高耸混凝土烟囱土-结构相互作用地震反应分析  

Seismic response analysis of high-rise RC chimney including soil-structure interaction

作　　者：周长东[1] 曾绪朗 潘庆龙[1] 

机构地区：[1]北京交通大学土木建筑工程学院,北京100044

出　　处：《地震工程与工程振动》2016年第3期140-150,共11页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金面上项目(51478033;51178029)~~

摘　　要：目前在高耸混凝土烟囱结构抗震设计和抗震性能评估中,由于缺乏合适的计算模型,一般采用刚性地基假定而忽略土-结构相互作用效应,或者采用传统的集中参数模型而忽略土的非线性特性。针对此不足,本文选用240 m高的钢筋混凝土烟囱作为研究对象,采用OpenSees程序,基于非线性文克尔地基梁模型和基于柔度法的分布塑性梁柱单元,建立了土体-基础-上部结构共同工作的整体非线性有限元分析模型,详细介绍了非线性文克尔地基梁模型主要参数的确定方法;研究了地基土非线性对高耸烟囱结构地震反应的影响,给出了考虑土-结构相互作用效应后结构周期、上部结构的内力和变形分布的变化规律。分析结果表明：考虑土-结构相互作用后,结构的自振特性、内力及节点位移都发生了不同程度的改变;考虑土体非线性特性的土-结构相互作用模型,峰值截面弯矩、剪力及截面曲率延性系数与不考虑土-结构相互作用时的结果之比分别介于0.921～1.219、0.732～1.29和0.822～1.536;而不考虑土体非线性特性的土-结构相互作用模型,峰值截面弯矩、剪力及截面曲率延性系数与不考虑土-结构相互作用时的结果之比分别介于0.838～1.578、0.92～1.76和0.656～2.831。不考虑土体非线性特性的土-结构相互作用模型的峰值截面弯矩、剪力及截面曲率延性系数的取值总体上较大,高估了烟囱结构在地震荷载作用下的内力需求。In the current design practice and seismic performance assessment of high-rise reinforced concrete（ RC）chimney,soil-structure interaction（ SSI） effects are not considered or accounted for based on the assumption of linear behavior in the soil,which mostly due to the absence of reliable nonlinear SSI modeling techniques. To bridge this gap,the main objective of the present study is to reveal the effects of SSI on the seismic response of tall RC chimney when the foundation nonlinearity is accounted for. For the purposes of the study,a 240 m high RC chimney is used as structural model. A detailed structural nonlinear analytical modeling included nonlinear SSI is developed using the finite element software OpenSees. The nonlinear SSI modeling techniques are also described in detail.The effects of SSI on the seismic response of the tall RC chimneys are studied. The results obtained indicate that SSI has the significant influence on both the natural vibration period and the amplitude and distribution of the seismic response with height of the reference chimney compared to the fixed base model. The calculated ratio of peaksection moment,peak section shear force and peak section ductility based on the nonlinear SSI model and without the SSI effect are distributed between 0. 921 ～ 1. 219,0. 732 ～ 1. 29 and 0. 822 ～ 1. 536. Meanwhile,the calculated ratio of peak section moment,peak section shear force and peak section ductility based on the SSI model and without the SSI effect are distributed between 0. 838 ～ 1. 578,0. 92 ～ 1. 76 and 0. 656 ～ 2. 831. It can been found that the effects of SSI on the peak section moment,peak section shear force and peak section ductility can lead to increases in response and the effect of linear SSI is on the whole stronger than the effect of nonlinear SSI. It indicates that no realistic prediction of soil reactions can be made and can lead to an overestimate of the seismic demand of the tall RC chimney if the nonlinear of the soil were ignored.

关 键 词：高耸混凝土烟囱结构 非线性文克尔地基梁模型 土-结构相互作用 地震反应 

分 类 号：TU279.741[建筑科学—建筑设计及理论] TU233