可更换损伤元钢框架结构抗震机理与设计方法

The emphasis for seismic design of building structures is now being shifted more on the resilience as well as replacing possibility of their damaged components during earthquake. This project shall study the steel frame composed with main-structure and replaceable damaged component whose feature is that the loading capacity and energy dissipating ability are combined together in the individual member or connection. Three kinds of components are to be studied to reveal their energy dissipating mechanism, deformability and the influence of constructional details, in order to improve their energy dissipating capacity and to keep them from early buckling or fracture. The earthquake response process of the frame system shall be investigated from damage free stage, damage control stage, the status after damaged component replaced, till to damage diffusion stage, to show the frame properties under dynamic loads, including damage distribution and development, and the restoring force mechanism making the frame recover its displacement. The threshold of residual displacement shall be checked and confirmed. The design strategy for the structure resilience shall be studied, one of main purposes is to establish the principle to make displacement compatibility between main-structure and the damaged components to preventing unexpected damage occurred at the member of main-structure during damage control stage. The new method to achieve the design target shall be explored. This research aims to set up applicable techniques for ordinary building structures to raise their resilience under expected earthquake action in a relatively low cost.

本项目着眼于建筑结构抗震性能要求提升为功能可恢复、损伤元件可更换的发展趋势，研究由主结构和可更换损伤元组成的钢框架体系，其特征为损伤元将构件承重功能与耗能功能集于一体。研究3种类型可更换损伤元的耗能机制、变形能力和构造参数，改进、提升其耗能能力，防止过早失稳和开裂。研究地震作用下钢框架从无损伤状态，损伤控制状态，更换损伤元后的恢复状态，至损伤超越状态的演化全过程，综合地震响应数值分析和振动台实验，揭示结构动力特征，损伤机制、恢复力机制，检验和确立满足损伤元可更换性的残余位移阈值。提出能够实现结构预设性态设计目标的要素配置方法和设计原则，重点解决地震过程中损伤元与主结构的变形相容问题，在两者性能配合上探索新的策略。研究成果将有助于建立相应技术体系，使普通建筑结构能以较低代价实现预期地震作用下的可恢复性能。

工程结构抗震设计的一个重要发展趋势是从防止结构倒塌转向结构功能可维持、可恢复。在地震作用下实现主要承载构件的免损伤或微损伤性能、以及地震作用后整体结构实现低残余变形是结构可恢复性的核心要求。本课题通过在钢框架结构中配置兼具承载和耗能能力的损伤元，利用结构体系中自身的主框架弹性恢复力，期望以较小的经济代价和相对简便的更换操作性实现钢框架震后的可更换性。从我国国情出发，在框架体系中采用既可承载又具有优良耗能能力的损伤元，提高结构的可恢复性仍是较为可行的方法。.提出并研究了可更换区段耗能梁、弧线角撑、开孔式斜缝钢板剪力墙的3种类型损伤元，研究了其构造参数与耗能能力、变形能力等关键指标的关联，建立了相应的力学模型和设计方法。提出了可更换跨-主框架跨的复合钢框架结构体系形式，以在结构遭遇设防烈度甚至大震水平的地震后能实现损伤控制、降低残余变形、损伤元易于更换等目标。试验研究表明，损伤元能起到先行集中损伤，保护其他构件的作用，且更换损伤元的操作简便、可行；可更换跨-主框架跨复合钢框架的结构体系形式中，损伤先行集中于可更换跨的损伤机制可行，主框架跨具备有效的弹性恢复力，震后结构体系没有明显的残余变形；提出了钢框架结构的损伤控制设计方法和考虑多屈服时序的推覆分析方法。.研究成果可促进我国钢结构抗震技术的发展，促进超高强度结构钢材在抗震区建筑结构中的应用，使普通建筑结构能以较低代价实现预期地震作用下的可恢复性，减少震后经济损失，为相应设计规范、标准的制定提供可参考的科学依据，具有重要的理论意义和工程实用价值。