The Stiffness Analysis And Experimental Study On Hollow Floor Of Small Spacing Steel Concrete

Hollow floor of small spacing steel concrete, which was suit for cassette steel structure made by academician of Ma kejian, was a new type of floor applied to residences. That main structure was that beam, which adopted the type of H, had a smaller spacing of 2m.Hollow floor of small spacing steel concrete,which combined the characteristics of steel structure floor and cast-in-situ concrete hollow floor, was a new type of the structure. Steel structure floor had advantages of high bearing capacity, good seismic performance, easy construction, etc.with many characteristics of saving concrete consumption, light weight, good heat preservation, sound insulation, heat insulation performance, cast-in-situ concrete hollow floor had a certain contribution to the steel beam floor stiffness.It could make up for the weakness of large carrying capacity while lacking of rigidity of small spacing beam floor, by the combination of cast-in-place concrete and steel beam floor.But so far, the literatures on this kind of concrete floor contributed to the stiffness of steel beam floor were less. This study researched the effects of cast-in-situ concrete hollow floor on the deformation of small spacing beam floor and degradation characteristics of whole floor stiffness through a common 1/2 simplified model test and numerical analysis. And as a result, we put forward to the deformation calculation method of small spacing beam cast-in-situ concrete hollow floor, which had a certain engineering significance and economic benefits to this kind of floor’s deformation calculation.Major works described as follows:(1) Designing, processing and producing a common 1/2 scale small span steel framework, and proceeding the framework with the vertical load test. After finished the stage of the test; then pouring on small span steel frame concrete hollow slab and the small distance between cast steel frame concrete hollow slab, and starting to regular maintenance; after reaching age, conducting on the vertical loading test;(2) By vertical loading test of small span steel structure based on small spacing of cast steel structure and concrete hollow slab, experimental phenomena and data analysis, we studied the influence of concrete core slab on steel floor stiffness and determined the influence coefficient of η;(3) By the deformation characteristics and strain measured values of steel girder and concrete hollow slab, we obtained the strain distribution characteristics along the height of steel girder cross section in strain as well as the concrete hollow slab beam vertical axis;(4) Based on the theory analysis of test and experimental study, we put forward to the calculation method of small span steel girder concrete hollow floor stiffness. Deflection calculation formula could provide a reference for this kind of floor engineering design;(5) Simulating the structure of one common small spacing steel frame and cast concrete hollow slab of small spacing beam floor respectively, by using finite element software MSC. MARC(2007 r2), and then comparing with the test result;(6)Whether we considered the effects of concrete core slab on floor stiffness or not, the respective design of girder section were needed after analysis of examples. We learned from the contrast results of two calculation: On one side, Without regarding to the contribution to stiffness of concrete hollow slab, deformation of the steel beam section height was depended on the floor; on the other side, considering the contribution to stiffness of concrete hollow slab, steel beam section height was depended on the bearing capacity. This illustrated that considering the floor’s contribution to the floor stiffness could reduce beam height, save the steel and lower the building height.