Comparative study on reinforced concrete and steel framed buildings with various floor systems

Abstract

Reinforced concrete and steel framed structures with various floor systems are being used for multistory buildings. So there are alternative options for designers to decide structural system for a particular building. A comparative study on RC and steel framed buildings with various floor systems is necessary to evaluate better structural system regarding overall economy, structural performance, construction time etc. This study will be helpful in deciding structural system for multistory industrial buildings. Past studies on multistory industrial building structures of Bangladesh are not much enough. This limits our ability in making decision about structural system of industrial buildings in Bangladesh. To conduct the intended research work, architectural layout plan of a six story garments factory is prepared. Following the layout plan, RC structure with flat plate and beam-slab floor system is formed. According to same plan, steel structure with non-composite and composite floor system is also formed. Structural modeling and analysis have been performed by STAAD.Pro. Loads are assigned following BNBC 1993. From analytical results, RC structures are designed following ACI Building Code 2008. Steel structures are designed following AISC LRFD 2010. Comparisons of structural behavior and cost analysis have been performed for the four types of structural system. The research outcome shows that building cost increases 1.6% for RC flat plate system, 1.8% for steel composite system and about 9% for steel non-composite system compared to RC beam-slab system. When floor system of steel structure is designed as composite then structural steel weight savings is about 18% for typical grid of 7.62m×7.62m. Composite system brings significant economic benefit for steel structure; for example structural steel cost decreases 18-19%, total structural cost decreases 9-11% and finally total building cost decreases by 6-8%. Compared to steel structure, foundation cost increases 22% for RC beam-slab system and 24% for RC flat plate system.