Numerical Modeling of Three Reinforced Concrete Bearing Wall Tests Subject to One-Sided Standard Fire

• Published in: ACI structural journal Vol. 116; no. 5; pp. 29 - 41
• Main Authors: Mueller, Kevin A., Kurama, Yahya C.
• Format: Journal Article
• Language: English
• Published: Farmington Hills American Concrete Institute 01.09.2019
• Subjects: Axial loads; Bearing; Behavior; Bending moments; Boundary conditions; Civil engineering; Compressive strength; Concrete; Heat transfer; Lateral displacement; Load; Mathematical models; Mechanics; Modulus of elasticity; Numerical analysis; Numerical models; Philosophy; Reinforced concrete; Reinforcing steels; Researchers; Shear forces; Spalling; Steel; Steel structures; Wall thickness; Belgium
• ISSN: 0889-3241; 1944-7361
• DOI: 10.14359/51716756

This paper describes the numerical modeling of the thermal and out-of-plane structural behaviors 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 modeling 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. Overall, the numerical models were able to capture the wall temperatures resonably 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. 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. Keywords: numerical modeling; reinforced concrete bearing walls; structural fire engineering.