Numerical Analysis Study on Membrane Action Focusing on Differences in the Direction of Unprotected Secondary Beams in a Composite Flooring System Exposed to Fire

다국어 초록 (Multilingual Abstract)

The purpose of this study was to investigate the membrane action in a fire of a flooring system consisting of a deck composite slab and an unprotected secondary beam. Thermal stress analysis was carried out for two different cases where an unprotected secondary beam was placed in the direction of the long span (long direction) and in the direction of the short span (short direction). The influence of the direction of the unprotected secondary beam on the deflection behavior of the flooring system and the stresses in the welded wire mesh were analyzed. The analysis was carried out on a previous large-scale fire test. The results indicated that when an unprotected secondary beam was placed in long direction, the deflection was larger at an early stage, and the membrane action developed earlier. From the middle of the heating process, the deflection behavior was almost identical when the unprotected secondary beam was placed in the long and short direction. During this period, the stresses in the welded wire mesh in the long direction were larger than in the short direction. In the ultimate state, the stresses in the welded wire mesh in the long direction were smaller when an unprotected secondary beam were placed in the long direction compared to that in the short direction.