RC框架结构面向目标保证率的抗连续倒塌设计方法研究

Progressive collapse of building structures caused by accidental local failure will cost severe casualties and economic loss. Uncertain factors, such as overload and deviation in material strength or component dimensions, are the major cause of structural progressive collapse. However, most of the existing progressive collapse design methods are only suitable for the deterministic structures under deterministic design loads. The influence of uncertainties is not well-considered, which results in an unguaranteed progressive collapse design outcome. In this project, the commonly used RC frame system is used as an example. Numerical simulations, big data analyses, and theoretical studies are combined to establish the correlation rules between the components’ progressive collapse probability and the structural progressive collapse performance. A target probability based progressive collapse design methodology is proposed for RC frame structures. The following topics are incorporated into this project: (1) Propose an analytical model and corresponding failure determination criteria suitable for the large-scale probability based progressive collapse analyses of RC frames; (2) Establish the structural level performance evaluation and uncertainty quantification framework based on the progressive collapse fragility curve cluster; (3) Propose the target progressive collapse probability calculation method and target probability based progressive collapse design methodology. It is foreseen that the outcomes of this project will assist in achieving a systematic control of structural redundancy and robustness against progressive collapse, enhancing the existing progressive collapse design theory and methodology, and providing a more scientific and rational engineering design solution, which will bring significant scientific importance and practical values for improving the progressive collapse resistance of building structures.

偶然局部破坏引起的结构连续倒塌会造成严重人员伤亡和财产损失。超载及材料强度、构件尺寸偏差等不确定因素是结构连续倒塌的重要诱因，然而，既有抗连续倒塌设计方法仅针对确定结构和确定荷载，对不确定性因素影响考虑不完善，无法保证结构抗连续倒塌性能。本项目以RC框架为例，结合数值仿真、大数据分析和理论研究，通过建立从构件连续倒塌概率到整体抗连续倒塌性能的关联准则，提出面向目标保证率的RC框架抗连续倒塌设计方法。重点研究：（1）适用于大规模概率不确定计算的连续倒塌理论失效判定方法；（2）基于易损性曲线簇的结构整体抗连续倒塌性能可靠性评价体系；（3）结构抗连续倒塌目标保证率量化准则及面向目标保证率的设计方法。通过本项目研究，可实现对整体结构抗连续倒塌冗余度和鲁棒性的科学控制，完善已有结构抗连续倒塌设计理论和方法，提供更科学合理的工程实用设计解决方案，对提升工程结构抗连续倒塌性能有着重要科学意义和工程价值。

偶然局部破坏引起的结构连续倒塌会造成严重人员伤亡和财产损失，本项目以RC框架为例，结合数值仿真、大数据分析和理论研究，开展了系列研究：（1）收集既有静力抗连续倒塌计算模型，建立连续倒塌试验数据库，基于多基因遗传算法（MGGP）提出了RC框架梁柱子结构和整体结构的连续倒塌抗力计算模型；（2）基于能量平衡原理，提出了考虑动力效应和参数不确定性的RC框架结构连续倒塌简化易损性分析方法，进一步提出了适用于整体结构连续倒塌可靠性评价的易损性曲线簇；（3）依据不同抗震设防烈度、层数、跨数等设计了一系列典型RC框架，采用易损性曲线簇量化了我国典型RC框架的抗连续倒塌性能，系统总结了结构中典型易损构件分布规律和结构安全储备；（4）基于智能优化算法和集群计算技术，提出了目标保证率下的抗连续倒塌设计方法，分析了构件设计顺序对整体结构抗连续倒塌性能和设计材料用量的影响，提出了结构连续倒塌优化设计策略；（5）提出了RC框架连续倒塌设计全寿命成本-效益分析模型，考虑灾害风险、结构易损性和折现率等，量化了不同设计场景的连续倒塌设计收益。项目研究成果可以帮助完善已有结构抗连续倒塌设计理论和方法，提供更科学合理的工程实用设计解决方案。