Loading tests of a brace-type multi-unit friction damper using coned disc springs and numerical assessment of its seismic response control effects

Abstract

In this paper, the performance of a multi-unit friction damper with high-tension bolts tightened via coned disc springs was experimentally investigated, and the response control effects achieved by the friction damper were numerically assessed. Elemental tests were performed to obtain the basic characteristics of dampers composed of two friction units. The dampers exhibited a stable rigid-plastic restoring force characteristic without significant degradation of the frictional force even under repetitive loading operations. In full-scale tests, the performance of a brace-type damper composed of eight or 10 friction units and incorporated into a steel frame was investigated. The brace-type damper demonstrated stable performance and showed no remarkable decrease in the sliding force, even under repeated loading. The damper was shown to produce a total frictional force approximately proportional to the number of the friction units. Thus, the total frictional force of the damper can be estimated as the sum of the contributions of the friction units. Moreover, adopting multiple friction units and assembling them permit the damper to achieve a high total frictional force capacity. Earthquake response analysis was conducted using a 30-story high-rise building model incorporating the brace-type dampers to assess their performance against various earthquake motions, including long-period, long-duration motions and pulse-like motions. By installing the high-capacity brace-type dampers into the two spans out of 12 spans for each floor of the main frame, a response reduction effect was obtained in most analytical cases compared to the model without dampers.