Comparative study of external and internal diagrid system of building structures using ETABS

Abstract

Diagrid structure become more popular choice of structure design since millennium due to it distinguish appearance and outstanding performance to resist lateral load. This study intends to evaluate the performance of external and internal diagrid system of building structures from the aspects of top deflection and quantity of material used. The model, design and analysis of the structure was carried out using ETABS 18 software. A 21 storey office building measure 38mx38mx79.8m was modelled for the study. Structure members were of combination steel and concrete. Beam, vertical column and slab were designed as composite structure which diagonal structures were designed as steel structure according to EN 1993 (Eurocode 3). Floor loads and wind loads imposed to the building were as per proposed in EN 1991 (Eurocode 1) with average windspeed in Malaysia was considered. The stress/capacity ratio generated by software was referred to ensure most appropriate members size were used. The result showed external diagrid is more effective and efficient that internal diagrid. External diagrid was 26.6% less top deflected and 18% less diagonal structural steel consumed than internal diagrid model. It was also observed that position of diagrid structure will affect the column group position in the building which indirectly affect the column size due to distribution of loads.