Shear tests in beams with low amounts of stirrups

Introduction 

This article discusses the use of the CSFM to analyze shear failures in beams with low amounts of stirrups. To this end, a selection of tests performed on simply supported reinforced concrete beams by Huber (2016), Piyamahant (2002) and Vecchio and Shim (2004) are analyzed. These tests comprised a wide number of parameters, including different sizes, shear slenderness and amounts of shear and longitudinal reinforcement. This section describes the analysis of 17 experiments from these campaigns using the CSFM, exploring the ability of the CSFM to properly model very different failure modes ranging from shear failures with and without rupture of the stirrups to bending failures and mixed shear-bending failures.  

Experimental setup Fig. 6.17 shows the geometry, test setups and reinforcement layouts of the analyzed experiments. Information on the shear reinforcement (diameter (Ø_t) , spacing (s_t) and geometric reinforcement ratio (ρ_t,geo)), the flexural reinforcement (number (n_l) and diameter (Ø_l)) and  geometry (effective depth (d), shear slenderness (a/d) and width of the beams (b)) is presented in Table 6.10. Tests R1000m60 and R500m351 conducted by Huber (2016) had one-leg hooks, while in all other tests used two-leg closed stirrups. In the analyzed tests from Piyamahant (2002) the geometry and the flexural reinforcement were kept constant, while in the other two studies they were varied.