Structural stability of steel frames damaged by earthquake at fire

Within three days immediately after earthquake fire often breaks out. When fire fighters cannot approach such a structure because of traffic congestion caused by earthquake, it is necessary to prevent somehow the structure from collapsing. Assuming that a steel building frame undergoes permanent relative horizontal story displacement and girder hinge due to an earthquake and it is subsequently subjected to fire, this paper has studied the ultimate temperature of the damaged structure. To this end, refined finite element analyses as well as a simplified theoretical analysis have been conducted. It is found that their ultimate temperatures are more or less decreased compared with those of frames without damage due to earthquakes.