Studies Of Shear Lag In Short Leg Walls By Finite Element Method

The development of short leg walls system can be attribute to usage demands and creative implementing of conceptual design. As a new structure system, the short leg walls system has the characters of both frame-structure and shear-wall structures, but it also has some new characters of its own.So far, most of the studies and experiments of this newly developed structure system are carried out on the whole structure. Few works are conducted on members level. This paper argues that it is the adoption of the new anti-literal force members that results in the specific behaviors of the system. By studying the shear lag phenomena of short leg walls, the author wants to show a peculiar aspect of this new structure system.After analyzing the working conditions of the short leg walls in the real structures, the paper deems that the plane-shell element can be used in establishing the finite element model of the short leg walls. The details are given of the stiffness matrix of the plane-shell element. To give more information about the shear lag phenomena in the short leg walls, a computer program of finite element analysis is compiled.Based on the calculated results of the computer program, varied stress contribution curves of short leg walls with T, L and + shaped sections are shown in the paper, together with deformation information of members. To measure the influence of shear lag, the equivalent bend stiffness of short leg walls is introduced. The discounting coefficients of the bend stiffness of members can be used in the bars-system models of short leg walls building structures.The load adopted in the model are very similar to real working conditions of the short leg walls in the actual structures. Works accomplished in this paper can replace some experimental studies.