带斜撑型直接空冷钢-混凝土竖向混合结构非线性地震响应分析

Nonlinear seismic response analysis of direct air-cooled vertical hybrid structures with diagonal bracing

带斜撑型钢-混凝土竖向混合结构是为将直接空冷技术推广应用于高烈度地区而提出的一种新型结构体系,根据上部结构平台型式的不同,可分为钢桁架+斜撑结构与实腹梁+斜撑结构两种类型。在钢桁架+斜撑结构模型抗震试验研究的基础上,采用ABAQUS有限元软件计算分析两类结构在不同强度地震作用下的基底剪力响应规律、变形性能与钢筋混凝土管柱的损伤演化特性。结果表明:提出的模型简化原则与有限元建模方法比较合理,计算值与试验值吻合较好;不同强度地震作用下,钢桁架+斜撑结构的最大基底剪力与剪重比均大于实腹梁+斜撑结构;两类结构的侧移变形随地震作用的增强均由弯剪型趋于剪切型,钢桁架+斜撑结构的牛腿及下部位移略大于实腹梁+斜撑结构,而牛腿上部位移则略小;钢桁架+斜撑结构的最大柱顶侧移角略小于实腹梁+斜撑结构;两类结构的抗震性能均较好,能够满足大容量机组火电厂在高烈度区的抗震需求。

Steel-concrete vertical hybrid structure with diagonal bracing is a new structure system which has been proposed for applying the direct air-cooled technology in high earthquake intensity areas, according to the type of platform. The structure can be divided into two types： steel truss-diagonal bracing structure and solid web girder-diagonal bracing structure. On the basis of the seismic experiments of steel truss-diagonal bracing model structures, finite element software ABAQUS was used to calculate and analyze the base shear response, deformation properties and damage evolution characteristics of reinforced concrete pipe columns of the two kinds of structures with diagonal bracing. The results show that： the proposed simplification principles and finite element modeling methods are reasonable, the calculated results agree well with the test results; under different earthquake intensities, the biggest base shear force and the shear-weight ratio of the steel truss-diagonal bracing structure are greater than those of the solid web girder-diagonal structure; the lateral displacement curves for the two kinds of structures are both shifting from shear-moment-type toward shear-type as the earthquake intensity increases; the lateral displacements on and below the corbel of the steel truss-diagonal bracing structure is slightly greater than those of the solid web girder-diagonal structure, while above the corbel, it is just the opposite; the lateral displacement angle at the top of the column for the steel truss-diagonal bracing structure is slightly smaller than that of the solid web good, which can meet the seismic girder-diagonal structure; seismic performances of the two kinds of structures are both requirement of the large-capacity units in high earthquake intensity areas.