Abstract
Shear design is an important part of structural design. External vertical prestressing rebars (EVPRs) have proven to be an effective way to enhance structural shear resistance. The objectives of this study are to simulate EVPR strengthening of concrete beams using a nonlinear three-dimensional finite element model and to explore its shear enhancement features under different EVPR stirrup ratios, vertical compressive stress degrees, and optimal arrangements of EVPRs. Concrete, common reinforced bars, and EVPRs use solid, steel, and truss elements, respectively. In addition, the total strain crack model is used to characterise the concrete. The results indicate that the EVPR stirrup ratio can reduce the diagonal crack width and improve the shear capacity, and the vertical compressive stress degree can effectively control crack development in the initial loading. A “small-area EVPR dense arrangement” is the recommended EVPR configuration method. Both experiments and numerical analyses show that EVPRs can effectively improve the shear performance of concrete.
Highlights
Shear failure of concrete beams is a sudden brittle failure
Recent research has been conducted on the shear theory of reinforced concrete (RC) beams, especially critical shear crack theory (CSCT) [1,2,3,4,5]
Lampropoulo [24] conducted a numeric study on full-scale beams strengthened with ultra-high performance fibre reinforced concrete (UHPFRC) layers and jackets, and the interface between the concrete beam and the UHPFRC was modelled using special two-dimensional elements, representing a well-roughened interface for the analysis of reinforcement technology
Summary
Shear failure of concrete beams is a sudden brittle failure. Once shear damage occurs, the consequences are very serious. erefore, in order to improve the shear strength of concrete beams, scholars have performed numerous studies. Aboutaha and Burns [20] used external prestressing bars to retrofit composite beams that originally lacked shear reinforcement and had a smooth interface bonded with epoxy Before retrofitting, these beams experienced sudden horizontal shear failure. An investigation conducted by Bolger [22] showed that the shear strengthening method of concrete girders using external vertical clamping with existing shear cracks repaired with epoxy injection is effective. Lampropoulo [24] conducted a numeric study on full-scale beams strengthened with ultra-high performance fibre reinforced concrete (UHPFRC) layers and jackets, and the interface between the concrete beam and the UHPFRC was modelled using special two-dimensional elements, representing a well-roughened interface for the analysis of reinforcement technology. (3) Given that testing is limited by conditions and that the study of specimens has been insufficient, this study takes a closer look at the following: (i) the parameters, including the vertical compressive stress degree and EVPR stirrup ratio; and (ii) the optimal arrangement of EVPRs
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