Improving the Behavior of Non-Uniform Tall Structures in Determining the Optimum Location of Belt Truss System

Abstract

The sensitivity of tall buildings subjected to the lateral loads is more than that of the gravity loads. Therefore, the conventional methods are not efficient yet, and new methods such as the use of the belt truss and outrigger systems are proposed by designers to reduce the structural roof displacement, shear lag, overturning moment, and also to increase the lateral resistance of the structures. In the design of tall structures, for economic reasons, it is desirable to reduce the lateral stiffness of the structures along with the height of the structure. In this paper, the framed tube and shear core are modeled using the energy method and the continuous beam model. The optimum location of the belt truss and outrigger system are calculated considering three lateral loading patterns. It is assumed that the lateral stiffness of the framed tube and shear core varies along with the height of the structure. The stiffness of the belt truss and outrigger system is also considered as an equivalent rotational spring. The results show that the optimum location of the belt truss and outrigger system depends on the type of the lateral load and also how to change the stiffness of the framed tube, shear core, and belt truss system along with the height of the structure.