Critical Factors Governing Crack Propagation at the Interface of Fire Insulation and Slender Steel Trusses

Abstract

This article presents a numerical approach in which the implicit finite element method and fracture mechanics concepts are applied to simulate crack propagation at the interface of fire insulation and truss members in steel framed buildings. An intrinsic cohesive zone model (CZM) in conjunction with contact interaction analysis is applied to model the progression of fracture at the interface of fire insulation and slender steel truss members. Experimentally determined cohesive zone properties are utilized to simulate the progressive delamination in three types of commercially available spray-applied fire-resistive material (SFRM) applied on a truss chord. The numerical model, which is initially validated against the previously conducted fracture experiments, is employed to perform a sensitivity analysis with respect to CZM parameters, SFRM elastic modulus, and thickness of SFRM. Results obtained from a sensitivity study are subsequently utilized to define a delamination characteristic parameter (