Evaluation of a Four-Point Bending-Test Method for Interface Shear Transfer in Concrete Members

Interface shear transfer (IST) is critical for achieving composite behavior in many concrete structures, such as between precast girders and cast-in-place decks. IST capacity has traditionally been tested using a push-off test method, in which direct shear is induced through compression loads placed at the ends of notched test specimens. In this study, a four-point bending test method as proposed by Iosipescu in 1967 was investigated for application to IST. The four-point bending test creates direct shear by strategically placing supports and loads on a beam. Its advantage is that the test specimens are easy to fabricate. In addition, it produces a more uniform stress state at the interface than the interface stress distribution of the push-off test, making the four-point bending test a better representation of the stress state at cast-in-place deck and bridge girder connections. In this study, these two test methods are compared and contrasted through an experimental program and analytical modeling. The conditions under which the proposed test method are similar and distinct from the push-off method are identified. © 2017 American Society of Civil Engineers.