Experimental Study on New Methods for Strengthening Shear Capacity of Concrete Beam

Abstract

This paper puts forward a new strengthening method in case of insufficient shear capacity of concrete beam, i.e. it adopts the after- anchor steel bar to be fixed in the shear area of concrete beam to play the role of stirrup or bent-up steel bar shearing resistance , and makes testal study on this by making test specimens. The results show that compared with the unreinforced construction members, after the reinforcement with this method, the existence of post-anchor stirrup delays the development of cracks, increases the cracking load, reduces the crack width under the same loads, changing the wide and sparse cracks to fine and dense cracks, shows good stress state and greatly improves the shear capacity of beam; considering the test phenomenon that the stress of post-anchor stirrup is relatively lagged behind, in terms of calculation method, this reinforcement method adopts calculation formula of bent-up steel bar shearing resistance of the concrete beam and estimates the bearing capacity after slight improvement, the calculation results being close to the measured values and having a certain emergency capacity; the anchoring of reinforcement materials in this method is featured with good effects, clear transmission and simple construction and a certain pre-stress could be imposed to better develop the feature of high tensile strength of reinforcement materials.