FEM modelling of dapped-end beams reinforced with post-installed bars

Dapped-end beam joints represent a discontinuity region in the stress flow within a beam and can be a vulnerability element for existing RC structures, such as bridges and viaducts, especially if they are subject to degradation. Nonlinear finite element modelling can be used to analyse the structural behaviour of these elements. Various literature researches have often shown some dispersion of simulated results from experimental data. This paper presents a comparison of two nonlinear finite element models, carried out using two different computational codes, used to simulate an experimental test performed on a dapped-end beam. The dapped-end beam was firstly damaged with a series of cyclic tests designed to produce the cracking pattern under the ULS load and, afterwards reinforced using an inclined steel bar. Then, the reinforced dapped-end beam was subjected to a monotonic load test till failure. Comparison of the prediction of the nonlinear behaviour - obtained through numerical analyses - with the actual behaviour recorded experimentally, allowed for identifying the most significant input parameters for FEM modelling of in situ existing dapped-end beams, subject to pre-damage and successive strengthening.