Diagrid Structural System for High Rise Buildings

Abstract

Advances in construction technology, materials, structural systems and analytical methods for analysis and design facilitated the growth of high rise buildings. Structural design of high rise buildings is governed by lateral loads due to wind or earthquake. Lateral load resisting structural systems of high rise buildings play an important role in strength of buildings and in maintaining lateral drift and human comfort level. Lateral load resistance is provided by interior structural system or exterior structural system. Usually shear wall core, braced frame and their combination with frames are interior system where lateral load is resisted by centrally located elements. While framed tube, braced tube structural system resist lateral loads by elements provided on periphery of structure. It is very important that the selected structural system is such that the structural elements are utilized effectively while satisfying design requirements. Recently diagrid structural system is used in tall buildings due to its structural efficiency and flexibility in architectural planning. Compared to closely spaced vertical columns in framed tube, diagrid structure consists of inclined columns on the exterior surface of building. Due to inclined columns lateral loads are resisted by axial action of the diagonal compared to bending of vertical columns in framed tubular structure. Diagrid structures generally do not require core because lateral shear can be carried by the diagonals on the periphery of building. In this paper analysis of diagrid structural system is presented. Comparison of structural behaviour of framed tube and diagrid structural system is discussed. Analysis of 36 storey building with framed tube and diagrid structural system is carried out. Top storey displacement, drift and member forces are compared for both the structural system.