Post-Fire Behaviour of Screwed CFS Frames Protected by Intumescent Coatings

Abstract

Thinner and lower-cost building elements have begun to be developed as technology advances around the world and in our country. Cold-formed steel construction elements are one of the structural elements produced. Although its use is growing, cold-formed steel frames have limited resistance to fires, which is a significant concern in buildings. Great damage will be incurred if precautions against fires in these structures are not adopted. There are various insulation materials in cold-formed steel structures to ensure the safety of life and property against fire. In this experimental study, screw column-beam joints' post-fire behavior was investigated by using fire-protective intumescent paint on frames made of cold-formed steel structures. The beams formed by placing a gusset plate between the cold-rolled C200 profiles back-to-back are connected with self-tapping screws. A total of ten experimental setups depending on stiffening plate were created using C200 beam profiles with two different wall thicknesses, three different gusset plate wall thicknesses, and two different paint thicknesses. All of the ten full-scale specimens were heated in the furnace according to the ISO834 standard fire. The behavior of the specimens after the fire exposure, including the moment-rotation curves and failure modes, was determined by arranging the data into four groups for comparison. In addition, the current studies existing in the literature on the behavior of unprotected members in fire were compared to the outcome reported in this paper. As a conclusion of the test results, the intumescent paint applied as a fire protection to the structural connections of the cold-formed steel members improved their fire resistance considerably.