Design and evaluation of UHPP steel bridge deck pavement for high-temperature and rainy regions

To enhance the serviceability of steel bridge deck pavement(SBDP)in high-temperature and rainy regions,a concept of rigid bottom and flexible top was summarized using engineering practices,which led to the proposal of a three-layer ultra-high-performance pavement(UHPP).The high-temperature rutting resistance and wet-weather skid resistance of UHPP were evaluated through composite structure tests.The internal temperature distribution within the pavement under typical high-temperature conditions was analyzed using a temperature field model.Additionally,a temperature-stress coupling model was employed to investigate the key load positions and stress response characteristics of the UHPP.The results indicate that compared with the traditional guss asphalt+stone mastic asphalt structure,the dynamic stability of the UHPP composite structure can be improved by up to 20.4%.Even under cyclic loading,UHPP still exhibits superior surface skid resistance compared to two traditional SBDPs.The thickness composition of UHPP significantly impacts its rutting resistance and skid resistance.UHPP exhibits relatively low tensile stress but higher shear stress levels,with the highest shear stress occurring between the UHPP and the steel plate.This suggests that the potential risk of damage for UHPP primarily lies within the interlayer of the pavement.Based on engineering examples,introducing interlayer gravel and optimizing the amount of bonding layer are advised to ensure that UHPP possesses sufficient interlayer shear resistance.

Design and Engineering of Urban Interchange Ramp Bridge Structure

This paper analyzes the structural design of an urban interchange ramp bridge from four aspects,which are the superstructure,pier structure,foundation structure,and deck structure design to summarize the structural design ideas of this urban interchange ramp bridge,which can be used as a reference for future construction of the same bridge.

Finite element simulation and optimal analysis of surfacing on steel orthotropic bridge deck

To analyze the stress state of steel orthotropic deck pavement and provide reference for the design of the overlay, the inner stress state and strain distribution of surfacing under the load of the deformation of the whole bridge structure and tyre load are analyzed by the finite element method of submodeling. Influence of surfacing modulus on the strain state of the overlay is analyzed for the purpose of the optimal design of the overlay structure. Analysis results show that the deformation of the whole bridge structure has no evident influence on the stress state of the overlay. The key factor of the overlay design is the transverse tensile strain in the overlay above the upper edge of web plate of rib. The stress state of the overlay is influenced evidently by the modulus of rigidity transform overlay. And the stress state of the overlay can be optimized and lowered by increasing the modulus and thickness of rigidity transform overlay, The fatigue test has been done to evaluate the fatigue performance and modulus of different deck pavement materials such as epoxy asphalt, SBS modified asphalt, rosphalt asphalt which can provide reference for deck pavement structure design.

Mechanical properties of epoxy asphalt mixture pavement with lightweight aggregate applied on bascule bridge

The high temperature anti-rutting performance,water stability and low temperature bending property of epoxy asphalt mixture with 0%,15%,25%,40%,and 70% granulated and circular lightweight aggregates by weight are tested,respectively.The dynamic responses under the vehicle load and in the opening process are analyzed to obtain the mechanical responses of pavements by using the finite element method.The complicated structure including a steel deck and a waterproof adhesive layer is made to verify the bond strength of the 2451-type epoxy asphalt binder.Research results show that the epoxy asphalt mixtures with lightweight aggregate replacement percentages from 0% to 70% all satisfy the requirements for steel bridge pavements.The epoxy asphalt mixture with a 70% circular lightweight aggregate replacement percentage is recommended because of its smaller density when compared with other epoxy asphalt mixtures.The shear stress increases with the increase in the opening angle and achieves its maximum at the maximum opening angle of 85°.Test results show that the Tianjin Bascule Bridge can be used for first opening after a 3 d pavement conditioning.

Design and laboratory evaluation of fog-sealed chip seal on epoxy asphalt pavement for steel bridge deck

In order to improve the surface performace of epoxy asphalt pavement （EAP） for steel bridge deck, an epoxy asphalt chip seal （ ECS） covered by a cationic emulsified asphalt fog seal （i. e., fog-sealed chip seal） isproposed and a laboratory study is conducted to design and evaluate te fog-sealed chip seal. First, the evaluation indices and methods of te chip seal on steel bridge deck pavement were proposed. Secondly, the worst pavement conditions during te maintenance time were simulated by te small traffic load simulation system MMLS3 and the short-term aging test for minimizing the failure probability of chip seal. Finally, the design parameters of fog-sealed chip seal were determined by the experimental analysis and the performance of the designed fog-sealed chip seal was evaluated in thelaboratory. Results indicate that the proposed simulation method of pavement conditions is effective and the maximal load repetitions on the EAPslab specimen are approximately 925 300 times. Moreover, the designed fog-sealedchip sealcan provide a dense surface with sufficient skid resistance,aggregate-asphalt aahesive performance and interlayer shearing resistance.

Real-Time Detection of Cracks on Concrete Bridge Decks Using Deep Learning in the Frequency Domain

This paper presents a vision-based crack detection approach for concrete bridge decks using an integrated one-dimensional convolutional neural network(1D-CNN)and long short-term memory(LSTM)method in the image frequency domain.The so-called 1D-CNN-LSTM algorithm is trained using thousands of images of cracked and non-cracked concrete bridge decks.In order to improve the training efficiency,images are first transformed into the frequency domain during a preprocessing phase.The algorithm is then calibrated using the flattened frequency data.LSTM is used to improve the performance of the developed network for long sequence data.The accuracy of the developed model is 99.05%,98.9%,and 99.25%,respectively,for training,validation,and testing data.An implementation framework is further developed for future application of the trained model for large-scale images.The proposed 1D-CNN-LSTM method exhibits superior performance in comparison with existing deep learning methods in terms of accuracy and computation time.The fast implementation of the 1D-CNN-LSTM algorithm makes it a promising tool for real-time crack detection.

Numerical investigation of temperature gradient-induced thermal stress for steel–concrete composite bridge deck in suspension bridges

A3D finite element model(FEM)with realistic field measurements of temperature distributions is proposed to investigate the thermal stress variation in the steel–concrete composite bridge deck system.First,a brief literaturereview indicates that traditional thermal stress calculation in suspension bridges is based on the2D plane structure with simplified temperature profiles on bridges.Thus,a3D FEM is proposed for accurate stress analysis.The focus is on the incorporation of full field arbitrary temperature profile for the stress analysis.Following this,the effect of realistic temperature distribution on the structure is investigated in detail and an example using field measurements of Aizhai Bridge is integrated with the proposed3D FEM model.Parametric studies are used to illustrate the effect of different parameters on the thermal stress distribution in the bridge structure.Next,the discussion and comparison of the proposed methodology and simplified calculation method in the standard is given.The calculation difference and their potential impact on the structure are shown in detail.Finally,some conclusions and recommendations for future bridge analysis and design are given based on the proposed study.

Fatigue damage analysis of epoxy asphalt pavement for steel bridges considering coupled effects of heavy load and temperature variations

To investigate the fatigue damage of epoxy asphalt pavement(EAP)under a heavy load and a d temperature load,the load-figure of the heavy load on the steel bridge deck pavement(SBDP)was simulated first,and the temperature distribution of SBDP during the temperature-fall period in winter was also calculated.Secondly,t e moving heavy load coupled W t the most unfavorable temperatre load was applied to the SBDP,and the tensile stress on the top of SBDP was calculated.Finally,the fatigue damage of EAP was evaluated considering the extreme situation of heavily overloaded and severe environments.The results show that botte heavy load and the temperature load during t e temperature-fall period c n increase the tensile stress on the top of SBDP significantly.In the exteme situation of heavily overloaded and severe environments,a fatigue crack is easily generated,and thus the SBDP should avoid t e coupling effects of the heavy loadand the temperature load in winter.

Wind-induced vibration control of bridges using liquid column damper

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

Double deck bridge behavior and failure mechanism under seismic motions using nonlinear analyzes

This paper investigates the behavior and the failure mechanism of a double deck bridge constructed in China through nonlinear time history analysis. A parametric study was conducted to evaluate the influence of different structural characteristics on the behavior of the double deck bridge under transverse seismic motions, and to detect the effect of bi- directional loading on the seismic response of this type of bridge. The results showed that some characteristics, such as the variable lateral stiffness, the foundation modelling, and the longitudinal reinforcement ratio of the upper and lower columns of the bridge pier bents have a major impact on the double deck bridge response and its failure mechanism under transverse seismic motions. It was found that the soft story failure mechanism ：is not unique to the double deck bridge and its occurrence is related to some conditions and structural characteristics of the bridge structure. The analysis also showed that the seismic vulnerability of the double deck bridge under bi-directional loading： was severely increased compared to the bridge response under unidirectional transverse loading, and out-of-phase movements were triggered between adjacent girders.

Effect of crack-closure treatment on fatigue durability of cracked rib-to-deck welded joints in steel bridge decks

To evaluate the effect of treating long cracks with the impact crack-closure retrofit(ICR)technique,three rib-to-deck welded specimens with a crack length of about 100 mm were tested.The metallographic structure,crack section,crack propagation life,and stress variation were analyzed.Finite-element models were also developed,and some optimal values of certain parameters are suggested according to the simulated results.The results show that new crack sources are generated on both sides of the ICR-treated region because of the stress distribution.The fatigue lives of cracked specimens with long cracks are significantly improved by the technique.Considerable residual compressive stress is also induced,and so it is suggested that the optimal impact angle to be applied to real bridges should be 70°.The stress at the weld root is distributed uniformly with the crack closed,and the optimal crack-closure depth is 4 mm.To evaluate the effect of different crack-closure depths in tests,it is recommended that a hot-spot stress method which is extrapolated by three reference points should be adopted.

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

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 midclle 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 con- crete 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.

Fatigue Crack Propagation Analysis of Orthotropic Steel Bridge with Crack Tip Elastoplastic Consideration

Due to the complex structure and dense weld of the orthotropic steel bridge deck(OSBD),fatigue cracks are prone to occur in the typical welding details.Welding residual stress(WRS)will cause a plastic zone at the crack tip.In this paper,an elastoplastic constitutive model based on the Chaboche kinematic hardening model was introduced,and the extended finite element method(XFEM)was used to study the influence of material elastoplasticity and crack tip plastic zone on the law of fatigue crack propagation.By judging the stress state of the residual stress field at the crack tip and selecting different crack propagation rate models to investigate the crack propagation law when plastic deformation was considered,the propagation path and propagation rate of fatigue crack of the OSBD were obtained.The results show that,whether the residual stress field is considered or not,the plastic deformation at the crack tip will not cause the obvious closure of the fatigue crack at the U-rib toe during the crack propagation process,but will significantly affect the crack propagation path.When material plasticity is considered,the propagation angle of fatigue crack at the U-rib toe basically remains unchanged along the short-axis direction of the initial crack,but is going up along the long-axis direction,and the crack tip plastic zone inhibits the propagation of the crack tip on one side.Compared with linear elastic materials,the crack propagation law considering material plasticity is more consistent with that in actual bridge engineering.In terms of the propagation rate,if the residual stress field is not considered,the fatigue crack propagation rate at U-rib toe with plasticity considered is slightly higher than that without plasticity considered,because plastic deformation will affect the amplitude of energy release rate.When considering the WRS field,the fatigue crack propagation rate at U-rib toe is increased due to the combined actions of plastic deformation and stress ratio R.

Cross-spectral recognition method of bridge deck aerodynamic admittance function

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. © 2015, Institute of Engineering Mechanics, China Earthquake Administration and Springer-Verlag Berlin Heidelberg.

Fatigue Performance of Bridge Deck Pavement Materials

Three beam samples of bridge deck pavement were prepared, with gradation types 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 samples decreases as the increase of the controlled strain fatigue resistance and bigger limiting bending strain at pared with single beam sample, the fatigue performance and testing temperature. Fatigue life of these level. The AC-13 beam sample exhibits better the given strain level and temperature. Corn- of combining beam samnle is relatively poor.

Applications of Glass and Glass Fiber Retrofit Polymer in Modern Footbridges

The architecture of footbridge design takes the form of a number of submissions from leading architects and engineers, each setting out their views on bridge design--present and future. It looks at the functions of a bridge, defining purpose of place and context, the spirit of creativity and the reasoned progression of an idea. It also explores the exploitation of materials technology and construction innovation and the tension between lightness and mass and between sculpture and scale. Present parameters of tempered and laminated glass create possibility of modern architecture of footbridges which are being full of transparency and light reflex effects. Four projects, using glass panels designed by Santiago Calatrava, have been presented in this paper. GFRP （glass fiber retrofit polymer） makes new horizon in material technology, helps to enrich new conception of structure with longer durability, low weight of deck and new creation of architecture line. The paper has described a few results of FEM （finite element method） analysis of footbridge with modular bridge GFRP deck system. The footbridge was excited by impact and human-induced vibrations. Composite material consists of glass fibers and polymer matrix is a promising alternative against traditional materials. New architecture and modern material engineering are looking for fresh possibilities of form and shape of structure, long durability and extraordinary technical parameters of building elements.

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

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.

Condition Assessment of August A. Busch Bridge Deck Using Portable Seismic Property Analyzer and Ground Penetrating Radar

Ground penetrating radar (GPR) and the portable seismic property analyzer (PSPA) have been extensively used in the past two decades for monitoring, quantifying, and mapping the deterioration of bridge decks. Using PSPA and GPR ensures regular monitoring of bridge conditions, leads to the early detection of deterioration. This research is to address the condition of August A. Busch bridge deck owned by the Missouri Department of Conservation. Visual inspection, GPR, and PSPA data were acquired on the bridge deck. Over 90% of the bridge deck was in fair to good condition with an average compressive strength of over 2500 psi. GPR data showed no indication of significant deterioration. The overall bridge deck was determined to be in fair to good condition.

Bridge Pressure Flow Scour at Clear Water Threshold Condition

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.

Spatiotemporal distribution characteristics of bridge deck runoff

The spatiotemporal characteristics of bridge deck runoff under a natural rainfall event are explored. The Taizhou Bridge is taken as a study case,and a hydrodynamic model based on the two-dimensional shallow water equations is used to analyze the runoff characteristics. The results indicate that the runoff velocity rate and depth are positively related to rainfall intensity,yet they have different response degrees to it. The inlet’s effect degree on lane water film has a positive relationship with rainfall intensity. A natural logarithm function( R^2= 0.706) can illustrate this relationship. However,the inlet’s effect degree on ponding at the curb shows a negative relationship with the rainfall intensity. A negative exponential function( R^2= 0.824) can reveal this relationship. With the decrease in the longitudinal slope SL,the ponding depth at the curb increases significantly at the bridge approach slab,whereas the lane water film thickness( WFT) is almost unchanged,but the lane WFT increases greatly at the location with the minimum longitudinal slope. It is concluded that the characteristics of the bridge deck runoff present apparent spatiotemporal differences,the inlet ’s effects on bridge deck runoff are quantitatively correlated with rainfall intensity, and the effective drainage measures are necessary for the bridge approach slab.