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. Analysis of Biaxially Stressed Bridge Deck Plates

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Bondum, Tommi Højer

    The ultimate state analysis of bridge deck plates at the intersection zone between main girders and transverse beams is complicated by biaxial membrane stresses, which may be in compression or tension in either direction depending on the bridge configuration and the specific location. This paper ...

  3. Cracking behavior of structural slab bridge decks

    Science.gov (United States)

    Baah, Prince

    Bridge deck cracking is a common problem throughout the United States, and it affects the durability and service life of concrete bridges. Several departments of transportation (DOTs) in the United States prefer using continuous three-span solid structural slab bridges without stringers over typical four-lane highways. Recent inspections of such bridges in Ohio revealed cracks as wide as 0.125 in. These measured crack widths are more than ten times the maximum limit recommended in ACI 224R-01 for bridge decks exposed to de-icing salts. Measurements using digital image correlation revealed that the cracks widened under truck loading, and in some cases, the cracks did not fully close after unloading. This dissertation includes details of an experimental investigation of the cracking behavior of structural concrete. Prism tests revealed that the concrete with epoxy-coated bars (ECB) develops the first crack at smaller loads, and develops larger crack widths compared to the corresponding specimens with uncoated (black) bars. Slab tests revealed that the slabs with longitudinal ECB developed first crack at smaller loads, exhibited wider cracks and a larger number of cracks, and failed at smaller ultimate loads compared to the corresponding test slabs with black bars. To develop a preventive measure, slabs with basalt and polypropylene fiber reinforced concrete were also included in the test program. These test slabs exhibited higher cracking loads, smaller crack widths, and higher ultimate loads at failure compared to the corresponding slab specimens without fibers. Merely satisfying the reinforcement spacing requirements given in AASHTO or ACI 318-11 is not adequate to limit cracking below the ACI 224R-01 recommended maximum limit, even though all the relevant design requirements are otherwise met. Addition of fiber to concrete without changing any steel reinforcing details is expected to reduce the severity and extent of cracking in reinforced concrete bridge decks.

  4. Renovation techniques for fatigue cracked orthotropic steel bridge decks

    OpenAIRE

    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-known example of fatigue cracks are those observed in the deck plate of the Van Brienenoord bascule bridge in 1997, at that time a 7 year old bridge. The renovation techniques are part of a proposed ma...

  5. Monitoring durability of new concrete bridge decks

    Science.gov (United States)

    Aktan, Haluk M.; Yaman, Ismail O.; Staton, John F.

    2001-08-01

    The ND durability monitoring procedure, which measures the soundness of field concrete, is based on the fundamental relationship between ultrasonic pulse velocity (UPV) and permeability of an elastic medium. An experimental study documented adequate sensitivity between UPV and concrete permeability. The durability monitoring procedure is based on a parameter developed as part of this study and called paste quality loss (PQL) which is computed from the probability density function parameters of ultrasonic pulse velocity measurements taken from standard and field concrete. For PQL computation, measurements taken on standard concrete specimens, which are made from field concrete mixture, are compared to field measurements. The verification tests on 1000 mm x 1500 mm x 230 mm lab-deck specimens indicated that the PQL parameter computed from the UPV measurements as early as the 28th day is a good predictor of soundness. The UPV measurements made at increasing age of concrete very clearly document the rapid loss of soundness of improperly cured concrete decks. Deck replacement projects on three NHS bridges were used in the implementation of durability monitoring by PQL (paste quality loss) evaluation. The respective 56-day PQL's were calculated as 15%, 31% and 9% indicating a significant variability in the three bridges.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. Documenting the Construction of a Plain Concrete Bridge Deck and an Internally Cured Bridge Deck

    OpenAIRE

    Di Bella, Carmelo; Schlitter, John; Carboneau, Neal; Weiss, Jason

    2012-01-01

    Durable and long lasting concrete is important, especially for bridge decks, which are susceptible to premature cracking and corrosion of the reinforcing steel. To increase the durability of the concrete and its service life, many transportation agencies use high-strength concretes. However, high-strength concretes often have problems with early age cracking due to shrinkage. These cracks can then open a path for chloride ions (found in road salts) to reach the reinforcing steel. The results ...

  11. 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...

  12. 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

  13. 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 cr...... cracking is introduced and the site dependency of corrosion is stressed. Finally, a recently developed optimal repair strategy for bridges is briefly explained....

  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. 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.

  16. Nonlinear Ultrasonic Testing on a Laboratory Concrete Bridge Deck

    Science.gov (United States)

    Roe, Shannon E.; Woodward, C.; Cramer, M. J.

    2007-03-01

    Nonlinear ultrasonic testing has been shown to be extremely sensitive to distributed damage in concrete. Nonlinear nondestructive ultrasonic tests were performed on a laboratory bridge to detect distributed damage in the deck after it had been overloaded. The NLUT detected damage throughout the deck, and of particular interest in locations where damage was not visible. These results were compared to results obtained using pulse velocity tests at the same locations. The nonlinear ultrasonics were several orders of magnitude more sensitive than results obtained from pulse velocity.

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

    OpenAIRE

    Jared R. Wright; Farshad Rajabipour; Jeffrey A. Laman; Aleksandra Radlińska

    2014-01-01

    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 ...

  19. Road Performance of Fiber Reinforced Asphalt Concrete Bridge Deck Pavement

    OpenAIRE

    Xiu Liu; Zhaojie Sun; Decheng Feng; Yixiang Cao

    2013-01-01

    As the problem of asphalt concrete bridge deck pavement is becoming more and more serious, how to improve its road performance has become the focus of the study. Considering fiber is widely used in road engineering, wheel tracking test, flexural test, immersion marshall test and freeze-thaw splitting test were carried out to study road performance of asphalt mixture with different fiber contents, analyzing the function mechanism of fiber reinforced asphalt ...

  20. 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...

  1. Fatigue lifetime estimation on the steel bridges with orthotropic decks

    Czech Academy of Sciences Publication Activity Database

    Culek jr., B.; Urushadze, Shota; Vágner, J.; Culek, B.; Frýba, Ladislav

    Siofók : Scientific Society for Mechanical Enginnering, 2011 - (Ódor, I.; Borbás, L.), s. 199-200 ISBN 978-963-9058-32-3. [Danubia- Adria Symposium SSME /28./. Siófok (HU), 28.09.2011-01.10.2011] Grant ostatní: GAČR(CZ) GA103/08/1340 Institutional research plan: CEZ:AV0Z20710524 Keywords : steel bridges * fatigue * orthotropic decks Subject RIV: JM - Building Engineering

  2. 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.

  3. Bridge weigh-in-motion on steel orthotropic decks and application to bridge assessment

    OpenAIRE

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

    2012-01-01

    Bridge weigh-in-motion uses an instrumented bridge as a scale to weigh vehicles. Several types of bridges may be used, if being sensitive to wheel or axle loads. Here some strains of steel orthotropic deck bridges are measured by extensometers and analyzed by software, to calculate axle loads and gross vehicle weights. Between 2009 and 2011, several large scale tests were done on the Millau viaduct (France), the tallest cable stayed bridge in the world. These tests showed that the system meet...

  4. 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...

  5. 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)

  6. 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...

  7. The Viability of Steel-Concrete Composite Girder Bridges With continuous Profiled Steel Deck

    OpenAIRE

    Hatlee, Jonathan Russell

    2009-01-01

    The continuous permanent metal deck form system provides a quick and efficient method of constructing short-span, simply supported composite steel girder bridges. However, because shear studs can only be welded to the girder through the steel deck at rib locations, the number of shear stud locations is limited to the number of ribs in the shear span while the spacing of the shear studs is restricted to the rib spacing of the steel deck. This results in a condition where various...

  8. 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,...

  9. 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.

  10. 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 ...

  11. 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...

  12. 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...

  13. 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

  14. Analytical Study of Vertical and Torsional Free Vibration of Cable Supported Bridge Decks

    Science.gov (United States)

    Gorman, Daniel J.

    The superposition method is employed to obtain an analytical type solution for the free vibration of cable supported bridge decks. Each pair of vertical elastic cables is considered to impart a vertical force to the deck by means of a rigid cross-member passing transversely beneath it. Rigid knife-edge support encountered at bridge towers is handled as well. In this introductory study the deck is treated as a thin isotropic plate. Any number of support cable pairs, of any stiffness, may be handled. Inter cross-member distances are referred to as spans. Free vibration eigenvalues and mode shapes are presented for three and four span illustrative cases.

  15. 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.

  16. 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.

    2016-05-01

    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.

  17. 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.

  18. 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.

  19. 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...

  20. 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

  1. 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...

  2. 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.

  3. 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...

  4. 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...

  5. 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.

  6. Experimental Analysis of Stiffness of the Riveted Steel Railway Bridge Deck Members' Joints

    Science.gov (United States)

    Gocál, Jozef; Hlinka, Richard; Jošt, Jozef; Bahleda, František

    2014-12-01

    The paper deals with the real behaviour of the riveted steel railway bridge deck members' connections with respect to their bending stiffness. Attention is paid to the stringer-to-cross beam connection as well as the cross beam-to-main girder connection. The stiffness of the two connections is investigated on the basis of evaluation of the experimentally determined stress response of the observed structural members to the actual traffic load on an existing railway bridge.

  7. Experimental Analysis of Stiffness of the Riveted Steel Railway Bridge Deck Members’ Joints

    Directory of Open Access Journals (Sweden)

    Gocál Jozef

    2014-12-01

    Full Text Available The paper deals with the real behaviour of the riveted steel railway bridge deck members’ connections with respect to their bending stiffness. Attention is paid to the stringer-to-cross beam connection as well as the cross beam-to-main girder connection. The stiffness of the two connections is investigated on the basis of evaluation of the experimentally determined stress response of the observed structural members to the actual traffic load on an existing railway bridge.

  8. Behavior of Concrete Bridge Decks and Slabs Reinforced with Epoxy Coated Steel

    OpenAIRE

    Hasan, Hendy Oetih; Ramirez, J A

    1995-01-01

    Thirty-four slab specimens with splices and transverse steel were tested in the laboratory to evaluate the structural performance of concrete bridge decks reinforced with epoxy-coated steel. Thirty specimens were tested under fatigue loading, and four were tested monotonically. Evaluations were made by comparing the performance of uncoated bar concrete specimens with that of epoxy-coated specimens under service and ultimate load conditions. In addition, a field evaluation of six bridges wa...

  9. Cross-spectral recognition method of bridge deck aerodynamic admittance function

    Science.gov (United States)

    Zhao, Lin; Ge, Yaojun

    2015-12-01

    This study proposes a new identification algorithm about the admittance function, which can estimate the full set of six aerodynamic admittance functions considering cross power spectral density functions about the forces and the turbulence components. The method was first numerically validated through Monte Carlo simulations, and then adopted to estimate the aerodynamic admittance of a streamlined bridge deck. The identification method was further validated through a comparison between the numerical calculation and wind tunnel tests on a moving bridge section.

  10. Evaluation of Epoxo 300-C nonskid coating for use on bridge decks

    Science.gov (United States)

    Kidd, S. Q.

    1984-01-01

    There is a problem of polishing steel grid bridge decks. The I-10 bridge over the East Pascagoula River is of particular concern because of the volume, speed of traffic, length of span, and the rapid decrease in skid numbers. In addition, the grid causes lateral movement which is critical with motorcycles. The purpose of the study was to find a better way to improve skid resistance on steel grid bridge decks. It appears from the tests that Epoxo will provide a good long-life skid resistant surface on concrete and also steel plate. On the steel grid the wear is much heavier because of the small contact area between the tire and the grid.

  11. 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.

  12. 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...

  13. 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.

  14. Early-age durability assessment of cast-in-place RC bridge deck

    Science.gov (United States)

    Aktan, Haluk M.; Yaman, Ismail O.; Udegbunam, Oge; Hearn, Nataliya

    2000-06-01

    A novel method for evaluating concrete permeability at an early age is being developed for use in performance-related specifications where the material durability is specified as a performance parameter. In developing the method, the fundamental relationship between ultrasonic pulse velocity (UPV) and permeability of a porous medium is derived. An experimental relationship between UPV and concrete permeability is also established which strongly correlates with its theoretical counterpart. This experimental relationship is developed from UPV and permeability tests conducted on specimens made from a series of concrete grades. The experimental relation utilized the data collected from specimens made from a total of 20 bridge deck normal concrete mixes corresponding to five w/c (water-cement ratio) groups of 0.35, 0.40, 0.45, 0.50 and 0.55. The implementation procedure developed is the application of the 'paste efficiency' principle. In implementing 'paste efficiency' principle during the casting of a bridge deck, standard specimens are prepared in the field and cured in the laboratory. UPV measurements are obtained at an early age both from the deck and the standard specimens. The decrease in UPV from standard specimens indicates paste quality loss (PQL) and is proportional to the increase in permeability of deck concrete.

  15. Assessment of concrete bridge decks with alkali silica reactions

    DEFF Research Database (Denmark)

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

    , 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...

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

    Science.gov (United States)

    Mazzeo, Brian A.; Patil, Anjali N.; Klis, Jeffrey M.; Hurd, Randy C.; Truscott, Tadd T.; Guthrie, W. Spencer

    2014-02-01

    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.

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

    International Nuclear Information System (INIS)

    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

  18. 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.

  19. 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.

  20. 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.

  1. 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 ...

  2. 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...

  3. 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...

  4. 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. ...

  5. 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...

  6. 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...

  7. 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.

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

    OpenAIRE

    Khalim A.R.; Sagar D.; Kumruzzaman M.D.; Hasan A.S.M.Z.

    2011-01-01

    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...

  9. 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

  10. Study of concrete drilling for automated non-destructive evaluation and rehabilitation system for bridge decks

    Science.gov (United States)

    Trkov, Mitja; Liu, Fei; Yi, Jingang; Baruh, Haim

    2011-04-01

    Robotic drilling is the basic process for the non-destructive rehabilitation (NDR) system in the Automated Non-destructive Evaluation and Rehabilitation System (ANDERS) for bridge decks. In this paper, we present a study and testing of a concrete drilling process that is used for robotic drilling process for bridge decks repair. We first review the ANDERS and NDR design. Then we present the experimental setup for the drilling process study. A set of testing experiments are performed considering drilling process parameters such as drill bit size, drill rotating speed, drill thrust force and types of concrete composites. Based on the experiments and analysis, we identify and find that the optimal set of drilling process parameters for the ANDERS application is 1/4-inch bit size, drill rotational speed of 1500 rpm and thrust force around 35 lbs. We also demonstrate that the monitoring of drill feeding displacement and thrust force cannot be used to detect and identify the cracks in bridge decks.

  11. 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.

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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...

  20. 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...

  1. The detection and thermal characterization of the inner structure of the ‘Musmeci’ bridge deck by infrared thermography monitoring

    International Nuclear Information System (INIS)

    In this study, the thermal monitoring of a bridge deck is carried out over several days thanks to an adapted infrared measurement system. This system does not just operate a single uncooled infrared camera but also other sensors (i.e., a weather station and a global positioning system (GPS). The detection of the inner structure of the deck is achieved by pulse phase thermography and principal component thermography approaches. A first characterization of the inner structure of the deck is proposed thanks to an original thermal modelling approach. The results obtained are discussed and analysed. (paper)

  2. 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 ...

  3. 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.

  4. Ground-penetrating imaging radar development for bridge deck and road bed inspection

    Energy Technology Data Exchange (ETDEWEB)

    Warhus, J.P.; Mast, J.E.; Nelson, S.D.; Johansson, E.M.

    1993-05-01

    Ground-penetrating imaging radar (GPIR) is proposed for large-area inspection of concrete and concrete/asphalt composite bridge decks and roadways. This technique combines ground-penetrating radar (GPR) with unique image reconstruction algorithms developed for identification and characterization of subsurface flaws and structural features. New data acquisition hardware and image reconstruction techniques, under development at LLNL, offer the possibility for reliable and efficient, high-resolution subsurface imaging through the use of improved ultra-wideband transmitters, antennas, and arrays, and enhanced image- and signal-processing software. A field test of a limited-capability prototype system is planned for FY-93, as is completion of a conceptual design for a practical inspection system. A follow-on program for FY-94 would focus on development and demonstration of an advanced bridge inspection system prototype based on the conceptual design completed during FY-93.

  5. Reinforced concrete bridge deck reliability model incorporating temporal and spatial variations of probabilistic corrosion rate sensor data

    International Nuclear Information System (INIS)

    The reliability of reinforced concrete (RC) bridge decks depends significantly on the rate of corrosion of the reinforcing steel. Structural health monitoring (SHM) techniques, including embedded corrosion rate sensors, can greatly improve the quantification of the steel corrosion rate, which can lead to improved estimates of structural safety and serviceability. Due to uncertainties in concrete properties, environmental conditions, and other factors, the rate of corrosion of reinforcing steel can be highly variable, both within a given structural component and over time. By placing multiple corrosion rate sensors throughout a structural component, such as a bridge deck, these spatial and temporal variabilities can be monitored and as such better predicted, for use in a reliability model. The objective of this investigation is to present a reliability model for a RC bridge deck incorporating both spatial and temporal variations of probabilistic corrosion rate sensor data. This objective is accomplished using a computational reliability model and Monte Carlo simulation. Corrosion rate sensor data is assumed for multiple critical sections throughout a RC bridge deck over time by applying empirical spatial and temporal relationships. This data is then used to improve an existing spatially invariant reliability model. The improved reliability model incorporates several sub-models to determine the changes in load effects on and resistance of a RC bridge deck slab over time, as well as spatial correlation of corrosion and a system approach to account for spatial variability. The improved reliability model incorporating both spatial and temporal variations in corrosion rate data provides a better estimate of the service life of a RC bridge deck slab

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

    Directory of Open Access Journals (Sweden)

    Petr Konečný

    2016-03-01

    Full Text Available 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 ions through a reinforced concrete bridge deck with and without the effect of waterproof membrane and on an estimate of the concentration of chlorides at the reinforcement level or in places with damage to the epoxide coating of the reinforcement. The model allows the incorporation of damage to the waterproof insulation under the asphalt coating. The time to chloride induced onset of corrosion is predicted and results are compared. The effect of water proof membrane reinforcement protection strategy typical for Central Europe and epoxy-coating protection widely used in North-Western United States is evaluated.

  7. 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...

  8. 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.

  9. 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.

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    Siekierski Wojciech

    2015-03-01

    Full Text Available 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.

  12. 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.

  13. 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.

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

    OpenAIRE

    Eyad Almaita; Ikhlas Abdel-Qader; Osama Y. Abudayyeh; Joseph Barbera; Hubo Cai

    2010-01-01

    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 ...

  15. 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.

  16. Validation of connection details between a UHPFRC ribbed slab and steel girders for a new composite bridge deck type

    OpenAIRE

    Toutlemonde, François; LAUVIN, Ludovic; Renaud, Jean Claude; BABY, Florent; Bouteille, Sébastien; RESPLENDINO, Jacques

    2008-01-01

    Within the French R & D project MIKTI focusing on innovative steel-concrete composite bridges, an exhaustive experimental program was carried out to provide an experimental validation of a new ultra-high performance fibre reinforced concrete (UHPFRC) 2 way-ribbed slab made of segments assembled by post-tensioning. Provisions concerning the realization of connection between the UHPFRC ribbed deck and steel profiles, which are critical for ensuring the composite behavior of the full structure, ...

  17. 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...

  18. 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.

  19. 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.

  20. Ground penetrating radar and microwave tomography 3D applications for the deck evaluation of the Musmeci bridge in Potenza, Italy

    International Nuclear Information System (INIS)

    An extensive experimental and numerical investigation has been carried out to assess the status of the 'Ponte sul Basento' (1967–1976), in the town of Potenza (Basilicata region, southern Italy), better known as the Musmeci bridge. Architecturally, the bridge is a considerable reinforced 20th century concrete structure that was designed and built by the Italian architect Sergio Musmeci (1926–1981). Moreover, the bridge represents an important element of the infrastructural network, linking the city centre to the Potenza-Sicignano highway, crossing the Basento river and the railway close to the main train station of the city. Recently, due to ageing and continuous and significant traffic, the bridge started to be affected by several problems such as water infiltration. Within the presented study, a widespread ground penetrating radar (GPR) survey has been designed to investigate the geometrical characteristics of the bridge deck (Gerber saddles, internal stiffening walls, pillar supports) and detect the presence of defects or damage due to water infiltration and traffic fatigue. Concerning this, a 900 MHz 3D GPR survey has been performed along a zone of one of the lanes on the road surface. Moreover, a second 1500 MHz 3D survey has been carried out at the bottom of the bridge deck in order to gain detailed information about an important structural element of the bridge, the Gerber saddle. Both results have been processed following two approaches: the first a classical time-domain processing session based on commercial software and the use of migration; the second in microwave tomography, an advanced frequency domain automatic PC-based inversion algorithm. In this paper, we present a comparative interpretation of both kinds of processed results, and provide considerations about the investigated structures

  1. 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.

  2. 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

  3. 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.

  4. Experimental Study on Sandwich Bridge Decks with GFRP Face Sheets and a Foam-Web Core Loaded under Two-Way Bending

    Directory of Open Access Journals (Sweden)

    Ruili Huo

    2015-01-01

    Full Text Available In recent years, the sandwich bridge decks with GFRP face sheets and light weight material core have been widely used in the world due to their advantages of low cost, high strength to weight ratios, and corrosion resisting. However, as the bridge decks, most of them are used in foot bridges rather than highway bridges because the ultimate bending strength and initial bending stiffness are relatively low. To address this issue and expand the scope of use, a simple and innovative sandwich bridge deck with GFRP face sheets and a foam-web core, manufactured by vacuum assisted resin infusion process, is developed. An experimental study was carried out to validate the effectiveness of this panel for increasing the ultimate bending strength and initial bending stiffness under two-way bending. The effects of face sheet thickness, foam density, web thickness, and web spacing on displacement ductility and energy dissipation were also investigated. Test results showed that, compared to the normal foam-core sandwich decks, an average approximately 657.1% increase in the ultimate bending strength can be achieved. Furthermore, the bending stiffness, displacement ductility, and energy dissipation can be enhanced by increasing web thickness, web height, and face sheet thickness or decreasing web spacing.

  5. 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

  6. 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

  7. 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.

  8. Seismic Integrity of a Long Span Bridge with Tower-Deck Buffers

    International Nuclear Information System (INIS)

    The wind action is acknowledged to be the primary environmental load in the design of suspension bridges. It affects both the performance of safety and serviceability. Nevertheless, the impact of earthquakes cannot be neglected especially when the construction site is located in a high seismicity region. The evaluation of the vulnerability of a suspension bridge requires a hazard analysis on the site, the definition of the seismic intensity related to the desired return periods, the generation of artificial signals for the reference site and the collection of critical records for integrity analyses,. The signals will then be used in the structural analyses for the verification of structural safety and structural robustness. This paper is focused on the generation of these critical signals, with their own a-synchronicity, and the associated numerical nonlinear analyses, which must be conducted in the time domain

  9. 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...

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

    DEFF Research Database (Denmark)

    Lárusson, Lárus Helgi; Fischer, Gregor

    2011-01-01

    water through the expansion joint and subsequent corrosion of girders and girder bearings. Investigations on joint-less superstructures using conventional steel reinforcement in so-called concrete link slabs indicate improved performance and economic feasibility. However, this concept requires...... relatively large amounts of steel reinforcement for crack control purposes and consequently provides a relatively large flexural stiffness and negative moment capacity at the joint between the spans. These contradicting requirements and effects in existing replacement concepts for damaged mechanical bridge...... 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...

  11. 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

  12. 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...

  13. 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.

  14. 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...

  15. 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.

  16. Stay-In Place Deck Panels - Part 1

    OpenAIRE

    Goldman, Ariel; Cohen, Menashi D.; Ramirez, J A

    1995-01-01

    The objective of this study was the evaluation of frost resistance of concrete bridge decks with stay-in-place galvanized steel deck forms. The evaluation included specific aspects related to the potential for D-cracking in concrete bridge decks with these forms. The experimental program has been set up so that the real parameters of the bridge deck overlays and the environmental conditions could have been modeled. The program included freezing-and-thawing testing of large concrete slab speci...

  17. 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.

  18. 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.

  19. 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.

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

    OpenAIRE

    Tamakoshi T.; Kubo S.; Izumi Y.; Sakagami T.

    2010-01-01

    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 si...

  1. 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.

  2. 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.

  3. 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.

  4. Use of Simulation Based Reliability Assessment Method to Evaluate the Resistance of Composite Bridge Decks to Cracking

    Czech Academy of Sciences Publication Activity Database

    Tikalsky, P.; Tepke, D.; Marek, Pavel

    Praha : ČVUT Stavební fakulta, Praha, 2003 - (Studnička, J.), s. 313-318 ISBN 80-01-02747-3. [Česká a slovenská mezinárodní konference - Ocekové konstrukce a mosty - 2003/20./. Praha (CZ), 17.09.2003-20.09.2003] R&D Projects: GA ČR GA103/01/1410; GA ČR GA105/01/0783 Institutional research plan: CEZ:AV0Z2071913 Keywords : Performance design * composite bridges * reducing the cracks effects Subject RIV: JM - Building Engineering

  5. 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。

  6. 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。

  7. 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

  8. Structural improvement of strengthened deck panels with externally bonded plates

    International Nuclear Information System (INIS)

    Concrete bridge decks require eventual replacement and rehabilitation due to decreasing load-carrying capacity. This paper compares different strengthening design procedures that improve the usability and structural performance of bridge decks. The failure characteristics of bridge decks strengthened with various materials such as carbon fiber sheet, glass fiber sheet, steel plate, and grid CFRP and GFRP are analyzed, and the theoretical load-carrying capacities are evaluated using traditional beam and yield line theory, and punching shear analysis. The strengthening materials increase the punching shear strength of the deck and change the failure mode of the strengthened panel

  9. 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。

  10. 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.

  11. 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.

  12. 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。

  13. 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

  14. 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.

  15. 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.

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

    OpenAIRE

    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 have shown that the bonding strength of membrane layers to the surrounding materials has a strong influence on the structural response of orthotropic steel bridge decks. The most important requireme...

  17. 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.

  18. 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...

  19. 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

  20. 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。

  1. Improvement of fatigue properties of orthotropic decks

    Czech Academy of Sciences Publication Activity Database

    Frýba, Ladislav; Urushadze, Shota

    2011-01-01

    Roč. 33, č. 4 (2011), s. 1166-1169. ISSN 0141-0296 R&D Projects: GA ČR GA103/08/1340; GA MŠk(CZ) 7E08098 Grant ostatní: BRIFAG -Bridge Fatigue Guidance(XE) RFSR_CT-2008-00033 Institutional research plan: CEZ:AV0Z20710524 Keywords : orthotropic deck * fatigue * prolonged life Subject RIV: JM - Building Engineering Impact factor: 1.351, year: 2011

  2. 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.

  3. 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.

  4. 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。

  5. 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...

  6. 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

  7. 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.

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

    OpenAIRE

    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 Chinese practices and experiences of deck pavement on long-spanned steel bridges, including issues of typical surfacing materials and their properties, main distresses in asphalt surfacing, and the basi...

  9. 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.

  10. Investigations of orthotropic decks

    Czech Academy of Sciences Publication Activity Database

    Urushadze, Shota; Frýba, Ladislav; Pirner, Miroš

    Praha : ÚTAM AV ČR,v.v.i, 2012 - (Náprstek, J.; Fischer, C.), s. 354-355 ISBN 978-80-86246-39-0. [Engineering Mechanics 2012 /18./. Svratka (CZ), 14.05.2012-17.05.2012] R&D Projects: GA ČR(CZ) GAP105/10/2159 Institutional support: RVO:68378297 Keywords : orthotropic decks * fatigue * stress Subject RIV: JM - Building Engineering

  11. 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 ...

  12. Two bridges with composite prestressed tension chord

    OpenAIRE

    Muttoni, Aurelio

    2002-01-01

    the bridges over the river Capriasca (1996) and over the river Ticino (1997) are characterised by the application of an innovative structural system. The central part of the main span of both bridges is constituted by the bridge concrete deck with two longitudinal stiffening girders, constituted by polygonal steel members that contain two prestressing tendons each.

  13. 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。

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

    OpenAIRE

    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 structure for orthotropic steel bridge decks mostly consists of five structural layers: top porous asphalt layer, guss asphalt layer, steel deck and two membrane layers. The five-point bending fatigue tes...

  15. 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...

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

    OpenAIRE

    Tubaldi, E; Dall’Asta, A.; Dezi, L.

    2015-01-01

    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....

  17. 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.

  18. 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...

  19. 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.

  20. Structural behavior and design criteria for bridge strengthening by tied arch. Comparison with network arch bridges

    OpenAIRE

    Valenzuela, Matías A.; Casas Rius, Joan Ramon

    2013-01-01

    This study focuses on a new strengthening method of continuous bridges with several spans that present extensive damage in their foundation/piers due to scour and erosion. The method consists on the construction of a new upper steel arch with a network hanger's arrangement over the original deck with the aim to hang the existing deck to the new arch. The deck is acting as a tie in the new structural configuration. This allows to remove the damaged foundations/piers, deriving on an arch bridge...

  1. History of cable-stayed bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    The principle of supporting a bridge deck by inclined tension members leading to towers on either side of the span has been known for centuries. However, the real development of cable-stayed bridges did not begin before the 1950s. Since then the free span has been increased from 183 m in the Strö...

  2. 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.

  3. 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).

  4. 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

  5. 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...

  6. 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.

  7. Finite Element Analysis of Composite Deck Slab Using Perfobond Rib as Shear Connection System under Vertical Loading

    Directory of Open Access Journals (Sweden)

    Omid Monshi Toussi

    2016-01-01

    Full Text Available Nowadays, the composite decks are very common to use in composite or steel construction. In this case of study the composite slabs have been investigated numerically by Finite Element Method (FEM. Five composite slabs were analyzed using finite element software LUSAS. The deflection of each model were obtained and compared with experimental test. Results showed a good agreement with the experimental data and indicate that the perfobond rib is appropriate shear connector for the bridges decks.

  8. Experimental Investigation of a Self-Sensing Hybrid GFRP-Concrete Bridge Superstructure with Embedded FBG Sensors

    OpenAIRE

    Wang, Yanlei; Li, Yunyu; Ran, Jianghua; Cao, Mingmin

    2012-01-01

    A self-sensing hybrid GFRP-concrete bridge superstructure, which consists of two bridge decks and each bridge deck is comprised of four GFRP box sections combined with a thin layer of concrete in the compression zone, was developed by using eight embedded FBG sensors in the top and bottom flanges of the four GFRP box sections at midspan section of one bridge deck along longitudinal direction, respectively. The proposed self-sensing hybrid bridge superstructure was tested in 4-point loading to...

  9. 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.

  10. Structural response of circular concrete filled tube piers in integral bridges

    OpenAIRE

    Kovac, Borisa

    2010-01-01

    Nowadays most of the bridges are designed with movable joints and bearings. They are used to allow for bridge deck displacements produced by: expansion and contraction of the bridge deck due to temperature changes, breaking or accelerating forces of vehicles and by long term changes of concrete such as creeping and shrinking. Joints and bearings are susceptible to durability problems and require maintenance and replacements. In order to reduce the maintenance costs and to lower the init...

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

    OpenAIRE

    Tolosana, N.; Cuartero, J.; Chiminelli, A.; Comino, P.; Ranz, D.; Calvo, I.; Mieres, J. M.; Miravete, A.

    2006-01-01

    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 sev...

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 46 CFR 108.486 - Helicopter decks.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Helicopter decks. 108.486 Section 108.486 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.486 Helicopter decks....

  18. 29 CFR 1918.33 - Deck loads.

    Science.gov (United States)

    2010-07-01

    ... Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED... inboard edge of the deck load having less than 24 inches (.61 m) of bulwark, rail, coaming, or other protection, those employees shall be provided with protection against falling from the deck load....

  19. 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...

  20. Acoustic Emission Health Monitoring of Steel Bridges

    OpenAIRE

    Pahlavan, Pooria Lotfollah; Paulissen, Joep; Pijpers, Richard; Hakkesteegt, Henk; Jansen, Rob

    2014-01-01

    Despite extensive developments in the field of Acoustic Emission (AE) for monitoring fatigue cracks in steel structures, the implementation of AE systems for large-scale bridges is hindered by limitations associated with instrumentation costs and signal processing complexities. This paper sheds light on some of the most important challenges in the utilization of AE systems for steel bridge decks. These challenges are mainly related to the multi-modal character of guided waves, and the expensi...

  1. Design of Steel Orthotropic Decks on Railway Bridges

    Czech Academy of Sciences Publication Activity Database

    Frýba, Ladislav

    Oxford : Elsevier, 1998 - (Dowling, P.; Harding, J.; Jorhovde, R.), s. 48-49 [World Conference on Steel in Construction /2./. San Sebastian (ES), 18.08.1998-20.08.1998] R&D Projects: GA ČR GA103/97/0139

  2. 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...

  3. Is deck C an advantageous deck in the Iowa Gambling Task?

    Directory of Open Access Journals (Sweden)

    Lin Ching-Hung

    2007-08-01

    Full Text Available Abstract Background Dunn et al. performed a critical review identifying some problems in the Somatic Marker Hypothesis (SMH. Most of the arguments presented by Dunn focused on the insufficiencies for replication of skin conductance responses and somatic brain loops, but the study did not carefully reassess the core-task of SMH. In a related study, Lin and Chiu et al. identified a serious problem, namely the "prominent deck B phenomenon" in the original IGT. Building on this observation, Lin and Chiu also posited that deck C rather than deck A was preferred by normal decision makers due to good gain-loss frequency rather than good final-outcome. To verify this hypothesis, a modified IGT was designed that possessed high contrast of gain-loss value in each trial, with the aim of achieving a balance between decks A and C in terms of gain-loss frequency. Based on the basic assumption of IGT, participants should prefer deck C to deck A based on consideration of final-outcome. In contrast, based on the prediction of gain-loss frequency, participants should have roughly equal preferences for decks A and C. Methods This investigation recruited 48 college students (24 males and 24 females as participants. Two-stage IGT with high-contrast gain-loss value was launched to examine the deck C argument. Each participant completed the modified IGT twice and immediately afterwards was administered a questionnaire to assess their consciousness and final preferences following the game. Results The experimental results supported the predictions regarding gain-loss frequency participants choose the deck C with nearly identical frequency to deck A, despite deck C having a better final outcome than deck A. The "sunken deck C" phenomenon is clearly identified in this version of IGT which achieves a balance in gain-loss frequency. Moreover, the "sunken deck C" phenomenon not only appears during the first stage, but also during the second stage of IGT. In addition

  4. 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...

  5. 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......, the flaps are regulated by a control algorithm so that the wind forces exerted on them counteract the deck oscillations....

  6. 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.

  7. An innovative steel-concrete joint for integral abutment bridges

    OpenAIRE

    Bruno Briseghella; Tobia Zordan

    2015-01-01

    Integral abutment bridges are becoming rather common, due to the durability problems of bearings and expansion joints. At the same time, among short- and medium-span bridges, multi-beam steel-concrete composite deck with hot-rolled girder is an economical and interesting alternative to traditional pre-stressed concrete solutions. The two concepts can be linked together to design integral steel-concrete composite bridges with the benefits of two typologies. The most critical aspect for these b...

  8. 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,...

  9. 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...

  10. 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.

  11. 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.

  12. A modular steel freeway bridge: design concept and earthquake resistance.

    Science.gov (United States)

    Wattenburg, W H; McCallen, D B; Murray, R C

    1995-04-14

    A modular multilane steel freeway bridge has been constructed from surplus railroad flatcar decks. It can be erected on-site in a few days' time. It has been built and static-load tested for emergency freeway bridge repair. This inexpensive modular bridge may also have broad application around the world for low-cost bridges in areas where funds are limited. On the basis of static-load testing performed by the California Department of Transportation and computer dynamic analysis, this simple modular-design concept has the potential of providing a strong bridge that can withstand the severe aftershocks expected immediately after a major earthquake. PMID:17814794

  13. Bridge? What's a Bridge?

    Science.gov (United States)

    Gutsche, George

    1996-01-01

    Considers the metaphor of the "bridge" as it applies to Russian-language courses at the university level. The article examines broader curricular issues of technology, innovation, and outside pressures on language teaching. (22 references) (CK)

  14. 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...

  15. 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...

  16. 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.

  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. 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...

  19. Demonstration of dual-band infrared thermal imaging for bridge inspection. Phase II, final report

    Energy Technology Data Exchange (ETDEWEB)

    Durbin, P.F.; Del Grande, N.K.; Schaich, P.C.

    1996-03-01

    Developing and implementing methods of effective bridge rehabilitation is a major issue for the Federal Highway Administration (FHWA). The nation spends $5 billion annually to replace, rehabilitate or construct new bridges. According to the National Bridge Inventory, over 100,000 U.S. bridges are structurally deficient. About 40,000 of these bridges have advanced deck deterioration. The most common causes of serious deck deterioration is delamination. Delaminations result when steel reinforcements within the bridge deck corrode, creating gaps that separate the concrete into layers. A reliable inspection technology, capable of identifying delaminations, would represent a power new tool in bridge maintenance. To date, most bridge inspections rely on human interpretation of surface visual features of chain dragging. These methods are slow, disruptive, unreliable and raise serious safety concerns. Infrared thermal imaging detects subsurface delaminations and surface clutter, which is introduced by foreign material on the roadway. Typically, foreign material which is not always evident on a video tape image, produces a unique IR reflectance background unlike the thermal response of a subsurface delamination. Lawrence Livermore National Laboratory (LLNL) uses dual-band infrared (DBIR) thermal imaging to identify and remove nonthermal IR reflectance backgrounds from foreign material on the roadway. DBIR methods improve the performance of IR thermal imaging by a factor of ten, compared to single-band infrared (SBIR) methods. DBIR thermal imaging allows precise temperature measurement to reliably locate bridge deck delaminations and remove wavelength-dependent emissivity variations due to foreign material on the roadway.

  20. 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...

  1. 46 CFR 132.320 - Helicopter-landing decks.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Helicopter-landing decks. 132.320 Section 132.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS FIRE-PROTECTION EQUIPMENT Miscellaneous § 132.320 Helicopter-landing decks. Each vessel with a helicopter-landing deck...

  2. 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 to fl...

  3. 46 CFR 178.430 - Drainage of well deck vessels.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Drainage of well deck vessels. 178.430 Section 178.430 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS... probable conditions of list and trim. (d) The deck of well deck vessel that operates on exposed...

  4. 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...

  5. 14 CFR 121.547 - 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. 121.547 Section... REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Flight Operations § 121.547 Admission to flight deck. (a) No person may admit any person to the flight deck of an aircraft unless the person being...

  6. Precast Pearl-Chain concrete arch bridges

    DEFF Research Database (Denmark)

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

    2015-01-01

    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......A Pearl-Chain Bridge is a closed-spandrel arch bridge consisting of a number of straight pre-fabricated so called Super-Light Deck elements put together in an arch shape by post-tensioning cables. Several Pearl-Chain arches can be positioned adjacent to each other by a crane to achieve a bridge of...... 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...

  7. Fatigue problems of steel bridges

    Czech Academy of Sciences Publication Activity Database

    Urushadze, Shota; Frýba, Ladislav; Škaloud, Miroslav; Pirner, Miroš; Zörnerová, Marie

    Stirlingshire : Civil-Comp Press, 2012 - (Pombo, J.), s. 142-151 ISBN 978-1-905088-53-9. ISSN 1759-3433. [International Conference on Railway Technology: Research, Development and Maintenance /1./. Las Palmas de Gran Canaria (ES), 18.04.2012-20.04.2012] R&D Projects: GA MŠk(CZ) 7E08098 Grant ostatní: evropská komise(XE) RFSR-CT-2008-00033 (BRIFAG); GA ČR(CZ) GA103/08/1340 Institutional support: RVO:68378297 Keywords : steel bridges * fatigue * S-N curve * orthotropic deck * web breathing Subject RIV: JM - Building Engineering

  8. 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.

  9. 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...

  10. 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.

  11. 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.…

  12. 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.

  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. 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.

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

    OpenAIRE

    Flaga Kazimierz; Furtak Kazimierz

    2015-01-01

    Steel-concrete composite structures have been used in bridge engineering from decades. This is due to rational utilisation of the strength properties of the two materials. At the same time, the reinforced concrete (or prestressed) deck slab is more favourable than the orthotropic steel plate used in steel bridges (higher mass, better vibration damping, longer life).

  16. 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.

  17. 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.

  18. Noise from Aft Deck Exhaust Nozzles: Differences in Experimental Embodiments

    Science.gov (United States)

    Bridges, James E.

    2014-01-01

    Two embodiments of a rectangular nozzle on an aft deck are compared. In one embodiment the lower lip of the nozzle was extended with the sidewalls becoming triangles. In a second embodiment a rectangular nozzle was fitted with a surface that fit flush to the lower lip and extended outward from the sides of the nozzle, approximating a semi-infinite plane. For the purpose of scale-model testing, making the aft deck an integral part of the nozzle is possible for relatively short deck lengths, but a separate plate model is more flexible, accounts for the expanse of deck to the sides of the nozzle, and allows the nozzle to stand off from the deck. Both embodiments were tested and acoustic far-field results were compared. In both embodiments the extended deck introduces a new noise source, but the amplitude of the new source was dependent upon the span (cross-stream dimension) of the aft deck. The noise increased with deck length (streamwise dimension), and in the case of the beveled nozzle it increased with increasing aspect ratio. In previous studies of slot jets in wings it was noted that the increased noise from the extended aft deck appears as a dipole at the aft deck trailing edge, an acoustic source type with different dependence on velocity than jet mixing noise. The extraneous noise produced by the aft deck in the present studies also shows this behavior both in directivity and in velocity scaling.

  19. 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.

  20. Active aerodynamic stabilisation of long suspension bridges

    DEFF Research Database (Denmark)

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

    2004-01-01

    use of control analysis and design techniques, a linear model of the structural and aerodynamic motion around equilibriun is developed. The model is validated through comparison with finite element calculations and wind tunnel experimental data on the Great Belt East Bridge in Denmark. The developed......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 make...... active control scheme is local in that the flap control signal at a given longitudinal position along the bridge only depends on local motion measurements. The analysis makes use of the Nyquist stability criteria and an anlysis of the sensitivity function for stability analysis. The analysis shows that...

  1. 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.

  2. 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.

  3. 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.

  4. A numerical investigation on the fire response of a steel girder bridge

    OpenAIRE

    Paya-Zaforteza, I.; Garlock, Maria E.M.

    2012-01-01

    The response of bridges subject to fire is an under researched topic despite the number of bridge failures caused by fire. Since available data shows that steel girder bridges are especially vulnerable to fire, this paper delves into their fire response by analyzing with a 3D numerical model the response of a typical bridge of 12.20 m span length. A parametric study is performed considering: (1) two possibilities for the axial restraint of the bridge deck, (2) four types of structural steel f...

  5. Myocardial Bridging.

    Science.gov (United States)

    Yuan, Shi-Min

    2016-02-01

    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. PMID:27074276

  6. 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.

  7. 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...

  8. 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...

  9. 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.

  10. 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

  11. 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...

  12. 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....

  13. 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 ...

  14. 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.

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

    OpenAIRE

    2014-01-01

    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...

  16. 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,...

  17. Prediction of fatigue life of reinforced concrete bridges using Fracture Mechanics

    OpenAIRE

    Biondini, Fabio; Frangopol, Dan; Rocha, Marina; Brühwiler, Eugen

    2012-01-01

    With the occurrence of higher and more frequent axle loads, bridges are more solicited by fatigue loading. Bridge elements like deck slabs are subjected to a high number of stress cycles at relatively small stress magnitudes. The application of Fracture Mechanics as a useful tool for the analysis of fatigue crack growth in steel elements was demonstrated by Paris et al. in the early 1960s. With respect to reinforced concrete, the fatigue strength of the steel reinforcement is determinant. The...

  18. Nonlinear Seismic Response Analysis of Curved and Skewed Bridge System with Spherical Bearings

    OpenAIRE

    Linzell, Daniel G.; Junwon Seo; Jong Wan Hu

    2013-01-01

    A three-dimensional (3D) modeling approach to investigate nonlinear seismic response of a curved and skewed bridge system is proposed. The approach is applied to a three-span curved and skewed steel girder bridge in the United States. The superstructure is modeled using 3D frame elements for the girders, truss elements for the cross-frames, and equivalent frame elements to represent the deck. Spherical bearings are modeled with zero-length elements coupled with hysteretic material models. Non...

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

    DEFF Research Database (Denmark)

    Andersen, Michael Styrk; Johansson, Jens; Brandt, Anders; Hansen, Svend Ole

    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...... 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....

  20. On using vibration data to detect damage in model-scale reinforced concrete bridges

    OpenAIRE

    Pearson, Steven R.

    2003-01-01

    This thesis reports the findings of an investigation into the feasibility of using vibration characteristics to monitor the structural health of bridges. The study is the second part of a larger project commissioned by the UK Highways Agency into the investigation of possible monitoring methods that can be used in a pass/fail/monitor inspection programme. To this end, ten one-quarter-scale 5m span reinforced concrete bridge decks were fabricated and loaded incrementally to failure in the labo...

  1. 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.

  2. Sudden lateral asymmetry and torsional oscillations of section models of suspension bridges

    Science.gov (United States)

    Plaut, R. H.; Davis, F. M.

    2007-11-01

    Cable-supported bridges typically exhibit minimal torsional motion under traffic and wind loads. If symmetry of the bridge about the deck's centerline is suddenly lost, such as by the failure of one or more cables or hangers (suspenders), torsional motion of the deck may grow and angles of twist may become large. The initiation of the disastrous torsional oscillations of the original Tacoma Narrows Bridge involved a sudden lateral asymmetry due to loosening of a cable band at midspan. The effects of these types of events on two-degree-of-freedom and four-degree-of-freedom section models of suspension bridges are analyzed. Vertical and rotational motions of the deck, along with vertical motions of the cables, are considered. A harmonic vertical force and an aerodynamic moment proportional to angular velocity are applied to the deck. Resistance is provided by translational and rotational springs and dashpots. Flutter instability and large oscillations occur under the aerodynamic moment, which provides "negative damping." In order to model the occurrence of limit cycles, nonlinear damping of the van der Pol type is included in one case, and nonlinear stiffness of the hangers in others. The frequencies of the limit cycles are compared to the natural frequencies of the system.

  3. 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.

  4. 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...

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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。

  10. WORM: A general-purpose input deck specification language

    International Nuclear Information System (INIS)

    Using computer codes to perform criticality safety calculations has become common practice in the industry. The vast majority of these codes use simple text-based input decks to represent the geometry, materials, and other parameters that describe the problem. However, the data specified in input files are usually processed results themselves. For example, input decks tend to require the geometry specification in linear dimensions and materials in atom or weight fractions, while the parameter of interest might be mass or concentration. The calculations needed to convert from the item of interest to the required parameter in the input deck are usually performed separately and then incorporated into the input deck. This process of calculating, editing, and renaming files to perform a simple parameter study is tedious at best. In addition, most computer codes require dimensions to be specified in centimeters, while drawings or other materials used to create the input decks might be in other units. This also requires additional calculation or conversion prior to composition of the input deck. These additional calculations, while extremely simple, introduce a source for error in both the calculations and transcriptions. To overcome these difficulties, WORM (Write One, Run Many) was created. It is an easy-to-use programming language to describe input decks and can be used with any computer code that uses standard text files for input. WORM is available, via the Internet, at worm.lanl.gov. A user's guide, tutorials, example models, and other WORM-related materials are also available at this Web site. Questions regarding WORM should be directed to wormatlanl.gov

  11. Stone bridges

    Czech Academy of Sciences Publication Activity Database

    Drdácký, Miloš; Slížková, Zuzana

    Prague : Institute of theoretical and applied mechanics AS CR, v.v.i, 2011 - (Drdácký, M.; Binda, L.; Hennen, I.; Kőpp, C.; Lanza, L.), s. 122-129 ISBN 978-80-86246-37-6 Grant ostatní: evropská komise(XE) CHEF-SSPI-044251 Institutional research plan: CEZ:AV0Z20710524 Keywords : flood * stone bridge * cultural heritage Subject RIV: AL - Art, Architecture, Cultural Heritage

  12. Assessment on transient sound radiation of a vibrating steel bridge due to traffic loading

    Science.gov (United States)

    Zhang, He; Xie, Xu; Jiang, Jiqing; Yamashita, Mikio

    2015-02-01

    Structure-borne noise induced by vehicle-bridge coupling vibration is harmful to human health and living environment. Investigating the sound pressure level and the radiation mechanism of structure-borne noise is of great significance for the assessment of environmental noise pollution and noise control. In this paper, the transient noise induced by vehicle-bridge coupling vibration is investigated by employing the hybrid finite element method (FEM) and boundary element method (BEM). The effect of local vibration of the bridge deck is taken into account and the sound responses of the structure-borne noise in time domain is obtained. The precision of the proposed method is validated by comparing numerical results to the on-site measurements of a steel girder-plate bridge in service. It implies that the sound pressure level and its distribution in both time and frequency domains may be predicted by the hybrid approach of FEM-BEM with satisfactory accuracy. Numerical results indicate that the vibrating steel bridge radiates high-level noise because of its extreme flexibility and large surface area for sound radiation. The impact effects of the vehicle on the sound pressure when leaving the bridge are observed. The shape of the contour lines in the area around the bridge deck could be explained by the mode shapes of the bridge. The moving speed of the vehicle only affects the sound pressure components with frequencies lower than 10 Hz.

  13. 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; Walther, Jens Honore

    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...... of four aerodynamically different bridge sections is compared to available wind tunnel data, showing good agreement between the two.......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...

  14. 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.

  15. 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.

  16. 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.

  17. An innovative steel-concrete joint for integral abutment bridges

    Directory of Open Access Journals (Sweden)

    Bruno Briseghella

    2015-08-01

    Full Text Available Integral abutment bridges are becoming rather common, due to the durability problems of bearings and expansion joints. At the same time, among short- and medium-span bridges, multi-beam steel-concrete composite deck with hot-rolled girder is an economical and interesting alternative to traditional pre-stressed concrete solutions. The two concepts can be linked together to design integral steel-concrete composite bridges with the benefits of two typologies. The most critical aspect for these bridges is usually the joints between deck and piers or abutments. In this paper, an innovative beam-to-pier joint is proposed and a theoretical and experimental study is introduced and discussed. The analyzed connection is aimed at combining general ease of construction with a highly simplified assembly procedure and a good transmission of hogging and sagging moment at the supports in continuous beams. For this purpose, the traditional shear studs, used at the interface between steel beam and upper concrete slab, are also used at the ends of steel profiles welded horizontally to the end plates. To better understand the behaviour of this kind of joints and the roles played by different components, three large-scale specimens were tested and an FE model was implemented. The theoretical and experimental results confirmed the potential of the proposed connection for practical applications and indicated the way to improve its structural behaviour.

  18. Commander Brand and Pilot Overmyer operate controls on forward flight deck

    Science.gov (United States)

    1982-01-01

    On forward flight deck, Commander Brand and Pilot Overmyer operate controls from commanders and pilots seats. Overall view taken from the aft flight deck looking forward shows both astronauts reviewing procedures and checking CRT screen data.

  19. 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.

  20. 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...

  1. Development of MIDAS/SMR Input Deck for SMART

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S. W.; Oh, H. K.; Lee, J. M.; Lee, J. H.; Yoo, K. J.; Kwun, S. K.; Hur, H. [KORTIC, Daejeon (Korea, Republic of)

    2010-01-15

    The objective of this study is to develop MIDAS/SMR code basic input deck for the severe accidents by simulating the steady state for the SMART plant. SMART plant is an integrated reactor developed by KAERI. For the assessment of reactor safety and severe accident management strategy, it is necessary to simulate severe accidents using the MIDAS/SMR code which is being developed by KAERI. The input deck of the MIDAS/SMR code for the SMART plant is prepared to simulate severe accident sequences for the users who are not familiar with the code. A steady state is obtained and the results are compared with design values. The input deck will be improved through the simulation of the DBAs and severe accidents. The base input deck of the MIDAS/SMR code can be used to simulate severe accident scenarios after improvement. Source terms and hydrogen generation can be analyzed through the simulation of the severe accident. The information gained from analyses of severe accidents is expected to be helpful to develop the severe accident management strategy

  2. 46 CFR 108.487 - Helicopter deck fueling operations.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Helicopter deck fueling operations. 108.487 Section 108.487 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fire Protection for Helicopter Facilities §...

  3. 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...

  4. 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...

  5. The Damage Effects in Steel Bridges under Highway Random Loading

    DEFF Research Database (Denmark)

    Agerskov, Henning; Nielsen, Jette Andkjær

    1996-01-01

    In the present investigation, fatigue damage accumulation in steel bridges under highway random loading is studied. In the experimental part of the investigation, fatigue test series on welded plate test specimens have been carried through. The fatigue tests have been carried out using load...... histories, which correspond 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. Both the results that have been obtained in the test series carried through and the results of fracture mechanics analysis...... indicate that the linear fatigue damage accumulation formula, which is normally used in the design against fatigue in steel bridges, may give results, which are unconservative....

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

    DEFF Research Database (Denmark)

    Lárusson, Lárus Helgi; Fischer, Gregor

    2011-01-01

    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...

  7. 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...

  8. 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

    of hollow core decks with different surfaces on the bottom are investigated: reference deck made of standard concrete and flat surface, deck with special mortar grooved tiles, deck with flat mortar tiles, deck with grooved mortar and phase change material tiles, deck with flat mortar and phase change...... material tiles. The experimental investigation presented in the paper is performed in the specially designed modified hot box apparatus that allows maintaining periodic steady-state tests with the full-scale concrete deck elements. The presented research investigates if the extended surface area and PCM...

  9. 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.

  10. Revisit of I35W Bridge Collapse: A preliminary analysis at 2007 and conclusions today

    International Nuclear Information System (INIS)

    August 1st of 2007, 6:05PM, the interstate highway I35W Bridge in the City Minneapolis, Minnesota, collapsed suddenly. The 8 traffic-lane, 1000-foot-long deck of the 1907-foot-long bridge fell into Mississippi River within seconds, resulted in 13 fatalities and 145 injuries. This paper is based on a report of a preliminary analysis of this disaster, which was submitted to the related administrative agencies at the September of 2007. By comparing the results in that report with the materials' evidences of National Safety Transportation Safety Board (NTSB) official investigation and recent in-depth analyses, it seems that the issues addressed in this earlier analysis may still have certain significance for the safety assessment of those similarly-structured steel bridges today. A bridge's service life is 75 years or longer. According to a NTSB's document, there are more than hundreds this kind of bridges still on service.

  11. 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.

  12. 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.

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

    Science.gov (United States)

    Flaga, Kazimierz; Furtak, Kazimierz

    2015-03-01

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

  14. 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...

  15. 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....

  16. 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...... and excitation from the deck and/or towers. Although some experiences have been done with full-scale measurements of inclined cables, many of the results available are based on wind tunnel tests and theoretical modelling. This paper presents results from full-scale measurements on the cables of the...... Øresund 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...

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Investigation of Concrete Mixtures to Reduce Differential Shrinkage Cracking in Composite Bridges

    OpenAIRE

    Nelson, Douglas A.

    2013-01-01

    The objective of the research presented in this thesis was to develop a concrete bridge deck topping mixture that resists the effects of differential shrinkage by decreasing shrinkage and increasing creep. . In addition, the amount of tensile creep that concrete experiences under long-term tensile stresses were quantified and compared to compressive creep values in order to gain a better understanding of how concrete behaves under tension. Test results show that the amount of tensile creep ex...

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  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. 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.

  8. 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.

  9. 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.

  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. 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.

  12. 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...

  13. 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...

  14. 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...

  15. 46 CFR 109.575 - Accumulation of liquids on helicopter decks.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Accumulation of liquids on helicopter decks. 109.575 Section 109.575 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.575 Accumulation of liquids on helicopter decks. The...

  16. 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.

  17. 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.

  18. 49 CFR 214.519 - Floors, decks, stairs, and ladders of on-track roadway maintenance machines.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Floors, decks, stairs, and ladders of on-track... SAFETY On-Track Roadway Maintenance Machines and Hi-Rail Vehicles § 214.519 Floors, decks, stairs, and ladders of on-track roadway maintenance machines. Floors, decks, stairs, and ladders of on-track...

  19. 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.

  20. Generalized Gaussian Bridges

    CERN Document Server

    Sottinen, Tommi

    2012-01-01

    A generalized bridge is the law of a stochastic process that is conditioned on linear functionals of its path. We consider two types of representations of such bridges: orthogonal and canonical. In the canonical representation the filtrations and the linear spaces generated by the bridge process and the original process coincide. In the orthogonal representation the bridge is constructed from the entire path of the underlying process. The orthogonal representation is given for any continuous Gaussian process but the canonical representation is given only for so-called prediction-invertible Gaussian processes. Finally, we apply the canonical bridge representation to insider trading by interpreting the bridge from an initial enlargement of filtration point of view.

  1. 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...

  2. 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....

  3. 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...

  4. Integration of energy management concepts into the flight deck

    Science.gov (United States)

    Morello, S. A.

    1981-01-01

    The rapid rise of fuel costs has become a major concern of the commercial aviation industry, and it has become mandatory to seek means by which to conserve fuel. A research program was initiated in 1979 to investigate the integration of fuel-conservative energy/flight management computations and information into today's and tomorrow's flight deck. One completed effort within this program has been the development and flight testing of a fuel-efficient, time-based metering descent algorithm in a research cockpit environment. Research flights have demonstrated that time guidance and control in the cockpit was acceptable to both pilots and ATC controllers. Proper descent planning and energy management can save fuel for the individual aircraft as well as the fleet by helping to maintain a regularized flow into the terminal area.

  5. 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.

  6. 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...

  7. Steady-State Cycle Deck Launcher Developed for Numerical Propulsion System Simulation

    Science.gov (United States)

    VanDrei, Donald E.

    1997-01-01

    One of the objectives of NASA's High Performance Computing and Communications Program's (HPCCP) Numerical Propulsion System Simulation (NPSS) is to reduce the time and cost of generating aerothermal numerical representations of engines, called customer decks. These customer decks, which are delivered to airframe companies by various U.S. engine companies, numerically characterize an engine's performance as defined by the particular U.S. airframe manufacturer. Until recently, all numerical models were provided with a Fortran-compatible interface in compliance with the Society of Automotive Engineers (SAE) document AS681F, and data communication was performed via a standard, labeled common structure in compliance with AS681F. Recently, the SAE committee began to develop a new standard: AS681G. AS681G addresses multiple language requirements for customer decks along with alternative data communication techniques. Along with the SAE committee, the NPSS Steady-State Cycle Deck project team developed a standard Application Program Interface (API) supported by a graphical user interface. This work will result in Aerospace Recommended Practice 4868 (ARP4868). The Steady-State Cycle Deck work was validated against the Energy Efficient Engine customer deck, which is publicly available. The Energy Efficient Engine wrapper was used not only to validate ARP4868 but also to demonstrate how to wrap an existing customer deck. The graphical user interface for the Steady-State Cycle Deck facilitates the use of the new standard and makes it easier to design and analyze a customer deck. This software was developed following I. Jacobson's Object-Oriented Design methodology and is implemented in C++. The AS681G standard will establish a common generic interface for U.S. engine companies and airframe manufacturers. This will lead to more accurate cycle models, quicker model generation, and faster validation leading to specifications. The standard will facilitate cooperative work between

  8. Performance monitoring of a short-span integral-abutment bridge using wireless sensor technology

    Science.gov (United States)

    Gangone, Michael V.; Whelan, Matthew J.; Fuchs, Michael P.; Janoyan, Kerop D.

    2007-04-01

    Discussed in this paper is the implementation of a wireless sensor system for performance monitoring of bridges. The advanced wireless sensor system, developed at Clarkson University's Laboratory for Intelligent Infrastructure and Transportation Technologies (LIITT), allows for structural monitoring of bridges. A short-span integral-abutment bridge located in New York State is instrumented with a wireless sensor system measuring acceleration, and strain to monitor the behavior of the structure under various loading conditions including ambient, environmental and traffic loading. Strain and acceleration measurements are recorded simultaneously and in real time to validate various performance characteristics of the bridge, including load distribution along an interior girder, as well as additional stiffness factors (end fixity and composite action of the beams and bridge deck), using existing bridge load testing and condition evaluation guidelines used by the New York State Department of Transportation (NYSDOT) and American Association of State Highway and Transportation Officials (AASHTO). Additionally, acceleration measurements are used to extract the superstructure's first five natural frequencies and corresponding mode shapes. Results are compared to a developed Finite Element Method (FEM) model based on the bridge as built drawings.

  9. Dynamic response of arch bridges traversed by high-speed trains

    Science.gov (United States)

    Lacarbonara, Walter; Colone, Valerio

    2007-07-01

    A mechanical model describing the planar elasto-dynamics of arch bridges with general arch profiles is presented. The model is amenable to analytical or semi-analytical treatments and is effective for parametric studies, design of control systems or structural optimizations. The Ritz's energy approach is employed to calculate the solutions of the vibration eigenvalue problem—natural frequencies and mode shapes—and the forced responses to external excitations, namely those induced by the passage of trains. A closed-form solution of the bridge dynamic response to the transit of trains with arbitrary load distributions and running speeds is found and the train-induced resonances are accordingly discussed. In particular, three European high-speed trains—the French TGV, the Italian ETR 500, and the German ICE—traversing a lower-deck steel arch bridge are considered and the ensuing responses are investigated.

  10. 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...

  11. 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

  12. I35W collapse, rebuild, and structural health monitoring - challenges associated with structural health monitoring of bridge systems

    International Nuclear Information System (INIS)

    During evening rush hour traffic on August 1, 2007, the major interstate highway bridge carrying I35W over the Mississippi River in Minneapolis catastrophically failed, tragically taking the lives of thirteen people and injuring many more. The steel truss bridge, constructed in 1967, was undergoing deck reconstruction during the collapse, and was estimated to carry more than 140,000 vehicles daily. This tragedy generated great interest in employment of structural health monitoring systems. The I35W St. Anthony Falls Bridge, a post-tensioned concrete box bridge constructed to replace the collapsed steel truss bridge, contains over 500 instruments to monitor the structural behavior. Numerical models of the bridge are being developed and calibrated to the collected data obtained from truck load tests and thermal effects. The data obtained over the first few years of monitoring are being correlated with the calibrated models and used to develop the baseline bridge behavior. This information is being used to develop a system to monitor and interpret the long-term behavior of the bridge. This paper describes the instrumentation, preliminary results from the data and model calibration, the plan for developing long-term monitoring capabilities, and the challenges associated with structural health monitoring of bridge systems. In addition, opportunities and directions for future research required to fully realize the objectives of structural health monitoring are described.

  13. 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.

  14. 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...

  15. Fire modeling for Building 221-T - T Plant Canyon Deck and Railroad Tunnel

    International Nuclear Information System (INIS)

    This report was prepared by Hughes Associates, Inc. to document the results of fire models for building 221-T Canyon Deck and Railroad Tunnel. Backup data is contained in document No. WHC-SD-CP-ANAL-010, Rev. 0

  16. 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.

  17. 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...

  18. 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

  19. SQUID array for magnetic inspection of prestressed concrete bridges

    Science.gov (United States)

    Krause, H.-J.; Wolf, W.; Glaas, W.; Zimmermann, E.; Faley, M. I.; Sawade, G.; Mattheus, R.; Neudert, G.; Gampe, U.; Krieger, J.

    2002-03-01

    For detection of tendon ruptures in prestressed members of bridges, a four-channel SQUID system was developed. The tendons are magnetized by scanning a yoke electromagnet over the concrete surface along the hidden member. Four HTS dc-SQUID magnetometers with ramp-type junctions, optimized for high-field performance, are mounted in an orientation-independent liquid nitrogen cryostat. The SQUIDs are integrated as a linear array within the yoke and operated in magnetic fields up to 15 mT, recording the stray field during magnetization as well as the remanent field after switching off the excitation. Unwanted signals from stirrups of the mild steel reinforcement are suppressed with two types of techniques: either the comparison of remanent field signals after changing the magnetization direction of the stirrups, or a best fit of typical stirrup signals to the stray field signal and their subtraction. Subsequent correlation analysis with the dipolar signal of a typical void yields rupture signal amplitudes. A finite element program was written to simulate stray field and remanent field traces of typical steel configurations. Excellent agreement with measured data was found. Results of measurements on a prestressed highway bridge are presented. Signal amplitudes above the threshold values were verified as originating from ruptures of the steel tendon by opening the bridge deck.

  20. 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

  1. Vibration tests on dismounted bridge beams and effects of deterioration

    International Nuclear Information System (INIS)

    This paper aims at describing the tests campaign carried out on five precast bonded post-tensioned concrete bridge beams, recently dismounted after a service life of 50 years. The girders were part of the deck of a recently dismounted viaduct of an Italian motorway. The beams showed different deterioration levels, mainly due to the different exposure to corrosive agents. The test campaign were designed for evaluating the residual load bearing capacity of the members. Dynamic measurements were acquired before and after the static tests by using different excitation sources. This experimental research highlights that the natural frequencies of the beams can be used as a predictor of the ultimate bending moment of an existing structure.

  2. Bridge Management Systems:present and future

    OpenAIRE

    Thoft-Christensen, Palle

    1997-01-01

    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.

  3. 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 Assessmentclose quotes 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 in a form that future inspections will have comparative information

  4. Structural assessment of roof decking using visual inspection methods

    Energy Technology Data Exchange (ETDEWEB)

    Giller, R.A.; McCoy, R.M.; Wagenblast, G.R.

    1993-10-01

    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.

  5. 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

  6. Bridging a cultural gap

    Science.gov (United States)

    Leviatan, Talma

    2008-09-01

    There has been a broad wave of change in tertiary calculus courses in the past decade. However, the much-needed change in tertiary pre-calculus programmes—aimed at bridging the gap between high-school mathematics and tertiary mathematics—is happening at a far slower pace. Following a discussion on the nature of the gap and the objectives of a potential bridging programme, this paper aims at demonstrating that the gap can be bridged, by presenting an ongoing modular bridging programme especially designed for the diverse types of student populations in teachers training colleges. We also present here some innovative teaching and assessment methods that were judged essential for the success of these programmes—focusing mainly on the "Questionnaire Based Instruction Method". Finally we suggest directions of follow up and research.

  7. 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...

  8. 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.

  9. 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.

  10. 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.

  11. 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

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

    International Nuclear Information System (INIS)

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

  13. Comparison of flutter derivatives for Kao Pin Hsi Bridge and flat plate

    Czech Academy of Sciences Publication Activity Database

    Buljac, A.; Pospíšil, Stanislav; Kozmar, H.; Kuznetsov, Sergeii; Král, Radomil

    Prague: Institute of theoretical and applied mechanics, Academy of Sciences of the Czech Republic, v. v. i., 2015 - (Náprstek, J.; Fischer, C.), s. 36-37 ISBN 978-80-86246-42-0. ISSN 1805-8248. [Engineering mechanics 2015 /21./. Svratka (CZ), 11.05.2015-14.05.2015] R&D Projects: GA ČR(CZ) GC13-34405J; GA ČR(CZ) GA15-01035S Institutional support: RVO:68378297 Keywords : bridge-deck section * vibrations * aeroelasticity * flutter derivatives * wind-tunnel experiments Subject RIV: JM - Building Engineering

  14. Flutter derivatives of the Kao-Pin Hsi cable-supported bridge

    Czech Academy of Sciences Publication Activity Database

    Buljac, A.; Pospíšil, Stanislav; Kozmar, H.; Kuznetsov, Sergeii; Král, Radomil

    Vol. 821. Zürich: Trans Tech Publications Inc, 2016 - (Fischer, C.), s. 172-179. (Engineering Mechanics. 821). ISBN 978-3-03835-700-1. ISSN 1660-9336. [Engineering mechanics 2015 /21./. Svratka (CZ), 11.05.2015-14.05.2015] R&D Projects: GA ČR(CZ) GA15-01035S; GA MŠk(CZ) LO1219 Institutional support: RVO:68378297 Keywords : bridge-deck section * vibrations * aeroelasticity * flutter derivatives * wind-tunnel experiments Subject RIV: JM - Building Engineering

  15. Identification of aeroelastic forces and static drag coefficients of a twin cable bridge stay from full-scale ambient vibration measurements

    DEFF Research Database (Denmark)

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

    2014-01-01

    excitation from the deck and/or towers. Although there have been many observations of large cable vibrations on bridges, there are relatively few cases of direct full-scale cable vibration and wind measurements, and most research has been based on wind tunnel tests and theoretical modelling.This paper...... presents results from full-scale measurements on the special arrangement of twin cables adopted for the Øresund Bridge. The monitoring system records wind and weather conditions, as well as accelerations of certain cables and a few locations on the deck and tower. Using the Eigenvalue Realization Algorithm......-scale measurements are compared with the theoretical damping matrices based on the quasi-steady theory, using three different sets of wind tunnel measurements of static force coefficients on similar shaped twin or single cables, with good agreement. The damping terms are found to be dependent on Reynolds number...

  16. 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...

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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 are...

  2. 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

  3. 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

    extent these simplified models estimate the heat storage potential of precast hollow-core concrete decks correctly. This study investigates various approaches on how to model the heat transfer within the air void in the deck. Furthermore, it is analysed how different heat transfer models influence the......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...... 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...

  4. Towards a characterization of information automation systems on the flight deck

    Science.gov (United States)

    Dudley, Rachel Feddersen

    This thesis summarizes research to investigate the characteristics that define information automation systems used on aircraft flight decks and the significant impacts that these characteristics have on pilot performance. Major accomplishments of the work include the development of a set of characteristics that describe information automation systems on the flight deck and an experiment designed to study a subset of these characteristics. Information automation systems on the flight deck are responsible for the collection, processing, analysis, and presentation of data to the flightcrew. These systems pose human factors issues and challenges that must be considered by designers of these systems. Based on a previously developed formal definition of information automation for aircraft flight deck systems, an analysis process was developed and conducted to reach a refined set of information automation characteristics. In this work, characteristics are defined as a set of properties or attributes that describe an information automation system's operation or behavior, which can be used to identify and assess potential human factors issues. Hypotheses were formed for a subset of the characteristics: Automation Visibility, Information Quality, and Display Complexity. An experimental investigation was developed to measure performance impacts related to these characteristics, which showed mixed results of expected and surprising findings, with many interactions. A set of recommendations were then developed based on the experimental observations. Ensuring that the right information is presented to pilots at the right time and in the appropriate manner is the job of flight deck system designers. This work provides a foundation for developing recommendations and guidelines specific to information automation on the flight deck with the goal of improving the design and evaluation of information automation systems before they are implemented.

  5. 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.

  6. 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.

  7. 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.

  8. Evaluating Nextgen Closely Spaced Parallel Operations Concepts with Validated Human Performance Models: Flight Deck Guidelines

    Science.gov (United States)

    Hooey, Becky Lee; Gore, Brian Francis; Mahlstedt, Eric; Foyle, David C.

    2013-01-01

    The objectives of the current research were to develop valid human performance models (HPMs) of approach and land operations; use these models to evaluate the impact of NextGen Closely Spaced Parallel Operations (CSPO) on pilot performance; and draw conclusions regarding flight deck display design and pilot-ATC roles and responsibilities for NextGen CSPO concepts. This document presents guidelines and implications for flight deck display designs and candidate roles and responsibilities. A companion document (Gore, Hooey, Mahlstedt, & Foyle, 2013) provides complete scenario descriptions and results including predictions of pilot workload, visual attention and time to detect off-nominal events.

  9. Building Migratory Bridges

    Science.gov (United States)

    Roy, Michael; Doss, Laurie K.

    2007-01-01

    The Building Migratory Bridges (BOMB) program--a collaboration between the Marvel wood School and Audubon Sharon in Connecticut and Conservation Research Education Action (CR EA), a U.S. not-for-profit in Panama--uses nontropical migratory bird research in the United States and Panama to demonstrate how negative environmental impacts in one…

  10. 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.

  11. 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

  12. 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...

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    The aim of this paper is to perform dynamic analysis of a multi-span railway bridge interacting with the underlying soil. A small-scale model of a bridge structure is constructed for experimental testing and the results are compared with a computational model. The computational model in this paper...... the numerical model which is found to reproduce the structural response of the experimental model fairly well....... is based on finite-element analysis for the bridge structure and a semi-analytical solution for the subsoil. The bridge deck and columns are modelled using three-dimensional beam elements. The foundations are implemented as rigid footings placed on the ground surface. The vehicle is modelled as a two...

  14. Numerical Modelling of the Dynamic Response of High-Speed Railway Bridges Considering Vehicle-Structure and Structure-Soil-Structure Interaction

    DEFF Research Database (Denmark)

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

    2015-01-01

    The aim of this paper is the dynamic analysis of a multi-support bridge structure exposed to high-speed railway traffic. The proposed computational model has a unified approach for simultaneously accounting for the bridge structure response, soil response and forces induced by the vehicle....... The bridge structure is modelled in three dimensions based on the finite element method using two-noded three-dimensional beam elements. The track structure is composed of three layers: rail, sleepers and deck which are connected through spring-dashpot systems. The vehicle travelling along a bridge...... is idealized as a multi-degree-of-freedom system, modelled with two layers of spring-dashpot suspension systems. Coupling the vehicle system and railway track is realized through interaction forces between the wheels and the rail, where the irregularities of the track are implemented as a random stationary...

  15. 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

    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...... 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...... 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...

  16. 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.

  17. 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.

  18. 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.

  19. Revised Rules for Concrete Bridges

    DEFF Research Database (Denmark)

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

    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....

  20. 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.

  1. Application of the three component deck model to the ΛK channel in pp reaction

    International Nuclear Information System (INIS)

    The three-Component-Deck-Model (TCDDM) is applied to the (ΛK) channel in pp reaction. The results are concluded to be very satisfatory and take account of the experience. Advantage is taken of the fact that spin-structure is the same as (Nπ) channel which has been in a previous paper. (Author)

  2. 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....

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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…

  8. Load test of the 277W Building high bay roof deck and support structure

    International Nuclear Information System (INIS)

    The 277W Building high bay roof area was load tested according to the approved load-test procedure, WHC-SD-GN-TP-30015, Revision 1. The 277W Building is located in the 200 West Area of the Hanford Site and has the following characteristics: roof deck -- wood decking supported by 4 x 14 timber purlins; roof membrane -- tar and gravel; roof slope -- flat (<10 deg); and roof elevation -- maximum height of about 63 ft. The 227W Building was visited in March 1994 for a visual inspection. During this inspection, cracked areas were visible in the decking, but it was not possible to determine whether these cracks extended completely through the decking, which is 2-in. thick. The building was revisited in March 1994 for the purpose of writing this test report. Because the roof requires personnel access, a test was determined to be the best way to qualify the roof. The conclusions are that the roof has been qualified for 500-lb total roof load and that the ''No Roof Access'' signs can be changed to ''Roof Access Restricted'' signs

  9. 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.

  10. 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.

  11. [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

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

    International Nuclear Information System (INIS)

    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

  13. 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.

  14. Nasal Bridge Intramuscular Hemangioma

    OpenAIRE

    Zulkifli Hamir Basah; Irfan Mohamad; Ramiza Ramza Ramli; Maha Khadum Gayadh; Samarendra Singh Mutum

    2015-01-01

    Intramuscular haemangioma (IMH) is a benign mesenchymal tumour. It appears as a deep, nontender mass within the soft tissue, particularly in the extremities. This tumour may not be obvious on clinical examination. Head and neck IMHs represent only 13.5% of the total IMHs. The most common site for a head and neck IMH is the masseter muscle, followed by trapezius, sternocleidomastoid, and very rarely temporalis muscle. We present a patient with left nasal bridge swelling which was excised and h...

  15. 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...

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Applications of infrared thermography for nondestructive testing of fatigue cracks in steel bridges

    Science.gov (United States)

    Sakagami, Takahide; Izumi, Yui; Kobayashi, Yoshihiro; Mizokami, Yoshiaki; Kawabata, Sunao

    2014-05-01

    In recent years, fatigue crack propagations in aged steel bridge which may lead to catastrophic structural failures have become a serious problem. For large-scale steel structures such as orthotropic steel decks in highway bridges, nondestructive inspection of deteriorations and fatigue damages are indispensable for securing their safety and for estimating their remaining strength. As conventional NDT techniques for steel bridges, visual testing, magnetic particle testing and ultrasonic testing have been commonly employed. However, these techniques are time- and labor- consuming techniques, because special equipment is required for inspection, such as scaffolding or a truck mount aerial work platform. In this paper, a new thermography NDT technique, which is based on temperature gap appeared on the surface of structural members due to thermal insulation effect of the crack, is developed for detection of fatigue cracks. The practicability of the developed technique is demonstrated by the field experiments for highway steel bridges in service. Detectable crack size and factors such as measurement time, season or spatial resolution which influence crack detectability are investigated.

  2. 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...

  3. Monitoring of concrete bridges

    Czech Academy of Sciences Publication Activity Database

    Pirner, Miroš; Urushadze, Shota

    Orlando,Florida: Society for Experimental Mechanics, Inc, 2007 - (Wicks, A.), s. 250-257 ISBN 0-912053-97-6. [IMAC, Conference & Exposition on Structural Dynamics/25./. Orlando (US), 17.02.2007-19.02.2007] R&D Projects: GA MDS(CZ) 1F45D/013/120; GA ČR(CZ) GA103/05/2066 Institutional research plan: CEZ:AV0Z20710524 Keywords : Long-term measurements * Dynamic response * Bridge * Strain gauges * Rain-flow Subject RIV: JM - Building Engineering

  4. 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

  5. Nondestructive testing for bridge diagnosis

    International Nuclear Information System (INIS)

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

  6. Modelling railway bridge asset management

    OpenAIRE

    Le, Bryant Linh Hai

    2014-01-01

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

  7. 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

    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 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...... scenarios outlined. LCA study is performed with the ReCiPe methodology with life cycle inventories data from public database. Five selected mid-point level impact categories and the energy consumption are presented. The result shows that the steel bridge has a better environmental performance due to the...

  8. 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.

  9. 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.

  10. Statics and dynamics of carbon fibre reinforcement composites on steel orthotropic decks

    Czech Academy of Sciences Publication Activity Database

    Frýba, Ladislav; Pirner, Miroš; Urushadze, Shota

    Southampton : WIT Press, 2009 - (Carlomagno, G.; Brebbia, C.), s. 117-123 ISBN 978-1-84564-187-0. [International Conference Computational Methods and Experimental Measurements /14./. Algarve (PT), 10.06.2009-12.06.2009] Grant ostatní: GA ČR(CZ) GA103/08/1340 Institutional research plan: CEZ:AV0Z20710524 Keywords : carbon fibre reinforced composite * orthotropic deck * fatigue life * dynamic load * crack propagation Subject RIV: JM - Building Engineering

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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...

  16. STS-33 crewmembers on OV-103's aft flight deck photograph Earth observations

    Science.gov (United States)

    1989-01-01

    STS-33 crewmembers are positioned on the aft flight deck of Discovery, Orbiter Vehicle (OV) 103, to record Earth observations. Mission Specialist (MS) Kathryn C. Thornton views Earth through an overhead window before taking a picture. A second crewmember behind Thornton, holding viewfinder to his eye, records the scenery. The view was taken by a crewmember on the middeck looking up through the interdeck access hatch.

  17. 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...

  18. Fatigue behaviour of carbon fibre reinforcement composites on steel orthotropic decks

    Czech Academy of Sciences Publication Activity Database

    Urushadze, Shota; Frýba, Ladislav; Pirner, Miroš

    Kuala Lumpur : ASEM, 2010 - (Daut Mohamad, D.; Ahmad, D.), s. 102-102 ISBN N. [International Conference on Experimental Mechanics 2010- ICEM 2010. Kuala Lumpur (MY), 29.11.2010-1.12.2010] R&D Projects: GA ČR(CZ) GA103/08/1340 Institutional research plan: CEZ:AV0Z20710524 Keywords : fatigue * carbon fibre reinforced composites (CFRC) * orthotropic decks. Subject RIV: JM - Building Engineering

  19. 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...

  20. 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 ...

  1. 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...

  2. 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.

  3. Automated analysis of long-term bridge behavior and health using a cyber-enabled wireless monitoring system

    Science.gov (United States)

    O'Connor, Sean M.; Zhang, Yilan; Lynch, Jerome; Ettouney, Mohammed; van der Linden, Gwen

    2014-04-01

    A worthy goal for the structural health monitoring field is the creation of a scalable monitoring system architecture that abstracts many of the system details (e.g., sensors, data) from the structure owner with the aim of providing "actionable" information that aids in their decision making process. While a broad array of sensor technologies have emerged, the ability for sensing systems to generate large amounts of data have far outpaced advances in data management and processing. To reverse this trend, this study explores the creation of a cyber-enabled wireless SHM system for highway bridges. The system is designed from the top down by considering the damage mechanisms of concern to bridge owners and then tailoring the sensing and decision support system around those concerns. The enabling element of the proposed system is a powerful data repository system termed SenStore. SenStore is designed to combine sensor data with bridge meta-data (e.g., geometric configuration, material properties, maintenance history, sensor locations, sensor types, inspection history). A wireless sensor network deployed to a bridge autonomously streams its measurement data to SenStore via a 3G cellular connection for storage. SenStore securely exposes the bridge meta- and sensor data to software clients that can process the data to extract information relevant to the decision making process of the bridge owner. To validate the proposed cyber-enable SHM system, the system is implemented on the Telegraph Road Bridge (Monroe, MI). The Telegraph Road Bridge is a traditional steel girder-concrete deck composite bridge located along a heavily travelled corridor in the Detroit metropolitan area. A permanent wireless sensor network has been installed to measure bridge accelerations, strains and temperatures. System identification and damage detection algorithms are created to automatically mine bridge response data stored in SenStore over an 18-month period. Tools like Gaussian Process (GP

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

    Science.gov (United States)

    Alani, Amir; Banks, Kevin

    2014-05-01

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

  5. 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.

  6. 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

  7. 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 wi...

  8. 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 endan...

  9. Superconductivity in small metal bridges

    International Nuclear Information System (INIS)

    Josephson effects in weaklinks are discussed for low and high frequency regimes using simple perturbation techniques. It is proven that no measurement of the supercurrent dependence upon frequency above the Riedel peak frequency can be made using rf sources whose frequencies are below the Riedel peak. Thus the bulk of work done in the field on the high frequency structure of the Josephson current is shown to be invalid. Metal bridges shorter than a newly defined temperature independent length for superconductors, l/sub PHONON/, are proven to be identical in their Josephson current behavior to tunneling junctions. The BCS gap equation is generalized to include voltage gradient effects on pairs within the bridge. The oscillation frequency for long bridges (l/sub BRIDGE/ greater than l/sub PHONON/) is shown to be limited to less than 10'' Hz. An experimental test of the new voltage dependent gap is made as well as tests of the pair reforming time of bridges

  10. Bridge Coupler for APT

    CERN Document Server

    Greninger, P T; Spalek, G; Greninger, Paul T.; Rodarte, Henry J.

    2000-01-01

    The Coupled Cavity Drift Tube Linac (CCDTL) used in the Accelerator for the Production of Tritium (APT) is fully described elsewhere [1]. The modules are composed of several machined and brazed segments that must account for the accumulation of dimensional tolerances in the build up of the stack. In addition, space requirements dictate that power fed to the accelerator cannot be through the accelerating cavities. As well, we would like to remove a single segment of the accelerator without removing additional segments. These requirements combined with phasing relationships of the design and space limitations have resulted in a different bridge coupling method used in the module comprising 3-gap segments. The coupling method, phasing relationships and other features that enhance the flexibility of the design will be discussed.

  11. Half Bridge Inductive Heater

    Directory of Open Access Journals (Sweden)

    Zoltán GERMÁN-SALLÓ

    2015-12-01

    Full Text Available Induction heating performs contactless, efficient and fast heating of conductive materials, therefore became one of the preferred heating procedure in industrial, domestic and medical applications. During induction heating the high-frequency alternating currents that heat the material are induced by means of electromagnetic induction. The material to be heated is placed inside the time-varying magnetic field generated by applying a highfrequency alternating current to an induction coil. The alternating electromagnetic field induces eddy currents in the workpiece, resulting resistive losses, which then heat the material. This paper describes the design of a power electronic converter circuit for induction heating equipment and presents the obtained results. The realized circuit is a low power half bridge resonant inverter which uses power MOS transistors and adequate driver circuits.

  12. 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

  13. Nanoparticle bridge DNA biosensor

    Science.gov (United States)

    Huang, Hong-Wen

    A new DNA sensing method is demonstrated in which DNA hybridization events lead to the formation of nanoparticle satellites that bridge two electrodes and are detected electrically. The hybridization events are exclusively carried out only on specific locations, the surfaces of C-ssDNA modified 50 nm GNPs. The uniqueness of this work is that only a small number of T-ccDNA molecules (target DNA and three-base-pair-mismatched DNA in 20nM concentrations. Three single-stranded DNA (ssDNA) system is used in our experiment which includes Capture-ssDNA (C-ssDNA), Target-ssDNA (T-ssDNA) and Probe-ssDNA (P-ssDNA). Both C-ssDNA and P-ssDNA are modified by a thiol group and can hybridize with different portions of T-ssDNA. T-ssDNA requires no modification in three ssDNA system, which is beneficial in many applications. C-ssDNA modified 50nm gold nanoparticle (C-50au) and P-ssDNA modified 30nm gold nanoparticle (P-30au) are prepared through the reaction of thiol-gold chemical bonding between thiolated ssDNA and gold nanoparticle (GNP) (C-ssDNA with 50nm GNP, P-ssDNA with 30nm GNP). We controllably place the C-50au only on the SiO2 band surface (˜ 90nm width) between two gold electrodes (source and drain electrodes) by forming positively- and negatively-charged self-assembled monolayers (SAMs) on SiO2 and gold surface, respectively. DNA modified GNP is negatively charged due to ionization of phosphate group on DNA back bone. C-50au therefore is negatively charged and can only be attracted toward SiO2 area (repelled by negatively charged gold electrode surface). The amine group of positively-charged SAMs on SiO2 surface is then passivated by converting to non-polar methyl functional group after C-50au placement. P-30au is first hybridized with T-ssDNA in the solution phase (T-P- 30au formed) and is introduced into DNA detection device in which C-50au are immobilized on ˜90nm width SiO2 band (between two gold electrodes). The passivation step ensures every TP-30au are attached

  14. 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

  15. 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

  16. 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.

  17. 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...

  18. 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...

  19. 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]....

  20. 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

  1. 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.

  2. 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.

  3. Evaluation of eddy current and magnetic techniques for inspecting rebars in bridge barrier rails

    Science.gov (United States)

    Lo, C. C. H.; Nakagawa, N.

    2013-01-01

    This paper reports on a feasibility study of using eddy current (EC) and magnetic flux leakage (MFL) methods to detect corrosion damage in rebars that anchor concrete barrier rails to the road deck of bridge structures. EC and MFL measurements were carried out on standalone rebars with and without artificial defects of 25% and 50% material loss, using a commercial EC-based rebar locator and a MFL system that was developed using giant magnetoresistance sensors to detect leakage fluxes from the defects. Both techniques can readily detect the defects at a distance of 2.5″ (63.5 mm). The amplitudes of the EC and MFL signals vary monotonically with the amount of material loss, indicating the potential of using the techniques to quantify material loss of standalone rebars.

  4. Bridging the urological divide.

    Science.gov (United States)

    Roberts, Robin

    2011-09-23

    The advanced disease clinical presentations, higher morbidity and mortality rates and lack of available treatment options in prostate cancer care, attest to disparities in the delivery and outcomes of urological services in Black men of African lineage in both the Developed and Developing countries. This gap in health care and services in the global management of prostate cancer denotes the urological divide.Through the experience of a Developing country urologist with a comparative literature review, this presentation defines the determinants of the disparity through deficiencies in human, material and financial resources, as is most prevalent in Developing countries.Solutions to ending health care disparities must take into account the existing development phase of Third World countries and thus determine whether the Developed countries should export a total service delivery system or seek primarily to advance the competence and skills of the existing Developing country resources.Collaboration in prostate cancer research has the greatest promise and sustainability of bridging this urological divide and is of mutual benefit to both entities. PMID:21992183

  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. Mineral bridges in nacre revisited

    CERN Document Server

    Checa, Antonio G; Willinger, Marc-Georg

    2012-01-01

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

  7. 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

  8. 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...

  9. 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.

  10. 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

  11. ANGIOGRAPHIC ASPECTS OF MYOCARDIAL BRIDGES

    OpenAIRE

    Sujatha M; V Subhadra Devi; C. S. S. Raju; B. Yugandhar; Nagaraju

    2015-01-01

    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 isc...

  12. SURGERY OF SYMPTOMATIC MYOCARDIAL BRIDGING

    OpenAIRE

    N. Maghamipour N. Safaei

    2007-01-01

    Myocardial bridging with systolic compression of the left anterior descending coronary artery (LAD) may be associated with myocardial ischemia. In symptomatic myocardial bridging unresponsive to medical treatment, surgical unroofing of the left LAD can be performed. Little information is available about the long-term prognosis of patients with this coronary anomaly after the surgical unroofing, so we decided to evaluate the result of this operation. A total of 26 patients underwent surgical u...

  13. 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.

  14. 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.

  15. SURGERY OF SYMPTOMATIC MYOCARDIAL BRIDGING

    Directory of Open Access Journals (Sweden)

    N. Maghamipour N. Safaei

    2007-06-01

    Full Text Available Myocardial bridging with systolic compression of the left anterior descending coronary artery (LAD may be associated with myocardial ischemia. In symptomatic myocardial bridging unresponsive to medical treatment, surgical unroofing of the left LAD can be performed. Little information is available about the long-term prognosis of patients with this coronary anomaly after the surgical unroofing, so we decided to evaluate the result of this operation. A total of 26 patients underwent surgical unroofing of myocardial bridging. Patients had a myocardial bridge of at least 3 cm in length in the middle of LAD and with more than 70% compression during systole. Unroofing was performed with cardiopulmonary bypass in 16 and with off pump technique in 10 patients. In 6 patients repeat angiographies for control of myotomy were done. In one of them a nonsignificant 20% narrowing was seen. Postoperative scintigraphic and angiographic studies demonstrated restoration of coronary flow and myocardial perfusion without residual myocardial bridges under beta-stimulation in 24 patients. Two patients had residual narrowing. With off pump technique, 1 patient had perforation of the right ventricle and 1 patient underwent reoperation because of incomplete unroofing during the first operation. None of the patients with cardiopulmonary bypass technique had residual chest pain or other complications. Surgical unroofing of myocardial bridging with the aid of cardiopulmonary bypass is a safe and easy procedure with low operative risk and with excellent functional results.

  16. Wave-current force on bridge foundation

    OpenAIRE

    Pan, J.N.; Wang, D.T.; Wang, X. G.; Nie, F

    2013-01-01

    Many cross-sea bridges have been constructed or in construction in the Chinese coastal areas, such as Hangzhou Bay Bridge, East China Sea Bridge and Hong Kong-Zhuhai-Macau Bridge, etc. Usually the foundations of cross-sea bridges will bear the load of wave and current simultaneously, the extreme value of which is an important factor for bridge design. It is quite difficult to estimate the extreme wave-current forces on bridge foundations due to their complex form, for example a polygonal plat...

  17. Comparison of Controller and Flight Deck Algorithm Performance During Interval Management with Dynamic Arrival Trees (STARS)

    Science.gov (United States)

    Battiste, Vernol; Lawton, George; Lachter, Joel; Brandt, Summer; Koteskey, Robert; Dao, Arik-Quang; Kraut, Josh; Ligda, Sarah; Johnson, Walter W.

    2012-01-01

    Managing the interval between arrival aircraft is a major part of the en route and TRACON controller s job. In an effort to reduce controller workload and low altitude vectoring, algorithms have been developed to allow pilots to take responsibility for, achieve and maintain proper spacing. Additionally, algorithms have been developed to create dynamic weather-free arrival routes in the presence of convective weather. In a recent study we examined an algorithm to handle dynamic re-routing in the presence of convective weather and two distinct spacing algorithms. The spacing algorithms originated from different core algorithms; both were enhanced with trajectory intent data for the study. These two algorithms were used simultaneously in a human-in-the-loop (HITL) simulation where pilots performed weather-impacted arrival operations into Louisville International Airport while also performing interval management (IM) on some trials. The controllers retained responsibility for separation and for managing the en route airspace and some trials managing IM. The goal was a stress test of dynamic arrival algorithms with ground and airborne spacing concepts. The flight deck spacing algorithms or controller managed spacing not only had to be robust to the dynamic nature of aircraft re-routing around weather but also had to be compatible with two alternative algorithms for achieving the spacing goal. Flight deck interval management spacing in this simulation provided a clear reduction in controller workload relative to when controllers were responsible for spacing the aircraft. At the same time, spacing was much less variable with the flight deck automated spacing. Even though the approaches taken by the two spacing algorithms to achieve the interval management goals were slightly different they seem to be simpatico in achieving the interval management goal of 130 sec by the TRACON boundary.

  18. Variations of Ship’s Deck Elevation Due to Stochastic Process of Containers Loading

    Directory of Open Access Journals (Sweden)

    Przemyslaw Krata

    2015-12-01

    Full Text Available The stochastic process of container loading is described in the paper with special emphasis to ship motion when she is lying at a quay. The 3 DOF system was applied to describe rolling, pitching and heaving of a vessel which may cause a significant variations of momentary deck elevation. The realistic range of such variations are assessed for a variety of cargo locations on-board and a phase shift between two independent gantries engaged in cargo operations. The process is modeled with regard to random character of crucial variables affecting ship motion due to cargo loading.

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

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl

    2015-01-01

    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......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...

  20. 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.

  1. 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.

  2. 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.

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

    International Nuclear Information System (INIS)

    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

  4. Redundancy Evaluation of Fracture Critical Bridges

    OpenAIRE

    Bapat, Amey Vivek

    2014-01-01

    Cases of brittle fractures in major bridges prompted AASHTO to publish its first fracture control plan in 1978. It focused on material and fabrication standards, and required periodic 24-month hands-on inspection of bridges with fracture critical members. The practical result of this plan was to significantly increase the life cycle cost of these bridges, rendering them uneconomical. Apart from the Point Pleasant Bridge that failed in 1967, no other bridge has collapsed in the USA following a...

  5. 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.

  6. 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.

  7. 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.

  8. Assessing factors causing severe injuries in crashes of high-deck buses in long-distance driving on freeways.

    Science.gov (United States)

    Chu, Hsing-Chung

    2014-01-01

    High-deck buses that have a higher center of gravity traveling at an excessive speed have a higher likelihood of causing serious and fatal accidents when drivers lose control of the vehicle. In addition, drivers who suffer from fatigue in long-distance driving increase the likelihood of serious accident. This paper examines the effects of risk factors contributing to severe crashes associated with high-deck buses used for long-distance driving on freeways. An ordered logit and latent class models are used to examine significant factors on the severity of injuries in crashes related to high-deck buses. Driver fatigue, drivers or passengers not wearing a seat belt, reckless driving, drunk driving, crashes occurred between midnight and dawn, and crashes occurred at interchange ramps were found to significantly affect the severity of injuries in crashes involving high-deck buses. Safety policies to prevent severe injuries in crashes involving high deck buses used for long-distance runs on freeways include: (1) restricting drivers from exceeding the limit of daily driving hours and mandating sufficient rest breaks; (2) installing an automatic sleep-warning device in the vehicle; (3) drivers with obstructive sleep apnea syndrome or sleep disorders should be tested and treated before they are allowed to perform long hours of driving tasks; (4) educating the public or even amending the seatbelt legislation to require all passengers to wear a seat belt and thus reduce the chance of ejection from a high-deck bus and prevent serious injuries in a crash while traveling at a higher speed on freeways. PMID:24144498

  9. 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...

  10. Load test of the 3701U Building roof deck and support structure

    International Nuclear Information System (INIS)

    The 3701U Building roof area was load tested according to the approved load-test procedure. The 3701U Building is located in the 300 Area of the Hanford Site and has the following characteristics: Roof deck--metal decking supported by steel purlins; Roof membrane--tar and gravel; Roof slope--flat (<10 deg); and Roof elevation--height of about 12.5 ft. The 3701U Building was visited in August 1992 for a visual inspection, but because of insulation an inspection could not be performed. The building was revisited in March 1994 for the purpose of writing this test report. Because the roof could not be inspected, a test was determined to be the best way to qualify the roof for personnel access. The test procedure called for the use of a remotely-controlled robot. The conclusions are that the roof has been qualified for 500-lb total roof load and that the ''No Roof Access'' signs can be changed to ''Roof Access Restricted'' signs

  11. 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.

  12. 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.

  13. 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.

  14. Bridge Decomposition of Restriction Measures

    CERN Document Server

    Alberts, Tom

    2009-01-01

    Motivated by Kesten's bridge decomposition for two-dimensional self-avoiding walks in the upper half plane, we show that the conjectured scaling limit of the half-plane SAW, the SLE(8/3) process, also has an appropriately defined bridge decomposition. This continuum decomposition turns out to entirely be a consequence of the restriction property of SLE(8/3), and as a result can be generalized to the wider class of restriction measures. Specifically we show that the restriction hulls with index less than one can be decomposed into a Poisson Point Process of irreducible bridges in a way that is similar to Ito's excursion decomposition of a Brownian motion according to its zeros.

  15. 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...

  16. 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.

  17. 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.

  18. 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 §...

  19. 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...

  20. 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

  1. 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 ...... information complemented by a knowledge-based interactive system, BRIDGE-1. To optimize management strategies at the headquarters, the BRIDGE-2 module was implemented, including three submodules: inspection strategy, maintenance and repair....... management systems are presently being implemented by bridge authorities in several countries. The prototype of an expert system for concrete bridge management is presented in this paper, with its functionality relying on two modules. The inspection module relies on a periodic acquisition of field...

  2. 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.

  3. 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.

  4. Artropathies that produce osseous bridges

    International Nuclear Information System (INIS)

    In this paper, it is reviewed the most common artropathies that are presented with osseous bridging, with emphasis in the radiological finding of the spine. Also, it's showed other different radiological finding that can help in the differential diagnosis of this disease, such us the sacroilitis in the ankylosing spondylitis or the osteolysis in the psoriatic arthritis

  5. 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 ...

  6. 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...

  7. Dynamic identification of paradela historic railway bridge

    OpenAIRE

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

    2013-01-01

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

  8. 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.

  9. 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).

  10. 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.

  11. 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.

  12. 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...

  13. Enhanced vision flight deck technology for commercial aircraft low-visibility surface operations

    Science.gov (United States)

    Arthur, Jarvis J.; Norman, R. M.; Kramer, Lynda J.; Prinzel, Lawerence J.; Ellis, Kyle K.; Harrison, Stephanie J.; Comstock, J. R.

    2013-05-01

    NASA Langley Research Center and the FAA collaborated in an effort to evaluate the effect of Enhanced Vision (EV) technology display in a commercial flight deck during low visibility surface operations. Surface operations were simulated at the Memphis, TN (FAA identifier: KMEM) airfield during nighttime with 500 Runway Visual Range (RVR) in a high-fidelity, full-motion simulator. Ten commercial airline flight crews evaluated the efficacy of various EV display locations and parallax and minification effects. The research paper discusses qualitative and quantitative results of the simulation experiment, including the effect of EV display placement on visual attention, as measured by the use of non-obtrusive oculometry and pilot mental workload. The results demonstrated the potential of EV technology to enhance situation awareness which is dependent on the ease of access and location of the displays. Implications and future directions are discussed.

  14. 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

    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...... of crack widths. Furthermore, the analysis shows that debonding is initiated for a certain crack width in the overlay. The load level where cracking and debonding is initiated depends on the stress-crack opening relationship of the material....... 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...

  15. The Naturalistic Flight Deck System: An Integrated System Concept for Improved Single-Pilot Operations

    Science.gov (United States)

    Schutte, Paul C.; Goodrich, Kenneth H.; Cox, David E.; Jackson, Bruce; Palmer, Michael T.; Pope, Alan T.; Schlecht, Robin W.; Tedjojuwono, Ken K.; Trujillo, Anna C.; Williams, Ralph A.; Kinney, J. Bryan; Barry, John S., Jr.

    2007-01-01

    This paper reviews current and emerging operational experiences, technologies, and human-machine interaction theories to develop an integrated flight system concept designed to increase the safety, reliability, and performance of single-pilot operations in an increasingly accommodating but stringent national airspace system. This concept, know as the Naturalistic Flight Deck (NFD), uses a form of human-centered automation known as complementary-automation (or complemation) to structure the relationship between the human operator and the aircraft as independent, collaborative agents having complimentary capabilities. The human provides commonsense knowledge, general intelligence, and creative thinking, while the machine contributes specialized intelligence and control, extreme vigilance, resistance to fatigue, and encyclopedic memory. To support the development of the NFD, an initial Concept of Operations has been created and selected normal and non-normal scenarios are presented in this document.

  16. 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.

  17. 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.

  18. Crew Alertness Management on the Flight Deck: Cognitive and Vigilance Performance

    Science.gov (United States)

    Dinges, David F.

    1998-01-01

    This project had three broad goals: (1) to identify environmental and organismic risks to performance of long-haul cockpit crews; (2) to assess how cognitive and psychomotor vigilance performance, and subjective measures of alertness, were affected by work-rest schedules typical of long-haul cockpit crews; and (3) to determine the alertness-promoting effectiveness of behavioral and technological countermeasures to fatigue on the flight deck. During the course of the research, a number of studies were completed in cooperation with the NASA Ames Fatigue Countermeasures Program. The publications emerging from this project are listed in a bibliography in the appendix. Progress toward these goals will be summarized below according to the period in which it was accomplished.

  19. Bridge spectra of iterated torus knots

    OpenAIRE

    Zupan, Alexander

    2013-01-01

    We determine the set of all genus g bridge numbers of many iterated torus knots, listing these numbers in a sequence called the bridge spectrum. In addition, we prove a structural lemma about the decomposition of a strongly irreducible bridge surface induced by cutting along a collection of essential surfaces.

  20. Stabilizer for seismically exposed bridge cranes

    International Nuclear Information System (INIS)

    The invention concerns a stabilizer for seismically exposed bridge cranes in reactor buildings. The trolley and the crane bridge are fitted with the stabilizer consisting of a bipartite safety catch which is connected with a joint and able to take up the vertical loads during an earthquake. This stabilizer is suitable for all kinds of bridge cranes operated in seismically active regions

  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. 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...

  3. Theory of water and charged liquid bridges.

    Science.gov (United States)

    Morawetz, K

    2012-08-01

    The phenomenon of liquid bridge formation due to an applied electric field is investigated. A solution of a charged catenary is presented, which allows one to determine the static and dynamical stability conditions where charged liquid bridges are possible. The creeping height, the bridge radius and length, as well as the shape of the bridge are calculated showing an asymmetric profile, in agreement with observations. The flow profile is calculated from the Navier-Stokes equation leading to a mean velocity, which combines charge transport with neutral mass flow and which describes recent experiments on water bridges. PMID:23005849

  4. 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

  5. Noise Considerations in Resistance Bridges

    DEFF Research Database (Denmark)

    Diamond, Joseph M.

    1963-01-01

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

  6. Full-bridge capacitive extensometer

    Science.gov (United States)

    Peters, Randall D.

    1993-08-01

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

  7. The radiography of Swaythling Bridge

    International Nuclear Information System (INIS)

    The particular application of high energy radiography described in this paper was developed by the Harwell Nondestructive Testing Centre (NDTC) under the sponsorship of Radiation Dynamics Ltd, (RDL) who manufacture the 'Super-X' linear accelerator (Linac) used for the work. An initial evaluation determined the limits for thickness of concrete structures which could be radiographed with the linac under practical conditions. The technique was then applied to carry out a test on a bridge carrying a main trunk road over a small river in an urban environment. A situation which demanded the utmost care in deciding safety parameters and minimal disturbance to the surrounding environment. The safety parameters were defined by the Environmental and Medical Sciences Division of AERE Harwell (EMSc). The test was successfully carried out, within all the control parameters laid down beforehand, and very important engineering data were obtained for the Bridge Engineering Departments of Hampshire County Council and Southampton City Council. (author)

  8. 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 psycholog......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...... psychologists can benefit from engaging with historical sources by being able to contextualise their findings and enrich their theoretical models. It is not only that all social and psychological phenomena have a history but this history is very much part of present-day and future developments. On the other...

  9. 2015 Bridge Inspection ERC Training

    OpenAIRE

    Dougherty, Merril

    2015-01-01

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

  10. Severe ASR damaged concrete bridges

    DEFF Research Database (Denmark)

    Antonio Barbosa, Ricardo; Gustenhoff Hansen, Søren

    2015-01-01

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

  11. Stability of Axisymmetric Liquid Bridges

    CERN Document Server

    Rubinstein, Boris

    2016-01-01

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

  12. The Bridge Program - Participant Perspectives

    OpenAIRE

    Rönnqvist, Riitta; Hakonen, Anu; Vartiainen, Matti

    2015-01-01

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

  13. Inspection Strategies for Concrete Bridges

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

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

  14. Adsorption of polymeric brushes: Bridging

    Science.gov (United States)

    Johner, Albert; Joanny, Jean-François

    1992-04-01

    We study the adsorption of grafted polymer layers on a planar surface parallel to the grafting surface. The layer consists of two types of chains: nonadsorbed chains with a free end and adsorbed chains forming bridges between the two plates. In the limit of strong adsorption a dead zone exists in the vicinity of the adsorbing plate; its size increases with the adsorption strength. Two adsorption mechanisms are possible: adsorption of the last monomer only and adsorption of all the monomers. In both cases the adsorption regimes at equilibrium (when no external force acts on the plates) are discussed within the framework of the self-consistent mean-field theory. We also give scaling laws taking into account excluded volume correlations. Finally, we consider situations where a finite external force, either tangential or normal to the plates, is applied on the adsorbing plate. Pulling and tangential forces both reduce the fraction of bridges and eventually lead to rupture, whereas compressional forces favor bridging. For normal forces, force vs distance profiles between planes and crossed cylinders are given.

  15. Halliburton Composite Bridge Plug Assembly

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-01-15

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

  16. Hybrid networking sensing system for structural health monitoring of a concrete cable-stayed bridge

    Science.gov (United States)

    Torbol, Marco; Kim, Sehwan; Chien, Ting-Chou; Shinozuka, Masanobu

    2013-04-01

    The purpose of this study is the remote structural health monitoring to identify the torsional natural frequencies and mode shapes of a concrete cable-stayed bridge using a hybrid networking sensing system. The system consists of one data aggregation unit, which is daisy-chained to one or more sensing nodes. A wireless interface is used between the data aggregation units, whereas a wired interface is used between a data aggregation unit and the sensing nodes. Each sensing node is equipped with high-precision MEMS accelerometers with adjustable sampling frequency from 0.2 Hz to 1.2 kHz. The entire system was installed inside the reinforced concrete box-girder deck of Hwamyung Bridge, which is a cable stayed bridge in Busan, South Korea, to protect the system from the harsh environmental conditions. This deployment makes wireless communication a challenge due to the signal losses and the high levels of attenuation. To address these issues, the concept of hybrid networking system is introduced with the efficient local power distribution technique. The theoretical communication range of Wi-Fi is 100m. However, inside the concrete girder, the peer to peer wireless communication cannot exceed about 20m. The distance is further reduced by the line of sight between the antennas. However, the wired daisy-chained connection between sensing nodes is useful because the data aggregation unit can be placed in the optimal location for transmission. To overcome the limitation of the wireless communication range, we adopt a high-gain antenna that extends the wireless communication distance to 50m. Additional help is given by the multi-hopping data communication protocol. The 4G modem, which allows remote access to the system, is the only component exposed to the external environment.

  17. Low speed wind tunnel test of ground proximity and deck edge effects on a lift cruise fan V/STOL configuration, volume 1

    Science.gov (United States)

    Stewart, V. R.

    1979-01-01

    The characteristics were determined of a lift cruise fan V/STOL multi-mission configuration in the near proximity to the edge of a small flat surface representation of a ship deck. Tests were conducted at both static and forward speed test conditions. The model (0.12 scale) tested was a four fan configuration with modifications to represent a three fan configuration. Analysis of data showed that the deck edge effects were in general less critical in terms of differences from free air than a full deck (in ground effect) configuration. The one exception to this was when the aft edge of the deck was located under the center of gravity. This condition, representative of an approach from the rear, showed a significant lift loss. Induced moments were generally small compared to the single axis control power requirements, but will likely add to the pilot work load.

  18. 粉房湾长江大桥主桥钢桁梁架设施工技术%Construction Techniques for Erection of Steel Truss Girder of Main Bridge of Fenfangwan Changjiang River Bridge

    Institute of Scientific and Technical Information of China (English)

    王存贵; 王殿永; 高杰; 靳春尚

    2012-01-01

    The main bridge of Fenfangwan Changjiang River Bridge in Chongqing City is a semi-floating system steel truss girder cable-stayed bridge with double pylons, double cable planes and with span arrangement (216. 5 + 464 + 216. 5) m. The main girder of the bridge is designed as the steel truss girder structure erected by the piece-by-piece assembling. In the light of the topographic conditions of the south and north banks, the asymmetric way of erection was chosen for the girder. The steel truss girder on the south bank side was erected from the side span towards the central span. The girder of the side span was assembled on the scaffolding, the girder in the middle was erected first and then the components like the edge stringers and edge deck plates were erected, using the deck truck cranes. The girder for the main span was erected by the cantilever assembling method. The girder of the north bank was erected by the balanced two-cantilever assembling method and the 5 blocks of the girder atop and on both sides of a main pier were assembled on the pier-side brackets.%重庆粉房湾长江大桥主桥为跨度(216.5+464+216.5)m的双塔双索面半飘浮体系钢桁梁斜拉桥,主梁采用钢桁梁结构.钢桁梁采取散拼架设,南、北岸钢桁梁根据地形情况选取了不对称的方式施工.南岸钢桁梁由边跨向中跨架设,边跨钢桁梁采用支架拼装,先架设中间桁架,再利用桥面汽车吊架设边纵梁、边桥面板等构件;主跨钢桁梁采用悬臂拼装.北岸钢桁梁采用双悬臂对称架设,主墩墩顶及两侧共5个节段钢桁梁采用墩旁托架拼装.

  19. 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.

  20. 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.