Improving the performance of composite floors subjected to post-earthquake fire. (December 2018)

• Record Type: Journal Article
• Authors: Suwondo, Riza; Cunningham, Lee; Gillie, Martin; Bailey, Colin
• Is Part Of: Fire safety journal. Volume 102(2018)
• Page Start: 18
• Page End: 26
• Publication Date: 2018-12
• Subjects: Tensile membrane action -- Fire engineering -- Fire insulation -- Composite building -- Post-earthquake fire; Fire prevention -- Periodicals; Incendies -- Prévention -- Recherche -- Périodiques; Fire prevention -- Research; Periodicals; 628.92205
• DOI: 10.1016/j.firesaf.2018.10.004
• Languages: English
• ISSNs: 0379-7112

Abstract

Abstract: It is well-known that tensile membrane action in concrete floor slabs can enhance the fire resistance of a composite steel frame building. Vertical supports provided by protected beams along the edge of slab panels play an important role in the development of the tensile membrane action. The present study investigates the effect of fire insulation delamination on protected beams, as might occur in an earthquake, on the fire resistance of composite floors subject to fire following an earthquake. The results show that fire insulation delamination considerably reduces the development of tensile membrane action. Based on the results obtained, two methods of improvement are presented to enhance the development of tensile membrane action concurrent with fire insulation delamination. It is found that increasing slab thickness and improving fire protection rating can enhance the fire resistance of the whole building even with fire insulation delamination. Highlights: Three-dimensional modelling of composite frames is essential in order to identify the benefits of tensile membrane action. Fire insulation delamination can reduce the development of tensile membrane action and accelerate the failure of composite buildings. Protected edge beams should be designed to have adequate strength and stiffness in order to utilise the benefit of tensile membrane action even when fire insulation delamination occurs. At high temperature, unprotected secondary beams lose their strength and stiffness significantly, resulting in loads being predominantly carried by the concrete floor slab. Reducing the maximum steel temperature by 25% through the use of a fire protection with improved insulation rating can reduce the deflection to half of that with the original fire protection even when local fire insulation delamination occurs.