The T-shaped friction damper (TFD) is a damping system that appropriately absorbs and dissipates input energy during seismic excitations. In this paper, a practical method for determining optimum slip load of TFDs in multi-storey steel frames is proposed. The seismic performance index (SPI) is used as a measure to quantify the effectiveness of TFDs in improving the seismic behaviour of prototype structures. The optimum slip load of TFDs is acquired based on this index. The endurance time (ET) method is a seismic analysis in which structures are subjected to gradually increasing dynamic excitation. It is shown that using the ET method, instead of the large number of time-history analyses, to obtain the SPI of the system, results in a considerable reduction in computational effort. An approximate relation to obtain the optimum slip load of the TFD is also proposed according to the design base shear of the frames. The performance of the TFDs in the steel frames is investigated by examining a prototype weak steel structure before and after rehabilitation using TFDs. The rehabilitated structure, by considering the optimum slip load of TFDs, satisfies the collapse prevention and life safety levels in BSE-2 and BSE-1 hazard levels, respectively.

中文翻译：

---

耐久时间法确定钢框架中T形减振器的最佳滑动载荷

T形摩擦阻尼器（TFD）是一种阻尼系统，可在地震激励过程中适当吸收和耗散输入能量。本文提出了一种确定多层钢框架中TFDs最佳滑移载荷的实用方法。抗震性能指数（SPI）用作量化TFD在改善原型结构抗震性能方面的有效性的量度。基于此指标获取TFD的最佳滑移载荷。耐久时间（ET）方法是一种地震分析，其中结构受到逐渐增加的动态激励。结果表明，使用ET方法代替大量的时间历史分析来获取系统的SPI，可显着减少计算量。根据框架的设计基准剪力，提出了获得TFD最佳滑移载荷的近似关系。通过检查使用TFD修复前后的原型弱钢结构，可以研究TFD在钢框架中的性能。通过考虑TFD的最佳滑移载荷，修复后的结构分别满足BSE-2和BSE-1危险等级的防塌保护和生命安全等级。