EFEITO DO SUBSTRATO DE TRANSIÇÃO SOBRE O REFORÇO À FLEXÃO DE VIGAS DE CONCRETO ARMADO COM CANTONEIRAS METÁLICAS

Abstract

There are different techniques available for strengthening of structural elements. Among them, the steel plate bonded technique presents the advantage on execution and minimal alteration in the structural element geometry. Moreover, in the case of strengthening with steel profile profiles application, other advantages can be added, such as on the columns removal. However, researches has shown that the steel plate bonding to reinforced concrete (RC) beams. The inability of mobilizing the full strength of the strengthened elements due to premature failure is already demonstrated. Thus, following previous studies and applying the transition layer concept, this paper analyzes the effect of tensile zone reconstruction beams on flexural behavior of the strengthened element with steel profiles. For this purpose, RC beams with (150 x 150) mm cross-section, 750 mm length was molded and submitted to four-point bending tests. In three groups, the tensile zone was demolished and subsequently reconstructed with different cementitious composites. The specimens gain ductility promoted by the tensile zone cracking control close to the steel profile and reduce premature peeling failure. Analytical models were used to estimate the theoretical loads and compare with those experimentally obtained. The results show significant improvement on the strengthened beams performance with the tensile zone reconstructed with fiber materials because of higher toughness and crack resistance. The failure mode of the retrofitted and strengthened beams has changed comparing to strengthened RC beams of groups 2 and 3, reaching up to 32% increase in peeling strength of group 5 when compared to group 2. The theoretical model used here was satisfactory presenting low divergence (around 10%) from experimental results.