PRACTICAL ESTIMATION OF 2-WAY SLAB DEFLECTIONS

The calculation of the deflection of a reinforced concrete element is usually troublesome, and is even more problematic for two-way slabs th an for beams. An algebraic equation was developed in this paper for es timating the midpanel deflections of the two-way slab systems subjecte d to uniform gravity loads. The proposed method was initially derived from the differential equation of plate and then calibrated using the results of finite-element analyses to estimate the elastic deflections of interior panels. The proposed procedure was further directed towar d the general problem concerning progressive cracking of concrete, var ied boundary conditions due to discontinuity of slab, and long-term ef fects. The resulting expression provides a more accurate representatio n of the midpanel deflection than does the simpler method outlined in the ACI Committee 435 report. The adequacy of the proposed procedure w as checked by comparing calculated deflections with experimental data reported in previous literature, and satisfactory correlation was foun d. Finally, this paper includes numerical examples to illustrate use o f the proposed equations.