different from the training samples. For damage region/type identification of the TKB, a series of pattern classes are defined to depict different scenarios with damage occurring at different portions/components. Research efforts have been focused on evaluating the influence of measurement noise level on the identification accuracy.

  2. A vibration powered wireless mote on the Forth Road Bridge

    Science.gov (United States)

    Jia, Yu; Yan, Jize; Feng, Tao; Du, Sijun; Fidler, Paul; Soga, Kenichi; Middleton, Campbell; Seshia, Ashwin A.

    2015-12-01

    The conventional resonant-approaches to scavenge kinetic energy are typically confined to narrow and single-band frequencies. The vibration energy harvester device reported here combines both direct resonance and parametric resonance in order to enhance the power responsiveness towards more efficient harnessing of real-world ambient vibration. A packaged electromagnetic harvester designed to operate in both of these resonant regimes was tested in situ on the Forth Road Bridge. In the field-site, the harvester, with an operational volume of ∼126 cm3, was capable of recovering in excess of 1 mW average raw AC power from the traffic-induced vibrations in the lateral bracing structures underneath the bridge deck. The harvester was integrated off-board with a power conditioning circuit and a wireless mote. Duty- cycled wireless transmissions from the vibration-powered mote was successfully sustained by the recovered ambient energy. This limited duration field test provides the initial validation for realising vibration-powered wireless structural health monitoring systems in real world infrastructure, where the vibration profile is both broadband and intermittent.

  3. Quantum Bidding in Bridge

    Science.gov (United States)

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

    2014-04-01

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

  4. Bridge of Light

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

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

  5. Bridge over troubled water?

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  6. Building Bridges to China.

    Science.gov (United States)

    Wasta, Stephanie; Scott, Margaret

    1998-01-01

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

  7. Simple Program to Investigate Hysteresis Damping Effect of Cross-Ties on Cables Vibration of Cable-Stayed Bridges

    Directory of Open Access Journals (Sweden)

    Panagis G. Papadopoulos

    2012-01-01

    Full Text Available A short computer program, fully documented, is presented, for the step-by-step dynamic analysis of isolated cables or couples of parallel cables of a cable-stayed bridge, connected to each other and possibly with the deck of the bridge, by very thin pretensioned wires (cross-ties and subjected to variation of their axial forces due to traffic or to successive pulses of a wind drag force. A simplified SDOF model, approximating the fundamental vibration mode, is adopted for every individual cable. The geometric nonlinearity of the cables is taken into account by their geometric stiffness, whereas the material nonlinearities of the cross-ties include compressive loosening, tensile yielding, and hysteresis stress-strain loops. Seven numerical experiments are performed. Based on them, it is observed that if two interconnected parallel cables have different dynamic characteristics, for example different lengths, thus different masses, weights, and geometric stiffnesses, too, or if one of them has a small additional mass, then a single pretensioned very thin wire, connecting them to each other and possibly with the deck of the bridge, proves effective in suppressing, by its hysteresis damping, the vibrations of the cables.

  8. 一种计入桥面铺装非完善接触效应的箱梁结构计算方法%Application of Deck Pavement into Box Girder Structure

    Institute of Scientific and Technical Information of China (English)

    董建兴

    2013-01-01

    The local simulation analysis is carried out for the imperfect contact between the bridge deck pavement and the box girder structure.Then the shear stiffness is obtained from load-slip curves.And a 3-D model for a real bridge structure is built and analyzed in which Spring elements are adopted to simulate the interface shear stiffness.By this calculation model the structural responses under some loads are acquired to explore the effect of considering interface slip between the concrete box deck and the pavement on the structural behavior of the bridge.The results indicate that the cracking load and ultimate bearing capacity of structure are advanced by the affect of the pavement.By comparing the data,the advice of analyzing the box girder with deck overlays is proposed,which has definite social and economic benefit.%采用有限元软件对桥面铺装与箱梁结构桥面板之间的非完善接触进行局部仿真分析,提取荷载一滑移曲线获得界面之间的剪切刚度,并在整体模型中用弹簧单元模拟界面之间的剪切刚度,对猫铺大桥结构进行三维空间分析.通过这种计算模式分析结构在荷载作用下的的整体响应,探讨比较了考虑混凝土与桥面铺装界面滑移对箱梁结构受力性能的影响.研究得出了考虑铺装层参与截面受力能提高结构开裂荷载和极限承载能力、增大结构刚度的结论.计算结果对考虑铺装层作用时箱梁计算提出合理建议,具有一定的经济和社会效益.

  9. Revised Rules for Concrete Bridges

    DEFF Research Database (Denmark)

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

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

  10. Non-destructive inspection protocol for reinforced concrete barriers and bridge railings

    Science.gov (United States)

    Chintakunta, Satish R.; Boone, Shane D.

    2014-02-01

    Reinforced concrete highway barriers and bridge railings serve to prevent errant vehicles from departing the travel way at grade separations. Despite the important role that they play in maintaining safety and their ubiquitous nature, barrier inspection rarely moves beyond visual inspection. In August 2008, a tractor-trailer fatally departed William Preston Lane, Jr. Memorial Bridge after it dislodged a section of the bridge barrier. Investigations following the accident identified significant corrosion of the anchor bolts attaching the bridge railing to the bridge deck. As a result of the information gathered during its investigation of the accident, the National Transportation Safety Board (NTSB) made recommendations to the Federal Highway Administration concerning Non-Destructive Evaluation (NDE) of concrete bridge railings. The Center for nondestructive evaluation (NDE) at Turner Fairbank Highway Research Center in McLean, VA is currently evaluating feasibility of using four technologies - ground penetrating radar (GPR), ultrasonic pulse-echo, digital radiography and infrared thermal imaging methods to develop bridge inspection methods that augment visual inspections, offer reliable measurement techniques, and are practical, both in terms of time and cost, for field inspection work. Controlled samples containing predefined corrosion levels in reinforcing steel were embedded at barrier connection points for laboratory testing. All four NDE techniques were used in the initial phase I testing. An inspection protocol for detecting and measuring the corrosion of reinforced steel embedded in the anchorage system will be developed as part of phase II research. The identified technologies shall be further developed for field testing utilizing a structure with a barrier in good condition and a structure with a barrier in poor condition.

  11. THE NON-LINEAR METHODS OF ANALYSIS IN MODERN DESIGNING (BY THE EXAMPLE OF GEOTECHNICS FACILITIES AND BRIDGES

    Directory of Open Access Journals (Sweden)

    N. N. Melnichuk

    2010-10-01

    Full Text Available Problem statement. Non-linear solutions are widely used within the framework of solution of the problems of development of the areas which were earlier unsuitable for construction (wetlands, slope areas; bases consisting of weak overwet soils.Results and conclusions. Design models and examples of practical implementa-tion of two groups of non-linear analysis in design of construction objects are considered. These are spatial deformation analysis of reinforced concrete decks of road bridges and elastoplastic numerical analysis of the bases, soil structures and structures interacting with soil structures.

  12. Full Scale Investigation of the Dynamic Heat Storage of Concrete Decks with PCM and Enhanced Heat Transfer Surface Area

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2013-01-01

    The paper presents the full-scale experimental investigation of the dynamic heat storage potential of the prefabricated hollow core deck elements with and without phase change material (PCM) and with and without increased bottom surface area of the decks. In the presented investigation five types...... can result in the increased heat amount that can be transferred and stored in the heavy construction element during the diurnal indoor temperature fluctuations.......The paper presents the full-scale experimental investigation of the dynamic heat storage potential of the prefabricated hollow core deck elements with and without phase change material (PCM) and with and without increased bottom surface area of the decks. In the presented investigation five types...

  13. 聚酯玻纤布在桥面防水粘结层中的应用%Application of Fiberglass Polyester Paving Mat in Waterproof Cohesive Layer on Deck

    Institute of Scientific and Technical Information of China (English)

    严恒; 战琦琦; 朱洪洲; 唐伯明

    2011-01-01

    In general coiled materials or coating materials chosen for waterproof adhesive layer in pavement of bridge deck on highways do not exhibit optimal effect. In order to improve the adhesive property between deck and asphalt pavement, the SBS modified asphalt + fiberglass polyester paving mat are selected as waterproof adhesive materials. The dosage of oil in adhesive layer is determined via shearing test, the test road is paved and the pull test is carried out. The test results show that the interlayer adhesive property of fiberglass polyester paving mat displays perfect property.%通常,公路桥梁桥面铺装防水粘结层选用的卷材或涂膜类材料效果均不佳,为了提高桥面与沥青铺装层之间的粘结性能,选用SBS改性沥青+聚酯玻纤布的形式作为防水粘结材料,通过剪切试验确定粘层油用量,铺筑试验路,并进行拉拔试验,结果表明,聚酯玻纤布的层间粘结性能良好.

  14. Key Techniques for Design of Main Bridge of Songhua River Highway-railway Bridge in Harbin-Bei’an Railway%滨北线松花江公铁两用桥主桥设计关键技术

    Institute of Scientific and Technical Information of China (English)

    续宗宝

    2016-01-01

    The Songhua River Highway-railway Bridge of Harbin-Bei’an Railway is the first modern highway-railway bridge in Chinese cold area,and the main bridge is a continuous steel truss beam bridge with a main span of 144 m.In the paper, the general idea of the main bridge design is introduced.Firstly,combined with the environment of the bridge site,the main bridge structure is studied according to the comparison and analysis.Secondly,the structure durability is studied through test under the ultra-low temperature environment.Finally,the truss height,truss width,bridge deck system and materials etc.,are adopted according to a series of researches.The obtained design results have great theoretical and prac-tical values for the design of similar type bridge.%滨北线松花江公铁两用桥是我国第一座严寒地区修建的现代化公铁两用桥,主桥采用主跨144 m 连续钢桁梁桥。介绍了主桥结构设计的总体思路,并结合桥位处环境,通过比较及分析计算研究了主桥结构形式,并通过试验对超低温环境结构耐久性进行了相关研究,根据研究确定了适用于该桥特点的桁高、桁宽、桥面系、材质等设计要素。本桥设计对该地区同类型桥梁的设计具有重要的理论意义和工程实用价值。

  15. Construction engineering of steel tub-girder bridge systems for skew effects

    Science.gov (United States)

    Jimenez Chong, Juan Manuel

    Closed structural sections, such as those having circular, rectangular or trapezoidal shape, possess high rotational rigidity when compared to open sections such as I-girders. The high torsional rigidity of closed sections makes them ideal for use in highly curved bridges. In this case, the geometry of the bridge results in large torsional forces. Because of structural efficiency and economy reasons, most of these closed-section bridges consist of a trapezoidal cross-section, with a top concrete slab and bottom and side steel plates. The slab is cast after the steel is erected and thus a system of internal diaphragms and braces is necessary to stabilize the system during erection. During the steel erection and the early stages of the concrete deck placement, the section can be considered as quasi-closed as the top concrete flange has not been cast or is not yet effective. During steel erection, undetermined and/or large torsional forces and/or displacements may result in fit-up problems requiring large stresses to overcome. During concrete deck placement, the undetermined displacements can affect the control of the deck thickness and the final deck geometry, such as the alignment of deck joints and the matching of stages in phased constructions projects. Due to the interactions between their various components, the behavior of curved and skewed tub-girder bridges is significantly more complex than that of straight bridges. When skewed supports are used in tub-girders, the interaction of the girder bending rotations and the displacement constraints induced by the skewed support diaphragms causes twisting of the girders at the supports. These twist rotations introduce additional torques into the system. Both curvature and skew can cause design and construction difficulties, especially at the supports, where the corresponding steel dead load deflections and the large torsional stiffness of the girders may lead to large fit-up forces. Currently, the general

  16. [Retention of adhesive bridges].

    Science.gov (United States)

    Raes, F; De Boever, J

    1994-04-01

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

  17. Human engineering analysis for the high speed civil transport flight deck

    Science.gov (United States)

    Regal, David M.; Alter, Keith W.

    1993-01-01

    The Boeing Company is investigating the feasibility of building a second generation supersonic transport. If current studies support its viability, this airplane, known as the High Speed Civil Transport (HSCT), could be launched early in the next century. The HSCT will cruise at Mach 2.4, be over 300 feet long, have an initial range of between 5000 and 6000 NM, and carry approximately 300 passengers. We are presently involved in developing an advanced flight deck for the HSCT. As part of this effort we are undertaking a human engineering analysis that involves a top-down, mission driven approach that will allow a systematic determination of flight deck functional and information requirements. The present paper describes this work.

  18. BRIDGING SERVICE QUALITY GAPS

    OpenAIRE

    BARKATH UNISSA

    2012-01-01

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

  19. Bridging as Coercive Accommodation

    CERN Document Server

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

    1995-01-01

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

  20. Nematic liquid crystal bridges

    Science.gov (United States)

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

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

  1. Effect of machined profile, zinc oxide and titanium dioxide particles on checking southern pine deck boards during weathering.

    Science.gov (United States)

    Akhtari, Maliheh; Nicholas, Darrel

    2015-06-01

    The aim of this research was to test the hypothesis that the combination of profiling, treatment and a surface coating with nanoparticles will be effective at reducing checking in deck boards exposed to the weather. In this study southern pine (Pinus sp.) deck boards were machined to flat (control) and ribbed surface profiles. The specimens were treated with aqueous copper amine azole (CA-C) using a vacuum/pressure method and coated with nano-ZnO and micronised TiO2. Boards were exposed to accelerated weathering for 576 h. The number, length and width of checks that developed in the boards were quantified and the average amounts of cupping, twist and bowing occurring in the weathered wood were examined. The results of the statistical analysis showed that all of the coated ribbed decking samples had lower average check numbers, lengths and widths compared to the end-matched flat untreated specimens. Checks were also shorter and narrower in the profiled southern pine deck board than in the unprofiled specimens. Furthermore, the lowest amount of cupping, twist and bowing were observed for specimens profiled and coated with the TiO2. Therefore, the authors conclude that the coated ribbed decks looked significantly better than the flat decking.

  2. STS-41 Pilot Cabana checks flight deck controls during training in JSC's SMS

    Science.gov (United States)

    1990-01-01

    STS-41 Pilot Robert D. Cabana checks forward flight deck overhead control panel switches during a simulation in JSC's Shuttle Mission Simulator (SMS). Cabana, wearing a launch and entry suit (LES) and launch and entry helmet (LEH), is seated at the pilots station and is surrounded by checklists, control panels, and various onboard equipment. The SMS is located in the Mission Simulation and Training Facility Bldg 5.

  3. The development of a durability procedure for pallets with structural panel decking

    OpenAIRE

    Cao, Jiqiang

    1993-01-01

    The Pallet Design System (PDS) is a widely accepted engineering procedure for comparing the performance of competing pallet designs. As part of a new version of the PDS, the objective of this study was to develop a durability model for pallets with structural panel decking. An accelerated rough material handling test system, "the VPI unit-load material handling FasTrack" , was developed to simulate pallets used in the unit-load material handling environments. 100 pallets representing 14...

  4. ANALISA KEKUATAN DECK TONGKANG MUATAN TIANG PANCANG 750 DWT DENGAN SOFTWARE BERBASIS METODE ELEMEN HINGGA

    OpenAIRE

    Sukanto Jatmiko; Saptadi Saptadi

    2012-01-01

    Pada  awalnya pihak pemilik kapal merencanakan material baja 200 ton untuk  pembangunan satu unit Tongkang ini akan tetapi supply material kemudian diperkecil menjadi 180 ton.Dengan demikian dalam tugas akhir ini penulis mencoba melakukan analisa kekuatan deck Tongkang ini untuk mengetahui keamanan terhadap beban-beban yang bekerja selama Tongkang beroperasi.                 Menganalisa konstruksi  gelad...

  5. 3-D seakeeping analysis with water on deck and slamming. Part 2: Experiments and physical investigation

    Science.gov (United States)

    Greco, M.; Bouscasse, B.; Lugni, C.

    2012-08-01

    A synergic 3-D experimental and numerical investigation is conducted for wave-ship interactions involving the water-on-deck and slamming phenomena. The adopted solver has been developed in Greco and Lugni (in press) and combines (A) a weakly nonlinear external solution for the wave-vessel interactions with (B) a 2-D in-deck shallow-water approximation, which describes water shipping events, and (C) a local analytical analysis of the bottom-slamming phenomenon. This solver can handle regular and irregular sea states and vessels at rest or with limited speed. The experiments examine a patrol ship at rest or with forward speed that is free to oscillate in heave and pitch in regular and irregular waves. In this study, the head-sea regular-wave conditions are examined in terms of (1) response amplitude operators (RAOs) and relative motions, (2) occurrence, features and loads of water-on-deck, bottom-slamming and flare-slamming events and (3) added resistance in waves. A systematic and comprehensive analysis of the phenomena is made available in terms of the Froude number, incoming wavelength-to-ship length ratio and wave steepness for the examined ship geometry. The main parameters that affect the global and local quantities are identified and possible danger in terms of water-on-deck severity and structural consequences are determined. Different slamming behaviors were identified, depending on the spatial location of the impact on the vessel: single-peak, church-roof and double-peak behaviors. A bottom-slamming criterion, using the Ochi's (1964) velocity condition and the Greco and Lugni's (2012) pressure condition, is assessed. A statistical analysis of more than 100 events is needed for the bottom-slamming pressure peaks. The numerical solver is promising. The major discrepancies with the experiments are discussed, and the importance of viscous hull damping and flare impact for the most violent conditions is emphasized. Inclusion of these effects improved the

  6. A Human-Interactive Course of Action Planner for Aircraft Carrier Deck Operations

    OpenAIRE

    Michini, Bernard J.; How, Jonathan P.

    2011-01-01

    Aircraft carrier deck operations present a complex and uncertain environment in which time-critical scheduling and planning must be done, and to date all course of action planning is done solely by human operators who rely on experience and training to safely negotiate off -nominal situations. A computer decision support system could provide the operator with both a vital resource in emergency scenarios as well as suggestions to improve e fficiency during normal operations. Such a decision su...

  7. STS-30 aft flight deck onboard view of overhead window, Earth limb, cow photo

    Science.gov (United States)

    1989-01-01

    Since the beginning of manned space travel, astronauts have taken onboard with them items of person sentiment. During STS-30 onboard Atlantis, Orbiter Vehicle (OV) 104, Mission Specialist Mark C. Lee brought along a photograph of a cow. The photo testifies to his background as one reared on a Wisconsin farm and is displayed on aft flight deck alongside an overhead window. Outside the window, some 160 nautical miles away, is the cloud-covered Earth surface.

  8. STS-43 Mission Specialist (MS) Adamson uses camera on aft flight deck

    Science.gov (United States)

    1991-01-01

    STS-43 Mission Specialist (MS) James C. Adamson points a 70mm HASSELBLAD camera out aft flight deck overhead window W8. Holding his position in the microgravity of space proves tricky. Notice that Adamson's feet are hooked around the commanders seat headrest. The onorbit station control panels appear above Adamson's head and the payload station with Development Test Ojective (DTO) 1208, Space Station Cursor Control Device Evaluation II and Advanced Applications, laptop computer at his back.

  9. A virtual experiment showing single particle motion on a linearly vibrating screen-deck

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A virtual sieving experimental simulation system was built using physical simulation principles.The effects of vibration frequency and amplitude,the inclination angle of the screen-deck and the vibration direction angle of screen on single particle kinematics were predicted.Properties such as the average velocity and the average throw height were studied.The results show that the amplitude and the angle of vibration have a great effect on particle average velocity and average height.The vibration frequency ...

  10. Coconut lumber for wood decks (Cocos nucifera L.):decay resistance against Basidiomycetes fungi

    OpenAIRE

    Jourez, Benoît; Verheyen, Cécile; Van Acker, Joris

    2011-01-01

    Since a couple of years, manufactured products of coconut wood for outdoor uses like wood decks have been proposed on the European market. These are presented as an alternative for traditional tropical timbers. In the past, coconut wood was neglected and burned for sanitary reasons and lack of interest at industrial scale. Plantation coconut trees at end of production of copra constitute a renewable resource with high added value. In order to convince the markets, natural durability for outdo...

  11. A NASTRAN correlation study for vibrations of a cross-stiffened ship's deck

    Science.gov (United States)

    Thornton, E. A.

    1972-01-01

    To evaluate the effectiveness of NASTRAN for predicting the vibration modes of panels with bending-membrane coupling, a cross-stiffened ship deck was analyzed. In correlation with experimental data, one NASTRAN finite element representation gave results slightly more accurate than a previous analytical solution. Computational time was excessively long, due to the Guyan method of reducing the eigenvalue problem. It is recommended that a more efficient method of matrix reduction be implemented for the lumped mass formulation.

  12. Human factors of flight-deck automation - Report on a NASA-industry workshop

    Science.gov (United States)

    Boehm-Davis, D. A.; Curry, R. E.; Harrison, R. L.; Wiener, E. L.

    1983-01-01

    The scope of automation, the benefits of automation, and automation-induced problems were discussed at a workshop held to determine whether those functions previously performed manually on the flight deck of commercial aircraft should always be automated in view of various human factors. Issues which require research for resolution were identified. The research questions developed are presented. Previously announced in STAR as N81-16022

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

    DEFF Research Database (Denmark)

    Du, Guangli; Karoumi, Raid

    2013-01-01

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

  14. Simulation of Wave Impact on Inclined Deck Based on VOF Method

    Directory of Open Access Journals (Sweden)

    Zhai Gangjun

    2013-03-01

    Full Text Available The increasing importance of the sustainability challenge in ocean engineering has led to the development of floating structure of various configurations. In this study, a numerical wave tank based on the Navier-Stokes equations has been established. The turbulence model, namely standard k-ε is incorporated to the numerical tank to broaden applicability of simulation. The VOF method has been widely used in the free-surface hydrodynamic flows with good accuracy. The wave impact phenomenon is extremely complicated and restriction of experimental condition. To better understand the mechanisms and rules of wave slamming on the floating structure, in the first instance, this study simplifies the problem and assumes 5 key gestures for floating structure with inclined angles (10°, 5°, 0°, -5° and -10° and secondly, a periodic motion deck model has been established. The computation result is in good agreement with the experimental data. The numerical method can predict the impact peak pressure and the distribution of wave impact along underside of the inclined deck. It is also significant to research the wave impact force of the inclined deck and has great scientific value and practical significance.

  15. Using neural networks to assess flight deck human–automation interaction

    International Nuclear Information System (INIS)

    The increased complexity and interconnectivity of flight deck automation has made the prediction of human–automation interaction (HAI) difficult and has resulted in a number of accidents and incidents. There is a need to develop objective and robust methods by which the changes in HAI brought about by the introduction of new automation into the flight deck could be predicted and assessed prior to implementation and without use of extensive simulation. This paper presents a method to model a parametrization of flight deck automation known as HART and link it to HAI consequences using a backpropagation neural network approach. The transformation of the HART into a computational model suitable for modeling as a neural network is described. To test and train the network data were collected from 40 airline pilots for six HAI consequences based on one scenario family consisting of a baseline and four variants. For a binary classification of HAI consequences, the neural network successfully classified 62–78.5% depending on the consequence. The results were verified using a decision tree analysis

  16. Research on Selections of Bridge Site and Type of Hutiaoxia Jinsha River Bridge%虎跳峡金沙江大桥方案研究

    Institute of Scientific and Technical Information of China (English)

    刘伟; 陈克坚; 游励晖

    2013-01-01

    Research purposes:The Hutiaoxia Jinsha River Bridge is the key project of Lijiang-Xianggelila Railway and is located in the sensitive environmental and high seismic intensity region with the active fault.The reasonable bridge site and type should be selected for this bridge on consideration of the railway alignment,environment protection,topography,geological condition and the plan of hydraulic engineering on the midstream of the river.Research conclusions:(1)Using the deck type steel braced arch at the No.8 bridge site(416m) of the Hutaioxia Jinsha River Bridge is the best engineering plan.Using the steel truss suspension bridge at No.27 bridge site (98 + 660 +98 m) can remain the condition for the hydroelectric plan of river and can get the better economic and social benefits.(2) The deck type steel braced arch has features of the good load bearing capacity,good rigidity and nice looking and is suitable for the high mountain and deep valley area,but it produces the impact on the water storage and shipping under bridge because the arch rib is installed on bottom of the structure.(3) The steel truss suspension bridge has the features of the fine anti-seismic performance and good rigidity to meet the train requirement.(4) The research result can provide the reference to the type selection of the large span railway bridge in mountain and deep valley area.%研究目的:虎跳峡金沙江大桥为丽香铁路的重点控制性工程.大桥桥址位于环境敏感区、高烈度地震区及断裂发育带,需要综合线路走线、环保、地形、地质情况及金沙江中游水电开发规划的影响,选择虎跳峡金沙江大桥的合理桥位及桥式方案.研究结论:(1)虎跳峡金沙江大桥的8号桥位416 m上承式钢桁拱桥是最优的工程方案,27号桥位(98+660 +98)m钢桁梁悬索桥可以为规划中的水电开发预留条件,整体上经济、社会效应更好;(2)上承式钢桁拱桥承载能力高、刚度大、造型优美,适用于

  17. Ash-Based Building Panels Production and Demonstration of Aerock Decking Building Product

    International Nuclear Information System (INIS)

    trials showed green product sagging, as a result of the die design. After the third die was acquired and fitted to the extruder, satisfactory decking and structural panels were produced. Cured decking was shipped to the US but experienced significant breakage and damage during transport. Subsequent evaluations concluded that an alternative die design was needed that would produce a more robust product resistant to damage. In summary, AeRock Decking can be a commercially-viable non-wood alternative decking product. This project has provided WRI and AeRock the knowledge and understanding to make AeRock Decking a commercial success. However, a commercial demonstration that produces quality product and the subsequent evaluation of its performance is needed before commercial acceptance of the AeRock product

  18. Research on the Interfacial Shear Resistant Performance of the Composite Deck System Composed of Orthotropic Deck and Ultra-thin UHPC Layer%钢超薄 UHPC 组合桥面板界面抗剪性能研究∗

    Institute of Scientific and Technical Information of China (English)

    邵旭东; 方恒; 李文光

    2016-01-01

    For the composite bridge deck system composed of orthotropic steel deck and ultra-high-per-formance concrete (UHPC)layer with 35 mm UHPC plate and 20 mm wearing layer,the UHPC layer is too thin to use conventional shear connectors.Therefore,an innovative shear connectors using the welded rebar mesh was proposed.Load-slip curve and ultimate bearing capacity were evaluated by push-out test. In the background of a Yangtze River Bridge,the optimal lay out of shear connectors was investigated by segmental model of a bridge deck.The test results showed that the brittle failure of the shear connectors occurred,and the ultimate bearing capacity of the shear connector with the 50 mm welded rebar mesh was 119kN.The slippage of the shear connector with the welded rebar mesh was less than that of the stud un-der the same load ratio.Furthermore,the stress at the bottom of UHPC layer should be considered in the arrangement of the shear connectors.Increased layout density of the shear connectors reduced the trans-versal and longitudinal tensile stress at the bottom of UHPC layer up to 36.3 %.%针对正交异性钢板超薄超高性能混凝土(Ultra High Performance Concrete, UHPC)(厚度为35 mmUHPC板+20 mm磨耗层)组合桥面板中,UHPC 层过薄而无法采用常规抗剪连接件形式的问题,提出一种新型钢筋网局部焊接抗剪连接件.通过推出试验测得了焊接抗剪件的荷载滑移关系曲线和抗剪承载力,以某长江大桥为背景,对焊接抗剪件的布置方式进行了研究.试验结果表明:焊接抗剪件的推出试验破坏过程属于脆性破坏,破坏前界面相对滑移较小,焊缝长度为50 mm的焊接抗剪件极限抗剪承载力为119 kN.与栓钉相比,相同荷载比值下采用焊接抗剪件的界面相对滑移小,焊接抗剪件的抗剪刚度大于栓钉.计算结果表明:钢超薄 UHPC 组合桥面板在布置抗剪件时,需关注 UHPC 层底部受力.加大抗剪连接件布置密度可减小UHPC层底部

  19. Vulnerability of bridges to fire

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  20. Theory of bridge aerodynamics

    CERN Document Server

    Strømmen, Einar

    2006-01-01

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

  1. 港珠澳大桥浅水区非通航孔桥组合梁设计%Design of Composite Girders for Non-Navigable Span Bridge of Hong Kong-Zhuhai-Macau Bridge in Shallow Water Area

    Institute of Scientific and Technical Information of China (English)

    罗扣; 王东晖; 张强

    2013-01-01

    The main part of the Hong Kong-Zhuhai-Macau Bridge is a part of the combined bridge and tunnel,of which the non-navigable span bridge in the shallow water area is the 85 m span continuous composite girder bridge that totally has 64 spans of the composite girders and is 5 440 m in length.The span arrangement of the bridge mainly includes two kinds of arrangement of 6)× 85 m and 5)× 85 m.The composite girders are the separated continuous single-cell singlebox girders with constant depth and specifically are composed of the open steel box girders and the concrete deck slabs that are connected each other via shear studs.A steel box girder is the inverted trapezoid structure,a concrete deck slab is the precast full slab in the transverse direction and the grooves are pre-reserved at the locations of the shear studs.To improve the transverse mechanical behavior of the deck slabs,the stringers are set in the sections of the composite girders and to keep the integrity of the slabs,the shear studs are arranged in a way of clustering.The composite girders are erected and installed in each full span by the large transportation and erection floating crane and the girders are closed span by span.%港珠澳大桥主体工程采用桥隧组合方案,其中浅水区非通航孔桥采用85 m连续组合梁桥形式,全长5 440m,共64孔,跨径布置主要采用6×85 m和5×85m2种形式.组合梁采用单箱单室分幅等高连续梁,由开口钢箱梁和混凝土桥面板通过剪力钉联结而成.钢箱梁为倒梯形结构;混凝土桥面板为横向整块预制,在剪力钉处设置预留槽.为改善混凝土桥面板的横向受力性能,该桥组合梁截面设置小纵梁;为保持桥面板的整体性,剪力钉采用集束式布置方式.组合梁采用大型运架一体浮吊整孔安装架设,逐孔合龙.

  2. Modelling railway bridge asset management

    OpenAIRE

    Le, Bryant Linh Hai

    2014-01-01

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

  3. Dynamic responses of cable-stayed bridges to vehicular loading including the effects of the local vibration of cables

    Institute of Scientific and Technical Information of China (English)

    He ZHANG; Xu XIE

    2011-01-01

    Stay cables,the primary load carrying components of cable-stayed bridges (CSBs),are characterised by high flexibility which increases with the span of the bridge.This makes stay cables vulnerable to local vibrations which may have significant effects on the dynamic responses of long-span CSBs.Hence,it is essential to account for these effects in the assessment of the dynamics CSBs.In this paper,the dynamic responses of CSBs under vehicular loads are studied using the finite element method (FEM),while the local vibration of stay cables is analyzed using the substructure method.A case study of a cable-stayed steel bridge with a center span of 448 m demonstrates that stay cables undergo large displacements in the primary mode of the whole bridge although,in general,a cable's local vibrations are not obvious.The road surface roughness has significant effects on the interaction force between the deck and vehicle but little effect on the global response of the bridge.Load impact factors of the main girder and tower are small,and the impact factors of the tension of cables are larger than those of the displacements of girders and towers.

  4. Synergistic Allocation of Flight Expertise on the Flight Deck (SAFEdeck): A Design Concept to Combat Mode Confusion, Complacency, and Skill Loss in the Flight Deck

    Science.gov (United States)

    Schutte, Paul; Goodrich, Kenneth; Williams, Ralph

    2016-01-01

    This paper presents a new design and function allocation philosophy between pilots and automation that seeks to support the human in mitigating innate weaknesses (e.g., memory, vigilance) while enhancing their strengths (e.g., adaptability, resourcefulness). In this new allocation strategy, called Synergistic Allocation of Flight Expertise in the Flight Deck (SAFEdeck), the automation and the human provide complementary support and backup for each other. Automation is designed to be compliant with the practices of Crew Resource Management. The human takes a more active role in the normal operation of the aircraft without adversely increasing workload over the current automation paradigm. This designed involvement encourages the pilot to be engaged and ready to respond to unexpected situations. As such, the human may be less prone to error than the current automation paradigm.

  5. Study on the Durability of Steel Deck Pavement Asphalt Mixture Based on Rubber Powder and SBS Compound Modified Technology%基于橡胶粉与 SBS 复合改性技术钢桥面铺筑沥青混合料耐久性试验研究

    Institute of Scientific and Technical Information of China (English)

    魏斌

    2015-01-01

    In order to satisfy the bridge deck pavement of asphalt concrete special performance re-quirements of asphalt binder,Improve the flexibility of bridge deck pavement asphalt concrete,by adding different proportions of rubber powder and SBS modified asphalt and composite mix performance test anal-ysis,discusses the composite rubber powder modified asphalt mixture by Sophie toughened,shear,impact mechanism water stability,and recommended significantly modified asphalt concrete composite best over-all performance rubber particles content.%为了满足桥面铺装沥青混凝土对沥青结合料的特殊性能要求,提高桥面铺装沥青混凝土的柔韧性,通过对不同掺加比例的橡胶粉与 SBS 复合改性沥青及其混合料的性能进行试验分析,探讨了橡胶粉对复合改性沥青混合料的增柔增韧、抗剪、水稳定性的影响机理,并推荐了可以显著复合改性沥青混凝土综合使用性能的最佳橡胶颗粒掺量。

  6. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

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

    2005-01-01

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

  7. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

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

    2004-01-01

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

  8. Development of cooperative system bridges

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhe; WAN Qi-bai; SHI Lei

    2008-01-01

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

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

    International Nuclear Information System (INIS)

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

  10. Super-light SL-Deck elements with fixed end connections

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl

    2015-01-01

    Super-light structures combining light and strong concrete are invented by the author at the Technical University of Denmark and commercialized by the spin-out company Abeo Ltd. The first product is the SL-Deck element that represents a number of strong improvements to the building industry among...... which improved sound insulation, low weight, low CO2 emission, 4 hour fire resistance, improved flexibility with respect to holes, services, curved edges, conical shapes, cross-reinforcements, included beams and edge stringers, balcony solutions, hung down elements, leaf-connections, and long spans due...

  11. American Flag and Mini-DVD Attached to Deck of Phoenix

    Science.gov (United States)

    2008-01-01

    This image, released on Memorial Day, May 26, 2008, shows the American flag and a mini-DVD on the Phoenix's deck, which is about 3 ft. above the Martian surface. The mini-DVD from the Planetary Society contains a message to future Martian explorers, science fiction stories and art inspired by the Red Planet, and the names of more than a quarter million earthlings. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  12. Attachments for fire modeling for Building 221-T, T Plant canyon deck and railroad tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Oar, D.L. [Westinghouse Hanford Co., Richland, WA (United States)

    1995-01-23

    The purpose of this attachment is to provide historical information and documentation for Document No. WHC-SD-CP-ANAL-008 Rev 0, ``Fire Modeling for Building 221-T--T Plant Canyon Deck and Railroad Tunnel``, dated September 29, 1994. This data compilation contains the following: Resumes of the Technical Director, Senior Engineer and Junior Engineer; Review and Comment Record; Software Files; CFAST Input and Output Files; Calculation Control Sheets; and Estimating Sprinkler Actuation Time in the Canyon and Railroad Tunnel. The T Plant was originally a fuel reprocessing facility. It was modified later to decontaminate and repair PuRex process equipment.

  13. Sumary of Tests and Studies Done Abroad on the Bubble Deck System

    Directory of Open Access Journals (Sweden)

    Sergiu Călin

    2009-01-01

    Full Text Available The procedure Bubble Deck was applied untill now in Europe, in countries like Austria, Belgium, Denmark, Germany, Iceland, Italy, United Kingdom, Holland, also in other continents, in Canada or USA. This constructive system could not be brought into practice in so many projects achieved, only based on fundamental research to prove its validity, therefore tests were made concerning: bending behavior, reaction to shear force, the behavior of mountings, the reaction to fire, the acoustic behavior of these floors and economic analysis.

  14. Cascaded resonant bridge converters

    Science.gov (United States)

    Stuart, Thomas A. (Inventor)

    1989-01-01

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

  15. 赵家沟大桥临时支架设计%Design of Temporary Support System for Zhaojiagou Bridge

    Institute of Scientific and Technical Information of China (English)

    孙九春

    2015-01-01

    新建浦东大道赵家沟大桥主桥为下承式系杆拱桥,采用先梁后拱的施工工艺,其中拱肋采用在桥面结构上搭设塔架施工的竖转提升工艺,纵、横梁及桥面板支撑采用混合支架。临时支架采用φ609钢管桩+贝雷梁+φ48小钢管组成的复合支架形式,承受桥道系结构施工时的荷载、预应力张拉引起的次效应以及竖转提升工艺所传递的荷载,受力较为复杂。采用精细化数值模拟技术对支架与结构在整个施工过程中的受力状态进行模拟,数值模拟结果及实践监测数据表明结构安全,支架的各部分构件受力满足要求,所设计的支撑柱改善了桥道系结构、贝雷梁以及钢管支架的受力状态。%T he main bridge of Zhaojiagou Bridge on the new ly built Pudong Avenue is a bow string tied arch bridge constructed by the process of girder first and arch later ,among w hich the arch ribs adopt the vertical rotating and lifting technique with the assistance of lifting frames erec‐ted on the bridge deck ,the stringers and cross beams and bridge deck are supported on composite scaffolds .The temporary support system is a combined system formed of theφ609 steel piles ,bai‐ley trusses and theφ48 small diameter steel pipes ,w hich bears the loads of the bridge deck system during the construction process , secondary effect caused by prestress tensioning and the loads transmitted by the vertical rotating and lifting technique ,therefore ,the load bearing condition is complex .The refined numerical simulation technique was used to simulate the load bearing condi‐tion of the support system and structure during the w hole construction process .T he results of the numerical simulation and the practical monitoring data demonstrate that the structure is safe ,and the load bearing capacity of each component of the support system meets the requirements and the designed supporting posts improve the load bearing

  16. A comparison study on the deck house shape of high speed planing crafts for air resistance reduction

    Directory of Open Access Journals (Sweden)

    Park Chung-Hwan

    2014-12-01

    Full Text Available Planing crafts were specifically designed to achieve relatively high speeds on the water. When a planing craft is running at high speed, dynamic pressure on the bottom makes the boat rise on the surface of the water. This reduces the area of the sinking surface of the boat to increase air resistance. Air resistance means the resistance that occurs when the hull and deck house over the surface of the water come in contact with the air current. In this paper, we carried out a CFD numerical analysis to find optimal deck houses that decreased air-resistance on the water when planing crafts are running at high speed. We finally developed the deck house shape of high-speed planing crafts that optimally decreased air resistance.

  17. Development of a Human Motor Model for the Evaluation of an Integrated Alerting and Notification Flight Deck System

    Science.gov (United States)

    Daiker, Ron; Schnell, Thomas

    2010-01-01

    A human motor model was developed on the basis of performance data that was collected in a flight simulator. The motor model is under consideration as one component of a virtual pilot model for the evaluation of NextGen crew alerting and notification systems in flight decks. This model may be used in a digital Monte Carlo simulation to compare flight deck layout design alternatives. The virtual pilot model is being developed as part of a NASA project to evaluate multiple crews alerting and notification flight deck configurations. Model parameters were derived from empirical distributions of pilot data collected in a flight simulator experiment. The goal of this model is to simulate pilot motor performance in the approach-to-landing task. The unique challenges associated with modeling the complex dynamics of humans interacting with the cockpit environment are discussed, along with the current state and future direction of the model.

  18. 乌苏大桥主桥上部结构设计与计算%Design and Calculation of Superstructure of Main Bridge of Wusu Bridge

    Institute of Scientific and Technical Information of China (English)

    康晋; 肖海珠; 徐伟

    2011-01-01

    The main bridge of the Wusu Bridge is a single pylon and single cable plane cablestayed bridge with span arrangement (140+140) m and with a structural system of rigid fixity of the pylon, pier and girder. A summarized account of the design and calculation of the superstructure of the bridge is presented herewith. The main girder of the bridge is a composite girder with long cantilevers, the central part of the girder is designed as a two-cell and single-box steel girder and the steel cantilever at each side of the girder is the variable depth I-beam and is provided wiht a trough stringer at the far side, which are all topped with 25 cm thick concrete deck slabs connected with the girder via shearing studs. The part of the main girder close to the pylon is designed as a prestressed concrete box girder to facilitate the fixity of the girder with the pylon. The pylon is the single column pylon, 117 m in height. The stay cables, made up of low relaxation galvanized high strength parallel steel wire strands, are of the harp pattern cable plane arranged in the central alignment of the bridge deck. The finite element software MIDAS Civil 2006 and the SCDS programme are employed to calculate and analyze structure of the bridge. The results of the calculation and analysis indicate that the static, stability and dynamic characteristics of the bridge can meet the requirements in the relevant codes.%乌苏大桥主桥为独塔单索面斜拉桥,跨径布置为(140+140) m,采用塔、墩、梁固结体系,综述该桥上部结构设计与计算.主梁为带大挑臂的钢箱结合梁,中间钢箱梁采用单箱双室截面,两侧钢挑臂为变高度工字形梁,挑臂端部设槽形小纵梁;混凝土桥面板厚25 cm,与钢梁通过剪力钉连接;塔根部主梁采用预应力混凝土箱梁,以方便与桥塔固结;桥塔采用独柱式塔,高117 m;斜拉索为竖琴形中央平行索面布置,采用低松弛镀锌高强度平行钢丝束.采用有限元软件MIDAS Civil

  19. Energy harvesting from electrospun piezoelectric nanofibers for structural health monitoring of a cable-stayed bridge

    Science.gov (United States)

    Maruccio, Claudio; Quaranta, Giuseppe; De Lorenzis, Laura; Monti, Giorgio

    2016-08-01

    Wireless monitoring could greatly impact the fields of structural health assessment and infrastructure asset management. A common problem to be tackled in wireless networks is the electric power supply, which is typically provided by batteries replaced periodically. A promising remedy for this issue would be to harvest ambient energy. Within this framework, the present paper proposes to harvest ambient-induced vibrations of bridge structures using a new class of piezoelectric textiles. The considered case study is an existing cable-stayed bridge located in Italy along a high-speed road that connects Rome and Naples, for which a recent monitoring campaign has allowed to record the dynamic responses of deck and cables. Vibration measurements have been first elaborated to provide a comprehensive dynamic assessment of this infrastructure. In order to enhance the electric energy that can be converted from ambient vibrations, the considered energy harvester exploits a power generator built using arrays of electrospun piezoelectric nanofibers. A finite element analysis is performed to demonstrate that such power generator is able to provide higher energy levels from recorded dynamic loading time histories than a standard piezoelectric energy harvester. Its feasibility for bridge health monitoring applications is finally discussed.

  20. Nonlinear Analysis of Cable Vibration of a Multispan Cable-Stayed Bridge under Transverse Excitation

    Directory of Open Access Journals (Sweden)

    Kun Lin

    2014-01-01

    Full Text Available The nonlinear vibrations of cable in a multispan cable-stayed bridge subjected to transverse excitation are investigated. The MECS (multielements cable system model, where multielements per cable stay are used, is built up and used to analyze the model properties of the multispan cable-stayed bridges. Then, a simplified two-degrees-of-freedom (2-DOFs model, where the tower or the deck is reduced to a beam, is proposed to analyze the nonlinear dynamic behaviors of the beam and cable. The results of MECS model analysis show that the main tower in the multispan cable-stayed bridge is prone to the transverse vibration, and the local vibration of cables only has a little impact on the frequency values of the global modes. The results of simplified model analysis show that the energy can be transformed between the modes of the beam and cable when the nature frequencies of them are very close. On the other hand, with the transverse excitation changing, the cable can exhibit richer quasi-periodic or chaotic motions due to the nonlinear terms caused by the coupled mode between the beam and cable.

  1. 33 CFR 149.419 - Can the water supply for the helicopter deck fire protection system be part of a fire water system?

    Science.gov (United States)

    2010-07-01

    ... § 149.419 Can the water supply for the helicopter deck fire protection system be part of a fire water system? (a) The water supply for the helicopter deck fire protection system required under § 149.420 or... Service regulations under 30 CFR 250.803; or (2) The fire main system under § 149.415. (b) If the...

  2. Liquid-Bridge Breaking Limits

    Science.gov (United States)

    Macner, Ashley; Steen, Paul

    2011-11-01

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

  3. Measurement of Prestressing Force in Pretensioned UHPC Deck Using a Fiber Optic FBG Sensor Embedded in a 7-Wire Strand

    OpenAIRE

    Jae-min Kim; Hyun-woo Kim; Song-yi Choi; Sung-yong Park

    2016-01-01

    This paper presents the results of the performance test and long-term monitoring of the prestressing force inside concrete performed on a pretensioned Ultra-High Performance Concrete (UHPC) deck. The force is measured by applying a 7-wire strand embedded with an FBG (Fiber Bragg Grating) sensor. The performance test was conducted on a 3.7 m × 1.8 m pretensioned deck specimen through wheel loading tests to verify the applicability of the measurement method. In addition, a 12.3 m long and 4.8 m...

  4. Children's exposure to arsenic from CCA-treated wooden decks and playground structures.

    Science.gov (United States)

    Hemond, Harold F; Solo-Gabriele, Helena M

    2004-02-01

    CCA-treated wood is widely used in the fabrication of outdoor decks and playground equipment. Because arsenic can be removed from the surface of CCA-treated wood both by physical contact and by leaching, it is important to determine whether children who play on such structures may ingest arsenic in quantities sufficient to be of public health concern. Based on a review of existing studies, it is estimated that arsenic doses in amounts of tens of micrograms per day may be incurred by children having realistic levels of exposure to CCA-treated decks and playground structures. The most important exposure pathway appears to be oral ingestion of arsenic that is first dislodged from the wood by direct hand contact, then transferred to the mouth by children's hand-to-mouth activity. The next most important pathway appears to be dermal absorption of arsenic, while ingestion of soil that has become contaminated by leaching from CCA-treated structures appears to be of lesser importance, except possibly in the case of children with pica. Considerable uncertainty, however, is associated with quantitative estimates of children's arsenic exposure from CCA-treated wood. Priorities for refining estimates of arsenic dose include detailed studies of the hand-to-mouth transfer of arsenic, studies of the dermal and gastrointestinal absorption of dislodgeable arsenic, and studies in which doses of arsenic to children playing in contact with CCA-treated wood are directly determined by measurement of arsenic in their urine, hair, and nails.

  5. STS-65 Commander Cabana with SAREX-II on Columbia's, OV-102's, flight deck

    Science.gov (United States)

    1994-01-01

    STS-65 Commander Robert D. Cabana is seen on the Space Shuttle Columbia's, Orbiter Vehicle (OV) 102's, aft flight deck with the Shuttle Amateur Radio Experiment II (SAREX-II) (configuration C). Cabana is equipped with the SAREX-II headset and holds a cable leading to the 2-h window antenna mounted in forward flight deck window W1 (partially blocked by the seat headrest). SAREX was established by NASA, the American Radio League/Amateur Radio Satellite Corporation and the Johnson Space Center (JSC) Amateur Radio Club to encourage public participation in the space program through a project to demonstrate the effectiveness of conducting short-wave radio transmissions between the Shuttle and ground-based radio operators at low-cost ground stations with amateur and digital techniques. As on several previous missions, SAREX was used on this flight as an educational opportunity for students around the world to learn about space firsthand by speaking directly to astronauts aboard the shuttle.

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  8. Complex Testing of the Bridges

    Directory of Open Access Journals (Sweden)

    Savić Adrijana

    2016-01-01

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

  9. General design of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  10. Thermal bridges of modern windows

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  11. Reliability Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

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

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

  12. Ash-Based Building Panels Production and Demonstration of Aerock Decking Building Product

    Energy Technology Data Exchange (ETDEWEB)

    Alan E. Bland; Jesse Newcomer

    2007-06-30

    commercial-scale production trials showed green product sagging, as a result of the die design. After the third die was acquired and fitted to the extruder, satisfactory decking and structural panels were produced. Cured decking was shipped to the US but experienced significant breakage and damage during transport. Subsequent evaluations concluded that an alternative die design was needed that would produce a more robust product resistant to damage. In summary, AeRock Decking can be a commercially-viable non-wood alternative decking product. This project has provided WRI and AeRock the knowledge and understanding to make AeRock Decking a commercial success. However, a commercial demonstration that produces quality product and the subsequent evaluation of its performance is needed before commercial acceptance of the AeRock product.

  13. 大门大桥引桥过桥管线作用效应研究%Study of Action Effect of Pipelines Across Approach Bridge of Damen Bridge

    Institute of Scientific and Technical Information of China (English)

    庄小将; 马芹刚; 王丰平; 庄庆华; 周海旺

    2011-01-01

    To study the degree of the influence of pipelines across bridge on the working performance of the bridge itself, the approach bridge (a continuous box girder bridge) of the Damen Bridge in Wenzhou City was cited as an example. On the basis of comparison of the different pipeline layout schemes, it was determined that the layout scheme of special zones for the pipelines on both sides of the deck of the bridge should be adopted and the dynamic and static force analysis and study were made for the influence of the pipelines on the bridge structure. The results of the analysis and study indicate that the midspan deflection of the bridge caused by the water load can be ignored as compared to the midspan deflection subjected to the short-term load combination. Thoughthe fluctuation ranges of natural frequency of the continuous girder structure of the bridge and constant flow frequency in the pipelines are different, the two kinds of the frequencies do not result in resonance. The stress increment in normal section of the bridge caused by the water load is less than 1 Mpa, which will be not enough to influence the safe operation of the bridge.%为了研究过桥管线对桥梁工作性能的影响程度,以温州市大门大桥工程引桥(连续箱梁桥)为工程背景,通过对管线布置方案的比选,确定该桥采用桥面两侧“管线专用区域”的布置方案;并就输水管道对桥梁结构的影响进行静、动力分析研究.研究表明,水荷载引起的桥梁跨中挠度与荷载短期效应组合下跨中挠度相比,可以忽略;连续梁结构的固有频率与输水管道内恒定流频率的波动范围不同,二者不会产生共振现象;水荷载引起的桥梁结构正截面应力增量小于1 MPa,不足以影响桥梁的安全运营.

  14. Discussion on Yun-Gui Railway Nanpanjiang Grand CFST Arch Bridge Construction Technology%云桂铁路南盘江特大劲性混凝土拱桥施工技术探讨

    Institute of Scientific and Technical Information of China (English)

    冯丛

    2012-01-01

    The paper, taking Yun-Gui Railway Nanpanjiang Grand CFST Arch Bridge as research object, and referring to construction technology of domestic and international long-span deck CFST arch bridges, discusses the 416 m deck CFST arch construction method of the Nanpanjiang Grand CFST Arch Bridge, and then decides the construction plan, technical difficulties and countermeasures, which can offer reference for bridge construction under the same conditions.%以云桂铁路南盘江特大劲性混凝土拱桥为研究对象,参考国内外大跨度上承式劲性混凝土拱桥施工技术,对南盘江特大劲性混凝土拱桥的416 m上承式劲性混凝土拱的施工方法进行探讨,确定施工方案、研究技术难点及相应施工工艺,可为同类条件桥梁施工提供借鉴。

  15. The Higgs Bridge

    CERN Document Server

    Allen, Roland E

    2013-01-01

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

  16. Mineral bridges in nacre revisited

    CERN Document Server

    Checa, Antonio G; Willinger, Marc-Georg

    2012-01-01

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

  17. Simulation of multivariate diffusion bridges

    DEFF Research Database (Denmark)

    Bladt, Mogens; Finch, Samuel; Sørensen, Michael

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

  18. Applications of overburden conveyor bridges

    Energy Technology Data Exchange (ETDEWEB)

    Schachtschneider, H.

    1987-06-01

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

  19. Bridge Culture of Langde Village

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

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

  20. ANGIOGRAPHIC ASPECTS OF MYOCARDIAL BRIDGES

    Directory of Open Access Journals (Sweden)

    Sujatha. M

    2015-12-01

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

  1. The stories of two bridges in Ghana

    DEFF Research Database (Denmark)

    Andreasen, Jørgen

    2004-01-01

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

  2. An Expert System for Concrete Bridge Management

    DEFF Research Database (Denmark)

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

    1997-01-01

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

  3. 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.

  4. 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.

  5. Stability of liquid crystalline bridges

    Science.gov (United States)

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

    1999-02-01

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

  6. Design of Main Bridge of Xi′nan Bridge in Guigang City,Guangxi%广西贵港西南大桥主桥设计

    Institute of Scientific and Technical Information of China (English)

    李翠霞; 张巨生

    2015-01-01

    广西贵港市西南大桥主桥为(46+88+280+88+46) m双塔双索面预应力混凝土边主梁斜拉桥。主梁采用等高度带悬臂的矩形混凝土边主梁与“工”字形钢横梁相结合的形式,整幅桥面宽36.5m,设双向2.0%横坡。桥塔采用“鱼”状流线弧形框架钢筋混凝土结构,塔柱高102.5 m,采用外侧为“D”形圆弧段的箱形截面。桥塔设上、下横梁,均采用预应力混凝土单箱单室结构。全桥共设136根斜拉索,斜拉索采用φs 15.2 m m镀锌钢绞线索,空间双索面扇形布置。桥塔墩采用分离式基础,上、下游分离式基础中心距34.7 m ,其下各设9根φ2.5 m钻孔桩。承台为正方形钢筋混凝土结构。4号墩顶面设一圆端形塔座。%The main bridge of the Xi′nan Bridge in Guigang City ,Guangxi is a prestressed concrete edge main girders cable‐stayed bridge with double pylons ,double cable planes and with span arrangement (46+88+280+88+46) m .T he main girders of the bridge are of the structural type combining the rectangular concrete edge main girders having constant depth and cantilevers with the I‐shape steel cross beams .The width of the whole bridge deck is 36 .5 m and the deck is provided with dual 2 .0% transverse slopes .A pylon of the bridge is the“fish”‐shape streamlined arc frame reinforced concrete structure that is 102 .5 m in height and the outer side of the pylon is of the“D”‐shape round arc box section .The upper and lower cross beams of the pylon are all the prestressed concrete single‐cell single‐box structures .There are totally 136 stay cables arranged for the whole bridge .The stay cables are the φs 15 .2 mm galvanized steel wire strand cables and are arranged in fan shape and spatial double cable planes .The pylon pier is supported on the sep‐arated foundations .T he center‐to‐center distance of the foundations on the upstream and dow n‐stream sides is 34 .7

  7. Cleaning-induced arsenic mobilization and chromium oxidation from CCA-wood deck: Potential risk to children.

    Science.gov (United States)

    Gress, J; de Oliveira, L M; da Silva, E B; Lessl, J M; Wilson, P C; Townsend, T; Ma, L Q

    2015-09-01

    Concern about children's exposure to arsenic (As) from wood treated with chromated-copper-arsenate (CCA) led to its withdrawal from residential use in 2004. However, due to its effectiveness, millions of American homes still have CCA-wood decks on which children play. This study evaluated the effects of three deck-cleaning methods on formation of dislodgeable As and hexavalent chromium (CrVI) on CCA-wood surfaces and in leachate. Initial wipes from CCA-wood wetted with water showed 3-4 times more dislodgeable As than on dry wood. After cleaning with a bleach solution, 9.8-40.3μg/100cm(2) of CrVI was found on the wood surface, with up to 170μg/L CrVI in the leachate. Depending on the cleaning method, 699-2473mg of As would be released into the environment from cleaning a 18.6-m(2)-deck. Estimated As doses in children aged 1-6 after 1h of playing on a wet CCA-wood deck were 0.25-0.41μg/kg. This is the first study to identify increased dislodgeable As on wet CCA-wood and to evaluate dislodgeable CrVI after bleach application. Our data suggest that As and CrVI in 25-year old CCA-wood still show exposure risks for children and potential for soil contamination. PMID:26004992

  8. 40 CFR Table 28 to Subpart G of... - Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks 28 Table 28 to Subpart G of Part 63 Protection of Environment ENVIRONMENTAL... specific information is available, these factors can be assumed to represent the most common bolted...

  9. 46 CFR 179.350 - Openings in the side of a vessel below the bulkhead or weather deck.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Openings in the side of a vessel below the bulkhead or weather deck. 179.350 Section 179.350 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) SUBDIVISION, DAMAGE STABILITY, AND WATERTIGHT INTEGRITY Watertight Integrity Requirements §...

  10. 46 CFR 108.141 - Boundary bulkheads and decks between the emergency power source and service generators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Boundary bulkheads and decks between the emergency power source and service generators. 108.141 Section 108.141 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Structural Fire Protection § 108.141...

  11. Evaluation and Research on Road Performance of Long Span Steel Deck Pavement Structures%大跨径钢桥面铺装典型结构路用性能评价与研究

    Institute of Scientific and Technical Information of China (English)

    郝增恒

    2012-01-01

    The performances of the asphalt concrete pavement materials on the long span steel deck have great influence on riding comfort and the surface material durability. Three typical composite pavement structures are proposed based on the knowledge of properties and applicability of all kinds of pavement materials and the high-temperature stability, low-temperature bending performance, fatigue performance and water resistance of the mentioned three composite pavement structures are comprehensively studied and the performance differences of them are compared, based on Zhoushan Xihoumen Bridge. Indoor composite-structure fatigue analysis testing model is established according to the finite element analysis, and the technical performances of the three composite pavement structures as steel deck pavement structure are proved, which provided certain theoretical basis for deck pavement engineering.%大跨径钢桥面沥青混凝土铺装材料的性能对行车舒适性及面层材料的耐久性有重要的影响.在了解各类铺装材料特性和适用性的基础上,提出了3种典型铺装结构方案.并以舟山西堠门大桥为项目依托,对钢桥面铺装3种复合铺装结构的高温稳定性、低温弯曲性能、疲劳性能以及防水性能进行了综合研究,对比了3种复合铺装结构的性能差异.在进行疲劳性能分析时,根据有限元分析结果,创新性地建立了室内组合结构疲劳分析试验模型.通过试验验证了3种复合铺装结构作为钢桥面铺装的综合技术性能,为今后的桥面铺装工程提供了一定的理论基础.

  12. A Usability and Learnability Case Study of Glass Flight Deck Interfaces and Pilot Interactions through Scenario-based Training

    Science.gov (United States)

    De Cino, Thomas J., II

    In the aviation industry, digitally produced and presented flight, navigation, and aircraft information is commonly referred to as glass flight decks. Glass flight decks are driven by computer-based subsystems and have long been a part of military and commercial aviation sectors. Over the past 15 years, the General Aviation (GA) sector of the aviation industry has become a recent beneficiary of the rapid advancement of computer-based glass flight deck (GFD) systems. While providing the GA pilot considerable enhancements in the quality of information about the status and operations of the aircraft, training pilots on the use of glass flight decks is often delivered with traditional methods (e.g. textbooks, PowerPoint presentations, user manuals, and limited computer-based training modules). These training methods have been reported as less than desirable in learning to use the glass flight deck interface. Difficulties in achieving a complete understanding of functional and operational characteristics of the GFD systems, acquiring a full understanding of the interrelationships of the varied subsystems, and handling the wealth of flight information provided have been reported. Documented pilot concerns of poor user experience and satisfaction, and problems with the learning the complex and sophisticated interface of the GFD are additional issues with current pilot training approaches. A case study was executed to explore ways to improve training using GFD systems at a Midwestern aviation university. The researcher investigated if variations in instructional systems design and training methods for learning glass flight deck technology would affect the perceptions and attitudes of pilots of the learnability (an attribute of usability) of the glass flight deck interface. Specifically, this study investigated the effectiveness of scenario-based training (SBT) methods to potentially improve pilot knowledge and understanding of a GFD system, and overall pilot user

  13. STS-57 MS2 Sherlock operates RMS THC on OV-105's aft flight deck

    Science.gov (United States)

    1993-01-01

    STS-57 Mission Specialist 2 (MS2) Nancy J. Sherlock operates the remote manipulator system (RMS) translation hand control (THC) while observing extravehicular activity (EVA) outside viewing window W10 on the aft flight deck of Endeavour, Orbiter Vehicle (OV) 105. Positioned at the onorbit station, Sherlock moved EVA astronauts in the payload bay (PLB). Payload Commander (PLC) G. David Low with his feet anchored to a special restraint device on the end of the RMS arm held MS3 Peter J.K. Wisoff during the RMS maneuvers. The activity represented an evaluation of techniques which might be used on planned future missions -- a 1993 servicing visit to the Hubble Space Telescope (HST) and later space station work -- which will require astronauts to frequently lift objects of similar sized bulk. Note: Just below Sherlock's left hand a 'GUMBY' toy watches the actvity.

  14. ANALISA KEKUATAN DECK TONGKANG MUATAN TIANG PANCANG 750 DWT DENGAN SOFTWARE BERBASIS METODE ELEMEN HINGGA

    Directory of Open Access Journals (Sweden)

    Sukanto Jatmiko

    2012-02-01

    Full Text Available Pada  awalnya pihak pemilik kapal merencanakan material baja 200 ton untuk  pembangunan satu unit Tongkang ini akan tetapi supply material kemudian diperkecil menjadi 180 ton.Dengan demikian dalam tugas akhir ini penulis mencoba melakukan analisa kekuatan deck Tongkang ini untuk mengetahui keamanan terhadap beban-beban yang bekerja selama Tongkang beroperasi.                 Menganalisa konstruksi  geladak dengan Software finite element .sehingga dapat diketahui penyebaran tegangan yang terjadi akibat beban muatan dan SWL dari crane. ditinjau dari angka faktor keamanan (margine of safety Hasil analisa menggunakan program Msc Patran dan Msc Nastran didapatkan hasil tegangan maksimum von mises sebesar 5.02E5 N/mm2. Dan berdasarkan pengecekan terhadap tegangan ijin bahan, hasil analisis menunjukkan bahwa sistem tersebut dinyatakan kuat menahan beban maksimum operasional crane.

  15. 黄冈公铁两用长江大桥斜拉索安装技术%Installation Techniques for Stay Cables of Huanggang Changjiang River Rail-cum-Road Bridge

    Institute of Scientific and Technical Information of China (English)

    左宏献; 张士轩; 付东

    2013-01-01

    The main bridge of Huanggang Changjiang River Rail-cum-Road Bridge is a steel truss girder cable-stayed bridge with double pylons, double cable planes and with span arrangement (81 + 243 + 567 + 243 + 81) m. On both sides of a pylon of the bridge, each 19 pairs of the stay cables are provided and for the whole bridge, there are totally 152 nos. of the cables. In this paper, the installation techniques for the cables are summarized. In the process of installation of the cables, the fully rotary deck crane was used to lift each reel of the cables to the bridge deck and the cables were stretched there by the fixed cable stretching reel with the aid of the deck crane. The installation scheme was that the cables on the pylons were installed first and those at the deck level were installed late. For the installation of the cables on the pylons, the tower cranes and the lifting frames at the tops of the pylons were used while for the installation of the cables at the deck level, the cables were hauled by the winches and pulley blocks. When the cables were hauled in place, the cables were anchored and after the installation of the cables at the deck level was completed, the cables No. 3~8 were directly rigidly hauled in the pylons and the cables No. 9~19 were first softly (with maximum soft hauling force being 1 200 kN) and then rigidly hauled in the pylons. In compliance with the design requirements, the cables were synchronously and symmetrically tensioned in steps and the installation of the whole 4 000 t stay cables of the bridge were finally completed within 7 months.%黄冈公铁两用长江大桥主桥为双塔双索面钢桁梁斜拉桥,跨度布置为(81+243+567+243+81)m.每桥塔两侧各设置19对斜拉索,全桥共有斜拉索152根,对该桥斜拉索安装技术进行总结.采用全回转架梁吊机将整盘斜拉索吊至桥面;采用全回转架梁吊机配合桥面上固定式放索盘进行桥面展索;斜拉索总体挂设采用先塔后梁的方案,

  16. Floating liquid bridge charge dynamics

    Science.gov (United States)

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

    2016-01-01

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

  17. On application of modern steel fiber concrete technique in road and bridge construction%现代钢纤维混凝土技术在路桥施工中的应用

    Institute of Scientific and Technical Information of China (English)

    吴漫

    2016-01-01

    介绍了钢纤维混凝土的新特性,从配比设计、钢纤维投放、桥面铺装、混凝土桩浇筑等方面,阐述了钢纤维混凝土的施工技术,并总结了钢纤维在路桥施工中的应用要点,旨在延长路桥的使用年限。%The paper introduces the new features of the steel fiber concrete,illustrates the construction technique for the steel fiber concrete from the proportional ratio,release of steel fiber,bridge deck pavement,and concrete pile grouting,and sums up the application for the steel fiber in the road and bridge construction,so as to prolong the lifespan of roads and bridges.

  18. Wind stability of three-tower suspension bridges under construction%三塔悬索桥施工过程抗风稳定性研究

    Institute of Scientific and Technical Information of China (English)

    张新军; 郭辉

    2011-01-01

    Taking the first three-tower suspension bridge in the world with a main span over 1000 meters - the Taizhou Highway Bridge over the Yangtze River as example, for three different construction sequences of the deck, erected symmetrically from the midpoints of the main spans to the pylons, from the pylons toward the midpoints of the main spans, and simultaneously from the pylons and the midpoints of the main spans toward the quarter points of the main spans, respectively, evolutions of the structural aerostatic and aerodynamic stability during the deck erection process are investigated numerically by 3-1) nonlinear aerostatie and aerodynamic analysis, and the favorable deck erection sequence is discussed with respect to wind stability. The results show that the best aerostatic and aerodynamic stability is achieved under the deck erection sequence of pylons to midspans, which is considered to be favorable for three-tower suspension bridges.%以目前世界首座跨度超千米的三塔悬索桥——泰州长江公路大桥为工程背景,分别模拟主梁从主跨跨中向两侧桥塔、从两侧桥塔向主跨跨中以及从两侧桥塔和主跨跨中同时向主跨四分点处对称拼装的施工顺序,采用三维非线性空气静力和动力稳定性分析方法,分析主梁拼装过程结构的空气静力和动力稳定性的演变规律,并从抗风稳定性角度提出三塔悬索桥适宜的主梁拼装施工顺序。结果表明:主梁从两侧桥塔向主跨跨中对称拼装施工时,结构的空气静力和动力稳定性最好,是大跨度三塔悬索桥一种适宜的主梁拼装施工顺序。

  19. 谈一座景观人行天桥的设计%Discussion on the design of a landscape-style pedestrian bridge

    Institute of Scientific and Technical Information of China (English)

    王佳

    2015-01-01

    Combining with a practical project,this paper introduces the design for the pedestrian bridge mainly by descrbing the landscape design in such aspects as the structure form,rail,bridge deck pavement,the stress,stiffness and natural vibration frequency of the bridge is analyzed by using finite element software,put forward the construction scheme of the pedestrian bridge. It can be consulted by similar bridge design.%以实际工程为例,简要介绍了天桥结合景观在结构形式、栏杆、桥面铺装等方面的设计手法,并采用有限元软件,对天桥应力、刚度及自振频率进行了分析,据此提出了桥梁施工方案,可为类似工程设计提供参考。

  20. Bridging history and social psychology

    DEFF Research Database (Denmark)

    Glaveanu, Vlad Petre; Yamamoto, Koji

    2012-01-01

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

  1. Structural Design of Multi-Pylon Cable-Stayed Bridge with Corrugated Steel Webs for Chaoyang Bridge in Nanchang%南昌朝阳大桥波形钢腹板多塔斜拉桥结构设计

    Institute of Scientific and Technical Information of China (English)

    陈水生; 钟志斌; 桂水荣; 刘旭政; 钟汉清

    2014-01-01

    The PC composite box girder with corrugated steel webs is applicable to bridges with a variety of structural types ,which exhibits superior durability and economic features as com‐pared with the common concrete box girder .The cable‐stayed bridge with corrugated steel webs is regarded as the type of structure where composite box girder with corrugated steel webs is ingen‐iously used ,making better use of the properties of the two structures . The main navigational bridge of the Chaoyang Bridge in Nanchang is a (79+ 5 × 150+79) m continuous composite box girder cable‐stayed bridge with corrugated steel webs .The bridge has six pylons and the stay ca‐bles are arranged in single cable plane .In addition ,the bridge has two layers of decks ,on the up‐per deck ,dual eight vehicle lanes (four lanes each side) are arranged and pedestrian and non‐mo‐torized vehicle lanes are arranged on the lower deck .Based on the analysis and study undertaken , small side span‐to‐main span ratio was chosen .Due to the multiple pylons ,the load path from the intermediate pylons to the side pylons is long and the effect of ancillary piers in the side spans is minimal ,as a result ,no ancillary piers are installed .In the structural system ,the pylons and the main girder are fixed while the girder and piers are separated .The box girder is 43 .84 m wide , with transverse steel diaphragms .The stay cables are fanned out in single cable plane .The pylon looks like the Chinese character“合“ ,and double bearings are installed at the pylons .T he stay vi‐bration mitigation bearings are used as the vibration mitigation and isolation devices of the super‐structure ,which are installed below the two side pylons .%波形钢腹板PC组合箱梁适用于不同结构形式的桥梁,相比普通混凝土箱梁具有显著的耐久性和经济性,波形钢腹板斜拉桥将波形钢腹板组合箱梁应用到斜拉桥中,充分发挥了2种结构的特点。南昌朝

  2. Excitation Methods for Bridge Structures

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-02-08

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

  3. Bridge Number and Conway Products

    OpenAIRE

    Blair, Ryan C.

    2007-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Shunquan Qin; Pu Zhou; Youheng Hua

    2004-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    LI Jian-jun

    2010-01-01

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

  6. Control of wind-induced vibration of long-span bridges and tall buildings

    Institute of Scientific and Technical Information of China (English)

    GU Ming

    2007-01-01

    With the rapid increase in scales of structures,research on controlling wind-induced vibration of large-scale structures,such as long-span bridges and super-tall buildings,has been an issue of great concern.For wind-induced vibration of large-scale structures,vibration frequencies and damping modes vary with wind speed.Passive,semiactive,and active control strategies are developed to improve the windresistance performance of the structures in this paper.The multiple tuned mass damper (MTMD) system is applied to control vertical bending buffeting response.A new semiactive lever-type tuned mass damper (TMD) with an adjustable frequency is proposed to control vertical bending buffeting and torsional buffeting and flutter in the whole velocity range of bridge decks.A control strategy named sinusoidal reference strategy is developed for adaptive control of wind-induced vibration of super-tall buildings.Multiple degrees of freedom general building aeroelastic model with a square cross-section is tested in a wind tunnel.The results demonstrate that the proposed strategies can reduce vibration effectively,and can adapt to wind-induced vibration control of large-scale structures in the uncertain dynamic circumstance.

  7. Low-cost, quantitative assessment of highway bridges through the use of unmanned aerial vehicles

    Science.gov (United States)

    Ellenberg, Andrew; Kontsos, Antonios; Moon, Franklin; Bartoli, Ivan

    2016-04-01

    Many envision that in the near future the application of Unmanned Aerial Vehicles (UAVs) will impact the civil engineering industry. Use of UAVs is currently experiencing tremendous growth, primarily in military and homeland security applications. It is only a matter of time until UAVs will be widely accepted as platforms for implementing monitoring/surveillance and inspection in other fields. Most UAVs already have payloads as well as hardware/software capabilities to incorporate a number of non-contact remote sensors, such as high resolution cameras, multi-spectral imaging systems, and laser ranging systems (LIDARs). Of critical importance to realizing the potential of UAVs within the infrastructure realm is to establish how (and the extent to which) such information may be used to inform preservation and renewal decisions. Achieving this will depend both on our ability to quantify information from images (through, for example, optical metrology techniques) and to fuse data from the array of non-contact sensing systems. Through a series of applications to both laboratory-scale and field implementations on operating infrastructure, this paper will present and evaluate (through comparison with conventional approaches) various image processing and data fusion strategies tailored specifically for the assessment of highway bridges. Example scenarios that guided this study include the assessment of delaminations within reinforced concrete bridge decks, the quantification of the deterioration of steel coatings, assessment of the functionality of movement mechanisms, and the estimation of live load responses (inclusive of both strain and displacement).

  8. Measurement of the Dynamic Displacements of Railway Bridges Using Video Technology

    Directory of Open Access Journals (Sweden)

    Ribeiro Diogo

    2015-01-01

    Full Text Available This article describes the development of a non-contact dynamic displacement measurement system for railway bridges based on video technology. The system, consisting of a high speed video camera, an optical lens, lighting lamps and a precision target, can perform measurements with high precision for distances from the camera to the target up to 25 m, with acquisition frame rates ranging from 64 fps to 500 fps, and be articulated with other measurement systems, which promotes its integration in structural health monitoring systems. The system’s performance was evaluated based on two tests, one in the laboratory and other on the field. The laboratory test evaluated the performance of the system in measuring the displacement of a steel beam, subjected to a point load applied dynamically, for distances from the camera to the target between 3 m and 15 m. The field test allowed evaluating the system’s performance in the dynamic measurement of the displacement of a point on the deck of a railway bridge, induced by passing trains at speeds between 160 km/h and 180 km/h, for distances from the camera to the target up to 25 m. The results of both tests show a very good agreement between the displacement measurement obtained with the video system and with a LVDT.

  9. Reliability assessment of offshore platforms exposed to wave-in-deck loading. Appendix F: Reliability analysis of offshore jacket structures with wave load on deck using the model correction factor method

    Energy Technology Data Exchange (ETDEWEB)

    Dalsgaard Soerensen, J. [Aalborg Univ., Aalborg (Denmark); Friis-Hansen, P. [Technical Univ. Denmark, Lyngby (Denmark); Bloch, A.; Svejgaard Nielsen, J. [Ramboell, Esbjerg (Denmark)

    2004-08-01

    Different simple stochastic models for failure related to pushover collapse are investigated. Next, a method is proposed to estimate the reliability of real offshore jacket structures. The method is based on the Model Correction Factor Method and can be used to very efficiently to estimate the reliability for total failure/collapse of jacket type platforms with wave in deck loads. A realistic example is evaluated and it is seen that it is possible to perform probabilistic reliability analysis for collapse of a jacket type platform using the model correction factor method. The total number of deterministic, complicated, non-linear (RONJA) analysis is typically as low as 10. Such reliability analyses are recommended to be used in practical applications, especially for cases with wave in deck load, where the traditional RSR analyses give poor measures of the structural reliability. (au)

  10. Architectural engineering of FRP bridges

    OpenAIRE

    Smits, J.E.P.

    2014-01-01

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

  11. Instability of the capillary bridge

    Science.gov (United States)

    Pare, Gounseti; Hoepffner, Jerome

    2014-11-01

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

  12. Bridge Aesthetics and Structural Honesty

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

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

  13. The Wien Bridge Oscillator Family

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2006-01-01

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

  14. Architectural engineering of FRP bridges

    NARCIS (Netherlands)

    Smits, J.E.P.

    2014-01-01

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

  15. 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.

  16. Dynamic identification of paradela historic railway bridge

    OpenAIRE

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

    2013-01-01

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

  17. Transition Slabs of Integral Abutment Bridges

    OpenAIRE

    Dreier, Damien; Muttoni, Aurelio; BURDET, Olivier

    2011-01-01

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

  18. Path transformations of first passage bridges

    OpenAIRE

    Bertoin, Jean

    2003-01-01

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

  19. 47 CFR 80.331 - Bridge-to-bridge communication procedure.

    Science.gov (United States)

    2010-10-01

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

  20. Removal of failed crown and bridge.

    Science.gov (United States)

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

    2012-07-01

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

  1. Remediation: Higher Education's Bridge to Nowhere

    Science.gov (United States)

    Complete College America, 2012

    2012-01-01

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

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

    Science.gov (United States)

    Matsutani, Akihiro

    2004-05-01

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

  3. Post Learning Sleep Improves Cognitive-Emotional Decision-Making: Evidence for a ‘Deck B Sleep Effect’ in the Iowa Gambling Task

    Science.gov (United States)

    Seeley, Corrine J.; Beninger, Richard J.; Smith, Carlyle T.

    2014-01-01

    The Iowa Gambling Task (IGT) is widely used to assess real life decision-making impairment in a wide variety of clinical populations. Our study evaluated how IGT learning occurs across two sessions, and whether a period of intervening sleep between sessions can enhance learning. Furthermore, we investigate whether pre-sleep learning is necessary for this improvement. A 200-trial version of the IGT was administered at two sessions separated by wake, sleep or sleep and wake (time-of-day control). Participants were categorized as learners and non-learners based on initial performance in session one. In session one, participants initially preferred the high-frequency reward decks B and D, however, a subset of learners decreased choice from negative expected value ‘bad’ deck B and increased choices towards with a positive expected value ‘good’ decks (decks C and D). The learners who had a period of sleep (sleep and sleep/wake control conditions) between sessions showed significantly larger reduction in choices from deck B and increase in choices from good decks compared to learners that had intervening wake. Our results are the first to show that post-learning sleep can improve performance on a complex decision-making task such as the IGT. These results provide new insights into IGT learning and have important implications for understanding the neural mechanisms of “sleeping on” a decision. PMID:25409323

  4. Post learning sleep improves cognitive-emotional decision-making: evidence for a 'deck B sleep effect' in the Iowa Gambling Task.

    Science.gov (United States)

    Seeley, Corrine J; Beninger, Richard J; Smith, Carlyle T

    2014-01-01

    The Iowa Gambling Task (IGT) is widely used to assess real life decision-making impairment in a wide variety of clinical populations. Our study evaluated how IGT learning occurs across two sessions, and whether a period of intervening sleep between sessions can enhance learning. Furthermore, we investigate whether pre-sleep learning is necessary for this improvement. A 200-trial version of the IGT was administered at two sessions separated by wake, sleep or sleep and wake (time-of-day control). Participants were categorized as learners and non-learners based on initial performance in session one. In session one, participants initially preferred the high-frequency reward decks B and D, however, a subset of learners decreased choice from negative expected value 'bad' deck B and increased choices towards with a positive expected value 'good' decks (decks C and D). The learners who had a period of sleep (sleep and sleep/wake control conditions) between sessions showed significantly larger reduction in choices from deck B and increase in choices from good decks compared to learners that had intervening wake. Our results are the first to show that post-learning sleep can improve performance on a complex decision-making task such as the IGT. These results provide new insights into IGT learning and have important implications for understanding the neural mechanisms of "sleeping on" a decision.

  5. Post learning sleep improves cognitive-emotional decision-making: evidence for a 'deck B sleep effect' in the Iowa Gambling Task.

    Directory of Open Access Journals (Sweden)

    Corrine J Seeley

    Full Text Available The Iowa Gambling Task (IGT is widely used to assess real life decision-making impairment in a wide variety of clinical populations. Our study evaluated how IGT learning occurs across two sessions, and whether a period of intervening sleep between sessions can enhance learning. Furthermore, we investigate whether pre-sleep learning is necessary for this improvement. A 200-trial version of the IGT was administered at two sessions separated by wake, sleep or sleep and wake (time-of-day control. Participants were categorized as learners and non-learners based on initial performance in session one. In session one, participants initially preferred the high-frequency reward decks B and D, however, a subset of learners decreased choice from negative expected value 'bad' deck B and increased choices towards with a positive expected value 'good' decks (decks C and D. The learners who had a period of sleep (sleep and sleep/wake control conditions between sessions showed significantly larger reduction in choices from deck B and increase in choices from good decks compared to learners that had intervening wake. Our results are the first to show that post-learning sleep can improve performance on a complex decision-making task such as the IGT. These results provide new insights into IGT learning and have important implications for understanding the neural mechanisms of "sleeping on" a decision.

  6. STS-54 Pilot McMonagle talks to radio station from OV-105's aft flight deck

    Science.gov (United States)

    1993-01-01

    STS-54 Pilot Donald R. McMonagle, holding microphone, participates in an interview with a radio station on the Continental United States (CONUS) from the aft flight deck of the Earth-orbiting Endeavour, Orbiter Vehicle (OV) 105. Behind McMonagle are Mission Specialist 3 (MS3) Susan J. Helms (left) and MS2 Gregory J. Harbaugh. A third crewmember's legs appear above McMonagle's head.

  7. 46 CFR 173.060 - Openings in the side of a vessel below the bulkhead or weather deck.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Openings in the side of a vessel below the bulkhead or weather deck. 173.060 Section 173.060 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO VESSEL USE School Ships § 173.060 Openings in the side of a vessel below the bulkhead...

  8. 大连星海湾跨海大桥主桥总体设计%Overall Design of Main Bridge of Xinghai Bay Sea-Crossing Bridge in Dalian

    Institute of Scientific and Technical Information of China (English)

    檀永刚; 陈亮; 张哲

    2015-01-01

    大连星海湾跨海大桥主桥为(180+460+180) m双层地锚式悬索桥,主梁为钢桁架结构形式,采用整体节点构造,上、下2层桥面板均采用正交异性钢桥面板,桥面上铺装5.5 cm厚双层环氧沥青。锚碇采用空腹三角形框架混凝土重力式锚碇,设置在水深20~30 m的海床上,锚碇基础采用整体大沉箱,单个沉箱重达26000 t ,在船坞内预制完成后用拖轮拖运到桥位处安装在碎石基床上,碎石基床采用升浆技术进行加固。桥塔采用钢筋混凝土框架结构,设上、下2道横梁。主缆由钢丝强度等级为1770 M Pa的平行钢丝索股组成,并用长达16 m的刚性拉杆锚固在锚碇上,同时采用除湿系统结合传统防腐涂装体系的结构进行防腐,以提高缆索系统的耐久性。%T he main bridge of Xinghai Bay Bridge in Dalian is a double‐deck earth‐anchored sus‐pension bridge with span arrangement of (180+ 460+ 180) m .The stiffening girder adopts the type of steel truss girder structure with integrated nodes .The upper and lower bridge decks are fitted with orthotropic steel plate deck paved with 5 .5 cm thick double‐layer epoxy asphalt .The anchorages are the concrete gravity anchor blocks with open‐web triangular framework ,sitting on the seabed that is 20~30 m under the sea ,the foundations of w hich adopt the large integrated cais‐sons ,each weighing up to 26 000 t .The caissons were prefabricated in the ship yard ,and then towed to the bridge site by the tug boats ,and sunk to the crushed stone seabed that are strength‐ened by prepackaged aggregate concrete technology .Bridge towers are the reinforced concrete frame structures ,equipped with an upper and a lower cross beams .The main cables are made up of prefabricated parallel wire strands ,each with a strength of 1 770 MPa ,anchored to the anchor blocks using the 16 m long rigid anchoring roads .T he main cables are corrosion

  9. The Effects of Infrared-Blocking Pigments and Deck Venting on Stone-Coated Metal Residential Roofs

    Energy Technology Data Exchange (ETDEWEB)

    Miller, William A [ORNL

    2006-01-01

    Field data show that stone-coated metal shakes and S-mission tile, which exploit the use of infraredblocking color pigments (IrBCPs), along with underside venting reduce the heat flow penetrating the conditioned space of a residence by 70% compared with the amount of heat flow penetrating roofs with conventional asphalt shingles. Stone-coated metal roof products are typically placed on battens and counter-battens and nailed through the battens to the roof deck. The design provides venting on the underside of the metal roof that reduces the heat flow penetrating a home. The Metal Construction Association (MCA) and its affiliate members installed stone-coated metal roofs with shake and S-mission tile profiles and a painted metal shake roof on a fully instrumented attic test assembly at Oak Ridge National Laboratory (ORNL). Measurements of roof, deck, attic, and ceiling temperatures; heat flows; solar reflectance; thermal emittance; and ambient weather were recorded for each of the test roofs and also for an adjacent attic cavity covered with a conventional pigmented and direct nailed asphalt shingle roof. All attic assemblies had ridge and soffit venting; the ridge was open to the underside of the stone-coated metal roofs. A control assembly with a conventional asphalt shingle roof was used for comparing deck and ceiling heat transfer rates.

  10. 整体桥面结构连接细部模型双向受拉疲劳试验研究%Fatigue Test Study of Model for Connection Detail of Integral Deck Structure Subjected to Two-Way Tensioning

    Institute of Scientific and Technical Information of China (English)

    徐海鹰; 陈金州

    2009-01-01

    The main bridge of Dashengguan Changjiang River Bridge in Nanjing is a six-span continuous steel truss arch bridge and the deck of the bridge makes use of the integral steel deck structure. The full-scale model for the connection detail between the deck and gusset plates of the bottom chord of the main truss is fabricated and the fatigue tests for the model are made in three stages. After the fatigue test in each stage is completed, the upper limit of the test load in that stage is used to continue to make the static load test. The analysis of the ANSYS shows that the design and loading of the model can meet the requirements for simulation and the loading applied in the tests can represent the force conditions of the actual structure. The static load test shows that under the action of different loading levels, the model is still in the state of elasticity and is almost without residual stress after unloading. The results of the fatigue tests further show that when the model was tested under different times of load cycling and the stress redistribution due to the fatigue damage influence does not occur. Under the action of loading according to the given calculated stress amplitude, the life of the model under constant stress amplitude loading is longer than 200×10~4 times of load cycling, the fatigue resistance is greater than the two-way stress amplitude of the designed test load and the connection detail between the deck and gusset plates has sufficient fatigue resistance capacity.%南京大胜关长江大桥主桥为六跨连续钢桁拱桥,采用整体桥面板结构.制作钢桥面板和主桁下弦杆节点板连接细节足尺模型,分3个阶段进行疲劳试验.每个阶段疲劳试验完成后,以该阶段试验荷载上限进行静力试验.ANSYS分析结果显示,模型设计及加栽满足模拟要求,试验加载能够反映实际结构的受力状况.静力试验结果表明,各级荷载作用下模型均处于弹性阶段,卸载

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

    OpenAIRE

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

    2015-01-01

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

  12. Design and Risk Evaluation of Highway Bridges under Effect of Railways and Flood%铁路及洪水影响下的公路桥梁设计与风险评估

    Institute of Scientific and Technical Information of China (English)

    王鹏; 王美馨; 汪宏; 李琦

    2014-01-01

    某高速公路桥梁与3座高速铁路桥梁交叉,公路桥梁下穿铁路桥梁,同时跨越嘉陵江支流,其建设、施工及运营安全受铁路施工、运营及嘉陵江洪水的影响,洪水位高出桥面最大约4.1 m。针对这一极端复杂环境条件,探讨公路桥梁结构及防、排水设计要点,研究桥梁建设条件、结构方案、施工、运营的主要风险源、风险等级及对策。%Some expressway bridge crosses with 3 high-speed railway bridges and railway bridges pass underneath, and meanwhile steps over branches of Jialing River, its development, construction and operation safety is affected by railway construction, operation and flood of Jialing River, the maximum flood level higher than the bridge deck is approximate 4. 1 m. In allusion to this extremely complicated environmental condition, this paper probes into key points in design of structure, water resistance and drainage of highway bridges and studies construction conditions, structure schemes of bridges and main risk sources and levels in construction and operation as well as countermeasures.

  13. The Design for a 132 m Double Track Simply Supported Steel Truss Beam of Guchengwan Main Bridge%古城湾特大桥主桥1孔132m双线铁路钢桁梁设计

    Institute of Scientific and Technical Information of China (English)

    吴文华

    2015-01-01

    研究目的:古城湾特大桥是集包第二双线铁路的控制性工程。主桥受控于地形、结构高度、场地等诸多因素,采用1孔132 m 下承式无竖杆三角型整体节点平弦简支钢桁梁跨越既有京包双线铁路,建成时为国内最大跨度的双线有砟铁路简支钢桁梁。本文针对该桥结构、桥面系比选、结构分析、低温防脆断跨繁忙铁路干线的桥梁施工方案进行研究和设计。研究结论:(1)桥面系采用纵横梁体系加 RPC 道砟槽板的方案,减轻了桥面系自重,解决了整体式道砟槽板后期维修和更换的难题,便于后期维护;(2)采用大跨简支结构的可行性,可以避免采用连续结构边跨的浪费;(3)采用合理的板厚、设计构造、焊缝分布、应力控制后,可以解决钢桥低温脆断的问题;(4)本桥采用无平衡重平转法施工方案,极大地减小了施工对既有铁路运输的影响;(5)本桥结构设计、新型的桥面系、创新的施工方案,可为今后设计和施工同类桥梁提供参考。%Research purposes:Guchengwan bridge is the key project of the second double track railway from Jining to Baotou.The main bridge adopts a steel truss beam with 132 m span,which is controlled by terrain,structure height, site and so on.The main span is a simply supported steel truss spanning Beijing -Baotou railway with no vertical member,triangular flat chord and integral joint node.It is the largest span in double line ballasted railway simple -supported steel truss bridge when it has been finished.The paper gives some conclusions about structure,bridge deck selection,structure analysis,preventing brittle breaking under low temperature,and construction schemes on spanning the busy main railway. Research conclusions:(1)Adopting longitudinal -transverse beam system and RPC ballast trough plate in bridge deck, not only could lighten deck weight,but also avoid difficulties such

  14. Vortex resonance depression mechanism of a bridge deck with aerodynamic measures%气动措施抑制桥梁涡振机理研究

    Institute of Scientific and Technical Information of China (English)

    许福友; 林志兴; 李永宁; 楼文娟

    2010-01-01

    通过表面测压方法研究了桥梁主梁基本断面、添加抑流板或导流板后断面的涡激共振特性;基于三种断面不同风速各测点压力时程,综合对比分析脉动压力系数均值、标准差、功率谱及局部与总体气动力相关性对涡振的影响,揭示了扭转涡振及气动措施抑振的机理.研究发现:扭转涡振的根本原因是上表面上游的分离使得中游和下游区域压力脉动非常强烈,各测点脉动压力具有相同卓越频率,且与总体气动力具有良好的相关性;抑流板改善了上表面流场分布,有效抑制了涡振;而导流板对上表面流场基本无影响,未能抑制涡振.

  15. Indoor Test Analysis on Performance of Waterproof Binding Course of Bridge Deck%桥面防水黏结层性能室内试验分析

    Institute of Scientific and Technical Information of China (English)

    朱建富

    2014-01-01

    对4种防水黏结材料进行黏结力试验,结果表明环氧沥青的黏结效果最优。不同试验温度及喷砂构造深度下的室内剪切试验结果表明:抗剪强度随试验温度的升高而减低,且在最佳构造深度时,抗剪强度达到最大。不同试验温度、浸水及冻融条件下的拉拔试验结果表明:防水黏结材料的拉拔强度随着温度的升高而明显降低,且温度越高,衰减越快;在浸水和冻融条件下,拉拔强度出现不同幅度的下降。%The cohesive force test is carried out on four kinds of waterproof. The results show that the ep-oxy asphalt is of the optimal binder effect. The results of indoor shearing tests with different temperatures and different sandblasting structure depth show that the shear strength decreases as the test temperature increases, and when the optimal sandblasting structure depth is achieved, the shear strength reaches maxi-mum. The results of drawing tests under the condition of different test temperatures, soaking and freeze thawing show that with the increase of temperature, the drawing strength of waterproof cohesive materials significantly reduces, the higher the temperature is, the faster the drawing strength decays, and under the condition of soaking and freeze-thaw, the drawing strength drops with different amplitude.

  16. Construction Technology of Sandblasting Rust Treatment for Steel Bridge Deck%钢桥面喷砂除锈施工工艺研究

    Institute of Scientific and Technical Information of China (English)

    谢孟华

    2014-01-01

    钢桥面防腐涂装层的质量对于工程造价、工期,特别是钢结构的使用年限影响极大.鉴于此,广泛调查钢桥面防锈处理情况,在总结国内外钢桥面防锈处理理论研究和实践经验的基础上,提出了钢桥面铺装防锈处理方法,研究了钢桥面喷砂除锈技术指标和施工工艺参数.

  17. 轻型组合桥面板的疲劳性能研究%Study on fatigue performance of light-weighted composite bridge deck

    Institute of Scientific and Technical Information of China (English)

    丁楠; 邵旭东

    2015-01-01

    疲劳性能是钢桥面板设计的主要关注点,为研究轻型组合桥面板的疲劳性能,以广东虎门大桥为背景,建立局部有限元模型,利用热点应力法,对不同厚度超高性能混凝土(UHPC)层情形下,钢桥面典型易疲劳开裂细节,进行应力幅计算.然后,对采用45mm厚UHPC层的轻型组合桥面板进行UHPC层及栓钉应力(剪力)分析,并依据前人和二次疲劳足尺模型试验对UHPC层的抗弯拉疲劳性能进行评价.研究结果表明:轻型组合桥面板中UHPC层对于钢面板与纵肋连接细节,应力幅改善作用很大,而对其余细节,其改善程度相对较小;采用45 mm厚UHPC层时,前者应力降幅高达51% ~82%,后者降幅为21%~28%;面板与纵肋连接细节、纵肋对接细节及横隔板弧形切口细节的疲劳开裂风险可完全消除;UHPC层峰值拉应力为11.91MPa,两次疲劳试验表明其抗弯拉疲劳性能远超虎门大桥的要求.

  18. VIBRATION AND ACOUSTIC RADIATION FROM SUBMERGED STIFFENED SPHERICAL SHELL WITH DECK-TYPE INTERNAL PLATE

    Institute of Scientific and Technical Information of China (English)

    ChenJnnming; HuangYuying

    2003-01-01

    Based on the motion differential equations of vibration and acoustic coupling system for thin elastic spherical shell with an elastic plate attached to its internal surface, in which Dirac-δ functions are employed to introduce the moments and forces applied by the attachment on the surface of shell, by means of expanding field quantities as Legendre series, a semi-analytic solution is derived for the vibration and acoustic radiation from a submerged stiffened spherical shell with a deck-type internal plate, which has a satisfactory computational effectiveness and precision for an arbitrary frequency range. It is easy to analyze the effect of the internal plate on the acoustic radiation field by using the formulas obtained by the method proposed. It is concluded that the internal plate can significantly change the mechanical and acoustic characteristics of shell, and give the coupling system a very rich resonance frequency spectrum. Moreover, the method can be used to study the acoustic radiation mechanism in similar structures as the one studied here.

  19. A comparison of ship and satellite measurements of cloud properties in the southeast Pacific stratus deck

    Directory of Open Access Journals (Sweden)

    M. A. Brunke

    2010-02-01

    Full Text Available Here, liquid water path (LWP, cloud fraction, cloud top height, and cloud base height are retrieved by a suite of satellite instruments (the CPR aboard CloudSat, CALIOP aboard CALIPSO, and MODIS aboard Aqua and compared to ship observations from research cruises made in 2001 and 2003–2007 into the stratus/stratocumulus deck over the southeast Pacific Ocean. It is found that CloudSat LWP is generally too high over this region and the CloudSat/CALIPSO cloud bases are too low which is to be expected from the increased sensitivity to precipitation by both the radar and lidar. This results in a relationship (LWP~h9 between CloudSat LWP and CALIPSO cloud thickness (h that is very different from the adiabatic relationship (LWP~h2 from in situ observations. Furthermore, comparing results from a global model (CAM3.1 to ship observations reveals that, while the simulated LWP is quite reasonable, the model cloud is too thick and too low, allowing the model to have LWPs that are almost independent of h. Such differences may be reduced in future versions of both the satellite data and the model.

  20. Full-Circle Color Panorama of Phoenix Lander Deck and Landing Site on Northern Mars, Animation

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on image to view the animation This view combines more than 500 images taken after NASA's Phoenix Mars Lander arrived on an arctic plain at 68.22 degrees north latitude, 234.25 degrees east longitude on Mars. This movie makes a slow tour around highlights of the image including the landscape and the spacecraft's science deck. The full-circle panorama in approximately true color shows the polygonal patterning of ground at the landing area, similar to patterns in permafrost areas on Earth. The center of the image is the westward part of the scene. Trenches where Phoenix's robotic arm has been exposing subsurface material are visible in the right half of the image. The spacecraft's meteorology mast, topped by the telltale wind gauge, extends into the sky portion of the panorama. This view comprises more than 100 different Stereo Surface Imager camera pointings, with images taken through three different filters at each pointing. It is presented here as a cylindrical projection. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.