SEISMIC DESIGN EVALUATION OF T SHAPED IRREGULAR RC BUILDING PLANS BY USING PUSHOVER ANALYSIS

Seismic design codes usually declare that their requirements lead to Life Safety (LS) and Performance Level (PL) of buildings. This is when many buildings, designed based on the current existing codes have shown inadequate performance, and even collapsed in some recent earthquakes. Based on this, it seems that the code provisions still require further improvement to create enough confidence in the civil engineering community. This study has been conducted to find out how Turkish seismic code 2007 is effective in providing the LS and PL in a regular and T shaped irregularity reinforced concrete multi-story buildings; with special lateral load bearing moment frame system. For this purpose, a set of multi-story buildings: one rectangular regular plan and three different T shaped plan residential buildings of three, six, nine and twelve stories were considered in the highest seismic hazard zone of Turkey (NAFZ), and were designed based on the code. Then, a static non-linear modal pushover analysis was conducted for all buildings. For being more consistent and realistic same materials and floor plans for both rectangular reference and various T shaped plans buildings were considered. In addition, for designing the structural components (columns and beams) the minimum (or close to minimum) sizing of sections concept was used. Base shear forces, roofs displacement and floor drifts for each building were computed. Besides, the formation trend of plastic hinges and their respective distribution in the entire structures were investigated for evaluating the seismic performances. Results show that under the given earthquake loads the buildings performance exceeds LS and PL, and even in some cases they reach Collapse Level (CL).