Life-cycle evolution of train running performance on prestressed concrete bridges: a train–track–bridge interaction analysis with material degradation

Prestressed concrete (PC) bridges using corrugated steel webbing have emerged as one of the most promising forms of steel-concrete composite bridge. However, their long-term behavior is not well understood, especially in the case of largespan bridges. In order to study the time-dependent performance, a large three-span PC bridge with corrugated steel webbing was compared to a similar conventional PC bridge to examine their respective time-dependent characteristics. In addition, a threedimensional finite element method with step-by-step time integration that takes into account cantilever construction procedures was used to predict long-term behaviors such as deflection, stress distribution and prestressing loss. These predictions were based upon four well-established empirical creep prediction models. PC bridges with a corrugated steel web were observed to have a better long-term performance relative to conventional PC bridges. In particular, it is noted that the pre-cambering for PC bridges with a corrugated steel web could be smaller than that of conventional PC bridges. The ratio of side-to-mid span has great influence on the long-term deformation of PC bridges with a corrugated steel web, and it is suggested that the design value should be between 0.4 and 0.6. However, the different creep prediction models still showed a weak homogeneity, thus, the further experimental research and the development of health monitoring systems are required to further progress our understanding of the long-term behavior of PC bridges with corrugated steel webbing.

To mitigate excessive long-term deflection observed in segmentally erected box girder bridges globally, engineers have proposed a novel structural form: the prestressed concrete bridge with a stiffened steel truss. Exhibiting enhanced rigidity, these bridges are particularly well-suited for high-speed rail applications, exemplified by successful implementations in northwest China. However, a comprehensive understanding of their long-term creep behavior remains a critical research gap. This study investigates a substantial four-span bridge on a high-speed railway line in northwest China as a representative case study. Utilizing in-situ concrete creep test data, a comparative analysis of the creep coefficient and classical creep models is performed. Subsequently, finite element modeling, incorporating optimized creep model parameters, is employed to analyze the long-term creep response of the reinforced steel truss prestressed concrete bridge, focusing on vertical deflection, longitudinal deformation, and prestress loss. The results indicate strong agreement between the in-situ creep coefficient and predictions derived from the ACI209 (1992) model. Finite element analysis, based on the ACI209 (1992) creep model, demonstrates that the incorporated stiffened steel truss significantly enhances bridge stiffness and mitigates vertical deflection. Furthermore, the stiffened steel truss prestressed concrete bridge exhibits reduced sensitivity to loading age and environmental humidity compared to conventional prestressed concrete bridges. These findings demonstrate that reinforced steel trusses effectively mitigate the adverse effects of creep in concrete bridge structures.

<p> The author has been developing a practical Bridge Management System that is referred to as the Japanese Bridge Management System (J-BMS) for existing concrete bridges. This paper introduces a newly developed bridge management system for the prestressed concrete (PC) bridges (J-BMS PC version) which integrated with the PC bridge rating expert system (PC-BREX). The proposed system is able to predict the deterioration process of the existing PC bridge superstructure components as well as assess a broad array of optional corrective strategies. The system also has the capability to search and retrieve from a J-BMS database system(J-BMS DB), the necessary information, carry out suitable analyses to arrive at some recommendations that would help users to optimize their decisions based on engineering aspects, cost and economic issues and bridge management policies. A comparison of the results of applying the system to some actual in-service PC bridges with a special designed survey form to experts shows that optimal maintenance planning as well as bridge rating can be predicted accurately by using the system.</p>

A practical Bridge Management System has been developed by the author, which is referred to as the Japanese Bridge Management System (J-BMS) for existing concrete bridges. This paper introduces a newly developed bridge management system for the prestressed concrete (PC) bridges (J-BMS PC version) which is integrated with the PC bridge rating expert system (PC-BREX). The proposed system is able to predict the deterioration process of the existing PC bridge superstructure components as well as assess a broad array of optional corrective strategies. The system also has the capability to search and retrieve from a J-BMS database system (J-BMS DB), the necessary information, carry out suitable analyses to arrive at some recommendations that would help users to optimize their decisions based on engineering aspects, cost and economic issues and bridge management policies. A comparison of the results of applying the system to some actual in-service PC bridges with a special designed survey form to experts shows that optimal maintenance planning as well as bridge rating can be predicted accurately by using the system.

The problem of cracking and long-term deflection in larger-span prestressed concrete box girder bridges exists throughout the world and has restricted the development of long-span concrete bridges to some extent. However, the understanding of cracking and deflection of concrete box girder bridges is still insufficient and many strengthening methods cannot reach anticipated effect. In this paper, a space-frame lattice model which is used to analyze the stress on the entire cross-section of the box girder bridge, is presented. The stress state of random grid elements in the model may be biaxial in plane. The model simulates the cracking and deflection of pre-stressed concrete box girder bridges. This model was applied for cracking and deflection analysis of the existing concrete box girder bridge with (80+100+80) m spans. The calculation results are compared with the actual status of the bridge. The paper indicates that cracking of girder becomes one of major factors which have influence on deflections of long span prestressed concrete bridges. The space-frame lattice model is an effective tool to analyze the cracking and deflection of prestressed concrete box girder bridges and merits further investigation.

Deterioration of pre-stressed concrete (PC) bridge structures due to overloading or extreme weather conditions is of significant concern for bridge administrators and engineers. To investigate the residual performance of PC bridge girders after years of service, PC girders salvaged from an abandoned 27-year-old bridge in Alberta are studied experimentally and analytically. This study aims at understanding the degraded structural behavior through numerical simulations by (1) comparing the analytically predicted and experimental behavior of the girders and (2) performing a parametric analysis via considering various possible defects in the PC girder. 2D nonlinear finite element models are developed to predict the flexural behavior of the PC bridge girders with different types of deteriorations of various levels. The effects of different deteriorations on PC girders presented here help to identify the main possible causes of the performance degradation of the PC girders. The insights into the structural behavior of PC girders with various defects are potentially beneficial for bridge inspectors and evaluators.

This article shows the strain analysis on two cantilever cast-in-place prestressed concrete bridges during construction. Strain gauges, measuring strain based on the change in electrical resistance, were installed on both structures in order to obtain strain results during and after construction. Nonlinear numerical models were made to simulate the realistic behaviour of the structure and show the effect of creep and shrinkage during the construction phases. The numerical model taking into account creep and shrinkage is validated and shows good overlap with the measured results. Relative compressive stresses as well as the necessary precamber are shown. The effects of creep and shrinkage are analysed. Finally, the data can be used to analyse and compare other similar bridges and validate different numerical models. A recommendation for the design of future prestressed concrete balanced cantilever bridges is given.

The Modern transport infrastructure necessarily utilizes pre-stressed concrete (PSC) girder bridges, which provide both efficient and secure passage for vehicles. But as they pass on their service life, these bridges experience a variety of environmental, traffic, and load-induced stresses that can endanger their structural integrity. To maintain the long-term safety and operation of PSC bridges, it is crucial to undertake periodic structural checks. For this work, a PSC Bridge with an average span length of 20 m has been chosen. This bridge’s fundamental structural element is I-section PSC girder. The bridge was built in compliance with the IRC 6 loading specifications. To ascertain the state of the road bridge, several non-destructive tests are carried out, including destructive testing, non-destructive testing, and visual inspection. The required strength and serviceability checks are carried out using the model created from the audit data using the MIDAS software. Wind and seismic analyses are carried out and comparison of results for current condition and initial condition is done. Bridge service life prediction is a critical component of infrastructure management, seeking to determine how long a bridge will continue to work and be structurally sound before requiring substantial repairs or replacement. It entails a thorough evaluation of the design, construction quality, materials, surrounding environment, maintenance procedures, and traffic loads.

A smart concrete girder bridge usually has various sensors, based on which several physical properties can be measured, and hence, the health condition can be evaluated. Cracks are always observed on a smart concrete girder bridge. In particular, some of the cracks are induced by overloaded vehicles, which is dangerous to its safe operation. However, due to the crack opening and closing effect, it exhibits nonlinear responses, posing challenges for accurately assessing its health condition. Influence lines (ILs) are a promising indicator for bridge damage. However, there is limited research on the effect of cracks on the ILs of a smart concrete girder bridge. A digital twin is commonly used to accompany the smart sensing system to accurately evaluate the health condition, where the finite element (FE) model is of great importance. Therefore, this study proposes an element size–independent FE model construction method based on the concrete damage plasticity (CDP) model to investigate the changes of displacement and strain ILs of different types of smart concrete girder bridges with bending cracks, which is helpful to guide how to use the ILs to identify the cracks and evaluate the health condition. Initially, a concrete constitutive model based on crushing/fracture energy is proposed, and the evolution law of tensile damage based on fracture energy is derived to construct the element size–independent FE model. Subsequently, experiments on a reinforced concrete (RC) simply supported beam and a prestressed concrete (PC) simply supported bridge subjected to bending failure are used to verify the FE models constructed by the proposed method. Finally, the FE models of a smart RC T‐beam bridge and a smart three‐span PC continuous bridge are established to study the changes in ILs caused by bending cracks. The change of displacement IL at the midspan due to cracks for the smart RC bridge exceeds 10% when the reinforcements yield, while it is less than 10% for the smart PC bridge even if the bridge is in the failure state. The change of both displacement and strain ILs becomes greater when the measurement point approaches the cracks, and the change of strain IL is only detectable when the measurement is close to the cracks. Due to the crack opening and closing effect, the displacement and strain ILs of a smart concrete girder bridge with bending cracks are inconsistent when different loads are applied. The findings can also be used as a pre‐IL‐based crack detection using the passing inspection vehicle‐induced dynamic response on a selection of type of ILs, determination of layout of sensors, and mass of inspection vehicle.

Long-span prestressed concrete (PC) bridges built decades ago often suffer from excessive deflection and cracking, which challenges serviceability and durability. Retrofitting with external prestressing tendons is commonly used to enhance structural performance, but the long-term behaviour of retrofitted bridges remains insufficiently understood. This study develops a multi-factor coupled numerical framework to simulate the time-dependent performance of retrofitted long-span PC bridges, integrating crack propagation, nonlinear creep under high stress, and prestress relaxation influenced by environmental temperature and cyclic fatigue. The framework is validated using a five-span, 1060 m long PC rigid-frame bridge, assessing stress redistribution, deflection evolution, and prestress loss over 24 years. Compared with in-situ measurements, the model predicts deflection with a 3.8% error and prestress loss with a 16.8% discrepancy. Results show that external tendons reduce mid-span deflection by 24.8% and reduce shear crack development. Prestress relaxation is identified as the primary factor governing long-term deflection, contributing ∼45–50% of total deflection, followed by concrete cracking. The proposed framework offers a reliable tool for evaluating retrofit effectiveness and long-term performance, providing insights for similar bridge structures.

The object of this paper analyzes the reliability level of pre-stressed concrete continuous girder bridges designed with the Chinese codes including the code for design of highway reinforced concrete and pre-stressed concrete bridges and culverts of JTG D62-2004 and JTJ 023-85 using cantilever construction method. Typical cross-sections used in the example bridge are considered at service stage. Load and resistance parameters are treated as random variables. The statistical parameters are based on the available literature, test data and survey results. Reliability indices are calculated by iterations using the first-order second-moment method. The calculated results indicate that the reliability indices on the code of D62-2004 vary considerably to the code of JTJ 023-85. And it could provide the references for the reinforcement of old bridges and the design of new bridges using the cantilever construction.

Seismic loads pose a potential threat to the high-speed railway bridges in China, which have been rapidly developing in recent years, especially for those subjected to the near-fault earthquakes. The previous researches on high-speed railway bridges usually concern the far-field earthquake, and the damage of high-speed railway bridge–track system subjected to the near-fault earthquake has not been well studied. In this article, a seven-span high-speed railway simply supported bridge–track system is selected to explore the seismic damage features under the excitation of near-fault earthquake which possesses characteristics of obvious velocity pulse and high-frequency vibration. First, a detailed finite element model of the selected bridge–track system is established and calibrated by the experimental data and design code. Then the low-frequency pulse-type portion and the high-frequency background portion are separated from the selected eight original near-fault records, and a series of nonlinear dynamic analysis is conducted. The results show that the background portion leads to more serious damage of the bridge–track system than the pulse-type portion. Due to the high stiffness of high-speed railway bridge–track system, the background portion with high-frequency vibration characteristic produces the main part of seismic response of system. As for the damage part of system, the weakest component of the bridge–track system is the sliding layer, followed by the shear alveolar.

Since the mid-twentieth century, prestressed concrete (PC) bridges have been significantly developed to become the most important type of bridge in the world. However, only a few studies have dealt with the reliability-based design optimisation (RBDO) of PC bridges despite the fact that RBDO demonstrates the real behaviour of structures. Moreover, the corrosion of post-tensioned tendon in PC bridges seriously caused sudden failures which have been recorded in the world. Since then, this study presents the probabilistic model and approach to formulate and analyse the RBDO of PC box girder bridges which consider the pitting corrosion phenomenon of shear, torsion reinforcements and post-tensioned tendon. A practical example of a typical PC box girder bridge is presented and discussed. Sensitive analyses are performed to evaluate the influence of ultimate target reliability index on the optimal solution. For the simple support PC box girder bridge, the ultimate target reliability index should be in the range of βult: 3.5–5 in order to produce the optimal design.

In-service reinforced concrete bridges, following prolonged operational periods, frequently undergo alterations in structural integrity and significant deterioration of material properties. As a result, it becomes imperative to evaluate and analyze these bridge structures. This study focuses on a specific in-service concrete bridge and employs finite element simulation analysis to investigate the failure behavior and degradation of load-bearing capacity in concrete beam bridge structures. The research examines the impact of various crack distributions and types, specifically addressing the effects of bending and shear cracks on the failure behavior and degradation of load-bearing capacity in concrete bridge structures. Load simulations are conducted on the bridge, revealing that bending cracks exert a relatively minor influence on the failure mode of the structures. The load-deflection curves demonstrate minimal variation across different crack heights, indicating that the structures do not experience abrupt brittle failure, and their structural performance is largely optimized in this context. Conversely, shear cracks have a pronounced effect on the failure mode of the bridge structures. Notably, when the crack height reaches 0.6h, the load-deflection curve exhibits a significant alteration, leading to brittle failure attributed to shear cracks, thereby indicating that the structural performance is not fully realized. Given that the deformations in cracked bridge structures comprise two components, stiffness reduction formulas are introduced. Utilizing the stiffness reduction formula outlined in the standard (JCT3362—2018) for cracked components, a formula for calculating residual load-bearing capacity is derived. Calculations pertaining to the mid-span section load-bearing capacity of the selected bridge reveal deviations within 5%. This study offers a valuable methodology and reference for assessing the residual load-bearing capacity of reinforced concrete bridges exhibiting crack damage.

An approach to analyzing the evolution of the failure patterns and ultimate load-carrying capacity of prestressed concrete (P.C.) cable-stayed bridges based on a mixture of inspection and structural health monitoring (SHM) techniques is proposed. Firstly, a finite element model (FEM) of a bridge structure was established based on the design blueprint and was updated using periodic inspection or SHM data. The relationship between girder section axial force and bending moment bearing capacity was analysed with the consideration of damage and performance deterioration. Then, using vehicle loading patterns, which can be obtained from SHM data or bridge design codes, vehicle loads are applied to the updated FEM to determine the internal forces in bridge components. Finally, the locations where loads exceed the bearing capacity of components are set as plastic hinges to model the nonlinear behaviour of the structure. This procedure is repeated with the load increasing continuously up to the ultimate load-carrying capacity of the bridge. The corresponding FEM at this point gives the failure mode of the bridge. A P.C. cable-stayed bridge with a 260-m main span was employed to validate the proposed approach for 4 representative states (healthy, damaged, strengthened, and re-damaged states). The results presented in this paper confirm the feasibility of the proposed approach, and indicate that durability damage (such as girder cracking and steel bar corrosion), variations in the cable forces, girder shape (i.e., girder deflection) and structural configuration (i.e., boundary condition variations) have significant effects on the failure mode and ultimate load-carrying capacity of the P.C. cable-stayed bridge.