EFFECT OF SEISMIC LOAD ON REINFORCED CONCRETE MULTISTORY BUILDING FROM ECONOMICAL POINT OF VIEW

This paper aims at studying the effect of earthquake loading on the constructional design of a 20-storey reinforced concrete residential building from economical point of view. This type of loading should be taken into considerations now in Iraq especially after the earthquake of 7.3 magnitude that occurred in November 2017 near the city of Halabja by about 31 kilometers. The same reinforced concrete multistory building was designed twice; once with traditional gravity dead and live loading and the second with adding earthquake loading in order to discuss the difference from structural and economical points of view. A commercial package ETABS2018 was used to analyze this 60-meter-high building. The building was analyzed according to the American code ASCE7-10, while it was designed according to ACI 318-14. A huge increase in the steel reinforcement amounts in columns, beams, slabs and shear walls were recorded due to taking the seismic load into considerations. More specifically, the reinforcing steel amounts increased by about 327%, 165%, 40% and 91.3% for columns, beams, slabs and shear walls, respectively. Therefore, cost was raised by about 328%, 165%, 40% and 91.3% for columns, beams, slabs and shear walls, respectively. It is worth to mention here that the maximum increase in main reinforcement of beams was observed on the storey 10. Whereas, in slabs, the maximum increase that was recorded in main steel reinforcement was happened from the storey 8 to the building top. In columns, the main reinforcement increase was seen on the 9th, 10th and 11th storeys. Finally, in shear walls, the main reinforcement increase was seen in the 1st, 2nd and 3rd storey due to effect lateral shear forces.