Simplified Calculation of Deflection in Flat Slabs Made of RC and PC Using a Modified Strip Method

In this article, the topic of reinforced and prestressed concrete (RC and PC) flat slabs deflection is addressed, focusing on a new method that facilitates a simplified calculation. The proposed calculation method is based on the strip method, and for its validation the results from a parametric case study are compared with those obtained by other calculation methods suitable for estimating the deflection of flat slabs. To be more practical, the proposed method is transformed into a coefficient method (closed form formula) and allows the calculation of the deflection also for external, corner and isolated slab panels, unlike the existing closed form formula approaches which are only available either for the internal or corner slab panels. In addition, the difference between the deflection values obtained considering the uncracked versus cracked concrete section, respectively between the instantaneous (short -term) deflection and the long-term deflection values of the RC and PC slabs is addressed.