爆炸荷载作用下钢筋混凝土板柱结构连续倒塌机理研究

The reinforced concrete flat plate construction systems are being widely used in residential and industrial buildings in many parts of the world. Compared with other forms of structure, this system is highly advantageous given that it reduces formwork cost and construction time, and eases installation. The reduced story height and increased architectural freedom in design also result in lower overall construction and maintenance costs. In the past, most of researches on concrete structure progressive collapse are mainly on column-beam structure, relatively few study is for flat plate structure (slab-column structure). The load-carrying system of flat plate structures is consisting of slab and column, the potential risk factors of progressive collapse of RC flat plate is quite different from progressive collapse of beam-column structures under blast loading. Therefore, the study for progressive collapse of RC flat plate structures under blast loading has important theoretical significance and application value. .In this study, the structural behavior and mechanical property of slab-column connection under blast loading are investigated by experimental research and theoretical analysis, and then the experimental research for RC flat plate structure frame models designed according to Chinese Code is carried. The structural behavior, structural dynamic response and progressive failure mode are analyzed; the variation of transmission mechanism and dynamic amplification factor of load could be obtained. The analysis method for resistant of flat plate structures progressive collapse is proposed and progressive collapse mechanism is investigated combine with numerical computation. An applicable and practical calculation method for progressive collapse of RC flat plate structure under blast loading would be proposed and it could be some references for the prevention of progressive collapse of RC flat plate structures.

由楼板和柱组成承重体系的钢筋混凝土板柱结构在建筑工程中应用较为广泛。该类结构在遭遇爆炸时，发生连续倒塌的潜在危险因素与梁柱结构有所不同。目前，关于混凝土结构防连续倒塌的研究多针对梁柱结构，而对板柱结构的研究较少。因此，开展爆炸荷载作用下钢筋混凝土板柱结构连续倒塌研究具有重要的理论意义和应用价值。项目结合已有的研究成果，采用试验研究和理论分析相结合的方式，研究爆炸荷载对板柱节点受力性能和破坏模式的影响，然后进行爆炸荷载作用下钢筋混凝土板柱结构连续倒塌试验研究，分析结构受力性能、动力响应特征和失效模式等，得到连续倒塌过程中结构传力机制变化规律和荷载动力效应对结构承载力影响程度。构建适用于板柱结构连续倒塌的分析方法，结合数值计算深入探讨板柱结构连续倒塌机理，提出爆炸荷载作用下板柱结构连续倒塌实用计算方法，为板柱结构防连续倒塌工程设计提供参考。

从历史上看，在偶然荷载下建筑物发生倒塌事故的例子并不鲜见。特别是近年美国俄亥俄州Alfred P.Murrah 大楼和纽约世贸双塔遭遇恐怖袭击，建筑发生部分和整体倒塌，更是把对建筑结构安全性能的研究，推到结构工程领域的前沿。由楼板和柱组成承重体系的钢筋混凝土板柱结构在建筑工程中应用较为广泛。该类结构在遭遇爆炸时，发生连续倒塌的潜在危险因素与梁柱结构有所不同。目前，关于混凝土结构防连续倒塌的研究多针对梁柱结构，而对板柱结构的研究较少。因此，开展爆炸荷载作用下钢筋混凝土板柱结构连续倒塌研究具有重要的理论意义和应用价值。项目结合已有的研究成果，采用试验研究和理论分析相结合的方式，研究爆炸荷载对板柱节点、梁柱节点受力性能和破坏模式。得到了试件破坏范围、剩余截面高度、梁柱节点支撑柱附加轴力等随混凝土强度、梁纵筋配筋率和剪跨比等参数变化规律，分析了爆炸荷载作用下RC节点动态响应特征和局部破坏特征。分析节点在塑性阶段和悬索阶段的抗连续倒塌机制。建立了爆炸荷载作用下梁柱节点动态响应数值模型，基于BP神经网络建立支撑柱爆炸附加轴力预测模型。通过爆炸荷载作用下钢筋混凝土板柱结构连续倒塌试验研究，分析结构受力性能、动力响应特征和失效模式，得到连续倒塌过程中结构传力机制变化规律和荷载动力效应对结构承载力影响程度。结构平板历经弹性阶段、压力薄膜阶段和拉力薄膜阶段。基于常规设计，通过完善构造措施等，可以保证中间区格钢筋混凝土板柱结构在经历中柱破坏后仍具有足够的抗连续倒塌能力。构建适用于板柱结构连续倒塌的分析方法，结合数值计算深入探讨板柱结构连续倒塌机理，提出爆炸荷载作用下板柱结构连续倒塌实用计算方法，为板柱结构防连续倒塌工程设计提供参考。