Journal of Bridge Engineering

Large earthquakes and tsunamis can damage or lead to the collapse of lifeline bridges, resulting in human and socioeconomic losses as well as prolonged recovery times. Although many simulation models are available for the individual effects of earthquake and tsunami hazards on bridges, there are limited modeling approaches for predicting damage from sequential earthquake and tsunami hazards. A bridge modeling approach, which includes soil–foundation–structure interaction effects, is developed within the finite-element framework OpenSees to quantify sequential earthquake and tsunami-induced damage. Multihazard interaction diagrams that relate earthquake and tsunami intensity measures to bridge system damage show that the residual effects of earthquake loading on the bridge system reduce resistance to subsequent tsunami loading.

For multispan suspension bridges, the slip between the main cable and middle saddle is a critical problem. It is therefore essential to find efficient antislip schemes and develop the corresponding evaluation method. In this study, the antislip conception of using horizontal friction (HF) plates is presented, and an analytical model is then established, taking into account the layer-by-layer slip behavior. Large-scale model tests are performed to reveal the effects of the HF plate and verify the proposed analytical model. A typical multispan suspension bridge, named Oujiang River North Estuary (ORNE) Bridge in China, is taken as a practical case for parametric analyses using the proposed methodology. The results validate that the proposed analytical model can provide reliable and adequate predictions for the slip behavior of multistrand cables. The HF plates can significantly improve the antislip capacity of such cables. A lower location of the HF plate leads to a greater enhancing effect and a larger unevenness ratio of strand tensions as well. The proposed methodology is promising to be extensively applied to the antislip designs for the multispan suspension bridges.

Staged construction is the practice in which traffic is maintained on a bridge while it is constructed in phases. When cast-in-place concrete decks are used with staged construction, the concrete deck must cure while subjected to loads and displacements caused by the adjacent traffic using the same structure. Traffic-induced displacements and vibrations may damage the freshly placed concrete, its bond with the embedded reinforcement, or the integrity of the concrete joint. To determine the effects, if any, of staged construction practices on long-term bridge performance, this research examined bridge decks in Wisconsin that were constructed or widened using staged construction through visual inspection, field monitoring, and finite-element modeling. Some minor defects were observed in the field inspections of slab-on-girder bridges, such as underconsolidated concrete in the construction joint region and leakage through the joint itself. The inspected haunched-slab bridges showed severe deterioration at the construction joints. Field-measured differential displacements were small, with a maximum of 1.1 mm (0.043 in.), both during construction and several weeks after. Finite-element modeling confirmed these observations. Modeling results indicated that as long as nominal stiffness was provided by the deck or even the formwork between girders adjacent to the longitudinal joint, these deflections were unlikely to cause deterioration. Longer-span bridges may experience larger differential displacements across the joint, but these may be controlled by preventing larger vehicles from using the lane adjacent to the fresh concrete for approximately one day.

Corrosion of metals is one of the primary factors leading to the deterioration of bridge structures in the US. Protective coatings applied to the surface of the metal have been widely used as a corrosion protection system for steel bridge components. Because the coating also can deteriorate over time, other strategies, such as using steels with better corrosion resistance (i.e., weathering steels), have also been adopted. A recently developed structural stainless steel has shown better performance than conventional weathering steels, particularly in harsh environments, but it comes with a high initial cost. The aim of this study is to compare the life-cycle costs (LCCs) of various corrosion management strategies for bridge steel structures, using either coated carbon steel or structural stainless steel. To evaluate the structural performance of the coated carbon steel structure, a new probabilistic corrosion model is developed for the first time that explicitly incorporates the coating degradation in the steel deterioration process. Using two case studies, this study compares the LCCs of cyclical- and condition-based maintenance strategies and investigates the impact of different coating systems on the LCC. The results show that the structural stainless steel may be more economically beneficial than coated carbon steel, but the payoff time depends on the parameters used in the LCC analysis, such as the maintenance strategies adopted for the coated carbon steel, the coating type, the discount factor, and the size of the structure considered.

The paper describes how two-dimensional (2D) digital image correlation (DIC) is used on underneath surfaces of concrete bridges with a wide-angle-lens camera during load testing, and how it has potential as a stop criterion in proof loadings. A method is proposed for correction of out-of-plane deflection including rotation of the surface. The method is applied to laboratory tests, using well-defined circular speckle patterns, as well as to a field-tested bridge (on raw concrete). The proposed correction corresponds to the level of pseudo strain but is very sensitive to precise surface deflection measurements. In the laboratory tests, a strain precision of the wide-angle-lens camera is compared to a regular-lens camera. The parametric study concludes that a pattern pixel relation (PPR), in the interval from four to nine pixels per pattern circle diameter, provides the optimal precision regardless of the camera type. The field-tested bridge has less good precision compared to most parameter combinations of the laboratory tests. Nevertheless, the field strain precision has potential for improvement based on results from the laboratory tests.

Epoxy resin joints for precast concrete segmental bridges protect internal posttensioned tendons from corrosion, compensate for irregularities between joint interfaces, and act as a joint lubricant. The shear strength, shear behavior, and crack pattern of the epoxy resin joints with castellated keys were investigated for 25 full-depth male–female shear key specimens match cast with a variety of key geometries, distances, numbers, and angles, internal tendon layouts and reinforcing bars. It was found that these design parameters not only effected joint shear strength but also changed epoxy resin joint failure modes and ductility. Several previous datasets were collected to evaluate six analytical expressions for epoxy resin joint shear strength, and recommendations for their use are presented. An improved analytical expression is proposed to predict the shear strength of epoxy resin joints with reinforced keys.

This study explored the application of two-dimensional digital image correlation (2D-DIC) for measuring deflections of in-service bridges. Within the emerging area of image-based structural health monitoring, this work builds from previous efforts to deploy vision-based sensing techniques for describing the operational behavior of structures. Whereas the literature includes deflection measurement systems using cameras mounted on fixed ground near the bridge span at maximum distances of approximately 300 m, this work proposes an innovative setup that enables deflection measurement in remote, offshore, and complex environments. This paper first describes a laboratory study aimed at evaluating the system performance and identifying the sources of measurement error, thus determining the level of confidence in the results and the range of applicability. The laboratory study demonstrated that the setup, designed using an inexpensive consumer-grade imaging system, had an average error consistently less than 0.2 mm (0.0075 in.). In addition, the system was deployed during a field test on a high-profile bridge structure nearly 1 mile offshore. The test program and results are presented to assess the logistics and performance of the system during load testing. Results from the study indicate the feasibility of the proposed setup for measuring deflections without a fixed ground reference.

Large wave forces induced by the combination of storm surge and hurricane waves have caused significant damage and failure of various coastal bridges in the Gulf of Mexico. Existing research studies are mainly focused on the wave forces generated by normal incident waves rather than oblique waves. In this study, wave forces induced by oblique hurricane-induced waves were investigated experimentally. A full bridge specimen, including superstructure, substructure, and neighboring segments, was manufactured and employed in this experiment to measure wave forces and wave-impact pressure. A detailed test covering different wave heights, clearances, and wave angles was conducted in the wave flume. The characteristics of wave forces under different wave conditions were analyzed to provide more insight regarding the oblique wave action on coastal bridges. The vertical wave force was found to reach the peak at a wave angle of 30° under a clearance of 4.0 cm. Wave overtopping was found to have a significant effect on the vertical force in the semisubmerged and submerged cases. The pressure distribution for an elevated case was also investigated to obtain a better understanding of the vertical wave force under oblique wave action.

Chloride penetration initiates the corrosion of the steel reinforcement and causes the deterioration of an RC bridge in a marine area. This study focuses on the probabilistic models in the chloride penetration process for the probabilistic corrosion initiation analysis of the steel reinforcement. The probabilistic model for the chloride diffusion coefficient is developed by adding correction terms to correct the potential bias in the existing deterministic model. The model parameters are calibrated and selected with the Bayesian approach based on long-term test data. The probabilistic models for the surface chloride concentration and chloride threshold are selected from reviews and discussions on the existing models. The probabilistic models developed or selected contain sufficient information on concrete quality and environmental condition influencing the anticorrosion performance of the RC structure. The corresponding probabilistic analysis approach is proposed with emphasis on the quantification for the influence of uncertainties presented in the model parameters. The time-variant probability curves of corrosion initiation for an example RC bridge are obtained using the proposed probabilistic models and analysis approach. The results show that the environmental condition has a great influence on the corrosion initiation reliability for steel reinforcement.

Digital sampling moiré (DSM) method is a vision-based technique that uses phase differences of the moiré fringes to measure two-dimensional (2D) translations. However, it assumes no in-plane rotation is present, and its accuracy would be affected if rotation is involved with translation. To decompose translation and rotation, we propose an enhanced DSM (EDSM) method in this study. First, the EDSM method used the derivatives of phase values to calculate the in-plane rotation angle, and then employed the 2D rigid transformation algorithm to compute the translation. We performed laboratory tests to compare the proposed EDSM method with the DSM method and the photogrammetric method using the Harris corner detector. The results revealed that the EDSM method outperforms the DSM method when rotation is applied in the motion, and the EDSM method is more robust to the image scaling factor compared with the photogrammetric method. To verify its applicability, we then applied the EDSM method to track displacements of a steel beam and a bamboo bridge. This study provides an accurate and robust method for structures’ in-plane motion measurement.

In bidirectional ductile end diaphragm systems (EDSs) in which buckling restrained braces (BRBs) are used as the hysteretic devices to provide ductile responses to earthquake excitations, BRBs that connect the abutments to the bridge’s superstructure span across the expansion joints. Therefore, these BRBs should not only be designed to resist significant forces from seismic excitations, but would also be expected to accommodate the displacements due to the expansion or contraction of the bridge as a consequence of temperature changes. Such displacement demands on the BRBs would produce cyclic stresses and strains in the BRB’s core plate, and the BRB must be designed to ensure that the low-cycle fatigue of the BRB is prevented over the design life of the bridge (or periodically replaced if having shorter low-cycle fatigue life). In the absence of such a consideration, BRBs would have to be connected to the abutment in series with lock-up devices to allow thermal expansion and contraction of the bridge under normal conditions but engaged during earthquakes, which is not a desirable detail. In this study, the low-cycle fatigue analyses of BRBs across bridge expansion joints are performed by subjecting a bridge to temperature changes from various cities to determine recommended design parameters. Resulting from these analyses, the minimum ratio of BRBs’ core plate yielding length over total bridge length is recommended as 3% to avoid low-cycle fatigue over 75 years of thermal changes on the bridge superstructure.

In this study, a smart rock, which is a magnet embedded in a concrete ball and whose direction is always pointing downwards, is proposed to monitor bridge scour depth. Based on the theory of magnetic field, the distribution of the magnet-induced magnetic field (MMF) induced by the smart rock was derived. An algorithm was developed to localize the position of the smart rock. Field tests were conducted at a bridge pier at three different times. Both the intensities of the ambient magnetic field (AMF) and the total magnetic field (TMF) were measured with a magnetometer. Results showed that the presence of steel reinforcement or steel girders in the bridge changed the distribution of the geomagnetic field. The algorithm successfully localized the position of the smart rock with an error ranging from 0.26 to 0.33 m, which satisfied the requirement for engineering applications. The effective monitoring range depends on the variation of the AMF, and the maximum monitoring depth ranged from 11.5 to 8.5 m as the standard deviation of the AMF increased from 32.3 to 80.75 nT.

Identification of overweight vehicles has been increasingly important due to the need for accurate information of actual live load, which is required for fatigue assessment of highway steel bridges. This study proposes a first-time application of polyvinylidene fluoride (PVDF)-based strain sensors for identification of vehicle weight using bridge weigh-in-motion (BWIM) algorithms in steel bridges. A portable sensor module consisting of a PVDF sensor, a charge amplifier circuit, a low-pass filter circuit, a gain amplifier, and a power supply circuit is developed. Performance of the sensor module was evaluated through laboratory experiments. Applicability of the sensor module for vehicle weight identification was validated through identification of a calibration truck during actual running tests in a RC deck steel bridge. Accuracy of vehicle speed and axle spacing identification by a pair of transverse sensors located on the same lane was verified using the measurement data of longitudinal sensors as a reference. In-lane transverse sensors exhibit sensitivity to individual axle passages; thus, they can be used for both axle-detecting and weighing sensors for a vehicle weight identification algorithm based on influence line method.

Particle swarm optimization–based finite-element (PSO-FE) method is introduced for the designs and analyses of the steel–concrete composite beams. After a brief explanation of the PSO-FE theory, the optimizations of shear connector distributions for the simply supported (SS) and continuous beams are carried out. An inverse calculation is firstly applied to determine the sensitivity range that is greatly varied by the shear connector stiffness. Then the patterns of shear connectors along the spans are tested for different scenarios. For an SS beam subjected to concentrated or uniformly distributed loads, the shear stiffness distributions in terms of the quadratic functions with optimized parameters could effectively reduce the interlayer slips and deflections compared with traditional uniform distributions. For a continuous composite beam after the optimization, the discrete shear connector distributions are designed in favor of real engineering construction and employed to explain the recently proposed uplift-restricted and slip-permitted connection at the negative-moment region. The PSO-FE method is thus demonstrated as an efficient and stable tool that can also be used for designs and optimizations in other aspects of composite structures.

Prefabricated and prestressed beams are integral to accelerated bridge construction (ABC) and other construction projects, but concerns exist regarding the development of cracks during curing, form removal, detensioning, transport, installation, and operation. Acoustic emission (AE) sensing techniques have the potential for detecting and locating cracking in prefabricated, prestressed concrete girders used as prefabricated bridge elements and systems (PBES) in ABC as part of a quality assurance/quality control (QA/QC) program. AE measures the elastic waves produced by crack nucleation and growth with an array of point sensors. The AE instrument system is relatively portable, which can allow for it to be an option for off-site fabrication QA/QC and on-site field QA/QC. This paper presents AE measurements and analysis on relatively small laboratory reinforced concrete beam specimens under pullout and three-point bending to demonstrate the efficacy of AE in detecting cracks. It then presents application of AE during detensioning and lifting of full-scale Northeast Extreme Tee (NEXT) beams and Bulb Tee. The results indicate that AE sensing is a practical QA/QC process for PBES elements.

Impact-induced loads associated with barge-to-bridge collisions frequently control the design of bridges spanning navigable waterways. To design for such loads, widely used bridge design standards use an approach in which impact loads are computed from the kinetic energy of either a single impacting barge or a multibarge flotilla. Within a flotilla, individual barges are arranged into columns and rows and are connected together with lashing elements, such as wire-rope cables. During impact these lashings elongate and may rupture, influencing the degree of overall flotilla mass that contributes to impact force generation. In this study, finite-element impact simulations are used to investigate lashing deformation and relative sliding between barge columns during flotilla impacts with bridge piers. After analytically quantifying the fraction of overall vessel mass, which contributes to impact load generation, an “effective flotilla mass” is formulated for use in bridge design. Importantly, the majority of impact simulation results indicate that the effective flotilla mass is nearly equal to total flotilla mass rather than the impacting-column mass presently assumed by bridge design standards.

The suspender cable is one of the most vulnerable components in suspension bridges. Vibration of the suspender cables will induce fatigue damage, and large vibrations of these cables under extreme weather can be a threat to traffic safety. Therefore, it is imperative to develop effective methods to mitigate such vibration. In this article, a new approach of equipping the ring-shaped tuned liquid damper (RSTLD) to mitigate the vibration of suspender cables is presented. The Xinghai Bay Cross-Sea Bridge was selected as the field experimental and numerical research object to validate the proposed method. The feasibility and the design method for the RSTLD were validated through a numerical model of a suspender cable in this bridge. The performance of the RSTLD was further examined through an in-field experiment conducted on a suspender cable with a length of 61.55 m. Two RSTLD designs with different containers and liquids were considered, respectively, and the response of the symmetric suspender cable without the damper on the other cable plane was collected for comparison between the controlled and noncontrolled cases. The experimental results show that when the liquid was water and the mass ratio was 3%, the variance of acceleration and maximum acceleration were reduced by 50 and 20–30% with the RSTLD, respectively. The vibration-mitigation effect will increase with the adoption of a greater liquid viscous damping ratio or a greater mass ratio. The mitigation effect in experiments was found to be close to that in the simulation. Both the experimental and numerical results show that the RSTLD can effectively reduce the vibration of the suspension bridge suspender cable. The proposed RSTLD has equivalently good vibration-mitigation ability in all excitation directions, and it has positive effects in terms of service safety and extending the service life of the suspender cable.

Movable bridges are interesting and feasible solutions at the crossover point of transportations, providing fascinating landscapes and significant engineering challenges. This paper presents a new structural system applied to a movable cable-stayed footbridge. It is an S-shaped curved bridge suspended by cables, and can be opened with a moving mechanism coupled with the torsional deformation. In this paper, we clarify the mechanical behavior of the structural system through a preliminary analysis. We propose novel concepts of the twistable deck, aiming to improve the dynamic performance of the structural system. We trace the moving process of the structure by decoupling the elastic deformation and the rigid displacement. We confirm the validity and versatility of the proposed structural system through the optimal shapes for the footbridges in different cases with respect to the symmetricity and serviceability. The concept of the movable structural system proposed herein is believed to be feasible for application to the design of movable footbridges based on the preliminary analysis.

In order to investigate the mechanical behavior of the steel–concrete joint with ultrahigh performance concrete (UHPC) grout in single cable–plane hybrid cable-stayed bridges, a model test with a scale of 1:3 for a hybrid girder consisting of a flat steel box girder, a prestressed concrete (PC) box girder, and a steel–concrete joint connecting the steel and prestressed concrete girders was conducted. Structural responses of large-scale specimens under combined actions of axial compression, bending, and twisting moments are presented and discussed. Experimental results indicated that steel–concrete joints with UHPC grout exhibited favorable combined behavior and adequate strength. Under a maximum applied load that is twice as much the design load, the system components, including surface plates/slabs, UHPC, perforated webs, and perforated rebars, behaved within the elastic range. Stresses generated at the steel–concrete joint were mainly determined by axial and flexure forces. The influence of torsion on joint behavior was insignificant. It was also shown that approximately 65% of the overall force transferred through the steel–concrete joint was in the form of compression effects between the bearing steel plate and UHPC, and that the remaining 35% force was dispersed via shear connectors. Furthermore, finite-element (FE) models were developed and calibrated with the experimental results. The numerical results indicated that load transferred via the bearing plate compression effect gradually increased with the steel cell height. The outcomes of this study provide a reference for future application of the steel–concrete joint with UHPC in hybrid girder bridges.

Imagery-based, three-dimensional (3D) reconstruction from unmanned aerial vehicles (UAVs) holds the potential to provide safer, more economical, and less disruptive bridge inspection. In support of those efforts, this paper proposes a process using an imagery-based point cloud. First, a bridge inspection procedure is introduced, including data acquisition, 3D reconstruction, data quality evaluation, and subsequent damage detection. Next, evaluation mechanisms are proposed including checking data coverage, analyzing point distribution, assessing outlier noise, and measuring geometric accuracy. The overall approach is illustrated in the form of a case study with a low-cost UAV. Areas of particular coverage difficulty involved slim features such as railings, in which obtaining sufficient features for image matching proved challenging. Shadowing and large tilt angles hid or weakened texturing surfaces, which also interfered with the matching process.

Construction technology has a considerable impact on the bearing behavior of bridge pile foundations. Considering practical bridge engineering, this study examined the mechanical characteristics of rock-socketed bored piles under different pile-forming methods using a self-balanced load test and explored the postgrouting effect on the load capacity of the piles. The results indicated that the dry rotary drilling pile method was conducive to ensuring the bearing strength of rock-socketed bored piles in bridge foundations, whereas the mud rotary drilling pile method significantly reduced the shaft resistance of rock-socketed bored piles as well as the pile-end resistance. The mud rotary drilling pile method also increased the settlement from the negative impact of sediment and the softening of carbonaceous shale. The postgrouting technique can effectively enhance the unit-shaft and end resistance of the rock-socketed bored pile and reduce its settlement by approximately 42 and 100% bearing capacity increment compared with dry and mud rotary drilling piles, respectively. Under their respective ultimate loads, the settlements also decreased by 37.5 and 54.4%. The postgrouting technique had a tremendous impact on the proportion of the end resistance to the shaft resistance, markedly increasing the end resistance for mud rotary drilling piles. These results provide an important reference for the design and construction of rock-socketed bored piles with a large diameter and length in bridge foundations.

Bridge inspections are important to proactively ensure that structures are safe for use by the traveling public. Accessibility challenges during inspections often necessitate the use of special equipment, such as underbridge inspection vehicles (UBIVs), which impact both cost and risk of inspections. The objective of this research is to develop and demonstrate a small unmanned aircraft system (sUAS) that can be used to perform bridge inspections that would typically require the use of a UBIV. The sUAS used for this project uses a laser range finder and an optical flow sensor to assist with obstacle avoidance in the GPS-restricted area underneath bridges. This paper provides an account of several demonstration sUAS bridge inspections with an emphasis on incorporating an sUAS into current inspection practices, including a discussion of the advantages and ongoing challenges. Recommended applications for sUAS bridge inspections are provided, including periodically replacing the use of a UBIV for routine inspections of bridges in good condition and inspecting structures with load restrictions, especially post-impact, which may prohibit the use of a UBIV.