Influence of Concrete and Steel outrigger and belt truss in high rise Moment Resisting Frames

The outrigger and belt truss system is one of the most efficient systems used to effectively control the excessive drift due to lateral load, so that, during small or medium lateral load due to either wind or earthquake load, the risk of structural and non-structural damage can be minimized. For high-rise buildings, particularly in seismic active zone or wind load dominant, this system can be chosen as an appropriate structure. This paper studies the efficient use of outrigger and belt truss system for high-rise concrete building subjected to wind or earthquake load. Seven 44 storey two dimensional models of outrigger and belt truss system are subjected to wind and earthquake load, analyzed and compared to find the lateral displacement reduction related to the types of outrigger and belt system. The analysis has been carried out to study the effect and performance of outrigger system in 44 storey building. The outrigger system is provided at different levels along the height of the building. The depth of the Outrigger and belt trusses is equal to the height of the typical story and maintained same in all the models. The key parameters discussed in this paper include lateral deflection, storey drifts, base shear and fundamental time periods. Loads are considered as per Indian Standards IS: 875(Part1)-1987, IS: 875(Part2)-1987, IS: 875(Part3)-1987 and IS: 1893(Part-1)- 2002. The modeling and analysis were performed using finite element software ETABS 15.2.2.