Structural retrofitting of impaired dapped-end beams: a review

The geometric reduction prevailing in dapped-end concrete beams forms a disturbed region into the beam-ends. Consequently, material deterioration- and reinforcement-detailing issues prevailing in the end region cause a series of structural distresses. In this light, distresses in dapped-end beams and potential retrofitting options are reviewed in this paper. It is found that the choice of the retrofitting configuration is governed considerably by the prevailing defect. The strength enhancement could be as high as 40%–50% upon the choice of correct configuration whereas possibly be negligible upon inappropriate selection. Generally, the use of diagonal bars and plate jacketing are promising with steel applications. The bars can be prestressed to enhance the retrofitting efficiency. For fibre-reinforced polymer applications, inclined/horizontal stripping and fabric wrapping are impressive approaches, while combined systems show better results. The review also identifies the required future research for formulating comprehensive retrofitting guidelines.