Conclusion:

In this study, a simplified method is proposed to analyse and design the flat plates with irregular column layout. These flat plates having the irregular column layout are first subdivided into triangular panels and then design the largest triangle slab panel using the ultimate-strength design method USD under the provisions of ACI building code of design (ACI 318-14).
Six different flat slabs with irregular column layouts (FS-1 to FS-6) were selected in this study to be analysed and designed using the simplified design method approach. These six slabs were also analysed and designed with computer software (SAFE). The average variation of analytically computed values to the finite element software was no more than 20% showing relatively satisfactory results. However the moment values for the SDM approach are slightly higher which makes this theoretical approach more conservative. Moreover the punching shear ratio obtained from the simplified design method approach is also less than < 1 for all of the studied slabs.
The obtained results indicates that the simplified design method SDM is safe, economical and quick approach to design irregular slabs sections and are also useful for the educational purposes where the students can easily analyse and design the flat slabs having the irregular column layout.