OVERSTRENGTH FACTOR AND DUCTILITY FACTOR FOR SEISMIC DESIGN OF RC BUILDINGS

Abstract

It is of utmost importance to design a structure such that they are economical and also has adequate strength to resist the loads applied on them. Due to this reason, the design lateral strength in most of the design codes including NBC 105: 2020 is lowered from the required elastic lateral strength by the combination of overstrength factor (Ωu) and ductility factor (Rµ) resulting in a smaller member section. The structural member sizes govern the time period and drift of the structure on which the overstrength factor (Ωu) and ductility factor (Rµ) is dependent. The total number of 36 configurations of low- rise building configurations most common in Nepal is selected and each building is analysed with two different structural member sizes. The NBC 105:2020 is selected for the seismic design of RC buildings and non-linear analysis is performed using a provision in FEMA 356:2000. The results indicated that the change in building configuration and structural member sizes affects the overstrength factor (Ωu) and ductility factor (Rµ).