Experimental And Mechanical Properties Of HDC Cold Formed Thin-wall Steel T-ribbed PKG Composite Floor

In the SSSCC residential structure system proposed by the research group for rural areas in Yunnan province,the floor structure adopts the new PKG plate,and has achieved certain results.The span is large,the bearing capacity is high,but the selfweight is too large,and the application has certain limitations in the area where the transportation is inconvenient.In order to continuously improve the floor structure of SSSCC residential structure system and realize the strategic goal of rural revitalization,this study proposes a HTPKG composite floor which is more suitable for rural areas in mountainous areas of Yunnan Province on the original basis.The floor adopts high ductility concrete(HDC)as the floor plate instead of the ordinary concrete floor plate in the new PKG plate.At the same time,the HDC’s ductility is utilized to eliminate the prestressed tendons in the new PKG panels,thus achieving the "slimening" effect,which lays a foundation for the popularization of multi-smallspan panels in SSSCC residential structural system.Based on the preliminary research of the research group in the early stage,this paper will use the combination of theoretical analysis,static load test and finite element simulation to deeply study the structural design of HTPKG composite floor and its important mechanical performance indexes such as stiffness,deflection and bearing capacity under the action of self-weight load,construction load and ultimate load.The main research contents are as follows:(1)The development history of composite floor and fiber-reinforced cement based composite material is reviewed,and the purpose and significance of the research on HTPKG composite floor is proposed.(2)The structural design of HTPKG composite floor slab;The flexural stiffness,deflection and ultimate bearing capacity were calculated by the derived theoretical formula.Analyze whether HTPKG bottom plate needs to be supported in the construction stage;The size of the member is optimized and the appropriate span range of the plate is proposed,which provides strong support for the experimental research and finite element analysis.(3)A uniform static load test was carried out on four prefabricated bottom plates and two composite plates.The effects of five parameters--span,upper flange width,web width,member type and steel composition amount of cold-formed thin-wall steel on the mechanical properties were studied.The test results show that the HTPKG plate has excellent cracking resistance,recovery performance and ductility characteristics,the small-span plate has high stiffness and bearing capacity,there is no relative slip between the composite surface,and the cohesiveness and integrity are good.The test results are consistent with the theoretical analysis results,and the final failure of each member is typical bending failure.(4)The mechanical properties of four prefabricated bottom plates are compared,and an optimal prefabricated bottom plate is selected,and the correctness of the assumption that the bearing capacity of cold-formed thin-wall steel under tensile and compressive load is 0.9 is analyzed in the structural design,and the mechanical properties of HTPKG plate and new PKG plate under the same span are compared.(5)The ABAQUS finite element software was used to analyze the four prefabricated plates and two composite plates.It was found that the failure mode of the plates was very similar to the test results,and the relevant mechanical properties were in good agreement with the theoretical and test results,which indicated that the finite element analysis had certain reliability and could further guide the theoretical analysis and test process.