Sensitivity analysis of restrained shrinkage stresses of concrete deck overlays

摘要

Concrete overlays are widely used to rehabilitate bridge decks. This investigation presents parametric and sensitivity analyses of the mechanical strains due to restraint of shrinkage of the overlay that may cause it to crack. The parametric analysis identifies the significant variables and the sensitivity analysis quantifies the correlations between these variables and the magnitude of mechanical strains. The strain analysis accounts for drying shrinkage using Fick's law, and for tensile creep strains. Total strains are computed by superposition, assuming a linear-elastic concrete behavior, using a time-history approach developed in a previous investigation. Concrete overlays on concrete slabs and composite systems are considered. Compressive strength of the overlay concrete, curing period, overlay thickness and environmental humidity contribute the most to the variability of the analytically predicted mechanical strains.