Title: Out-of-Plane Behavior of Two Reinforced Concrete Bearing Walls under Fire: A Full-Scale Experimental Investigation

Author(s): Kevin A. Mueller, Yahya C. Kurama, and Michael J. McGinnis

Publication: Structural Journal

Volume: 111

Issue: 5

Appears on pages(s): 1101-1110

Keywords: curvature; digital image correlation; gas fire furnace; infrared thermography; reinforced concrete bearing walls; structural fire engineering

DOI: 10.14359/51686814

Date: 9/1/2014

Abstract:
This paper discusses the measured out-of-plane thermomechanical behavior of two full-scale reinforced concrete (RC) bearing wall test structures subjected to fire loading. A special skid-mounted movable gas furnace was designed and constructed for heating of one face of each wall specimen over half of the wall height through the ASTM E119 standard fire time-temperature curve. Each specimen formed one face of the furnace (that is, the specimen was not enclosed by the furnace), allowing easier visual inspections and monitoring of out-of-plane behavior on the unexposed surfaces, and the application of gravity and lateral loads on the structure. In addition to an array of discrete thermocouples, strain gauges, and displacement/rotation sensors, full-field deformation and temperature response of selected surfaces of the test specimens were captured using digital image correlation (DIC) and infrared thermography. Both test specimens were fixed at the base and free to displace vertically and rotate at the top. A constant axial load representing tributary gravity loading was applied at the top. In the out-of-plane lateral direction, the top of the first specimen was restrained, while the top of the second specimen was allowed to displace under increasing temperatures and a step-wise increasing external lateral load. The test results show that RC bearing walls are robust structures that can withstand long periods of extreme fire exposure. The out-of-plane lateral strength and stability under gravity loads, however, can be compromised due to the unsymmetrical deterioration of the concrete and reinforcing steel over the wall thickness, as well as the development of significant out-of-plane shear forces due to restrained thermal bowing.