Effects of heat sinks on evolution of longitudinal temperature distributions in steel structures

Evolution of longitudinal temperature distributions along steel frame components during fire is an inherent thermodynamic behavior, stemming from differences in the properties of columns and beams, and from heat sinks above and below the fire-room. Despite early literature clearly indicating that these may affect structural response, the phenomenon has not been investigated. This paper presents analysis of partial effects of heat sinks on longitudinal temperature distributions by means of an advanced non-linear numerical model. It includes representative results and trends of temperatures and influence-distance versus some main geometric factors affecting the longitudinal distribution. Results indicated that these factors are the values of virtual thickness, the column-to-beam. ratios, and a combined factor of cross-sectional area and virtual thickness ratio to which joint temperature is highly correlated. A simplified lumped-mass linear model, applied preliminarily to evaluate the order of magnitude of temperature reduction in the vicinity of the joint, is appended. (C) 2002 Elsevier Science Ltd. All rights reserved.