Seismic analysis of RC building with plan irregularity in Baghdad/Iraq to obtain the optimal behavior

Abstract

A study was conducted for four-story reinforced concrete (RC) structure existing in Baghdad-Iraq (residential building) to evaluate the accuracy and reliability of the equivalent lateral force procedure (ELFP) analysis and the response spectrum model (RSA) according to Iraqi seismic code (ISC 2016) for designing and analyzing irregular buildings. The building was classified as an irregular in plan according to American Society of Civil Engineers (ASCE 7-16). The seismic behavior of the building was investigated by verifying many parameters: the ratio of shear demand to shear strength on the columns (VV/Vn{V}_{n}), internal force (bending moment, shear force, and axial force) for beams and columns, and the inter-story drift ratio (IDR) obtained from the (ELFP and RSA); then, the results were compared with the nonlinear static procedure (NSP) and the nonlinear dynamic procedure (NDP) according to ASCE 7-16. Also, this study investigated the effects of the higher modes in the plan (roof plan displacement). From the results, it can be concluded that ELFP and RSA are not a suitable analysis for asymmetric structures and should use appropriate methods such as the NSP and NDP.

Keywords

• rc irregular buildings
• equivalent lateral force procedure
• response spectrum model
• nonlinear static procedure
• nonlinear dynamic procedure