The American Concrete Institute (ACI) has released a paper called Numerical Modeling of Three Reinforced Concrete Bearing Wall Tests Subject to One-Sided Standard Fire.
ACI says the paper describes numerical modelling of the thermal and out-of-plane structural behaviours of three full-scale reinforced concrete (RC) bearing wall specimens under fire
The test specimens were heated on one surface over half of the wall height through the ASTM E119 standard fire time-temperature curve, while simultaneously being subjected to a near-constant axial load and out-of-plane lateral mechanical boundary conditions at the top. Steep thermal gradients developed through the wall thickness, resulting in eccentric out-of-plane loading conditions due to the unsymmetrical degradation of the reinforcing steel and concrete (but with no concrete spalling).
“The philosophy for the numerical modelling was to evaluate the capability of a commercially available sequential structural fire analysis program to capture the measured temperatures, lateral and axial displacements, and shear forces and bending moments of the walls,” ACI adds.
Overall, the numerical models were able to capture the wall temperatures reasonably well. The analyses that corresponded to the experimental control scheme for the mechanical boundary conditions at the top of the wall in each test (that is, displacement-controlled or load-controlled) also provided reasonable comparisons with the measured wall displacements, shear forces and bending moments.
According to ACI, “Two main sources for discrepancy were the inability of the analyses to accurately model the concrete compression strength and elastic (Young’s) modulus, and to capture the second-order effects from the large axial load applied on each wall.”
Two main sources for discrepancy were the inability of the analyses to accurately model the concrete compression strength and elastic (Young’s) modulus, and to capture the second-order effects from the large axial load applied on each wall.
The paper was written by Kevin A. Mueller and Yahya C. Kurama.
