Journal of Bridge Engineering

The experimental results for large-scale slender circular reinforced concrete (RC) columns are presented and discussed in this study. One reference column was reinforced with steel bars and spirals, and five columns were reinforced with glass fiber–reinforced polymer (GFRP) bars and spirals. The columns were tested under axial loads with variable eccentricities or flexural loading configurations. The test variables included reinforcement type (GFRP and steel), loading type (axial and four-point bending), the ratio of eccentricity-to-column diameter, and the slenderness ratio. Test results revealed that as the eccentricity increased, the peak axial load and the axial and lateral stiffness decreased significantly. Similarly, for the same eccentricity, a reduction in the peak load and both axial and lateral stiffnesses was observed when the slenderness ratio increased. In addition, interaction diagrams for circular GFRP-RC short and slender columns were developed from the experimental results and compared to those obtained analytically. Moreover, a simple modification to account for the slenderness effect on the interaction diagram was proposed.

Quantification of the mechanical properties of suspension bridge main cables during fire hazards is a vital part of holistic safety assessment of infrastructure. While some researchers have examined the response of main cables to thermomechanical loading, all of these studies have mentioned the limitations of their predications due to the dearth in high-temperature data for ASTM A586 high-strength wire. The wire manufacturing process produces steel with very unique microstructural properties. Due to the high degree of cold-working involved, industry standards for the high-temperature performance of structural steel framing cannot be applied to bridge wire. This article presents the results of an exhaustive experimental investigation performed to empirically characterize many aspects of the high-temperature performance of the bridge wire. In addition to the typical engineering parameters of elastic modulus, yield strength, and ultimate strength, temperature dependence of proportional limit, work-hardening coefficient, work-hardening exponent, and ultimate strain is also determined. Two temperature-dependent models of the wire stress–strain behavior are presented herein. The models represent the mean behavior of multiple tension tests at each temperature, and models far more accurate high-temperature A586 wire behavior than was previously possible.

Columns are the primary load-carrying components in the bridge, and column failure could initiate the collapse of the entire bridge. Estimates of residual axial capacity for round, bridge pier columns under combined vehicle collision and air blast were studied using high-fidelity, fully coupled finite-element computational models. The models included single reinforced concrete (RC) columns, pile foundation systems, and surrounding soil and air volumes. Modeling techniques were validated with existing full-scale, impact and blast experimental results. Validated column models were subsequently impacted by a Ford F800 Single-Unit Truck (SUT) and subjected to an air blast created by considering fluid–structure interaction (FSI) using a multimaterial arbitrary Lagrangian–Eulerian (MM-ALE) formulation. A parametric study was completed that examined effects of load parameters, column diameter and height, axial load ratio, longitudinal reinforcement ratio, and shear reinforcement spacing on column residual axial capacity to establish critical parameters influencing performance. An empirical equation estimating residual axial capacity was developed using multivariate regression analysis involving the critical parameters. Based on the proposed equation, the column residual axial capacity could be estimated to predict its resistance against failure and assess collapse risk for the bridge when subjected to collision and blast combination.

This paper will focus on experimental and analytical investigations into the shear capacity of precast concrete (PC) shear keys with ultrahigh-performance concrete (UHPC) as the connection (UHPC–connection PC shear keys). First, 30 shear key specimens with different configurations will be designed and tested statically under shear loads and various compressive stresses. Two major failure modes were observed during the tests, which included PC failure and UHPC connection shear-off failure, which is similar to the failure modes of conventional shear keys. Therefore, it is suitable to apply UHPC as the connection for PC shear keys. The equations to estimate the shear capacity of shear keys in the literature and current codes will be reviewed and compared with the test results. However, none of the equations accurately predicted the shear capacity of all the test specimens. Two improved analytical models will be proposed based on both observed failure modes to estimate the shear capacity of the shear keys. Satisfactory agreement was obtained for the comparison of shear capacity between the proposed analytical models and the experimental data. Therefore, the proposed analytical models could be used for the design of UHPC–connection PC shear keys. The results from this paper could guide the design of UHPC–connection PC shear keys and promote the application of UHPC materials in prefabricated structures.

The cracking of concrete bridge decks is a nationwide problem. The results of over 100 crack surveys on 40 monolithic composite concrete bridge deck placements supported by steel girders were used to evaluate the factors contributing to bridge deck cracking and determine the factors that have the greatest influence. The parameters considered were the material properties, such as paste content (volume of cement and water), slump, compressive strength, and air content, and environmental factors, such as air temperature range, high air temperature, and time of placement on the day of construction. Results showed that, within the ranges studied, paste content has a dominant effect on cracking, with cracking increasing substantially when the volume of paste exceeds a threshold value of 26.4% of concrete volume while being insensitive to changes in paste content below this threshold. Bridge decks placed and finished between midnight and noon exhibited substantially lower cracking than those placed and finished between early morning and late night. Other factors such as slump, compressive strength, and air content affected cracking to a limited degree, with a higher slump, greater compressive strength, and lower air content, resulting in slightly higher cracking, effects that are not statistically significant.

Although highway bridges are among the most critical components in transportation infrastructure systems, different jurisdictions typically allocate only limited annual budgets to address issues pertaining to aging and deteriorating bridges. In addition, most published studies have focused only on component-by-component risk analysis (i.e., risk of individual bridge failure/closure/becoming a safety hazard) to inform bridge rehabilitation project managers. However, the network-level cascade (systemic) impacts of an individual bridge(s) closure on the network-level are often dealt with through, for example, detouring, rather than a systemic-risk-guided strategy. In this respect, the current study first utilizes a complex network theoretic approach to quantify the topological characteristics of bridge networks and subsequently their network-level robustness and node vulnerability. These measures are then integrated into a multiscale (i.e., component and network) bridge classification platform guided by the systemic-risk consequences of possible bridge closure on the entire network. To demonstrate its application, the platform is operationalized in Canada on the Province of Ontario’s bridge network. It is found that component- and network-level measures are not correlated, which highlights the importance of considering the network-level measure to inform bridge rehabilitation decision making. The current study calls for a paradigm shift in the strategy guiding prioritizing bridge rehabilitation projects to account for the risk imparted by specific bridge criticality on the entire network, rather than solely on the individual bridge’s structural conditions.

Three experimental structural models of a small radius curved bridge, which include a three-span small radius curved bridge model and its corresponding two different simplified models that are widely used (e.g., one mass simplified model and one single pier simplified model), will be constructed, and then three bridge structure–foundation soil system models will be designed to carry out shaking table tests. From the shaking table tests on the three models under different input motions, the dynamic soil–structure interaction effects on the dynamic characteristics, seismic response rules, and damage modes of the three models will be studied and compared. Before the test, the measured fundamental frequency of the single pier simplified model was minimum and that of the mass simplified model was maximum in the three test models. In the test, with an increase in the input motion peak ground acceleration (PGA), the soil disturbance and deformation increased gradually, and the foundation soil separated gradually from the model structures, and local damage to the structures occurred, and the fundamental frequency of the curved bridge model structure decreased most significantly in the three models. The test phenomena and measured results indicate that the single pier simplified model could be used to approximately simulate the acceleration and displacement responses of the fixed pier and corresponding pile of the curved bridge, and the single pier simplified model could be used to approximately simulate the strain response of the fixed pier and corresponding pile. The mass simplified model was not suitable to simulate the acceleration, displacement, and strain responses of the fixed pier and corresponding pile. It is not appropriate to use the mass simplified model and the single pier simplified model to simulate the pile–soil contact pressure of the fixed pier model. In addition, the single pier simplified model could not reflect the torsion characteristics of a curved bridge.

Full-scale fracture tests on mechanically fastened steel built-up tension members have shown that these members can be resistant to complete member fracture when a single component suddenly fractures. This characteristic of built-up steel members is referred to in this research as cross-boundary fracture resistance (CBFR). A comprehensive finite-element model-based parametric study, calibrated to the after-fracture static load redistribution behavior of the experimental fracture specimens, was also performed to study the after-fracture load redistribution behavior of multicomponent built-up steel members. Simplified closed-form solutions were developed for engineering analysis of built-up members to evaluate for internal member redundancy and estimate safe inspection intervals that are based on the fatigue life of the member in the assumed faulted condition. An internally redundant member is defined as a primary steel bridge member in tension, or with a tension element, which has redundancy within the cross section, such that fracture of one element will not propagate through the entire member and is discoverable by the applicable inspection protocol.

The balanced cantilever method is the most widely used technique for the construction of large-span segmental prestressed concrete box-girder bridges. In order to control shear cracks at the service limit state, the principal tensile stresses in the webs are analyzed for all segmental bridges. Web shear cracking may occur for a number of reasons, one of them is the ignoring of shear stresses induced by the anchorage of cantilever tendons during the cantilevering process. This study aims to provide a clear understanding of anchorage-induced shear stresses in the webs of segmental box-girder bridges, including the underlying mechanisms, mechanical models, adverse effects, and design considerations. Case studies show that the peak shear stresses in the webs might have a significant increase due to this localized effect, while it cannot be captured by the beam-element analysis and is usually not considered in the routine design. To solve this problem, a practical approach is developed for evaluating the anchorage-induced shear stresses in the webs of segmental concrete box-girder bridges.

Ambient and vehicle-induced bridge vibration tests are two important ways of collecting data for the purpose of system identification and performance evaluation of bridges. A common bridge form that has been very popular over the past number of decades is the steel truss bridge; this paper presents the vibration data of a steel truss bridge situated in Japan: the Old ADA bridge. The target bridge was built in 1959 and removed in 2012. Prior to the removal of the bridge, both ambient and vehicle-induced vibration data were collected. Five different damage scenarios were designed to represent different real-world cases by introducing artificial damage in the truss. In Case A, there was no damage; in Case B, one vertical member of the truss was cut to half its section depth at the bridge midspan; in Case C, the same vertical member at midspan was fully cut; in Case D, the vertical member cut was repaired and recovered; in Case E, one vertical member at the 5/8th span was fully cut. Ambient and vehicle-induced vibration data were collected for each case. Full-scale bridge damage tests of this nature are rare, and thus the collected data will be helpful in the research of system identification and damage detection using both ambient and vehicle-induced vibration data, providing a benchmark structure for structural health monitoring using data in real bridges.

Vibration serviceability under crowd-induced loading has become a key design criterion for footbridges. Although increased research efforts are put into the characterization of crowd-induced loading, including related interaction phenomena, and first-generation design guides are available, a major challenge lies in the further development and validation of prediction models for crowd-induced vibrations. Full-scale benchmark datasets that simultaneously register structural and crowd motion make an invaluable contribution to meeting this need by providing detailed information on representative operational loading and response data. Currently available datasets either (1) involve a (too) small number of pedestrians or (2) do not involve the simultaneous registration of pedestrian and bridge motion, or else they involve a footbridge (3) where only a single mode or a very limited number of modes are sensitive to walking excitation, (4) for which no suitable digital twin is available, or (5) that is not open access. This paper therefore presents a new and publicly available full-scale dataset collected specifically for the further development and validation of models for crowd-induced loading. The dataset is collected for a real footbridge, with a number of modes that are sensitive to pedestrian-induced vibrations, and with a digital twin available. The pedestrian and bridge motions are registered simultaneously using wireless triaxial accelerometers and video cameras. In addition to two data blocks involving purely ambient excitation, four data blocks are collected for two pedestrian densities, 0.25 and 0.50 persons/m², representing a total of more than 1 h of data for each pedestrian density. Analysis of the structural response shows that the different data blocks can be considered representative for the involved load case. The identified distribution of step frequencies in the crowd indicates a significant contribution of (near-)resonant loading for a number of modes of the footbridge. Furthermore, the dataset displays clear signs of human–structure interaction, suggesting a significant increase in effective modal damping ratios due to the presence of the crowd.

To select the parameters of double launching noses during the launching construction of multi-span concrete continuous girder bridges, a simplified calculation model for the main girder and double launching noses was constructed in this study based on the example of a three-span concrete continuous girder bridge. First, the analytical expressions for the internal forces of each node were derived. Second, the influence of different launching nose parameters on the maximum negative moment at the fulcrum and the maximum positive moment within the span were studied. Finally, taking a real bridge as an example, a reasonable and rigorous method for optimizing the launching nose parameters was proposed to consider the optimization of the maximum negative moment at the fulcrum and the maximum tensile stress at the section; the optimal launching nose parameters were obtained through iterative calculations. The proposed optimization method for launching nose parameters is simple and can be used for specific optimization of different section forms. The results of this study suggest a reliable and rigorous optimization calculation method for launching nose parameters.