Comparative Study of Reinforced Concrete, Structural Steel and Steel Concrete Composite Buildings

Abstract

The majority of structural building structures are designed and constructed in reinforced concrete which are mainly depends upon availability of the constituent materials and the level of skill required in construction, as well as the practicality of design codes. Reinforced concrete building used high material usage because of their increased dead load, hazardous formwork. The use of steel in construction industry is very low in Ethiopia compared to many developing countries. There is a great potential for increasing the volume of structural steel in construction, especially in the current development. In Ethiopia, structural steel is not using as an alternative construction material and not using it where it is economical in a heavy loss for the country. Steel-concrete composite construction has gained large acceptance all over the world as a substitute for pure steel and pure concrete construction. In Ethiopia, many consulting engineers are reluctant to accept the use of composite steel-concrete structure because of its unfamiliarity and complexity in its analysis and design. However, this approach is a new concept for construction industry. This research discusses comparative study of reinforced concrete, structural steel and steelconcrete composite building structures by analysis of G+5, G+8 and G+11 modeling. Modal response spectrum analysis for seismic zone III was carried out based on ES EN-8 using packaged software ETABS 2016. The span length, interstorey height and loading systems was kept constant. The main parameter discussed on this study are the sory response such as storey shear, storey drift, story displacement, modal frequency and time period; construction costs such as direct cost; and self-weight of the buildings. As per the comparisons made, the steel-concrete composite building showed a reduction in base shear, story drift and story displacement for G+5, G+8 and G+11 as compared to the reinforced concrete and structural steel building. And also the steel-concrete composite building showed a reduction in modal period compared to the reinforced concrete and structural steel building for G+5; increased compared to the reinforced concrete and reduced compared to structural steel building for G+8 and G+11. The reinforced concrete building showed a reduction in modal frequency for G+5, G+8 and G+11 compared to the steel-concrete composite and structural steel building. The structural steel building showed a lighter in self-weight for G+5, G+8 and G+11 as compared to reinforced concrete and steel-concrete composite building whereas steel-concrete composite building is lighter compared to reinforced concrete building at G+5, G+8 and G+11. The steel-concrete composite building showed a reduction in direct cost as compared to the reinforced concrete and structural steel building for G+8 and G+11, but it showed an increased in direct cost compared to reinforced concrete building for G+8 whereas reinforced concrete building is cheaper compared to structural steel building at G+5, G+8 and G+11.