Performance Evaluation of R/C Setback Structu...

Performance Evaluation of R/C Setback Structures using Time History Analysis

Author Name : Mr. Akshay V. Nikam, Prof. D. N. Mandlik

ABSTRACT

Irregularities in a building can be due to the uneven distribution of mass, stiffness and geometry of the structure. Setback Structures are structures with vertical irregularities. A common type of vertical geometrical irregularity in building structures arises is the presence of setbacks, i.e., the presence of abrupt reduction of the lateral dimension of the building at specific levels of the elevation. This building category is known as ‘setback building’. This building form is becoming increasingly popular in modern multi-storey building construction mainly because of its functional and aesthetic architecture.The behaviour of a multi-storey framed building during strong earthquake motions depends on the distribution of mass, stiffness, and strength in both the horizontal and vertical planes of the building.

In multi-storeyed framed buildings, damage from earthquake ground motion generally initiates at locations of structural weaknesses present in the lateral load resisting frames.In some cases, these weaknesses may be created by discontinuities in stiffness, strength or mass between adjacent storeys. Such discontinuities between storeys are often associated with sudden variations in the frame geometry along the height. A common type of vertical geometrical irregularity in building structures arises from abrupt reduction of the lateral dimension of the building at specific levels of the elevation.

This building category is known as the setback building. Many investigations have been performed to understand the behaviour of irregular structures as well as setback structures and to ascertain method of improving their performance.Pushover analysis is a nonlinear static analysis used mainly for seismic evaluation of framed building. Time history analysis is Nonlinear Dynamic Analysis. The models will be made and analysed using ETABS 18 software. We had used ELCENTRO earthquake parameters for time history analysis.From the ETABS results we will get the idea about analysis of R/C setback structure using time history analysis.

Keywords: building irregularity, ETABS, time history analysis, setback structures, vertical irregularity, structural irregularity, ELCENTRO