Laboratory investigation of shear repair of reinforced concrete beams loaded in flexure

The structural rehabilitation of reinforced concrete beams in shear was studied, with particular attention paid to resin injection. Other shear repair techniques that were examined include post-tensioning in shear, bar bonding, and stitching. Emphasis was placed on the influence of damage across the repair interface due to unloading while propping during the repair stage. A series of model beams, unreinforced in shear, were loaded in the laboratory until a major diagonal tension crack developed on both shear spans. Individual beams were unloaded to a set proportion of that load, repaired, and again loaded to failure. Scaled field-size beams were also tested. The repair strength achieved for resin-injected reinforced concrete beams was shown to be influenced by the condition of the major diagonal crack after initial damage. This conclusion was supported by surface strain measurements, load-deflection data, and crack measurements.