Experimental Study on Shear Behavior of Non-Stirrup Ultra-High Performance Concrete Beams

Abstract

Due to the high tensile strength of ultra-high performance concrete (UHPC), the shear stirrups in UHPC beams could potentially be removed. The aim of this study is to assess the shear performance of non-stirrup UHPC beams. Six UHPC beams were tested and compared with three stirrup-reinforced normal concrete (NC) beams, taking into consideration the testing parameters of steel fiber volume content and shear span-to-depth ratio. The findings demonstrated that incorporating steel fibers can efficiently strengthen the ductility, cracking strength, and shear strength of non-stirrup UHPC beams and alter their failure mode. Additionally, the shear span-to-depth ratio had a significant impact on the shear strength of beams, as it was negatively related to it. This study revealed that the French Standard and PCI-2021 formulae were suitable for designing UHPC beams with 2% steel fibers and no stirrups. When applying Xu’s formulae for non-stirrup UHPC beams, taking into account a reduction factor was necessary.

Experimental Investigation on Shear Behavior of Non-Stirrup UHPC Beams under Larger Shear Span–Depth Ratios

“…The test results confirmed the role of steel fibers in improving the shear resistance of non-stirrup UHPC beams. This finding is in accordance with the experimental results of Li et al [50], although the ductility coefficients of the UHPC beams in this study were lower than those of the aforementioned study. This discrepancy may be attributed to the differing shear span-to-effective depth and reinforcement ratio between this study and that of Li et al [50].…”

“…For the French standard formulae, the ratio V u1 /V u,test ranged from 0.51 to 1.44, with a mean of 0.91, an STDEV of 0.33, and a coefficient of variation of 0.36. Comparison with Li et al's [50] experimental findings suggested that the formulae were more accurate for UHPC beams with larger shear span-depth ratios. In addition, the average ratio of the calculated shear capacity to the tested shear capacity for the French standard formulae was closest to 1.00.…”

“…It was found that Xu's formulae significantly underestimated the shear capacity of non-steel fiber-reinforced UHPC beams. Comparison with Li et al's [50] experimental findings indicated that Xu's formulae were more accurate for UHPC beams with larger shear span-depth ratios. Moreover, they were more accurate in predicting the shear capacity of steel fiber-reinforced UHPC beams rather than non-steel fiber-reinforced UHPC beams.…”

Analytic Investigation of Hooked Stirrups on Seismic Behavior of Reinforced Concrete 3D Frame Buildings

“…In order to obtain a comprehensive assessment of the seismic behavior of reinforced concrete structures, this study specifically focuses on the effect of two different types of stirrups, i.e., hooked and unhooked stirrups. Previous research has shown that hooked stirrups can improve energy dissipation and ductility by providing additional restraint to the concrete core, while unhooked stirrups, although widely used, may provide relatively limited benefits in this regard [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Rosso et al [19] estimated the effect of corrosion on the capacity and ductility in their study.…”