Experimental Study on Shear Capacities of Reinforced Concrete Beams Strengthened by Direct-shear-bolted Side-plates near Beam Ends Under Different Interfacial Conditions

Abstract:

This paper presents a test program of shear capacities of reinforced concrete beam strengthened by direct-shear-bolted side-plates near beam ends. The test program consists of one control shear span and five shear spans strengthened in shear. Test parameters involve interfacial conditions and depth of side-plates. Test results show that all kinds of adhesion interfaces are eventually de-bonded in loading process， without affecting shear capacities whether the adhesion is weak or strong. Shear capacities are effectively improved by increasing the plate depth and the number of corresponding direct-shear bolts. There are two mechanisms in the shear strengthening of direct-shear-bolted side-plates system， i.e.， the constraint mechanism and the composite action mechanism. The constraint mechanism takes effect by constraining the development of diagonal crack width， and in the composite action mechanism the bolted side-plates directly transfer part of the shear force to the support. Steel plates with lower depth are mainly in the constraint mechanism， while steel plates with higher depth work both in the constraint mechanism and composite action mechanism.

Key words:structural strengthening;strengthening with bolted steel plates;strengthening with direct-shear-bolted side-plates;interfacial conditions;constraint mechanism;composite action mechanism