Comparative structural performance of diagrid and bracing system in mitigation of lateral displacement

Abstract

The design of high rise building with more than 10 stories is controlled by lateral drift which increases the cost rapidly with the number of stories. Recently, the diagrid structural system has emerged and in fact has been widely used for high rise buildings. How effective is a diagrid system in mitigating the lateral displacement of a high rise building? Thus, the objective of this research is to compare the lateral displacement of high rise building that adopts diagrid system with those that use X-bracing and frame system, due to wind. This research also explored the effect of using diagrid, X-bracing and frame system to the natural frequency of high rise building. Two diagrid systems which are 60°-diagrid and 80°-diagrid that has an angle of inclination of 60 degrees and 80 degrees, respectively, were studied. STAAD Pro software was used to analyse twelve building models to determine the lateral displacement due to wind load and the natural frequency in the along wind, across wind and torsional directions. Building with 80°-diagrid has the least lateral displacement, followed by buildings with the X-bracing, 60°-diagrid and frame for 40 and 60 storey buildings. Further study showed that X-bracing became the most effective system to lower the lateral displacement compared with the diagrid and frame when the number of storey of the building exceeds 71 storeys. Natural frequency was not affected by the different systems used except for torsional natural frequency that increased substantially by the use of 60°-diagrid.