Research On The Design And Structural Behavior Of PKG Prestressed Concrete Composite Floor

The existing floors are divided into two types on cast-in-situ and assembly through different manufacturing processes.The earthquake resistance and integrity are good for the cast-in-situ floors.But many templates and support will be consumed in the construction,which is not conducive to environmental protection,and the construction cycle is long,the industrial production is complex,and temperature cracks are prone to occur for the cast-in-situ floors.The fabricated floors is easy to assemble,but its integrity,earthquake resistance and crack resistance are very inferior so that it has been restricted to employ.To inherit the advantages of the cast-insitu and fabricated floors,and to avoid its shortcomings,people have researched the assembled monolithic floors,namely precast part is used at the bottom of the composite floor,and a layer of composite concrete is casted in the upper the composite floor,the precast part and composite concrete together form the overall mechanical structure,which is called composite floor,and it have many features,such as its stiffness is big,the integrity and earthquake resistance are good,saving materials,the construction is simple and can shorten the construction period,etc.The research and application of composite floor have many years,the traditional composite floor is made of slab precast part,which has great loss in transportation and construction,its quality is difficult to control,and it should be set in support in the construction so that the technology is complex.To improve the interface performance of prefabricated part and pouring composite concrete,people have made use of ribbed precast slab instead of the precast solid slab,which has improved its rigidity and bearing capacity and strengthened the cohesive force of precast slab with composite surface,and the precast slab is thinner and lighter weight,but it can only realize one-way reinforcement and one-way bearing,and crack resistance of orthogonal direction with rib is inferior.Based on this,fang-bo wu proposed the precast prestressed ribbed slab concrete composite floor of holes with rib,and then setting horizontal perforated steel bar in the hole,meanwhile decorating anti-crack reinforced at precast slab abutted seam,and then with pouring composite concrete form two-way reinforced composite floor.therefore,it has implemented two-way reinforcement and stress distribution of the ribbed precast slab composite floor,as PK prestressed concrete composite floor,which was referred to as PK slab.However,the rib part of PK precast slab is necessary to use the template in the prefabrication process,its supporting template also is complicated,and due to the existence of prestress,the protection of finished products is more difficult with increase of slab span.therefore,for improving the complicated supporting template and difficult finished product protection problems of PK slab,and for further improving stiffness and industrialization degree of the precast slab and composite floors.this paper made further improvement on the basis PK slab,namely outsourcing cold-formed thin-wall inside edge C channel steel on the PK precast slab concrete rib,which was named PKG prestressed concrete composite floor(as PKG slab).In this paper,the PKG composite floors are used as the research object,and the following work is mainly completed:1.This paper has calculated and compared the bearing capacity,stiffness,loss of prestress,deformation and other important mechanical performance index of the PK slab and the PKG slab,the results show that the PKG slab has better mechanical performance than PK slab,which explains that it is significant to improve for PKG slab on the basis of PK slab.2.MATLAB program was compiled,the iterative optimization design of PKG slab can be done only inputing the span and width of the slab.The PKG composite floors of the span of 2.4m~9m with reasonable section and good mechanical properties was designed by calculation.3.This paper has used ladder variable section beam slab bending theory,the orthotropic theory and plastic hinge line theory,the author has analyzed the stiffness and deformation of PKG precast slab,and orthotropic characteristics of stiffness for PKG composite floors,and considering the two-way composite slab elastic-plastic calculation and design of orthotropic characteristics effects with its stiffness,which will provide the theory basis for engineering design and application of the PKG composite floors.4.The PKG precast slab and unidirectional composite slab as the research object with 9000 mm long,and 500 mm wide,and ANSYS program was compiled,at the same time,the composite floors of PKG precast slab assembling with 18 pieces 9 m long and 0.5 m width were analyzed in the finite element,and compared with theoretical research results,they are in good agreement.5.This paper has introduced briefly some key points and problems of the PKG slab design,production and construction,which will provide reference for engineering design,industrial production and construction application of the PKG composite floors.