Seismic Retrofit with Energy Dissipators

该项目得到了美国国家科学基金会第90-23号公告“结构抗震修复与恢复研究”的支持。在带有碟形弹簧垫圈的开槽孔中使用螺栓的初步试验表明，由于隔板表面之间的滑动，在严重的循环载荷下具有很好的能量消散潜力。这样的测试表明，在多次荷载反转期间，例如在严重地震期间，可能会出现稳定的重复滞后行为。连接处的滑移发生在螺栓上的滑移临界剪力处。因此，可以精确地设计支撑和其他构件，使它们不会在地震事件引起的力的作用下屈曲或屈服。这将消除在传统设计的钢支撑中出现的最不受欢迎的行为。在本项目中，早期的研究将扩展到更大范围的螺栓尺寸和循环载荷类型。还将研究在循环载荷作用下连接处的几个螺栓的行为。在对这些结果进行分析后，将设计出用于台面试验的模型试验架。通过对框架进行模拟地震荷载试验，研究消能节点的实用设计方法和适用范围。预计使用传统制造工艺的拟议系统将在实际应用中具有极高的性价比。

This project is supported under NSF Announcement No. 90-23 "Repair and Rehabilitation Research for Seismic Resistance of Structures." Pilot tests using bolts in slotted holes with Belleville spring washers show an excellent potential for energy dissipation during severe cyclic loading due to slip between faying plate surfaces. Such tests indicate stable repetitive hysteretic behavior during numerous load reversals such as may occur during a severe earthquake. The slip at a connection occurs at a slip-critical shear force on the bolts. Therefore it is possible to accurately design braces and other elements such that they would not buckle or yield under forces caused by a seismic event. This would eliminate the most undesirable behavior occurring in conventionally designed steel bracing. In this project the earlier studies will be extended to a larger range of bolt sizes and types of cyclic loading. The behavior of several bolts at a connection under cyclic loading will also be investigated. After analysis of these results, a model test frame for experiments on the table will be designed. Practical design procedures for energy dissipating connections and the range of their applicability will be developed by testing the frames with simulated earthquake loadings. It is expected that the proposed system utilizing conventional fabrication procedures will be exceptionally cost effective for practical applications.