Comparative Study of Structural Systems for High Rise Steel Buildings

Abstract

The structural design of high-rise buildings is governed by the lateral loads caused by wind or earthquake. In tall structure, stiffness is generally more important than its strength. As tall structures are considered as vertical cantilever, lateral load increases rapidly with increase in structure's height. Under wind loading the overturning moment at the base of a building is proportional to the square of the height of building and deflection is proportional to the fourth power of the building height. So, the structural system selected should have the adequate stiffness against the lateral loading caused by the wind or earthquake. Different structural systems are suitable for high-rise building to satisfy the design requirements. But it is important that the selected structural system should be such that the structural members can be utilized to its full design capacity. In the present study Moment Resisting Frame, Shear-Wall Frame and Outrigger structural systems are considered for design of 50 storey steel building. In case of Moment resisting frame hollow steel columns are provided at internal and at periphery of the structure. Unstiffened steel plate shear wall at central core is considered in Shear-Wall frame system while in Outrigger system, single outrigger provided at mid-level of building height is considered for the study. The comparison of analysis results of structural systems in terms of time period, top storey displacement and maximum drift is presented. Comparison of amount of steel required for satisfying the strength and serviceability requirement in all three structural systems is also presented.