Structural Behaviour of Slim Floor Slabs with Prestressed Hollow Core Elements at Room Temperature and in Fire

Abstract

Slim floor composite slabs are made of asymmetric steel beams with a wide lower flange supporting composite decks with profiled steel sheets or prefabricated concrete elements (mainly precast hollow core elements). The gap between steel beam and hollow core elements is filled with concrete. Models for the fire behaviour of slim floor slabs with hollow core elements were developed and checked with 6 fire tests and 65 tests at room temperature [1,2]. SUMMARY OF FIRE TESTS ON SLIM FLOOR SLABS WITH HOLLOW CORE ELEMENTS To understand the fundamental behaviour of slim floor slabs with prestressed concrete hollow core elements in case of fire, an extensive series of tests was performed at ETH Zurich and tests by others were analysed. A set of tests with hollow core slabs [1] was made to analyse the failure modes and the structural resistance at room temperature as a basis for the fire tests. The test results were in good correspondence with the known calculation models [3, 6]. A second set of tests with Hollow Core (HC) slab elements was performed to study the structural fire behaviour of slim floor slabs [1, 4]. These fire tests investigated different designs of supporting the HC elements on the lower beam flange and their effect on the structural behaviour of the slim floor slab. Table 1 shows the results of the six fire tests made at the EMPA in D0bendorf. Further it describes fire tests made at CTICM in Meziere-les-Metz [10] and in Denmark [15], as well as a description by Crespo and Rui-Wamba of a real fire in one of the exhibition halls of the EXPO in Seville, which damaged the HC elements [12].