Derivation of an Approximate Method for the Analyses of Ribbed Slabs (A Finite Element Approach)

This study introduces a new approximate method for analyzing ribbed slabs, named Calibrated Eurocode Results (CER) or Ogbonna-Umeonyiagu's method, based on finite element method (FEM) results. The method was developed by calibrating existing approximate techniques, specifically the ACI coefficient and Eurocode methods, through comparison with FEM results obtained using SAFE 2016. Manual analyses were conducted on ribbed slabs with varying boundary conditions, revealing significant discrepancies between existing approximate methods and FEM results for ribbed slabs. Notably, the Eurocode method showed considerable convergence with FEM results. A statistical regression analysis was performed, yielding calibration factors that improved the accuracy of the Eurocode method, bringing its results within 6% of FEM values, compared to a previous discrepancy of 65%. The newly developed method offers enhanced bending moment coefficients for ribbed slabs, performing better than existing methods and facilitating easier analysis of two-way slabs. A Java program was also created to implement this method, demonstrating its effectiveness and adding to the repertoire of tools available for slab analysis.