大空间地下工程钢筋混凝土支撑体系研究

以上海虹桥综合交通枢纽地铁虹桥西站为背景,针对大空间地下工程钢筋混凝土支撑体系,提出按刚度均匀分布的支撑布置原则,以及大空间钢筋混凝土支撑体系等效线刚度的概念和计算法,计算分析考虑温度应力以及支撑立柱隆沉对支撑体系的影响,并通过现场监测对比分析验证理论分析与技术参数选取的合理性。

Buckling of stepped beams with elastic supports

The tangent stiffness matrix of Timoshenko beam element is applied in the buckling of multi-step beams under several concentrated axial forces with elastic supports. From the governing differential equation of lateral deflection including second-order effects,the relationship of force versus displacement is established. In the formulation of finite element method (FEM),the stiffness matrix developed has the same accuracy with the solution of exact differential equations. The proposed tangent stiffness matrix will degenerate into the Bernoulli-Euler beam without the effects of shear deformation. The critical buckling force can be determined from the determinant element assemblage by FEM. The equivalent stiffness matrix constructed by the topmost deflection and slope is established by static condensation method,and then a recurrence formula is proposed. The validity and efficiency of the proposed method are shown by solving various numerical examples found in the literature.

考虑板筋参与梁端承载力贡献的设计方法及抗震性能研究

通过考虑一定有效翼缘宽度范围的楼板内钢筋对梁端负弯矩承载力贡献并进行梁端配筋设计,研究楼板与梁的共同工作性能。应用对梁、柱采用考虑钢筋和混凝土的纤维梁模型,楼板采用考虑钢筋和混凝土的复合材料分层壳单元模型,建立可考虑楼板对梁刚度及承载力贡献的整体弹塑性有限元分析模型,对影响RC框架结构的屈服机制的主要因素进行了研究。不同算例的分析结果表明,楼板对梁端的承载力贡献及梁柱等效相对线刚度比对其屈服机制和结构的抗倒塌能力具有较显著的影响。