不同预应力度简支梁拉压杆模型  

Strut-and-tie model of simply supported beams under different prestressing degree

作　　者：仲济涛[1] 刘钊[1] 

机构地区：[1]东南大学混凝土及预应力混凝土结构教育部重点实验室,南京210096

出　　处：《东南大学学报（自然科学版）》2013年第5期962-966,共5页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51278120)

摘　　要：为研究预应力混凝土简支梁的传力路径及其拉压杆模型设计方法,提出一种改进的双向渐进结构优化算法.按照Von Mises应力准则,以单元应变能为结构性能指标,自行编制了单元生死并行的双向渐进结构拓扑优化程序,实现了混凝土结构拉压杆模型的自动构形.优化程序中引入单元生长与删除加速度因子,有效防止了无效拓扑的出现.通过把预应力等效为外部荷载,将寻找预应力混凝土梁拉压杆模型的问题转化为连续结构的拓扑优化问题.在此基础上讨论了不同预应力度下混凝土简支梁的受力行为并揭示了其合理的力学模型:钢筋混凝土梁可采用桁架模型,部分预应力梁可采用桁架-拱叠合模型,全预应力梁可采用拱模型或拱-桁叠合模型.To investigate the load path and the strut-and-fie models （STM） of the prestressed concrete simply supported beam, an improved approach based on bi-directional evolutionary structural optimization （BESO） is presented. According to the Von Mises stress criterion, a programmed procedure on BESO is used to realize automatic generation of STM for concrete structures, in which two accelerate factors are introduced to prevent invalid topology process. The searching procedure for STM of prestressed concrete beams is converted into the topology optimization problem of elastic continuum. Then, the mechanical behaviors of the prestressed concrete simply supported beam under different degrees of prestress are studied. Reasonable mechanical models are put forward; that is, the truss model can be adopted in reinforced concrete beams, the truss-arch combined model for partially prestressed concrete beams, and the arch model or the arch-truss combined model for fully prestressed concrete beams.

关 键 词：预应力 简支梁 拉压杆 构形 

分 类 号：U441[建筑科学—桥梁与隧道工程]