Journal of Bridge Engineering

Use of precast elements in the design and construction of bridges, especially for accelerated bridge construction (ABC), has been gaining traction to minimize the impact of closures resulted from cast-in-place construction. One such element being investigated is the integral abutment. This is to eliminate the need for expansion joints between the substructure and the superstructure, where the penetration of water and deleterious agents can cause long-term performance issues. The integral abutment alleviates the need for an expansion joint by having the superstructure rigidly connected to the foundation, ensuring that they act together in response to traffic loads, as well as thermal expansions and contractions. Due to this connection needing to be heavily reinforced, congestion issues often arise. Moreover, the construction tolerance and weight of the integral abutment can introduce practical challenges. Addressing such issues, especially for ABC applications, was the main motivation for the current study, in which two novel integral abutment connection details were investigated. The developed details included grouted reinforcing bar couplers, along with normal-strength and ultrahigh-performance concrete materials for the joint. As a control specimen, a cast-in-place integral abutment was investigated as well. The performance of the connection details was evaluated through full-scale laboratory tests, in which simulated thermal and live loads were applied to the specimens. A complementary set of three-dimensional finite-element simulations were also conducted to further extend the findings obtained from the laboratory experiments. This was with a focus on the couplers and how they contribute to the structural response. The outcome of this study provides original information, particularly to improve the connection details used in integral abutments.

This paper proposes a lightweight low-profile steel plate-reinforced ultrahigh-performance concrete (UHPC) deck panel with only longitudinal ribs as an alternative to traditional bridge decks for long-span bridges. The bottoms of the longitudinal ribs were reinforced with 8-mm-thick steel plates that act as flexural reinforcement, and head studs (φ13 × 180 mm) were welded to the steel plates as shear reinforcement, which can also guarantee the composite action between the steel plates and UHPC. Experimental tests were conducted to investigate the flexural and shear behaviors of the steel plate-reinforced UHPC deck panel with longitudinal ribs. According to the flexural test results, the use of 8-mm-thick steel plates could effectively control the crack propagation in UHPC, and the nominal cracking strength of the steel plate-reinforced UHPC deck specimen was 20.4 MPa, which was 90.6% higher than that of its counterpart traditional steel bar-reinforced UHPC deck panel. In addition, the shear test results indicate that the use of head studs (φ13 × 180 mm) as shear reinforcement not only could effectively control the propagation of diagonal shear cracks but also could guarantee sufficient shear resistance to avoid the shear failure for the UHPC deck specimen. Compared with the specimen with short head studs (φ13 × 40 mm), at the initiation of diagonal shear cracks, the maximum vertical shear stress in the specimen using head studs (φ13 × 180 mm) improved by 74%, and the estimated shear resistance of the specimen was 20.9% higher than required by current French standards. Thus, the aforementioned experimental investigations verified that using steel plates could enhance the crack resistance of the UHPC deck panel with longitudinal ribs, and 180-mm-high head studs could provide sufficient shear resistance in the shear zone. Currently, the proposed new UHPC deck panel has been applied to a real bridge in China, namely, the Qinglong Island Bridge.

Maintaining the structural reliability of highway bridges under a budget constraint necessitates the development of accurate prediction models of bridge deck deterioration to maximize bridge service life while minimizing life-cycle costs. Traditionally, the structural condition of a bridge deck is assessed using ordinal discrete indices, referred to as condition ratings (CRs), assigned based on an assessment of the visible signs of deterioration. Nondestructive evaluation (NDE) is being increasingly utilized to gain objective insights into structural deterioration. The impact echo (IE) test is a common NDE technique that relies on the acoustic resonance response of a bridge deck to detect subsurface delamination that can lead to spalling. However, IE data interpretation is largely done manually and the connection between the IE results and CRs is not fully explored. The aim of this study is to model the spectral characteristics of IE signals to quantify the structural integrity of bridge decks and predict CRs. First, a nearest neighbor clustering of IE signal energy distribution in the frequency domain is conducted to generate condition labels for each IE response (good, fair, poor) automatically. The condition labels are then input to a support vector machine (SVM) classification model to predict the CRs. The models are trained and tested using data from the Long-Term Bridge Performance (LTBP) data set pertaining to 38 tested bridges with recorded NDE data collected over a span of 2 years on average. The findings indicate that the proposed model is capable of automatically predicting CRs for bridge decks given the raw IE test data with an accuracy of 87.5%.

Concrete-filled steel tube (CFST) trusses are the most common elements used in long-span CFST bridges; however, the temperature actions have not been systematically investigated. This paper presents a long-term temperature measurement on a CFST truss segment and decompose its temperature actions into uniform temperature, vertical temperature difference (VTD) between upper and lower chords, and lateral temperature difference (LTD) between left and right chords. Based on the recorded long-term meteorological data, empirical formulae were established to predict these temperature actions and prove with a high degree of confidence. Subsequently, an effective extreme value analysis (EVA) based on the Monte Carlo method was presented to calculate the representative values of these temperature actions. All these values are greater than the recommended values in the Chinese Code Specification. Based on a series of frequency analysis on each temperature action, three potential combinations were finally determined. The combinations were all input into a frame finite-element model of a 220 m span CFST arch bridge for the thermal response calculation and comparisons with the Specification temperature actions and dead load. These efforts suggest that the investigative methodology and the proposed temperature action combinations can expand the provisions of the Chinese Code Specification and are more suitable for the thermal response calculation and design of CFST arch bridges with a truss arch rib.

Joints are always the key issue of the precast bridge structures for accelerated construction. In this paper, the transverse joint of a fully precast steel–UHPC lightweight composite bridge was proposed. Based on the first small–medium-span fully precast steel–UHPC lightweight composite bridge in China, the flexural test of the proposed T-shaped joint was conducted. The test result showed that no apparent crack can be seen in the middle of the specimen, and the successively poured joint interface was the weak link of the design. The equations of the joint interface maximum crack width and the ultimate bearing capacity were presented through theoretical analysis, and the prediction and the experimental results were generally consistent. The length of the proposed T-shaped joint upper part was discussed with the spans of 20–50 m, and the value of 0.1L was finally determined.

A validated computational model is used to investigate the response of concrete barriers subjected to impact by single-unit trucks and tractor-semitrailers with different weights and approach speeds. The computational results are used to formulate a performance-based design (PBD) framework in terms of impact demand and barrier capacity. Impact demands for both truck categories are expressed as a function of truck speed and weight, whereas barrier capacity is judged in terms of flexural rotation at the base of the barrier. Based on the computational data, an argument is made that adopting the proposed PBD methodology for impact-resistant barrier design can allow bridge designers to meet predetermined performance objectives for given vehicular impact scenarios.

A new framework to establish a traffic control strategy is proposed for sea-crossing bridges. This new framework is particularly focused on the threat posed by strong winds, and two geometric characteristics of bridges – deck shape and road alignment – were considered. First, the entire bridge was subdivided based on the deck shape and the road alignment. Wind-tunnel testing was used to evaluate the deck shape and road alignment for each of the subdivided sections and determine the effect on vehicle aerodynamics. The minimum critical wind speeds were then estimated for each traffic lane on each segmented road section along the bridge based on vehicle analysis by simulating the length, curvature, cant, and elevation of each section. Finally, a traffic-control strategy was established based on the critical wind-speed curves developed for all wind directions. As a numerical example, the developed framework was applied to a double-deck suspension bridge. The proposed framework resulted in a traffic control strategy that accounts for the deck shape and road alignment along the bridge. A series of comparative studies were performed to clarify the influences that deck shape and road alignment exert on vehicle stability.

This article aims to develop a hybrid approach of complementary ensemble empirical mode decomposition (CEEMD) and random decrement technique (RDT) for identifying the modal parameters (i.e., natural frequency and damping ratio) of structures using high-rate (50 Hz) global navigation satellite system and real-time kinematic (GNSS–RTK) measurement data. The framework of the proposed approach included two stages: (1) CEEMD was first used to derive a set of single-component signals, called intrinsic mode functions (IMFs); and (2) RDT was employed to extract the free decaying signals from the IMFs, including the main frequency information of structures. Subsequently, a three-story shear building model and an actual multispan bridge were used to validate the proposed approach. Additionally, a finite-element (FE) model of the bridge was built for comparing with the experimental case. Finally, the results indicated that the GNSS–RTK technique is capable of monitoring the dynamic displacements of multispan bridges with reliable accuracy. The proposed method performed better than the classical natural excitation technique—eigensystem realization algorithm (NExT–ERA) and stochastic subspace identification (SSI) algorithm—and was viable in practical applications.

Marine, coastal structures, and bridges deteriorate prematurely due to corrosion. Numerous failures have occurred in substructure members of these structures, such as piles, leading to very high repair and replacement costs. Problems related to corrosion could be resolved through the use of noncorroding materials such as fiber-reinforced polymer (FRP) bars. This paper presents the design, construction details, driving test procedures, and results of the field dynamic driving testing of precast glass-FRP (GFRP) reinforced concrete (RC) piles, as well as laboratory test results, to determine the piles flexural strength. Four piles were longitudinally and transversally reinforced with GFRP bars, spirals, and ties. Two of the piles were 6.0 m (approximately 20 ft) long, were fabricated, instrumented, and were laboratory tested for flexural strength. The other two piles were 18.0 m (approximately 60 ft) in length, were field installed and dynamically monitored. They were driven and monitored at the Arthur Drive Bridge project site in Lynn Haven, Panama City, Florida. Pile driving and testing were performed with a Vulcan 512 single-acting air hammer. The embedded data collectors (EDCs) were used to monitor the piles during driving operations. Field driving observations and results indicate that no pile damage occurred during installation. GFRP spirals successfully confined the concrete core of the piles and prevented cover spalling during driving. The maximum tensile and compressive stresses measured in the piles were well within the allowable design limits. Design aids and recommendations for good driving practices for GFRP-RC piles were presented. The promising results presented for the driven precast GFRP-RC piles represent a further step toward field application.

How to identify modal parameters accurately and automatically is an important issue in structural health monitoring. In this paper, two aspects of this issue are investigated based on the algorithm of natural excitation technology (NExT) in conjunction with the Eigensystem realization algorithm (ERA): (1) First, the selection of the user-defined parameters (sampling points of the fast Fourier transform and the data length) is discussed. Based on this, an empirical equation for determining the dimensions of the Hankel matrix is presented; (2) Second, we propose an improved stabilization diagram to determine the physical modes automatically. The modal frequency, damping ratio, extended modal amplitude coherence (EMAC) and modal amplitude coherence (MAC) are applied as criteria. The reliability of the proposed method is verified by a numerical simulation and two applications to a large-scale bridge. It is shown that the proposed method can distinguish the physical modes from spurious modes effectively and the most reliable physical modes can be automatically identified.

Rapid or unexpected bridge deterioration can lead to partial collapse, which can subsequently hinder transportation activities and result in economic and human losses. Heavily adopted by the research community, Markov chain-based deterioration models assume that bridge conditions exhibit stationary transitions over time. This assumption requires a significantly large, and often difficult to obtain, number of historical records. As such, Markov chain-based deterioration models have been developed within classical nonlinear optimization frameworks that might result in local optimal solutions. Therefore, to enhance the model capability to simulate the temporal state transition, this study develops a Markovian-based deterioration model embedded within a genetic algorithm (GA) framework—a class of evolutionary computing techniques, to overcome local optimality issues. To demonstrate its applicability, the developed model was applied to a relevant data set of previously rehabilitated and unrehabilitated concrete and steel bridges. The developed GA-Markovian model was able to replicate the actual state probabilities for the unrehabilitated bridges within both the calibration and validation periods. The model performance was slightly lower for the previously rehabilitated bridges due to the inherited nonstationary transition. The model developed in the present study can be used to guide effective rehabilitation and replacement strategies, prioritize available resources, and devise data-driven predictive bridge asset management policies and standards.

Fiber reinforced concrete (FRC) has been gradually applied to the construction of precast segmental bridges, but due to the discontinuity of the joint structure and the existence of keys, the stress at the joint is complex. Taking the number of keys at the joint, the presence or not of reinforcement in keys, the height to width ratio of specimens and joint angle as the design parameters, 10 pairs of specimens with 2% fiber ratio and 100.1 MPa FRC dry joint matching were tested under combined bending and shear load in this study. The crack development process, failure mode, cracking load, and ultimate load were also observed. The results show that the mechanical properties of specimens with 30° and 60° joint angle are better than that of 45° for both single-keyed and double-keyed specimens. With the increase in the number of keys and the ratio of height to width, the cracking load, ultimate load, and overall stiffness of the specimens are greatly improved. The internal reinforcement in the specimen can increase the cracking load and ultimate load, change the failure mode and increase the integrity of the specimen. The reinforcement in the key has little effect on the mechanical properties and could not change the failure mode of the specimens under combined bending and shear load. In addition, a numerical analysis model was established based on a concrete damage plasticity model in ABAQUS software to investigate structural behavior of keyed dry joints under combined bending and shear load. Fortunately, the cracking evolution history and final crack pattern presented from finite element analysis results are in good agreement with the experimental results. Moreover, the average deviation of cracking load and ultimate load is only 7.3% and 2%, respectively.

New methods are required for sustainable and economical management of bridges. Efficient management can be achieved by a detailed understanding of bridge behavior through monitoring and model-based data interpretation. This paper presents a methodology to evaluate the fatigue safety of existing bridges based on conducting measurements onsite and interpreting measurement data using physics-based behavior models. The methodology combines data from different nondestructive measurements with structural models to develop a suitable set of feasible models that describe accurately structural behavior. The methodology is illustrated with a case study of a composite steel–concrete road viaduct instrumented with acoustic emission channels and strain gauges. Information from measurements is used to update a set of structural models and then evaluate the fatigue safety of the viaduct. While commonly used curve-fitting methods are inaccurate, this methodology is useful to accurately employ the measured behavior of existing civil infrastructure for evaluating nonaccessible elements and scheduling inspections and decision-making related to actions such as strengthening and retrofit.

In this study, the seismic performance of a precast bridge substructure from an urban viaduct is investigated via shake table tests. A simple beam bridge is formed by using two precast bridge pier specimens, and one pier is implemented with an improved grouted splice sleeve coupler (GSSC) design with a shallow recess in the footing for achieving better integrity, while the other is implemented with a conventional GSSC in the pier and flat grouting bed. The two precast bridge pier specimens are first compared with each other. Another bridge specimen is then created and compared, which is supported by two cast-in-place (CIP) references with identical dimensions and mild rebars. The two bridge specimens are first tested with an isolated bearing system, followed by the fixed bearing system. From the test results, it is revealed that the isolated system with lead-rubber bearings retains good seismic isolation capability. The damage to the plastic hinge region of the CIP specimens is more severe with rebar buckling, while the strengthening effect of the GSSC elements in the pier prevents the rebars of the precast specimens from buckling. The GSSCs also limit the peak lateral displacement of the precast columns and redistribute the strain values along the longitudinal rebars. Finally, finite-element models are developed by OpenSEES with fiber elements and alternative bond–slip simulation approaches, which are in acceptable correlation with the test results.

A prerequisite to the implementation of accelerated bridge construction (ABC) in moderate and high seismic regions is reliable data proving that bridges constructed by assembling precast elements can emulate the seismic performance of cast-in-place bridges. Previous seismic studies have not provided sufficient information about the interaction of conventionally reinforced precast concrete elements and connections when they are integrated within a bridge system. This paper addresses this knowledge gap by conducting biaxial shake table tests on a 0.35-scale, two-span bridge model that incorporated 38 precast reinforced and prestressed concrete elements. The elements were joined by using six connection types joining column to footing, column to cap beam, girder to cap beam, deck panels (two types), and deck to girder. The bridge and the connections performed well even under earthquake motions beyond the design-level earthquake and combined large drift ratio demands and substantial in-plane rotation. Although the load path was affected by the interaction among different components, no adverse effect was observed.

Conventionally, for turbulence-induced buffeting vibrations, the Gaussianity assumption is applied to all three subsequent stages of turbulence, wind loads, and structural vibrations because of its wide applicability and mathematical simplicity. However, non-Gaussian turbulence does exist in the boundary-layer atmosphere, especially near the tropical cyclone center. Non-Gaussian turbulence represents short duration and high-speed airflow, which is unfavorable for structural dynamic performance and reliability. It is necessary to analyze the non-Gaussian turbulence effect on flexible structures, especially long-span bridges, and compare the wind-induced vibration against responses caused by conventional Gaussian turbulence. The time domain bridge buffeting analysis method with unsteady aeroelastic force and aerodynamic admittance approximated by rational function was employed to calculate the vibrations excited by Gaussian and non-Gaussian turbulence, which were simulated using the spectrum representation method and the Hermit polynomial translation process method. A Monte Carlo simulation of bridge buffeting was conducted in this study. The statistical results show that the bridge response, excited either by Gaussian or non-Gaussian turbulence, still follows the Gaussian process assumption. However, for the same wind speed, Monte Carlo simulation shows that the vibration amplitudes increases with turbulence skewness in terms of RMS and extreme values. However, the increment ratio decreases with greater mean wind speeds. The peak factors also increase slightly for greater turbulence skewness.

This paper investigates the effects of corrosion and scouring on the barge impact fragility of bridge structures. A typical four-span continuous reinforced concrete (RC) bridge is selected as the baseline structure, and a detailed finite-element (FE) model of the structure is developed to simulate a barge collision. Corrosion of the bridge pier, scouring, and collision-induced soil–pile interaction are taken into account in the FE model. Surrogate models based on the response surface theory and FE model results are developed to efficiently generate the barge impact fragility surfaces using the Monte Carlo method. It is found for the baseline bridge structure that damage of the piles is not an increasing function of the barge’s velocity. In other words, the use of the maximum impact velocity for the barge-impact-resistant design cannot always lead to conservative results. Besides, scouring may have a net positive effect on the pier column response and bring more damage to the pile foundation.

Recently, vehicle collisions with bridge piers have occurred frequently, which have attracted the attention of researchers. However, as one of the most important research methods, vehicle collision tests for reinforced concrete (RC) bridge piers are limited. The impact responses and damage characteristics of full-scale RC piers have seldom been studied in actual truck collision tests, which hinders further development in this research area. Therefore, a medium-duty truck will be employed to carry out a full-scale crash test on an RC single-column pier 1 m in diameter in this study. The crashing truck had a mass of 7.76 t and a collision speed of 81 km/h. The damage and failure level of the vehicle and RC pier will be examined, and some critical data will be obtained from the test, such as the displacement, velocity, and acceleration time histories of the truck, and the deflection, acceleration, and reinforcement strain time histories of the RC pier. In addition, based on the accelerations of the cargo box and engine, the vehicular impact forces will be derived approximately and discussed. This will provide valuable experimental data for the study of vehicular collisions with RC bridge piers, especially in the calibration and validation of the finite element (FE) models for truck collisions and the impact resistance evaluation of RC bridge piers.