考虑蠕变的索杆结构安全年限研究  

Study on safety life of cable-strut structures considering cable creep

作　　者：邓满宇 袁行飞[1] 冯越 何振翔 DENG Manyu;YUAN Xingfei;FENG Yue;HE Zhenxiang(Space Structure Research Center,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]浙江大学空间结构研究中心,浙江杭州310058

出　　处：《华中科技大学学报(自然科学版)》2024年第12期135-141,共7页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(51878600,52278224)。

摘　　要：针对索杆结构的拉索在长期服役过程中会发生蠕变及松弛,导致结构刚度降低和内力重分布的问题,为保证结构的安全性能,基于可靠度理论与结构的两种极限状态,分别建立了极限状态方程与不等式.推导了基于长度为变量的钢索内力与节点位移变化公式,引入钢索蠕变模型并结合数学规划,提出了一种考虑蠕变效应的索杆结构钢索蠕变伸长限值及结构安全年限计算方法.对一莱维(Levy)型索穹顶算例进行分析,并取多个可靠度指标与规范限值及蠕变模型计算结果进行对比.结果表明:现有规范的可靠度指标取值偏小,计算出的钢索蠕变伸长限值及结构安全年限大于蠕变模型计算结果;按该值对结构进行设计维护,将有较大的失效概率使得结构在服役期间突破极限状态,因此应综合考虑规范限值及对应的结构极限状态进行取值.Aiming at the problem that the cables of the cable-strut structure would creep and relax during long-term service,resulting in a decrease in structural stiffness and redistribution of internal forces,and to ensure the safety performance of the structure,the limit state equations and inequalities were respectively established based on the reliability theory and two structural limit states.The formula for the members′internal force variation as well as nodal displacement variation of cable-strut structure due to variation of the member length was derived,and the method to determine the creep elongation limit and structural safety life of cable-strut structure was proposed combined with the mathematical programming and the cable creep model.The numerical example of a Levy cable dome was carried out,and multiple reliability indexes were compared with the limit values in specification and finite element numerical solutions.Results show that the reliability indexes values in specification are relatively small,and the calculated creep elongation limit of steel cables as well as the structural safety life are greater than numerical simulation results based on cable creep model.If the structure is designed and maintained according to these values,there will be a greater probability of failure,causing the structure to break the limit state during service.Therefore,the reliability indexes in specification and corresponding structural limit states should be taken into consideration together.

关 键 词：索杆结构 蠕变 数学规划 蠕变伸长限值 安全年限 

分 类 号：TU323[建筑科学—结构工程]