面向“韧性需求”的地震与连续倒塌综合防御混凝土框架结构及其能量设计方法

Improving structural multi-hazard resistance and resilience has been well recognized to be a future development trend in civil engineering. Reinforced concrete (RC) frame structures are one of the most commonly used construction systems worldwide. Earthquakes and progressive collapses initiated by local failure are two major types of hazards threatening the safety of multi-story RC frames. Conventionally, seismic design and progressive collapse design requirements for RC structures are implemented separately with respect to the specific hazard. Such a design process has shown to not only result in an increased consumption of construction materials but also a substandard overall structural performance, as revealed by published studies. To achieve an integrated design methodology for earthquake and progressive collapse resistant RC frames, the structural system is expected to have adequate capacities to meet the requirements of “Large rotation, Low damage, Self-center, High energy dissipating and Easy to repair”. This project thus intends to develop a novel multi-hazard resistant RC frame system encompassing high capacity structural components and energy dissipating devices, and the associated energy-based design method. This will be done through the following key tasks: (1) Propose a novel earthquake and progressive collapse resilient RC frame and its key structural components; (2) Perform structural- and component-level behavior analyses of the novel structural system under earthquake and progressive collapse, and establish the corresponding computational models; (3) Study the seismic and progressive collapse energy input and dissipation characteristics of the novel system; (4) Develop an energy-based design method for the multi-hazard resistant RC frame. It is envisaged that the outcomes of this project will assist in future construction of high-performance multi-hazard resilient RC frame structures against earthquake and progressive collapse, which will bring important scientific significance and practical values to further enhance China’s international standing in disaster prevention and mitigation.

提升多灾害防御能力和“韧性（Resilience）防灾”是土木工程未来的发展趋势。混凝土框架结构是最常见的结构体系之一，地震和偶然局部破坏引起的连续倒塌是影响多层钢筋混凝土框架安全的主要灾害。研究表明，按现行方法分别进行抗震和抗连续倒塌设计，不仅会浪费材料，综合防灾性能也不理想。因此，本项目综合考虑抗震及防连续倒塌对框架结构的大转动、低损伤、可复位、高耗能、易修复等需求，研发新型混凝土框架结构体系、构件、耗能装置以及相应的能量设计方法。重点研究：1.面向“韧性防灾需求”的新型混凝土框架结构体系及关键构件；2.结构体系和关键构件的地震和连续倒塌灾变演化规律和计算模型；3.新型结构体系的地震和连续倒塌能量输入和耗散规律；4.基于能量平衡原理的新型框架结构工程设计方法。通过本课题的研究，可实现混凝土框架结构地震和连续倒塌的综合韧性防御，对提升我国工程结构防灾减灾能力有重要的科学意义和工程价值。

RC（Reinforced Concrete）框架结构，是目前最常用的建筑结构体系之一，地震灾害和偶然局部破坏引起的连续倒塌破坏则是影响多层RC框架结构安全的主要灾害。并且，“韧性防灾”有助于降低灾损及灾后恢复时间，目前已成为工程结构防灾研究的前沿需求。因此，本研究将发展面向“韧性防灾”需求的地震与连续倒塌多灾综合防御新型RC框架结构。但是，以下关键问题依旧有待解决：.（1）缺乏地震与连续倒塌综合韧性防御新型RC框架结构体系；（2）缺乏结构体系和关键构件的灾变演化规律和计算模型；（3）缺乏新型结构体系的地震和连续倒塌能量输入和耗散规律；（4）缺乏新型结构体系性能指标及其工程设计方法。.研发新型韧性综合防灾结构体系及其设计方法，具有重要的科学意义和实用价值。针对以上新型结构体系研发存在的难题，本研究从高性能关键元件与结构体系的提出、试验研究、数值模型开发及设计方法提出等方面开展了系统性研究。提出了满足地震和连续倒塌的综合防御需求的装配式钢筋混凝土框架体系（新型MHRPC框架），通过使用自复位预应力钢筋、可更换耗能装置和大变形抗剪板等高性能构件，有效提升框架结构的抗震和抗连续倒塌韧性性能；针对该新型MHRPC框架开展相应的抗震子结构与抗连续倒塌子结构试验，揭示了结构灾变机理，并基于MSC.Marc与OpenSees有限元软件开发了耗能角钢等关键构件与结构的多尺度计算模型；基于能量守恒原理研究连续倒塌能量输入与耗散规律，基于结构弹塑性动力时程分析研究地震作用下结构能量输入与耗散规律；提出考虑压拱效应的连续倒塌承载力计算方法、地震和连续倒塌综合防御预制装配式框架承载力计算方法，构建新型综合防御框架结构体系的构件性能目标，以及基于韧性性能的结构设计方法。.本研究通过提升工程结构的防灾能力及恢复能力，从而达到降低地震和连续倒塌灾害损失和恢复时间的目标，充分提高结构的多灾害防御水平，是未来结构工程的发展趋势。研究成果被《建筑结构抗倒塌设计规范T/CECS 392-2021》采纳。