Structural reliability of ultra-high-performance fiber reinforced concrete beams in shear

A study on the shear model uncertainty and structural reliability of ultra-high-performance fiber reinforced concrete (UHPFRC) beams with stirrups is presented. Model uncertainty for the shear models given in the JSCE, AFGC and ACI 544 standards are characterized by comparison to nonlinear finite element analyses (NLFEA). In comparison to other shear basic parameters, a notable negative correlation between model uncertainty the transverse shear reinforcement ratio (rho(w)f(ywm)) is observed. When combined with stochastic descriptions of the remaining parameters that describe these analytical models, reliability values for beams designed to the JSCE and AFGC specifications are found to fall 6%, and 12%, respectively, below the target values of these standards, while reliability values for the ACI 544 exceed the target value specified for this standard by 8%.