Determining shear capacity of ultra-high performance concrete beams by experiments and comparison with codes

In this research, 19 specimens of ultra-high performance ber-reinforced concrete rectangular beams were made and their shear resistance was determined experimentally. The results were compared with estimations by ACI 318, RILEM TC 162- TDF, Australian guideline, and Iranian national building regulations. To compare the code estimations, the ratio of experimental shear strength to predicted shear strength was calculated for each code. This ratio is in fact a measure of safety factor on the one hand and a measure of precision of the estimation on the other hand. Based on the results of both studies, the authors concluded that the Australian guideline, with the amount of 2.5, provided the minimum experimental to predicted ratio, while the Iranian National Building Regulations, with the amount of about 10, provided the highest one. The ratios obtained by ACI and RILEM were about 8 and 3.6, respectively. The Iranian and ACI codes basically provided the same strength estimation. Both were very conservative, which might mainly be because the codes were dubious about the precision of their own estimations. However, RILEM and Australian codes estimated the shear resistance with reasonable margin of safety.