Performance-based seismic design and assessment of low-rise steel special moment resisting frames with block slit dampers using endurance time method

Block Slit Dampers (BSDs) are recently developed metallic yielding dampers for passive structural control. This type of damping devices can provide designers with an option of using highly ductile systems, such as steel special moment resisting frames (steel SMRFs), in important structures located in regions of high seismicity. The aim of this study is to obtain a performance-based seismic design (PBSD) procedure for these devices, and to assess the seismic performance levels of low-rise steel SMRF equipped with BSDs using the endurance time (ET) dynamic analysis method. For this purpose, first, the simplified behavioral model of these devices was established based on the analysis of available experimental data. Afterwards, the effects of the geometric dimensions of the damper on its hysteresis behavior were investigated through a parametric study conducted using ABAQUS software. Next, based on the results of the parametric study, the design formulations were developed. In the next step, a step-wise guideline was developed for the PBSD of BSD devices used in a low-rise steel SMRFs. In this guideline, ET dynamic analysis method was used to reduce the calculation costs and complexities of PBSD. Then, a six-story steel SMRF equipped with BSD devices was designed using the developed guideline, and the seismic response of this structure was compared to that of a companion conventional SMRF without BSD devices. The results show that through the use of BSD devices, which have a unique secondary hardening portion in their hysteresis behavior, it becomes possible to satisfy performance objectives of flexible steel SMRFs in regions of high seismicity. In addition, like stiff lateral resisting systems, BSD devices can reduce the inter-story drift ratios (ISDRs) of steel SMRFs. Controlling the absolute floor accelerations (AFAs) and non-structural element damages also become easier with the use of BSD devices. These results indicate that BSD devices are hysteretic devices that are well suited for design and retrofit of flexible steel SMRFs. In the final part of the study, the ET analysis results were compared to the results obtained from a response history analysis (RHA) method conducted using a set of 22 scaled FEMA P695 far-field earthquake records. This comparison shows the suitability of ET method in PBSD of steel SMRFs equipped with BSD devices.