Equivalent Frame Analysis Methods for Gravity Loading in Flat Slab Structures

This paper compares three equivalent frame analysis methods with experimental results obtained from 1/3-scale models of flat slab exterior panels. The unique experimental results were obtained by measuring strains in reinforcing bars at approximately 200 selected locations throughout a slab panel. The measured strains were used to calculate curvature, and hence, bending moments and these were used along with moments in the columns to assess the accuracy of the equivalent frame methods. Two code methods were examined: BS 8110 and ACI 318, and one further method which, like that in ACI 318, makes allowance for the effects of the torsion of the free edge. In addition to the distribution of bending moment between hogging and sagging regions, the distribution between column and middle strips was also studied. Recommendations are made concerning the width of slab, which is effective at edge column locations.