我国多地工业园区内，建设有化工运输管廊，这些管廊多采用钢结构支架为其提供 支撑。但随着钢支架结构服役年限的增长，存在着不同程度的锈蚀问题，开展服役期内 钢支架抗震性能及破坏概率的研究，对保证运输管廊支架结构安全性具有显著的工程意 义。本文结合工程项目对一化工管廊钢支架进行结构设计，选取其中长度为89.5米， 宽度为6米的5层化工管廊钢支架结构建立非线性模型，进行非线性动力时程响应分析， 采用增量动力分析（IDA）方法，以探究在地震作用下，支架结构超越4类极限状态的 概率。并进一步量化分析了不同服役年限后，锈蚀钢支架结构的地震易损性，以预测管 廊支架结构的损坏程度。本文主要研究内容及结论如下： （1）首先结合实际工程项目使用PKPM软件，对5层化工运输管廊钢支架结构进 行结构设计；再使用SAP2000软件建立三维弹塑性分析模型，对结构进行模态分析， 与SATWE分析结果的自振周期及振型对比。两种模型分析结果表明其振型相同，自振 周期误差较小，从而验证所建模型的有效性。 （2）对比钢支架结构在地震动一致激励，和考虑行波效应沿纵向地震波波速分别 为250m/s、500m/s和 1000m/s非一致多点激励作用下，结构顶点位移时程曲线和结构 两端相对位移时程曲线，可以发现考虑行波效应后，纵向地震波波速越小，沿长度方向 支架两端相对位移越大，结构动力响应越显著，对结构越不利。 （3）选取12条天然地震动记录和2条人工地震动记录，对钢支架结构进行增量动 力分析，选取合适地震动强度参数和结构损伤指标，对钢支架整体结构和局部桁架部分 分别进行易损性分析。分析结果表明：该钢支架结构在未发生锈蚀时抗震性能良好，结 构整体满足“三水准”设防目标；桁架部分在面对8度罕遇地震时，结构保持基本完好 极限状态的概率为100%。 （4）考虑不同服役龄期锈蚀对钢支架结构构件截面尺寸、材料参数等的影响，将 服役40年和50年后钢支架结构在增量动力分析的基础上进行易损性评价。分别采用 “未修正极限状态限值”和“锈蚀后修正极限状态限值”进行分析，结果表明：锈蚀对钢支架结构抗震性能的影响不可忽略，随着服役年限的增长，钢支架结构抗震性能会有 所减弱，且采用“未修正极限状态限值”会高估发生锈蚀后运输管廊钢支架结构的抗震 性能。如在服役龄期为40年时，设防地震作用下，管廊支架结构基于“修正限值”与 “未修正限值”相比，正常使用超越概率增大7.23%，立即使用超越概率增大1.97%， 生命安全超越概率增大0.02%。在服役龄期为50年时，设防地震作用下，管架结构基 于“修正限值”较“未修正限值”得到的超越概率，正常使用极限状态增大22.8%，立 即使用极限状态增大1.36%，生命安全极限状态增大0.34%。

In many industrial parks in China, there are chemical transportation pipe corridors, and most of these pipe corridors use steel structure supports to provide support. However, with the increase of the service life of the steel support structure, there are different degrees of corrosion problems, and the research on the seismic performance and failure probability of the steel support during the service period has significant engineering significance to ensure the safety of the support structure of the transportation pipe gallery. In this paper, the structural design of the steel support of a chemical pipe gallery is carried out in combination with the engineering project, and a nonlinear model of the steel support structure of the five-layer chemical pipe gallery with a length of 89.5 meters and a width of 6 meters is selected to establish a nonlinear model, and the nonlinear dynamic time history response analysis is carried out, and the incremental dynamic analysis (IDA) method is used to explore the probability of the support structure exceeding the limit state of four types under the action of earthquake. The seismic vulnerability of the corroded steel support structure after different service years was further quantitatively analyzed to predict the damage degree of the pipe gallery support structure. The main research content and conclusions of this article are as follows: (1) Firstly, combined with actual engineering projects, use PKPM software to design the steel support structure of the 5-story chemical transportation pipeline gallery; Further use SAP2000 software to establish a three-dimensional elastic-plastic analysis model, perform modal analysis on the structure, and compare the natural vibration period and mode with the results of SATWE analysis. The analysis results of the two models indicate that their vibration modes are the same and the error of their natural vibration period is small, thus verifying the effectiveness of the constructed models. (2) Comparing the time history curves of the displacement of the vertex of the structureand the relative displacement time history curves of the two ends of the structure considering the traveling wave effect under the uniform excitation of ground motion, and the non-uniform multi-point excitation of the longitudinal seismic wave velocity along the longitudinal seismic wave of 250 m/s, 500 m/s and 1000 m/s, respectively, it can be found that the smaller the longitudinal seismic wave wave velocity and the greater the relative displacement of the two ends of the support along the length direction, the more significant the dynamic response of the structure is, and the more unfavorable it is to the structure. (3) Select 12 natural seismic records and 2 artificial seismic records to conduct incremental dynamic analysis on the steel support structure. Select appropriate seismic intensity parameters and structural damage indicators to conduct vulnerability analysis on the overall structure and local truss parts of the steel support. The analysis results indicate that the steel support structure has good seismic performance without rusting, and the overall structure meets the "three levels" of fortification goals; The probability of the truss part maintaining a basic intact limit state when facing a rare earthquake of 8 degrees is 100%. (4) Considering the influence of corrosion of different service years on the cross-sectional dimensions and material parameters of steel bracket structural components, the vulnerability of steel bracket structures after 40 and 50 years of service was evaluated on the basis of incremental dynamic analysis. The results show that the influence of corrosion on the seismic performance of steel bracket structure cannot be ignored, and the seismic performance of steel bracket structure will be weakened with the increase of service life, and the use of "unmodified limit state limit" will overestimate the seismic performance of the steel support structure of the transportation pipe gallery after corrosion. For example, when the service age is 40 years, under the action of fortification earthquake, the pipe gallery support structure is based on the "modified limit" and "unmodified limit", the normal use of the probability of exceeding the probability of increasing by 7.23%, the immediate use of the probability of exceeding by 1.97%, and the probability of life safety exceeding the probability of 0.02%. When the service life is 50 years, under the action of fortification earthquake, the probability of exceeding the pipe frame structure based on the "modified limit" compared with the "unmodified limit" increases by 22.8% in the normal service limit state, 1.36% in the immediate service limit state, and 0.34% in the life safety limit state.