Journal of Bridge Engineering

Posttensioned bridge rocking systems have emerged as an alternative to traditional ductility design where substructure elements, such as columns and piles, are designed to dissipate energy through the formation of localized plastic hinges. Posttensioned rocking bridge systems have evolved from pure rocking structures to hybrid solutions that combine self-centering and dissipating capabilities, often in the form of central posttensioning and dissipation devices, respectively. Posttensioned rocking bridges provided a resilient solution with little to no damage or disruptions after a seismic event. For this reason, there has been increased interest amongst bridge asset managers and researchers in the development and application of these “low-damage” systems. This paper presents a state-of-the-art review of the evolution of posttensioned rocking bridge substructure systems, with an emphasis on column and joint details to reduce or eliminate local damage in bridge piers. This review also includes energy dissipation solutions and examples of operational bridges that have adopted posttensioned rocking column systems. This paper concludes with a comprehensive discussion that covers knowledge gaps and suggestions for future research.

The long-span bridges could frequently experience complex dynamic interactions with wind and traffic, which makes the dynamic response evaluation crucial for ensuring structural and vehicle driving safety. Previous studies have shown that the acceleration/deceleration of vehicles may have a remarkable influence on the bridge dynamic performance, but such influence has seldom been addressed for the long-span bridge under combined actions from the random traffic flow and wind. In the present study, the acceleration/deceleration of the vehicle in random traffic flow is adequately modeled by means of vehicle inertia force (VIF), which is further incorporated into the novel framework of wind–traffic–bridge (WTB) coupled analysis. Subsequently, the established WTB framework is applied to a prototype long-span suspension bridge, in which the influence of VIF on the bridge vertical vibration is investigated comprehensively. The parametric analyses are first conducted to evaluate the influence of VIF on the bridge vertical vibration by varying the key parameters in the WTB system including the traffic density, traffic proportion, gross vehicle weight, road roughness, and wind speed. Furthermore, statistical analyses are also performed to show how the randomness of traffic flow affects the associated dynamic bridge responses. The present study presents a comprehensive perspective on the vertical bridge vibration under wind and traffic considering VIF, which can further serve as a reference for practical design.

This paper proposes an innovative method to calculate the normal stress of concrete slabs near the intermediate support for composite girder bridges with corrugated steel webs (CSWs). The shear stiffness of CSWs is lower than that of concrete webs, which will lead to significant shear deformation. For composite girders near intermediate supports, the shear deformation of CSWs will be constrained by the crossbeam, resulting in additional stresses in the top and bottom concrete slabs. The constrained effect of the shear deformation is not considered in most design codes, which will lead to unsafe designs. Therefore, analytical solutions of the concrete normal stress under different boundary and load conditions were derived based on the elastic bending theory considering the shear deformation of the CSWs. Experimental analysis and finite-element analysis (FEA) were carried out to further validate the analytical solutions. The results show that the proposed analytical equations can be used to accurately predict the normal stress of concrete slabs. The additional stress exists in the concrete slabs near the intermediate supports, and the plane-section assumption is not applicable in this area. The value of the additional stress decreases to zero with the increase of the distance from the fixed end. The additional stress is in the same direction as the general bending stress at the upper edge of the top concrete slab and the lower edge of the bottom concrete slab, which will increase the peak tensile and compressive stress of the whole section. Finally, a practical simplified calculation method of the concrete normal stress near the intermediate supports is proposed, and the calculation procedure is plotted. All the findings can be used for the design of composite girder bridges with CSWs.

Experimental testing and numerical modeling were performed on novel precast TL-5 barriers subjected to centered and eccentric loadings in a quasi-static mode. The mechanical behavior of two precast barrier configurations was analyzed and compared: a hybrid barrier including a normal strength concrete (NSC) core and a ultrahigh performance fiber reinforced concrete (UHPFRC) shell with a UHPFRC barrier–slab connection, and a precast version of a cast-in-place QMT301 barrier made of NSC with a UHPFRC barrier–slab connection. Laboratory experiments on 2-m precast barriers under eccentric loading applied on 0.7 m demonstrated a shear failure in the upper portion of the hybrid and QMT barriers while the UHPFRC connection recess remained elastic, as observed in the cast-in-place solution. The longitudinal connection between precast barriers increased the maximal capacity under eccentric loading at the connected end. Numerical models were carried out on 2–6 -m precast barriers, under centered and eccentric loading, with 0.7 and 2.4 m loading lengths. Models showed the critical effects of shorter barrier length (2 m), shorter loading length (0.7), and eccentric loading as these factors significantly reduce the ultimate capacity of the precast barrier. Models validated with experiments confirmed that the load-carrying capacities of the developed precast TL-5 hybrid and QMT301 barriers surpass the minimum CSA and AASHTO design load requirements when considering 4-m barrier modules loaded on 2.4 m, whether or not there is a longitudinal connection and whether the loading is centered or eccentric.

Evaluating the aerodynamic instability of a bridge girder fitted with bridge attachments such as handrails is critical for the wind-resistance design of a long-span bridge. However, the effects of the detailed configuration of handrails on the aerodynamic performance of a bridge girder have not been sufficiently studied. In this study, the heaving vortex-induced vibration (VIV) of a box-girder bridge was evaluated for nongrid and grid-like handrail cases by free vibration wind tunnel tests. The VIV amplitude decreased with the increase in the porosity ratio of handrails. However, the aerodynamic behaviors of the grid-like handrails are different from the nongrid ones. For the nongrid handrails, VIV amplitude was reduced with the increase of the number and the side ratio of middle horizontal bars. For the grid-like handrails, increasing the number of vertical bars have adverse effects on VIV whereas the number of horizontal bars had no influence on VIV. This study also provides new ideas on the optimization of handrail configuration with good aerodynamic properties and the simplification of handrail models for evaluating the aerodynamic properties of a bridge girder in the design process.

Periodic and exceptional inspections provide information about the condition of bridges to support decisions on maintenance or repair activities needed to counteract defects and damages efficiently. Inspections are carried out on a regular basis or after special events. In different states, diverse approaches to visual inspections have been developed to support bridge integrity management. In the literature, several comparative studies have been published on inspection procedures; however, most of them compare a very limited number of countries due to a lack of information or language barriers. In this paper, the inspection practices adopted in several countries and regions worldwide are critically examined through a comprehensive survey of the available standards, guidelines, and best practices. The novel contribution of this paper concerns the application of a new method to classify and assess different bridge inspection procedures. This is achieved through the definition of indicators relating to different aspects of the quality of data collected during the inspections.

Hinge joint damage is the main defect that affects the safety of assembled hollow slab bridges. There are some studies on vibration-based damage detection for hinge joints. However, the effect of hinge damage on the modal parameters of bridges lacks in-depth analysis. The sensitivities of different order modes to hinge damage are dissimilar. This study determines the orders of modes sensitive to hinge damage in assembled hollow slab bridges, which is instructive for vibration-based hinge damage detection. First, the effect of the degree and location of the damage on the frequencies and curvature mode shapes is theoretically analyzed using a novel equivalent model. The orders of the modes sensitive to hinge damage are determined. Then, the numerical analysis of a bridge is performed. The equivalent model is proven to accurately reflect the dynamic characteristics by comparing it to the entity reference model. Various scenarios are established to quantitatively analyze the influence of joint damage on the partial order frequencies and mode curvatures. The accuracy of the sensitivity analysis is verified. Damage detection based on frequencies and curvature mode shapes sensitive to hinge damage is discussed briefly.

A practical identification method based on single-degree-of-freedom (SDOF) forced vibration was proposed and its application to obtain 16 aerodynamic derivatives of a box-girder bridge deck with twin active flaps (termed as the deck–flap system) was discussed in detail. Two-dimensional numerical simulations based on the unsteady Reynolds-averaged Navier–Stokes (URANS) approach with the shear stress transfer (SST) k–ω turbulence model were conducted to investigate transient motion-induced aerodynamic forces, which were further calculated by the present method to acquire aerodynamic derivatives of the deck–flap system. Moreover, cases of a separate bridge deck and a plate–flap system were taken as examples, and the corresponding results were in good agreement with experimental data and theoretical values, respectively, demonstrating the reliability and accuracy of the proposed identification method. Based on the effects of vibration amplitude and phase angle, the application scope of the present method was discussed to verify its usage in physical wind tunnel experiments.

Model updating seeks to update a finite-element model to reduce discrepancies between predicted and measured data. Metamodel-based model updating using bridge influence lines is a very promising method. However, the accuracy of traditional metamodel methods is not high due to the traditional metamodels being fitted in the entire parameter space using limited sample data. To address this problem, a model updating procedure based on the adaptive metamodel global optimization method is proposed. First, a systematic model updating theory using influence lines is developed, including three different objective functions and a selection of model updating parameters. Then, the adaptive metamodel-based global optimization method is proposed. The adaptive metamodel is iteratively fitted using the automatically added sample data by the mode-pursuing sampling method in the process of optimization. To improve the efficiency of finding the global optimal solution, a two-stage optimization strategy is presented. Finally, the proposed procedure is applied to numerical and practical examples of a long-span suspension bridge. In the numerical example, the global optimal solution is found successfully compared with the traditional metamodels. Excellent agreements are observed between the updated influence lines and measured influence lines in both numerical and practical examples. Based on the proposed theory, the accuracy and efficiency of model updating can well meet engineering requirements.

Design, construction, and maintenance of large-span bridges require an accurate assessment of the temperature field in flat steel box girders (FSBGs). While this field is controlled by various environmental (meteorological) factors, including temperature, solar radiation, humidity, wind speed, and wind direction, there is no comprehensive model for its prediction based on multiple environmental variables. Given this, two novel methods for calculating the cross-sectional effective temperature (ET) of the FSBG were proposed in this study. Based on the bridge’s environmental variables measured on-site, regression models for predicting ET and vertical temperature difference (VTD) in FSBG were introduced, including a random forest (RF) model and empirical formulas. The RF model’s hyperparameters were derived by the Bayesian optimization algorithm. The proposed approach was applied to the case study of the Sutong Bridge, China, using 2 years’ data samples collected via the bridge health monitoring system and Copernicus Climate Change Service. The model’s training and testing results proved that the predictive performance of the multifactor random forest model significantly exceeded that of the single-factor linear model by about 60%. The RF model’s accuracy in the ET/VTD prediction also outperformed the support vector regression model and back-propagation neural network model. Besides, the correlation analysis of environmental variables revealed a significant time-lag between ET/VTD and the surface solar radiation intensity (about 3 h). The predictive performance of the RF model considering the time-lag effect was further improved (by about 20%–30%).

The static and dynamic effects of a railway bridge subjected to train loads have been investigated and analyzed to assess its condition. This paper investigates the potential of using repeated dynamic measurements taken on a passing train to determine the condition of a bridge. The results indicated that instrumented trains could be successfully used for ongoing monitoring of condition and, by implication, for identification of the need for repair or rehabilitation. This full-scale approach expands the potential for applications of bridge–vehicle dynamic interaction responses, along with their ability to be demonstrators of successful implementations of decisions on public infrastructure. The work also provided insights into the impact of a stiffer foundation at one pier and greater stiffness in two spans of a viaduct, for which experimental evidence is rarely available. The work also identified some of the challenges of such detection, such as accurate positioning and variability in the speeds of the passing trains.

For long-term continuous structural health monitoring to be effective, a process of continuous modal identification that should preferably be automated is required. This case study paper describes a robust, fully automated approach for continuous modal identification and tracking. The approach is demonstrated on a long-span suspension bridge under operational conditions. Contributions are made in three stages: eliminating the spurious modes, extracting the physical modes, and estimating the precision. The proposed approach helps avoid any manual intervention, requires no manually tuned thresholds or prior assumption, and is robust. One week of field monitoring data are analyzed to validate the process. Modal tracking is conducted to show the stability of continuous analysis and to track the evolution of modal parameters. Parametric analysis is conducted to demonstrate the robustness. The case study shows that the proposed approach yields better results than alternative approaches and successfully identifies and tracks multiple closely spaced modes without any manual intervention.