STUDY THE EFFECT OF DIFFERENT PARAMETRES ON THE LATERAL STABILITY OF HIGH-RISE REINFORCED CONCRETE BUILDING FRAME

Major Advisor :Kabtamu Getachew (PhD) ABSTRACT Now days, lateral instability is a relatively common cause of high rise building structural failures. High rise reinforced concrete building development has been rapidly increasing worldwide introducing new challenges that need to be met through engineering judgment. However, as the height increases, the rigidity and stability requirements become more important and they are often the dominant factors in the design. The magnitude of lateral displacement is an important factor to be considered as it indicates the damage state and vulnerability of the building. The main objective of this research is to study the effect of parameters such as material strength, cross sectional size of columns and height of building columns on lateral displacement of high rise buildings under seismic forces. In this thesis, effect of different parameters was studied for three high rise buildings having stories 9,12 and 15. Concrete compressive strength variations C25 to C50Mpa were applied on the columns building frame models. The frame analysis was done using ETABS version 2016 and the building frame was loaded and analyzed based on EBCS 2,1995 and UBC 1997.Linear dynamic response spectrum analysis was performed on the structure to get the seismic behaviors. From the analysis, it observed that the displacement of the column building frame model decreases as the concrete strength increases. It also investigated from the analysis of the model the displacement and inter storey drift were increased as the cross sectional size of column decreased. In addition, as storey number increases the storey drift slightly increased. For the same cross sectional size of column as the column height increases the displacement and inter storey drift also increases. The study shows that Time period of vibration are elongated when high strength concrete and second order effects of pdelta are accounted for in the analysis and the maximum shear is obtained with considering pDelta effect. Storey drift and Drift Ratio(DR) limitations were made according to the codes and it was found that for models storey drift was less than 75mm and drift ratio 2.5% respectively. Keywords: Lateral instability; High rise; Inter storey drift; Column Cross section size; Concrete strengt