Analysis, Design & Performance
Full Session with Abstracts
339072-3 - Fire Collapse of Plasco Building – The Role of Steel Joist Connections
Friday, April 20
9:30 AM - 10:30 AM
On January 19, 2017, Tehran iconic Plasco building collapsed due to a fire that started at around 7:30 AM local time (4:00 GMT) and lasted for about 3 hours. Sixteen firefighters and six civilians were killed, and many businesses were destroyed as a result of the collapse of this 15-story building. This incident also marked the first tall building of modern urban character in Iran to have entirely collapsed due to fire. A preliminary investigation into this disaster indicated failure of connections as one of the main causes of the progressive collapse of Plasco building in fire. Therefore, a detailed study of fire behavior of the connection types used in the Plasco building is essential in reconstructing the event, and in developing knowledge on how to prevent such collapses in future.
The aim of the work presented here is on examination of the behavior of connections in Plasco building under the conditions of elevated temperatures representing structural fire. Following an introduction to the structural system of the Plasco building, this paper presents the results of a failure analysis of the connections as part of the composite floor system consisting of joists, tie beams, and main truss beams with concrete deck on top. The main focus is on the composite steel joist connections. More specifically, finite element simulations are employed to investigate the behavior of steel joists and their connections in the collapsed portion of the 11th floor of Plasco building in fire. To quantify fire effects on the connections, the fundamental moment-curvature-temperature (M–Φ–T) response of composite steel truss beams are constructed. In addition, rotational and shear capacity of the connections as well as flexural behavior and moment capacity of composite steel truss beams at elevated temperatures are evaluated. Finally, failure modes of steel joists and their connections in Plasco building are identified and discussed.