Evaluation of shear design provisions for shear-critical concrete beams

Shear provisions of ACI 318-11, general procedure and simplified procedure for prestressed and non-prestressed concrete beams using AASHTO LRFD (2008. Bridge design specification and commentary. Interim 2008. Washington, DC: AASHTO LRFD, 5.59–5.84) are comparatively studied. Experimental results from 34 simply supported and continuous non-prestressed shear-critical beams were selected to assess the accuracy of Response-2000 as an analytical tool implementing the Modified Compression Field Theory. On average, the shear capacity of simply supported beams was slightly underestimated while that of continuous beams was quantified accurately. Shear provisions of all of the three aforesaid procedures were examined using a variety of reinforced and prestressed concrete beams. These beams included six simply supported prestressed double-T with harped strands, continuous prestressed bulb-T having both straight and harped strands, simply supported and continuous reinforced deep rectangular beams with or without longitudinal crack control reinforcement. Results of this comparative study considering critical parameters, such as minimum transverse reinforcement, design spacing of the transverse steel and longitudinal crack control reinforcement are detailed in the conclusions followed by some recommendations.