钢框架中的一种易复位可更换抗弯耗能连接的抗震机理与性态优化

The trends of the seismic energy-dissipative devices for civil structures are: the concentration of damage, the passive response adaptive capability, the reduced residual drifts, less occupation of architectural space, and the replaceability after earthquakes. The project proposes an innovative replaceable link, namely the re-centering viscoelastic moment-resisting link, that could be installed at the beam ends of the steel moment frames. Viscoelastic material is used to significantly increase the system damping. Meanwhile, the proposed link is passive adaptive: after the inter-story drift exceeds a prescribed value, the seismic damage is assembled to a weakened portion. The seismic energy is dissipated throughout the ductile buckling performance from the flange of the weakened portion while the integrity of the system is secured. In addition, the proposed link has a re-centering mechanism, which is designed to easily eliminate the possible residual drifts after the earthquakes. Consequently, the damaged portion of the proposed link could be easily replaced. In addition, the project includes experiments, numerical simulations, and theoretical derivations in order to comprehend the material properties, the hysteretic behavior, and the re-centering capability of the proposed link. First, the mechanical properties and re-centering capability will be tested via full size experiments. Then, the numerical simulations will be performed to validate its effectiveness and applicability. Thirdly, the dimensional analysis will be used to optimize the parameters of the proposed link without the influence of different ground motions. Finally, the seismic performance of the proposed link will be further evaluated and improved at the systematic level under the performance-based earthquake engineering framework.

结构体系耗能构件的发展趋势是损伤集中、地震自适配、低残余位移、占用空间小以及震后可更换。本申请项目提出一种安装于钢框架中钢梁一端的易复位、可更换的抗弯型耗能连接。该连接使用粘弹性材料显著提升系统阻尼；同时具有一定自适配性，在层间位移角超过预设的临界值后，能将地震损伤集中于其可更换的强度削弱段，通过翼缘屈曲变形提供延性耗能，并且保证结构整体稳定性；另外，该连接自带转动回位钮，易于修复震后残余位移。为深入把握该连接的材料特性、力学性能及可复位性，明确其损伤递进机理和参数优化方法，拟采用试验、模拟和理论结合的研究方法。通过材料和节点足尺试验把握结构力学性能和可复位性；通过局部和整体结构数值模拟研究其有效性和适用性；采用消除了地震不确定性影响的无量纲分析方法优化其抗震参数；并用基于性能的抗震设计方法宏观上建立更全面、科学的响应评价机制，进一步优化其在整体结构中的抗震效果。

本项目在钢框架结构体系中提出一种抗弯粘弹性耗能可更换节点，粘弹性材料的运用提供了结构小变形情况下良好的系统阻尼。另外，在结构产生较大形变时，本项目提出的抗弯节点的回位钮将自动锁死，从而将弯矩传送到连接的另一半“保险丝”上，通过“保险丝”的屈曲变型提供耗能与一定的延性，满足了被动自动适配的需求。在地震后，一旦因“保险丝”部分的破坏而造成了一定残余位移，可以通过回位钮提供节点的易修复特性，在室内完成残余位移的复位。同时，该连接不额外占用建筑空间。所提出的装置作为一种装配型钢结构构件，高度契合当前装配化建筑的发展趋势。.经过三年多的项目周期，项目迎来了最终的结题。在此期间项目负责人通过理论与试验相结合的方法深度对项目展开了研究，最终项目取得了丰硕的成果：获得授权发明专利一项，发表国际SCI论文4篇，国内EI论文1篇。项目取得了多个重要结果，在土木工程 – 黏弹性阻尼器上取得了重要突破，同时，项目为韧性结构提供了一种新的阻尼器思路。本项目对揭示带有易复位可更换抗弯耗能连接的钢框架结构体系工作机理和复位性能有十分重要的科学意义，通过基于性能的设计方法为可恢复功能结构及其可更换连接提供抗震性能优化，能为相关设计手册或技术标准的制定提供理论支撑，对推动我国可恢复功能结构的发展有重要实际价值。.项目培养了多名土木工程-结构工程领域的硕士与博士，同时，通过2018年在洛杉矶召开的美国地震工程会议（NCEE），项目负责人将研究成果与国内外学者进行交流，将本项目提出的关键核心技术与问题在世界范围展示，获得国内外学者的认可。.