横向荷载作用下RC多T梁上部结构的受力性能

基于实体退化壳单元理论,采用分层单元模拟了混凝土和构造钢筋,采用组合单元模拟了受力纵筋;并利用弥散裂缝模型、关联流动法则和Madrid强化准则等来描述了混凝土的材料非线性,推导了非线性薄壁壳单元的统一单元模式,研究了横向荷载作用下RC多T粱上部结构的裂缝发展和钢筋屈服等性能.结果表明,RC多T梁的主梁先于横隔板开裂,与偏载加载或中载加载的加载方式无关;横隔板开裂削弱整体横向联系,使主梁协同受力性能减弱,受载较大的主粱荷载横向分布系数略趋于不利变化;偏载加载至结构破坏时,部分主粱的纵向受力钢筋已进入塑性阶段,而中载加载至结构破坏时,所有主粱的纵向受力钢筋均进入塑性阶段.所得结论为多T梁设计提供参考.

Mechanical Properties of Upper Structure of RC Multi-T Girders Subjected to Transverse Loads

Based on the shell element degraded from the continuous body, concrete and configured steels are modeled by the layered shell element, and the vertical steels burdened with added loads are completed by the combined shell element. Then, with the smeared crack model, associated flow rule and Madrid hardening model, the material nonlinearity of the concrete is depicted. The stiffness matrix of nonlinear thin-walled shell element is deduced. As for RC multi-T girders subjected to transverse loads, the properties, such as crack expanding and steel yielding, are studied. Results indicate that the cracks generate earlier in the beam than in the diaphragm and the mechanical phenomenon is unrelated to disposal of offset loads or symmetric loads. The cracks in the diaphragm weaken the transverse connections between the beams, thus leading to the unsatisfying change of the transverse distribution of the loads. When the RC multi-T-girder structure is out of commission on the offset loads, some of the main steels reach the yielding stress; when it does on the symmetric loads, all of the main steels reach the yielding stress. The conclusions provide a reference for the design of multi-T girder structures.