Shear capacity of lightweight concrete beams without shear reinforcement

This paper shows the results from a recent investigation on the shear strength of LWA concrete, where 9 beams without shear reinforcement were tested in shear by two-point loading. The main test parameters were the shear span ratio (a/d = 1.5, 2.3 and 4.0) and the amount of tensile reinforcement (ρs = 1.2, 1.8 and 3.2 percent). The size of the beams were 150x250x2900 mm. The LWA concrete used had natural sand in the fine fraction. The density of the fresh concrete was about 1750 kg/m 3 and the cylinder strength at the time of testing about 37.0 MPa. A similar investigation has earlier been carried out on LWA concrete with lightweight aggregates in all fractions (ALWA concrete). By direct comparison, the average ratio between the shear strength of the ALWA and the LWA concrete beams was 0.75. Comparing the shear strengths of NS 3473, ENV 1992-1-4 and prEN 1992-1 with the results from three investigations on LWA concrete, the lowest variability was obtained for the formula in prEN 1992-1. It is, however, need for an extra reduction factor on this formula for ALWA concrete.