Study Of Fire Resistance Of The Composite Slabs Consisting Of Thin-walled Stell Beam With Openings And Lightweight Aggregate Concrete

The composite slabs consisting of thin-walled steel beam with openings and lightweightaggregate concrete is a new lightweight composite floor, which has the advantages of lighterweight, higher bearing capacity, being convenient for construction and less wet work, etc.Furthermore, the concrete made by the lightweight aggregate instead of the natural aggregate hasadvantages of excellent thermal insulation properties and better fire-resistant performance.However, the strength of the composite slab will reduce rapidly and composite slabs will come intofailure for that the bearing component at bottom side of the composite slab is thin-walled steelbeams with openings, if the composite is under fire. Therefore, study of fire resistance of thecomposite slabs consisting of thin-walled beam with openings and lightweight aggregate concretehas a profound theoretical significance and important value of engineering application.There has been more research work on study of the mechanical performance of ordinaryprofiled sheet concrete composite slabs for the both conditions of room temperature andelavated temperature, and much achievements has been obtained. However, there is fewerresearch on the new composite slabs consisting of thin-walled beams and lightweightaggregate concrete. Therefore, based on experiments and finite element methods, the fireresponse and the post-fire mechanical behavior of eight thin-walled beam lightweightaggregate concrete composite slabs were experimentally studied, and the effect factors such asdimension and number of openings set in the web of the thin-walled steel beam, type of theshear keys and its number and form of precast concrete slabs are considered.The research results show that characteristics of the cross section of the steel beam has noeffect on displacement of the composite slabs under fire, but has great effect on post-fire behaviourof the composite slabs. It is concluded that strength of the connection of shear keys and steel beamis related to the fire response and the post-fire behavior of the slabs presented here. The embossingset in the prefabricated concrete slabs has no effect on the post-fire mechanical performance of thecomposite slabs, but the steel link bars fitted in the slots of the prefabricated concrete slabs whichconnect two adjacent prefabricated slabs is helpful for preventing cracks from ceramsite concreteand making the composite slabs after fire has better entirety.