Underwater shaking table test and seismic fragility assessment of free-spanning submarine pipelines under offshore spatial motions

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures Pub Date : 2025-04-07 DOI:10.1016/j.tws.2025.113276

Haiyang Pan , Chao Li , Hong-Nan Li , Jiahui Hu , Ruisheng Ma

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引用次数: 0

Abstract

Offshore seismic motions typically undergo remarkable variation at different locations of submarine pipelines due to the spatial effects of ground motions. Therefore, this paper intends to contribute to an insight into the seismic performance of FSSPs subjected to offshore spatial earthquake motions and identify the critical impacts of seismic excitation type, coherence loss effect and ground motion directionality. In view of this, a suite of underwater shaking table tests were firstly conducted to investigate the elastic seismic responses of the FSSP under offshore spatial motions. Subsequently, a response difference factor (

χ_{R . i j}

) is defined to quantify the structural response discrepancies caused by the seismic excitation type and coherence loss effect. Then, a numerical modelling scheme for FSSP is developed and its excellent response prediction capacities are verified through shaking table test results. Based on the validated numerical model, seismic fragility curves of the FSSP are established by performing the probabilistic seismic demand analyses. Furthermore, the FSSP fragilities under different seismic inputs and coherence degrees are comprehensively compared and discussed in terms of the damage probability and fragility median PGA. Finally, the FSSP fragilities are assessed under offshore spatial motions with various horizontal incidence angles. Both experimental and numerical results consistently highlight the significance of considering the seismic excitation type and coherence loss effect in seismic performance assessment of FSSPs. Additionally, as the seismic incidence angle gradually increases, the FSSP fragilities increases first and then decreases, and the most favorable and adverse seismic incident angles are 45^° and 90^°, respectively. This study can contribute to a valuable reference for realistically evaluating the seismic performance of FSSPs subjected to offshore spatial earthquake motions.

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海上空间运动条件下自由跨越海底管道的水下振动台试验和地震脆性评估

由于地震动的空间效应，海上地震运动在海底管道的不同位置会发生显著的变化。因此，本文旨在深入研究海上空间地震运动下fssp的抗震性能，并确定地震激励类型、相干损失效应和地震动方向性对fssp的关键影响。为此，首先进行了一套水下振动台试验，研究了FSSP在海上空间运动下的弹性地震响应。随后，定义了响应差分因子（χR.ij）来量化地震激励类型和相干损失效应引起的结构响应差异。在此基础上，提出了FSSP的数值模拟方案，并通过振动台试验结果验证了其良好的响应预测能力。在验证的数值模型基础上，通过概率地震需求分析，建立了FSSP的地震易损性曲线。在此基础上，从损伤概率和易损性中值PGA两方面对不同地震输入和相干度下的FSSP易损性进行了综合比较和讨论。最后，在不同水平入射角的海上空间运动条件下，评估了FSSP的脆弱性。实验和数值结果都一致强调了在fssp抗震性能评价中考虑地震激励类型和相干损失效应的重要性。随着入射角的逐渐增大，FSSP脆性先增大后减小，最有利入射角为45°，最不利入射角为90°。本研究可为实际评价海上空间地震作用下fssp的抗震性能提供有价值的参考。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Thin-Walled Structures 工程技术-工程：土木

CiteScore

9.60

自引率

20.30%

发文量

801

审稿时长

66 days

期刊介绍： Thin-walled structures comprises an important and growing proportion of engineering construction with areas of application becoming increasingly diverse, ranging from aircraft, bridges, ships and oil rigs to storage vessels, industrial buildings and warehouses. Many factors, including cost and weight economy, new materials and processes and the growth of powerful methods of analysis have contributed to this growth, and led to the need for a journal which concentrates specifically on structures in which problems arise due to the thinness of the walls. This field includes cold– formed sections, plate and shell structures, reinforced plastics structures and aluminium structures, and is of importance in many branches of engineering. The primary criterion for consideration of papers in Thin–Walled Structures is that they must be concerned with thin–walled structures or the basic problems inherent in thin–walled structures. Provided this criterion is satisfied no restriction is placed on the type of construction, material or field of application. Papers on theory, experiment, design, etc., are published and it is expected that many papers will contain aspects of all three.