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Highlights • FRP bridge deck that incorporates PU foam was developed for ABC and repair. • Results of testing indicated that the deck significantly exceeded the AASHTO requirements. • The decks behaved linearly-elastically throughout the full range of loading. • The experimental results were used to evaluate the applicability of existing FRP design equations. Abstract A fiber-reinforced polymer (FRP) bridge deck panel that incorporates a polyurethane foam core was developed for accelerated bridge construction and repair. This low cost panel was tested under monotonic loading and compared to applicable FRP design equations. This new prototype system consisted of two stiff facesheets of stitch bonded plain-weave woven E-glass fabric with sloping webs of E-glass woven fabric that are separated by trapezoidal-shaped, low-density polyurethane foam. The polyurethane foam was used in an attempt to reduce initial costs. The panels used in this study were manufactured using a one-step, vacuum-assisted, resin transfer molding process (VARTM) using a newly formulated, two-part, thermoset, polyurethane resin developed by Bayer MaterialScience to facilitate the infusion process. The results of the flexural and shear testing indicated that the prototype panels significantly exceeded the AASHTO Design Code Strength requirements by nearly three times. Even more importantly, the panels behaved linearly-elastically throughout the full range of loading and possessed significant post-buckling strength. In addition, the results of these full-scale panels were used to evaluate the applicability of existing FRP design equations when used for the design of the VARTM- manufactured, prototype FRP bridge deck. Results showed that the existing FRP design equations correctly predicted a flexural failure due to local buckling of the compression flange and a bearing failure due local buckling of the webs beneath the concentrated load. [ABSTRACT FROM AUTHOR]

Highlights • The fluctuating pressures of bridge decks were measured with different turbulence. • The coherences of the buffeting force of the box bridge decks were investigated. • An Empirical formula for the 3D aerodynamic admittance was proposed. • An Empirical formula for the coherence of buffeting forces was proposed. Abstract Via wind tunnel tests, the fluctuating pressures on the surfaces of three streamlined box bridge models are measured in two turbulent flow-fields with different turbulence characteristic parameters. The distributions of the fluctuating pressures on the models are presented and discussed in detail. The correlations between the fluctuating pressures on a crosswise section and the coherences of the buffeting force along the spanwise direction of the models are investigated. Furthermore, the 3D aerodynamic admittances of the models are identified and analyzed. An empirical formula for determining the 3D aerodynamic admittance of a streamlined bridge deck is proposed based on the extensive results of the experimental data and analysis. Clarifications are made regarding the differences between the real 3D aerodynamic admittances and the existing formulas. It is then further revealed that the real value of a 3D aerodynamic admittance is not between 1 and the number determined by the Sears function. This is followed by a rational explanation for the observations based on the experimental results. [ABSTRACT FROM AUTHOR]

By using a multi-scale simulation together with the pseudo-cracking method, the remaining fatigue life of real RC bridge decks is estimated based upon their site-inspected surface crack patterns of a wide variety, and it is confirmed that the crack location and its orientation are primary factors on the remaining life together with crack width. For quick diagnosis for the remaining fatigue life at the site, an artificial neural network (ANN) to correlate the fatigue life with observed cracks is built up based upon large numbers of assessed fatigue life related to wide range of crack patterns and their widths. Artificially created crack patterns associated with the firm coupling of shear and flexure are also included in training dataset to cope with indeterminate crack events which may arise in future and to assure a robust and reliable artificial neural network model. It is recognized by conducting the cross-validations that the training data-set for ANN shall include crack patterns rooted in mechanically possible modes of failure. Otherwise, the risk of wrong assessment due to overlearning will arise. [ABSTRACT FROM AUTHOR]

The present wind-tunnel study focuses on the effects of roadway wind barriers on aerodynamic and aeroelastic characteristics of bridge decks characterized by various aerodynamic shapes of the cross section. Three bridge-deck sections are studied, i.e., streamlined, semi-bluff, and bluff sections. The standard 5 m high (full-scale) wind barrier with 30% porosity is placed at the windward (leading) edge of the bridge-deck sections. Aerodynamic forces and overturning moment are determined at various wind incidence angles. Galloping stability is studied using the quasi-steady theory. Flutter derivatives are determined to evaluate flutter sensitivity of the studied bridge-deck sections with the wind barrier in comparison with the empty bridge-deck sections. The experimental results indicate some important features. In particular, the drag force coefficient is increased for all bridge-deck sections when the wind barrier is in place. This feature is particularly exhibited for the streamlined bridge-deck section. The wind barrier alters the trends and values of the lift force coefficient, while the influence of the wind barrier on the pitch moment is particularly exhibited for positive wind incidence angles, which is characteristic for all bridge-deck sections. The wind barrier does not influence the galloping sensitivity of the studied bridge-deck sections, while it deteriorates their dynamic stability with respect to torsional flutter. [ABSTRACT FROM AUTHOR]

Composite bridge decks provide higher flexural moment capacity and stiffness compared to their non-composite counterparts. In order to achieve composite behavior, differential slip between the steel member and the concrete slab must be restrained by means of shear connectors. In older bridge decks composite behavior is uncertain. Uncertainty arises, among other things, due to lack of knowledge regarding the type of shear connector used (if any), cumulative damage due to fatigue, and aging effects. In this paper the authors propose the use of sensitivity-based finite element model updating to determine the degree of composite behavior of operational bridge decks with uncertain shear connectors. The free parameters of the models are: rigidity per unit length of the beam-slab interface and the elastic modulus of the concrete slab. The features used in the model updating procedure are the identified modal frequencies from operational acceleration measurements. A sequential sensitivity-based weighted least-squares solution was implemented. The proposed methodology is verified in various simulated bridge deck structures and validated in an operational and partially instrumented bridge deck with uncertain composite action. [ABSTRACT FROM AUTHOR]

Segmental construction of prefabricated full-depth concrete bridge deck systems results in numerous transverse and longitudinal joints as well as shear connector pockets that receive cast-in-place concrete or grout. In such systems, it is necessary to overlay the bridge deck to provide smooth riding surface and to protect the underlying deck reinforcement from the deicing salts-induced corrosion and consequent spalling and delamination of the concrete. This paper reports on results and findings obtained from a non-linear finite element analysis (NLFEA) of a prototype prefabricated full-depth precast concrete bridge deck panel system before and after being overlaid with various plain and fibrous latex-modified concrete (LMC) and microsilica concrete (MSC) overlays. The NLFEA were validated with experimental results obtained from full-scale testing of the prototype bridge system. The benefits of the NLFEA can be highly appreciated when visualizing the substantial time and cost savings, the ability to change any parameter of interest, and the capability of demonstrating any interesting response at any load value and at any location in the system. The most attractive results were: (1) adequately bonded LMC or MSC overlay significantly improves the stiffness, cracking load, and ultimate strength capacity of the system, (2) AASHTO HS20 truck induced bond stresses were below the bond strength of bonded LMC and MSC overlays, (3) the fibrous overlay has desirable crack arresting characteristic. [ABSTRACT FROM AUTHOR]

In this article, the accuracy of standard computational fluid dynamics techniques and turbulence models in predicting the critical flutter speed of streamlined and bluff deck sections is investigated. It is well known that such numerical tools can provide inaccurate prediction of the flow field around bluff bodies which reflects in biases in their aeroelastic behavior. Aiming at systematically study the effects of such inaccuracies, in this article, six deck sections are analyzed by numerically extracting flutter derivatives and calculating the critical flutter speed for a set of representative test structures. It is shown that the flutter onset velocity is mainly underestimated but cases showing opposite behavior are identified and discussed. Two simulation strategies are adopted: the differences in the flutter mechanism between such two approaches are taken as an indicator of possible strong inaccuracies. [ABSTRACT FROM AUTHOR]

Abstract: This study presents the details and assessment of the effectiveness of an innovative retrofit methodology aims at improving both the strength and ductility of existing reinforced concrete (RC) floor slabs and bridge decks. The innovative retrofit system comprises of a polymeric hybrid composite system made of high performance concrete (HPC) and a carbon fiber reinforced polymer (CFRP) unidirectional laminates. The proposed retrofit system is designed to avoid the difficulty and restricted accessibility associated with applying conventional steel and fiber reinforced polymeric (FRP) composite systems to the underside of existing floor slabs or bridge decks for positive moment capacity enhancement. The proposed system is applied only to the top of the slabs or decks resulting in a shorter application time and minimizing service disturbance of the lower floor or traffic interruption under the bridge overpass. The flexural enhancing mechanisms of the proposed system to the RC floor or bridge deck sections at both the positive and the negative moment zones are discussed. Three full-scale one-way slabs having two continuous spans were tested. The results showed that the proposed system can be easily installed and that the ultimate flexural capacity and ductility of retrofitted RC slabs can significantly increase. [Copyright &y& Elsevier]

Abstract: This paper describes an experimental study of two joint configurations, one with only reinforced polymer concrete (RPC) infill, the other with RPC infill and bonded GRP plates, to overcome shear and moment discontinuities in GRP bridge decks transverse to the bridge’s main girders. Fabrication, instrumentation and combined moment/shear force loading of these joints are reported. The joints occupied the full 0.9 m widths and the central 1 m lengths of simply supported deck specimens of span 2.7 m. Cutting out of GRP from the deck to create holes for pouring the concrete into the voids of the deck did not appear to compromise joint integrity under short-term load. Rosettes on the webs of the deck lead to the deduction that over 90% of shear force in the joint was carried by the RPC infill at only 30% of the length of the joint inwards from one end of the infill. Beam theory reliably predicts the neutral axis heights in both joint sections after cracking of the polymer concrete, and also predicts the cracking load for the joint with only RPC infill. For the joint with RPC infill and GRP plates, the test data appear to be elusive in showing a clear cracking load. The GRP plates significantly improved cracked section stiffness beyond that for the RPC alone. A peak load of 500 kN over a 300 mm×300 mm patch damaged but did not fail the deck specimen with either joint. For the RPC-only joint, an unexplained 45% drop in strain occurred in the compression concrete during sustained load over 80 minutes. Practical fabrication issues and further potential research into these joints are discussed. [Copyright &y& Elsevier]

Abstract: This article describes an application of nonlinear finite element modeling (FEM) and analysis in the selection of design details to provide desirable performance in reinforcement-free concrete highway bridge decks. The FEM approach was used to predict the ultimate capacity and failure modes of decks considered as constrained membranes. Lateral constraint of the deck (membrane) provides extra wheel load capacity for reinforcement-free bridge decks on bulb tee wide flanged concrete girders. The wide flange precast prestressed concrete girder sections currently used in bridges result in a shorter effective span for the bridge deck between the wide girder top flanges. The failure mode of concrete decks on these girders with wheel loading is expected to be punching shear. The shear forces from the vehicle wheel loads in the reinforcement-free bridge deck are designed to be carried by compressive membrane action without using reinforcing in the concrete. The compressive membrane action is enhanced by the natural lateral stiffness of the wide girder flanges and by tying adjacent girders together with steel rods placed between the webs. An experimental study of a restrained deck element was performed to identify the failure mode and to use as a basis for verifying the nonlinear properties used in finite element analysis. A parametric study using nonlinear finite element analysis was performed to investigate the factors affecting the ultimate capacity and the failure modes of reinforcement-free bridge decks on wide flange precast girders and to provide a basis for selecting desirable design details. [Copyright &y& Elsevier]

Abstract: This paper studies the influence of spatially varying near-source ground motions and soil–structure interaction (SSI) on the relative response of two bridge frames. The spatial ground motions are simulated according to a near-fault ground motion model with different wave apparent velocity and a coherency loss function. Numerical calculations of bridge structure responses including pounding and SSI effect to a number of simulated spatially varying ground motions are carried out. The study reveals that the assumption of uniform ground excitation and fixed base in the analysis and design might not provide a realistic estimation of the pounding responses of bridge frames. The consequence of adjusting bridge fundamental frequency ratio towards unity to minimize relative response and consequently girder pounding potential as recommended by current design regulations is also evaluated. [Copyright &y& Elsevier]

Abstract: This paper presents a case study on the sliding of bridge decks and pounding at abutment-backfill. It involves a multi-span concrete bridge supported on simple rubber bearings, subjected to longitudinal as well as vertical ground motions from the 1999 Chi-Chi earthquake. To account for soil–structure interaction, the stiffness and strength constants of backfill soils are determined by relating the tilting movement of the abutment to the bearing pressure of backfill soils. In order to evaluate the performance of the bridge, incremental time history analyses are conducted on a number of discrete mass-spring models to simulate various nonlinear behaviors of the bridge including frictional sliding at bearings, pounding among decks/abutments and elasto-plastic compression of backfill soils. Major parameters in the models are varied in ranges, which include gaps at expansion joints, friction coefficients at bearings, and strength limits in soils. Simulation results demonstrate that frictional sliding on bearing pads together with plastic deformation in backfill soils are essential to preventing deck fall-off disaster during large earthquakes. In the case the friction coefficient at bearings rises from 0.1 to 0.2, the maximum abutment tilting by pounding is reduced by ten times. Even if the soil strength were down by half, the maximum deck movement would be less than doubled. In any case, deck fall-off is very unlikely. [Copyright &y& Elsevier]

• Bridge VIV system with different Scruton numbers are simulated in wind tunnel. • Instantaneous properties of aeroelastic damping and stiffness are obtained. • A method to obtain periodic equivalent damping of VIV models is proposed. • Capabilities of commonly used VIV models are examined. The capabilities of some commonly used single-degree-of-freedom (SDOF) VIV models for bridge decks are examined through wind tunnel experiment. The VIV responses of a sectional deck model at different Scruton numbers are measured. An instantaneous identification method is adopted for obtaining the properties of aeroelastic damping and stiffness of the VIV system. The simulated aeroelastic damping by these models as well as the predicted VIV responses of the deck at different Scruton numbers are compared with experiments. The results indicate that the more accurate the simulated aeroelastic damping by an empirical model, the smaller the prediction errors by this model will be. Through directly fitting the aeroelastic damping, the prediction errors by an empirical model can be further reduced. [ABSTRACT FROM AUTHOR]