Analysis of Concrete Construction Live Loads on Newly Poured Slabs

Abstract

The stochastic modeling of construction loads on newly poured slabs during construction of multistory concrete buildings is presented in this paper. The purpose of the study is to calculate the equivalent uniformly distributed load (EUDL), i.e., the uniform load that will produce (statistically) the same load effect in formwork members as the actual live loads. To achieve this objective the spatial correlation of construction live loads as well as the influence surfaces of various formwork member load effects must be determined. In this study, the construction live load covariance function is modeled as an exponential function. Influence surfaces for formwork shore axial forces and stringer bending moments and shear forces are also investigated for several formwork designs. The statistical moments and a distribution function for construction live load EUDLs are presented. The 0.99 fractiles of EUDLs are compared with the current design load specifications for slab formwork design. Load reduction equations are presented for slab formwork design loads.