砖墙基础托换的钢梁-砖砌体Timoshenko组合梁模型分析

Timoshenko composite beam model analysis of steel beam and brick masonry for foundation underpinning of masonry wall

将钢夹梁和钢梁间的砖砌体等效为组合梁,基于Timoshenko弹性梁理论,建立了钢梁-砖砌体组合梁弯曲变形的控制方程,给出了钢梁-砖砌体组合梁弯曲变形的解析解.在此基础上,考虑砖砌体墙的拱效应,研究了砖砌体墙的基础托换问题,得到了不同型号工字钢夹梁的钢梁-砖砌体组合梁最大挠度和最大应力,以及基础单段托换的最大长度.研究结果表明:钢梁-砖砌体组合梁挠度和应力随着工字钢型号编号的增加而减小,但钢梁承担的荷载以及锚栓承担的压力不变.同时,Timoshenko模型的组合梁挠度大于Euler模型的组合梁挠度,但两种模型的应力及紧箍压力相同.因此,Euler组合梁模型可用于基础托换设计中的强度分析,而刚度分析建议采用Timoshenko组合梁模型.

Regarding the steel clamping beams and brick masonry between them as a composite beam and based on the Timoshenko elastic beam model, the governing equa- tion for bending deformation of composite beam is established. The analytical solution for bending deformation of the composite beam of steel and brick masonry is presented. Con- sidering the arch effect of the brick masonry, the foundation underpinning of the brick wall of masonry structure is investigated. The maximum deflection and maximum stresses of the steel-brick masonry composite beam for different models of H-type steel clamping beam are obtained, and the maximum length of the foundation underpinning for single stage is given. It is shown that deflection and stresses of the steel-brick masonry composite beam decrease with the model number of the H-type steel beum increasing, but the load held by the steel beam and the confining pressure of the steel-brick masonry composite beam are unchanged. Furthermore, the deflection of the Timoshenko composite beam is larger than that of the Euler composite beam, but the stresses and confining pressure are the same.Therefore, in the foundation underpinning design, the model of an Euler composite beam can be used for strength analysis, and the Timoshenko composite beam model can be used for stiffness analysis.