Research On The Mechanical Behavior Of Continuous Span Concrete Composite Slab

In recent years,as the advancement of human society,improvement of life quality,and electricity consumption in industry and residents gradually increasing,accordingly,the number of substations and building area have also quickly increased.The fabricated steel structure has the advantages of light weight,good seismic performance,high material reuse rate and fast construction progress.About the fabricated steel structure slabs,there are commonly used plate types which are pressed steel plate composite slabs,reinforced truss slabs and prefabricated SP slabs.Although the assembly can be realized,construction process is too complicated.Based on the substation project actual demand,this paper improves the traditional reinforced truss slabs and laminated slabs,proposes a new type of slab connection form "open-hole slab joints",and the properties of the improved prefabricated steel structure floor slab and the beam-slab connector are studied by experiment,finite element and theoretical calculation:(1)The vertical static load test was carried out on two consecutive spanned concrete slabs with stud shear members and open-hole folding plate connectors,and the test phenomena and test results were analyzed,and the overall and local mechanical properties of the structure were studied.The results show that the whole process of continuous spanning concrete slabs from loading to failure is divided into four stages: elastic stage,concrete cracking stage,yielding stage and failure stage;Compared with the bolted specimen,the yield strength and ultimate strength of the perforated fold-plate connector are improved,and the mechanical performance is better;Both the yield strength and the ultimate strength are improved,and the force performance is better.The load of the two specimens reaching the normal deflection limit is smaller than the ratio of the yield load to the ultimate load,and the stiffness is large.(2)The finite element analysis of the continuous span concrete slabs was carried out by using finite element software.The results show that the finite element analysis can better reflect the variation of the bending resistance of continuous span concrete slabs,and the results are in good agreement with the experimental results.Based on the finite element analysis of the specimen in four aspects,such as the thickness of the concrete strength of the plate with thick span and the thickness of the shear member,it is found that the strength of concrete and the thickness of the shear member have almost no influence on the flexural performance of the composite slab of continuous span concrete,but the connection between the slab and the steel beam can be strengthened by the connection between the plate and the steel beam.The thickness and span of the slab have a great influence on the bending resistance of the continuous spanned concrete slab.The peak load of the specimen increases with the increase of the slab thickness and decreases with the increase of the span.(3)On the basis of the existing calculation theory of the stiffness of the superimposed flexural members in the domestic and foreign,according to the cross-section characteristics of the self-supporting reinforced concrete truss concrete slabs,according to the difference of the relative positions of the neutralization axis and the superimposed surface of the prefabricated members,The short-term stiffness of the prefabricated component is calculated to calculate the deflection of the continuous spanned concrete slab during the test.