Journal of Bridge Engineering

The blast performance of concrete-filled fiber-reinforced polymer (FRP) tube (CFFT) bridge columns was studied through a two-phase study comprised of blast and residual axial capacity experiments. Two one-fifth-scale CFFT columns and two one-fifth-scale conventional RC columns having comparable flexural capacities were subjected to distinct levels of explosive loading, causing damage but not complete failure. The blast resilience of the damaged columns was quantified by measuring the residual axial capacity of each column. The damaged CFFT columns exhibited superior strength and ductility retention compared with the damaged RC columns. Additionally, the damaged CFFT columns demonstrated a more predictable axial compressive mode of failure because the exterior FRP tube resisted the shear crack initiation observed in the damaged RC columns.

Structural temperature is an important form of loading for bridges, particularly for long-span steel structures. In this study, the temperature distribution of the Humber Bridge in the United Kingdom is investigated using numerical simulation and field measurements. A two-dimensional fine finite-element model of a typical section of the box girder of this long-span suspension bridge is constructed. The time-dependent thermal boundary conditions are determined using field meteorological measurements with external surface heat-convection coefficients varying according to differing local wind speeds they experience. Preanalysis is adopted to determine the initial thermal condition of the model, then transient heat-transfer analysis is performed and the time-dependent temperature distribution of the bridge is obtained, leading to numerical temperature data at different locations in different times that are in good agreement with the measured counterparts. The vertical and transversal temperature differences (TTDs) of the box girder are also investigated. Both measured and numerical results show that the transversal temperature variation across the streamlined girder is significant. The effects of the box-girder shape, pavement of the upper webs, and bridge orientation on the TTD are finally investigated.

Laminated elastomeric bridge bearings incorporating a flat sliding layer of polytetrafluoroethylene (PTFE) provide service-level thermal displacement capacity to accommodate movements of a bridge superstructure in regions of low to moderate seismicity. These components also provide a potential source of displacement capacity, which is frequently neglected in seismic design. An experimental program has been carried out to evaluate behavioral characteristics and performance of steel-reinforced, laminated elastomeric bearings with PTFE at a flat sliding layer (which had not been designed for seismic demands) as primary quasi-isolation components for earthquakes by permitting large sliding displacements at a stainless steel-on-PTFE interface. The PTFE surfaces tolerated stress concentrations associated with eccentric loading stress distributions at moderate top plate displacements, with up to approximately 25% of the PTFE exposed at peak displacements. Larger displacements resulted in delamination and tearing of the PTFE, potentially leading to steel-on-steel sliding between the independent components. Bearings with moderately tall elastomer blocks were also susceptible to unstable rotated configurations with increasing displacements of the sole plate. Unseating of the sole plate from the elastomeric component occurred at displacements corresponding to the elastomer plan dimension in the direction of horizontal motion.

Development and testing of a new type of bridge weigh-in-motion system (BWIM) based on the measurement of shear forces near the supports of the bridges is described. The proposed system is applicable to both determinate as well as indeterminate bridges. Fiber-optic Bragg grating rosette sensors were used in this approach. Formulations are based on the establishment of shear influence lines in terms of axle weights and spacings. The system further involves calibration for the estimation of a bridge parameter $\alpha$, which is a function of the cross-sectional and material properties of the bridge. Three different bridges, one box-girder prestressed concrete bridge and two concrete-slab-on-steel-girder bridges with different span lengths, were instrumented for the evaluation of the proposed BWIM system. Field implementation involved a series of truck runs for calibration and evaluation of the BWIM system. Measured and actual truck-axle weights, spacings, and axle speeds as well as the gross vehicle weights yielded comparable results.

The first full-depth precast ultrahigh-performance concrete (UHPC) waffle panels have been designed and implemented in a bridge replacement project to use accelerated bridge construction and increase bridge deck longevity. This paper first evaluates the structural performance of this bridge using a combination of field live-load testing and analytical modeling. The collected data for vertical deflections and strains at discrete critical locations on the bridge deck, subjected to static and dynamic truck loads, demonstrated satisfactory performance of the bridge deck and correlated well with the results obtained from the analytical model. Thereupon, options to optimize the bridge deck are examined to minimize the UHPC volume and associated labor costs. Using the analytical model, an optimization of the waffle panels was undertaken by varying the number of ribs as well as spacing between the ribs. An optimized panel was achieved by reducing the interior ribs per panel from four to two, or zero, in the longitudinal direction and six to two in the transverse direction, without compromising the panel’s structural performance.

This paper presents the effect of corrosion damage on the service response of prestressed concrete bridge girders strengthened with posttensioned near-surface-mounted (NSM) carbon fiber–reinforced polymer (CFRP) strips. Three-dimensional finite-element modeling, validated against experimental data, is conducted to deterministically study the static and dynamic behavior of the girders subjected to chloride-induced corrosion for a period of 100 years. With an increase in corrosion damage, the efficacy of the posttensioned NSM CFRP augments from a serviceability perspective. Modal analysis identifies critical regions along the girder where strain localization occurs at certain dynamic excitation frequencies. The unstrengthened girders are more reactive to dynamic responses than their strengthened counterparts; however, both exhibit similar ride quality. Corrosion damage significantly decreases the equivalent flexural rigidity of the decrepit girders up to 30% relative to that of the control girders. The level of damage and the extent of the total potential for the strengthened girders are correlated with the magnitude of their fundamental frequencies.

This study addresses the durability of glass fiber–reinforced polymer (GFRP) pultruded structural sections used in bridge-deck applications, namely, a flat plate with T-shaped ribs (R-GFRP) and a corrugated plate (C-GFRP). Standard coupons were aged for up to 224 days at 23, 40, and 55°C in separate baths of 3% salt solutions simulating deicing conditions. The tensile-strength retentions and Young’s moduli were measured periodically. Data were assessed using ANOVA. Microstructure assessments using differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy were carried out to provide additional assessment of degradation. It was shown that after 224 days, the tensile strength retentions of the R-GFRP and C-GFRP were similar, and that they decreased from 77 to 63% as the temperature increased from 23 to 55°C. The observed reductions were confirmed by micrographs showing some surface cracks and separations between the fibers and the matrix, but results also showed that the polymer matrix was not fully degraded by the hydrolysis because no significant changes occurred in the glass transition temperature after exposure. When data were fitted in the Arrhenius service-life model, it showed that after 100 years, R-GFRP will suffer more deterioration than C-GFRP because the strength retentions at a location with annual mean temperatures of 10°C were 42 and 61%, respectively.

This paper presents the evaluation of an innovative low-cost small-scale prototype deck panel under monotonic and fatigue bending. This new system introduces a trapezoidal-shaped polyurethane foam core with a thermoset polyurethane resin that has a longer pot life to facilitate the infusion process. The proposed panel exhibited a higher structural performance in terms of flexural stiffness, strength, and shear stiffness. The panels consist of two glass fiber–reinforced polymer (GFRP) facings with webs of bidirectional E-glass–woven fabric that are separated by a trapezoidal-shaped low-density polyurethane foam. The GFRP panels were manufactured using a one-step vacuum-assisted resin transfer molding process. The specimens studied were constructed in the Composite Manufacturing Laboratory in the Mechanical and Aerospace Engineering Department at Missouri University of Science and Technology. Small-scale prototype deck panels were tested both statically and dynamically in four-point bending to investigate their flexural behavior. The ultimate bearing capacity of the proposed sandwich panels was determined from compression crushing tests. In addition, the load-deflection behavior of the proposed panel was investigated under three loading conditions: compression, static flexure, and dynamic flexure. The initial failure mode for all panels was localized outward-compression skin wrinkling of the top facing. The ultimate failure was caused by local crushing of the top facing under the loading point due to excessive compressive stresses. First-order shear deformation theory was used to predict the panel deformation in the service limit state. In general, the analytical results were found to be in good agreement with the experimental findings.

Concrete hinges are a robust structural concept attributed to Eugène Freyssinet and further developed by Fritz Leonhardt and others. Leonhardt and coworkers also developed simple analysis models that are still used today. Recently, concrete hinges have seen a renewed interest in research and practical applications in various bridges. This is mainly because of advanced concrete technology available and the drive towards more durable and hence sustainable structures by building without bearings. In this context, this paper investigates possible applications of concrete hinges in integral bridge piers. A computational model is introduced with consideration of various limit states for the design of concrete hinges. A comparison is made between standard integral piers and those with concrete hinges. Example computations are presented to show the calculation procedure to design a concrete hinge for an integral bridge.