Research On The Mechanical Properties Of The New Type Of Steel Bar Truss Concrete Superimposed Slab

Along with the constantly deepening process of urbanization, construction industrialization have been the inevitable trend, integral assembly buildings in line with the requirements of construction industrialization. Self-supported steel bar truss concrete superimposed slab has been used in the prefabricated construction, on the basis of the self-supported steel bar truss concrete superimposed slab, the number of steel truss is reduced, and the number of stressed steel bars is increased to form the new type of steel bar truss concrete superimposed slab, the economy and construction convenience of laminate can be promoted.In order to study the stress and deformation performance of the new type of steel bar truss concrete superimposed slab and perfect its design theory, in this paper, the calculation formulas of the bending stiffness of concrete composite members in the relevant specifications and literatures are summarized, based on the equivalent stiffness method, the short term stiffness formulas of the new type of steel bar truss concrete superimposed slab are derived, the applicability of these formulas are verified through a numerical example. The finite element method is used to complete the revision of the deprived calculation formulas of stiffness, and the parameters affecting the short-term stiffness during the construction stage are analyzed. Using the finite element method completed the analysis of the new type of steel truss hoisting process. Combined with the current standards and the finite element method, the mechanical properties of new steel truss concrete composite slab during using stage are analyzed.Through the study, we can get the following conclusions: The calculation formulas of short term bending stiffness of concrete composite members in relevant literatures and specifications are verified not applicable for new steel truss concrete composite slab, the formulas which deprived by the method of equivalent inertial moment without considering cracking status and need to combine the cracking status when use the formulas. Parameter analysis shows that, parameter analysis in construction stage,each increase of 10 mm thickness, laminate floor stiffness increased 300%, each increase of a steel truss chord truss or each increase of the bar diameter 2mm, the equivalent stiffness of laminate during construction stage increased 20%~30%. The calculation formulas of stiffness are modified according to the crack state, and the difference between the calculated results and the finite element calculation results are less than 15%. By means of finite element analysis, it is found that lifting scheme can meet the requirements of hoisting. At the same time, the effect of bond slip between steel bar and concrete can be ignored in the calculation of hoisting process, but the rope’ role can’t be ignored. The error between the results of ultimate bearing capacity formula during using stage and finite element calculation are less than 10%.Through the research of this paper, the research conclusions provide the necessary theoretical basis for the design and analysis of the new type of steel bar truss concrete superimposed slab and its engineering application. The research content provides the necessary basis for the preparation of 15G366-1 "truss reinforced concrete composite plate(60mm thick plate)". The research content provides the necessary basis for the preparation of 15G366-1 "truss reinforced concrete composite plate(60mm thick plate)". The results can lay a theoretical foundation for the further application of the new type of steel bar truss concrete superimposed slab.