Key Takeaways & Executive Findings
- •• • Under frequent earthquakes, HSRSSB designs satisfy all three functional performance requirements (PTF, SBF, CRF), confirming that current seismic design provisions ensure operational continuity and structural safety for typical simply supported bridges. • • Under design-level earthquakes, the structural bearing function (SBF) remains in a slight damage state, while the post-earthquake traffic function (PTF) exhibits varying degrees of damage that worsen as pier height increases; this height-dependent degradation directly impacts post-earthquake traffic resumption decisions and requires height-specific mitigation strategies. • • The pier structure satisfies seismic demands even under rare earthquake conditions, demonstrating adequate collapse resistance function (CRF) and validating the effectiveness of current ductile detailing for HSR bridge piers in high-seismicity regions. • • The proposed framework integrates the probability density evolution method and vulnerability method to compute damage probabilities at three functional levels, enabling quantitative assessment of operational, structural safety, and structural integrity requirements for HSRSSBs.
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Abstract
Current seismic damage assessments for high-speed railway (HSR) bridges primarily focus on overall structural safety, lacking evaluations from multiple performance perspectives, which affects post-earthquake traffic decision-making. This study proposes a performance-based comprehensive functional damage probability assessment framework for high-speed railway simply supported bridges (HSRSSBs) under earthquakes. The framework categorizes bridge functions into three levels: post-earthquake traffic function (PTF), structural bearing function (SBF), and collapse resistance function (CRF), corresponding to operational, structural safety, and structural integrity requirements, respectively. By analyzing damage states of key bridge components during earthquakes, functional damage probability assessment indicators and classification thresholds are established according to various performance requirements. Damage probability calculations are conducted using the probability density evolution method and vulnerability method. Based on the relationship between damage probabilities at different functional levels, a comprehensive damage probability assessment framework considering the three-level performance requirements of HSRSSBs is developed, and the influence of varying pier heights on the functional damage probability relationship is examined. Results indicate that current HSRSSB designs meet all performance requirements under frequent earthquakes. Under design-level earthquake conditions, the SBF remains in a slight damage state, while the PTF exhibits varying degrees of damage, which worsens as pier height increases. The pier structure satisfies seismic demands even under rare earthquake conditions.
1. Introduction
High-speed railway (HSR) bridges are critical infrastructure in seismically active regions such as China, Japan, Nepal, the Philippines, Pakistan, and Turkey. Earthquake-induced damage threatens lives, property, and the economic viability of these networks, particularly in mountainous western China where HSR bridges face frequent and intense seismic activity. Existing seismic damage assessments for HSR bridges predominantly focus on overall structural safety, neglecting multiple performance perspectives that are essential for post-earthquake traffic decision-making. This gap hinders the ability to rapidly assess whether a bridge can resume operations, whether structural repairs are needed, or whether collapse is imminent.
To address this bottleneck, this study proposes a performance-based comprehensive functional damage probability assessment framework for high-speed railway simply supported bridges (HSRSSBs). The framework categorizes bridge functions into three levels: post-earthquake traffic function (PTF), structural bearing function (SBF), and collapse resistance function (CRF), corresponding to operational, structural safety, and structural integrity requirements. By analyzing damage states of key bridge components, functional damage probability assessment indicators and classification thresholds are established. Damage probabilities are computed using the probability density evolution method and vulnerability method, and a comprehensive assessment framework is developed based on the relationship between damage probabilities at different functional levels. The influence of varying pier heights on the functional damage probability relationship is also examined, providing a quantitative basis for post-earthquake traffic decisions and seismic risk mitigation.
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ZHOU Gaoyang, ZHU Zhihui, ZHENG Weiqi, TANG Yongjiu (2026). Performance-based comprehensive functional damage probability assessment framework for high-speed railway bridge under earthquake. Railway Engineering Science (铁道工程科学). https://doi.org/10.1007/s40534-025-00395-3
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Frequently Asked Questions
What are the specific functional damage states and thresholds for post-earthquake traffic function (PTF) in HSRSSBs?
The paper establishes classification thresholds for PTF based on damage states of key bridge components. Under design-level earthquakes, PTF exhibits varying degrees of damage, with the severity increasing as pier height increases. However, exact numerical thresholds (e.g., displacement limits, residual drift ratios) are not provided in the extracted text; the framework defines them according to operational performance requirements.
How does pier height influence the functional damage probability relationship among PTF, SBF, and CRF?
The study finds that under design-level earthquakes, the SBF remains in a slight damage state, while PTF damage worsens as pier height increases. This indicates that taller piers are more susceptible to functional damage affecting traffic, whereas the structural bearing function remains relatively stable. The CRF is satisfied even under rare earthquakes, suggesting that collapse resistance is not compromised by pier height within the studied range.
What methods are used to calculate damage probabilities, and why were they chosen?
The probability density evolution method and vulnerability method are employed. The probability density evolution method captures the stochastic response of nonlinear systems under random ground motions, while the vulnerability method provides a probabilistic framework linking intensity measures to damage states. Their combination allows for efficient and accurate computation of damage probabilities at multiple functional levels.
What are the limitations of the proposed framework regarding bridge component types?
The framework is specifically developed for high-speed railway simply supported bridges (HSRSSBs), which are the most common type in HSR. The authors acknowledge that further research is needed to investigate the influence of other critical bridge components, such as bearing types and track structure types, on functional damage probabilities at different levels. Thus, the framework's applicability to other bridge configurations requires validation.
What are the practical implications of the results for post-earthquake traffic decision-making?
The results indicate that under frequent earthquakes, all performance requirements are met, allowing immediate traffic resumption. Under design-level earthquakes, while the SBF remains in slight damage, PTF damage varies with pier height, meaning that taller piers may require inspection or restricted traffic until repairs are made. Under rare earthquakes, the pier structure satisfies seismic demands, implying no collapse risk, but functional damage may still affect traffic. This three-level assessment enables informed decisions on traffic resumption, repair prioritization, and risk mitigation.
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