基于抗倒塌机制的空间钢框架抗力分析及设计方法研究

In view of the current shortage of progressive collapse analysis and design of steel frame, theoretical analysis, model test and numerical simulation are combined and used to make the study on resistance analysis and design method of space steel frame based on the anti-collapse mechanism: Firstly, the nonlinear anti-collapse mechanism models of space steel frame are constructed based on energy principle and stability analysis, so their failure modes and mechanism of action should be further observed. After the complete description of their mechanical properties is realized, the component resistance demand is obtained. Secondly, make the structural resistance demand as research target, the static and dynamic distribution laws of space steel frame are explored for beam mechanism and catenary mechanism, considered the influencing factors such as initial conditions, beam column system, floor system. The structural failure modes and the performance characteristics of anti-collapse mechanism corresponding are obtained, and then the relationship between structural resistance and component resistance is described fully. Thirdly, combined with the seismic design, the design method of progressive collapse of space steel frame is put forward based on the performance analysis of anti-collapse mechanism. After this study, the progressive collapse resistance capacity of space steel frame could be analyzed and evaluated, which promote the development of progressive collapse of building structure. So this study has important scientific significance and application value.

针对当前钢框架连续倒塌分析和设计上的不足，采用理论分析、模型试验和数值模拟相结合的方法，开展基于抗倒塌机制的空间钢框架抗力分析及设计方法研究：基于能量原理和稳定分析，构建空间钢框架抗倒塌机制的非线性力学模型，并就其破坏模式和作用机理进行深入分析，实现对其力学性能的完整描述，获得基于抗倒塌机制的构件抗力需求；以结构抗力需求为研究目标，探讨梁机制和悬链线机制下空间钢框架的静、动力分布规律，并考虑初始条件、梁柱系统、楼板系统等影响因素，通过分析结构的破坏模式及相应的抗倒塌机制性能特征，实现对结构抗力和构件抗力之间的关系描述；结合抗震设计，以抗倒塌机制的性能分析为基础，提出空间钢框架连续倒塌的设计方法。本项目可对空间钢框架抗连续倒塌能力进行分析和评价，促进了建筑结构连续倒塌研究的发展，具有重要的科学意义和应用价值。

本项目通过理论分析、模型试验和数值模拟相结合，深入研究了在连续倒塌条件下梁柱子结构的破坏模式、力学形态和抗力转换机理，构建了钢框架抗倒塌机制的非线性力学模型，并对比分析了不同跨度比、不同节点连接方式对结构抗倒塌性能的影响，获得了钢框架抗倒塌机制的性能特征和结构连续倒塌的抗力转化规律，初步实现了对钢框架连续倒塌性能的完整力学描述。针对刚性节点钢框架，一般性地的提出了梁柱子结构抗倒塌过程可划分为四个阶段，即弹性阶段、弹塑性阶段、过渡阶段和悬链线阶段，并采用约束系数法和变形协调原理推导了梁柱子结构在不同阶段下的抗倒塌承载力及其挠度变形的计算公式，分析了其由抗弯向拉弯转化并最终主要依靠拉力抵抗外荷载的全过程，满足工程计算的精度要求。对不同连接节点形式的两跨三柱型梁柱子结构进行了共12个试件的连续倒塌试验研究，并在考虑材料非线性、几何非线性、接触非线性以及钢材断裂破坏下，采用显式动力准静态方法分析计算了梁柱子结构精细化数值模型，对不同刚度连接和不同跨度比情形下的梁柱子结构进行了抗连续倒塌数值模拟，深入研究了结构内力的重分布和抗力发展全过程。通过构建梁柱节点的简化模型，定量描述了结构抗力和构件抗力之间的关系规律，从而实现对局部构件受损后结构的鲁棒性评价，基本完成了预期的研究目标。本项目重点研究了结构由于撞击、爆炸引发的连续倒塌作用机理及抗力转化规律，其研究成果促进了建筑结构连续倒塌研究的发展，特别是对钢框架抗连续倒塌分析和设计具有重要的理论科学意义和工程应用价值。