Direct Displacement Based Design Method

569 WordsFeb 22, 20182 Pages
In most of the performance design concept is based on assessment of the performance of building designed by existing code. In those case, the structure is first designed based on the expected seismic load according to existing code, then the performance is evaluated to check the real performance of the structure, and design may repeated, if needed. Those design methods are not truly performance-based seismic design procedure. In a PBSD, the design of a structure should be based on required performance such as displacement, curvature, damage index ,etc. In Direct Displacement Based Design (DDBD) method, the displacement demand is calculated for specific performance objective and compared to the displacement of static analysis or response history analysis. DDBD was proposed (Humar and Ghorbanie-Asl, 2005) to estimate the design base shear for concrete shear wall systems by using a target roof displacement. Based on the period of the structure, Multi-storey building can be converted into equivalent Single degree of freedom system. According to " Equivalent Principle", for each mode structural lateral elastic displacement could be determine (Cui, Liang and Xin 2009). The structural target lateral displacement for each mode could be estimated and the storey shear is gained by SRSS rule based on acceptable storey drift ratio. Calculation of target displacement and minimum base shear for particular performance objectives are given below: Natural Modes and period of vibration of a
Open Document