Flat Slab Thickness Effect on T-shaped Multistory Building as Per BNBC 2020 by Using ETABS

Abstract

In this project, an 8-story T-shaped building model was analyzed with various slab thicknesses and column sizes in ETABS software (ETABS - Documentation - Computers and Structures, Inc. - Technical Knowledge Base, n.d.) to address the slab thickness effect on the flat slab and to found the minimum slab thickness that can handle the different applied loads without undesired slab deflection. The analyzed model had an overall height of 25.5 m, and story to story height of 3m, and a building plan area of 384 m2. According to BNBC 2020 (BNBC, 2020), 4.8KN/m2 of live load, 1.2 KN/m2 of floor finish, and a partition wall of 33% of live load were applied in the model, as well as In Bangladesh Seismic Zone 2, earthquake and wind loads have also been applied from the building's base to the roof. So, the minimum slab thickness that can handle those loads without excessive deflection was discovered to be 250mm with column size 750mm by 750 mm after analyzing different 32 cases. A significant amount of deflection change was also observed when the slab thickness was changed while using the same column, this demonstrates how the slab thickness affects the structure's stability. This research also discovered that there is a column size effect, which gradually increases with column size. However, this column size effect is less than that of the slab effect in terms of deflection and it is greater in large column sections and decreases as the column size section decrease.