Comparison between experimental and analytical results for seesaw energy dissipation systems using fluid viscous dampers

This paper presents results of experimental and numerical investigations of a seesaw energy dissipation system （SEDS） using fluid viscous dampers （FVDs）. To confirm the characteristics of the FVDs used in the tests, harmonic dynamic loading tests were conducted in advance of the flee vibration tests and the shaking table tests. Shaking table tests were conducted to demonstrate the damping capacity of the SEDS under random excitations such as seismic waves, and the results showed SEDSs have sufficient damping capacity for reducing the seismic response of flames. Free vibration tests were conducted to confirm the reliability of simplified analysis. Time history response analyses were also conducted and the results are in close agreement with shaking table test results.

Experimental study on slender buckling-restrained knee braces with round steel bar cores

This study aimed to investigate a novel slender buckling-restrained knee brace damper (BRKB) for welded and weld-free steel framing systems. The proposed BRKB adopts steel bar cores connected by a central coupler and restrained by tube buckling restrainers with a cover tube supporter. The advantages of the proposed damper include easy assembly compared to conventional buckling restrained braces, and high architectural flexibility for the retrofitting of large-span weld-free or welded steel moment-resisting systems. Specifically, by increasing the number of contraction allowances, undesirable failure mechanisms that are global instability and local buckling of the restrainer ends can be effectively suppressed because the more uniform plastic deformation of the core bar can be achieved longitudinally. In this study, displacement-controlled compression and cyclic loading tests were carried out to investigate the deformation capacities of the proposed BRKBs. Structural performance metrics associated with both loading tests, such as strength capacities, strains at the cover tubes and buckling restrainers, and hysteretic behaviors of the proposed damper under cyclic loads, were measured and discussed. Test results revealed that the geometrical characteristics of the cover tubes and adopted contraction allowances at the dampers play essential roles in their load-bearing capacities.

地震作用下钢结构的破坏及抗震性能的提高

首先探讨了地震对现代钢结构建筑的破坏情况,主要介绍了1995年兵库县南部地震的震害情况。研究了地震作用对梁柱节点、柱、梁、支撑以及柱脚的破坏。对非结构构件在地震作用下的破坏以及结构对长周期地震的响应进行了研究。其次,列出了钢结构抗震性能提高和抗震评估的方法。对改进的梁柱节点形式,例如改进扇形开孔形状和减小梁截面等进行了研究并建议在实际工程中采用。介绍并探讨了约束屈曲支撑和阻尼器的应用。最后,列出了对既有钢结构建筑抗震性能的评估方法。