Seismic Performance of Tall Buildings with Different Structural Systems: Fid-Bau Portal

Seismic Performance of Tall Buildings with Different Structural Systems

Borah, Mayuri / Choudhury, Satyabrata

In the present world scenario, construction of tall building is being preferred due to rapid increase in the cost of land, lack of land availability and also to preserve land in rural areas for agricultural use (Smith and Coull 1991). The design of tall buildings is primarily governed by wind and seismic loads (Chaudhary et. al. 2019). The performance of the buildings depends on the structural configuration and the present study aims at comparing the performance of tall building with different configurations. In the present study, tall buildings have been investigated under the effect of seismic loads with different structural, namely, (i) special moment resisting frames, (ii) frame-shear wall buildings, (iii) outrigger systems, (iv) braced model and (v) hybrid model. The building models are assumed to be located in Guwahati, Assam which is one of the most earthquake-prone zones in India. A detailed analysis of the building system is done by modeling the geometry, material section properties and boundary conditions. The sections are discretized using FE mesh using software “ETABS 2016”. Appropriate finite elements are assigned to beams and columns; slab is modeled as a rigid diaphragm to simulate the dynamic behavior of tall building structures. Initially, a modal analysis has been performed to get the natural frequency/period of the buildings. Further, seismic analysis has been carried out to get the performance levels and other responses. Firstly, pushover analysis is performed to obtain the collapse states of the buildings. Then, time-history analyses are carried out to get the dynamic behavior of the buildings. Five spectrum compatible ground motions compatible to Indian design spectrum at maximum earthquake level are considered for the time-history analysis. With the results obtained, a comparison is made for the performances of different structural systems. A detailed procedure of analysis of tall building systems has been discussed. The braced building has performed better as compared to the rigid frame structure. However, the frame-shear wall buildings give the best performance out of all building types. The outrigger and hybrid stiffening buildings over-estimate the performance levels. The conclusions drawn from this study are expected to be useful for academicians and structural designers/practicing engineers.