Further Tests of the Punching Shear Strength of Lightly Reinforced Isotropic Bridge Decks

摘要

Five one-half scale concrete bridge decks incorporating 0.3% isotropic reinforcement top and bottom were load tested. Four of the decks were supported on steel girders, while one was supported on Florida standard bulb-tee girders. The decks conformed to the empirical design procedure of the Ontario Ministry of Transportation, except that the transverse span to thickness ratios were between 18 and 22, greater than the maximum of 15 permitted in Ontario. One edge of each specimen was equipped with a Florida standard parapet barrier, while the other edge was free. Three specimens on steel girders, as well as the specimen on bulb-tee girders, were loaded monotonically to failure at several locations on the deck, including the interior and adjacent to the edges. Punching loads were compared with loads to produce a yield line pattern, AASHTO design vehicle loads, and failure loads predicted by the ACI and AASHTO equations. The fourth specimen on steel girders was loaded cyclically at several locations, to simulate fatigue loading. The Kinnunen and Nylander model was used to study the inplane compression developed during loading, and a linearly elastic finite element analysis was used to estimate the stresses developed in the bracing.