Analysis and Design of Conjoined Tall buildings

Abstract

The current situation of rapid urbanization, rising land prices, and diminishing agricultural land are increasing the need for multi-storey buildings. The structural system of multi-storey buildings is governed by the stiffness along with strength due to significant effect of lateral loads due to earthquake and wind. A variety of structural systems for tall buildings like wall-frame, tubular, outrigger-belt truss, diagrid structures, have been developed for resisting lateral loads. Connecting two or more individual buildings at different levels along the height has created a new structural system, known as conjoined building. Due to increased lateral stiffness conjoined building is an efficient alternative structural system for tall buildings. Present study focuses on analysis and design of conjoined tall buildings. The individual wall-frame building considered for the current study has a plan size of 30 m × 30 m and different number of storey as 30, 40, 50, and 60. Conjoined buildings are created by connecting four individual buildings at the top. Four individual buildings are arranged in two rows with two buildings in each row. The clear spacing between the buildings is 20 m. Seismic and wind forces are considered according to IS 1893 (Part 1):2016 and IS 875(Part 3):2015 respectively. Interference effect is considered to evaluate dynamic wind load on conjoined buildings. To model and analyse structures, ETABS software is used. For both the individual and conjoined buildings, analysis results are compared in terms of natural time period, base shear, lateral displacement and inter-story drift. For both the type of buildings sizes of structural elements along with governing load cases are presented. The results of the present study demonstrate that as building height increases, a conjoined structural system becomes more effective at resisting lateral forces.