PUNCHING SHEAR FAILURE IN CONCRETE DECKS AS SNAP-THROUGH INSTABILITY

This paper presents part of an investigation on the failure modes in r einforced concrete bridge decks subjected to monotonic static concentr ated wheel-loads. The punching shear deck failure appears to be interr elated with a snap-through instability of an ''arching'' action mechan ism activated in the deck. The predicted critical deflection of about 25% of the deck thickness at instability of a two-dimensional laterall y restrained three-hinge compressive strut mechanism correlates well w ith the measured static ultimate deck deflection values of bridge deck s that failed primarily in punching. There is also good agreement betw een the predicted critical applied static concentrated load at instabi lity of the proposed three-hinge truss and the experimental static dec k ultimate strength values.