The Design And The Theoretical Study On Two-way Effects Of Concrete Composite Slab With Precast Prestressed Key Frame

In this paper, the concrete composite slab with precast prestressed key frame is a new type of composite slab conducted on the basis of traditional prestressed composite plate development innovation and the development. The prefabricated composite of the slab is a prestressed panel and has key frames along its length wise direction.In the precast slab,the prestessed reinforcement are arranged along the longitudinal and the imprestressed reinforcement which have a certain length of overhanging are arranged along the transverse.The precast slabs are jointed together in the construction site,and then the top rebars are arranged above the precast slab,and a prestressed two-way composite slab is formed after the concrete cover is casted.The concrete composite slab with precast prestressed key frame has the following advantages.Compared with the traditional concrete reiteration plate,this slab has merits of good integrity and high bearing capacity because of the prestessed reinforcement and the key frame in the precast slab.Compared with cast-in-place concrete floor,the concrete composite slab with precast prestressed key frame don’t need bottom die,and need less the support even don’t need the support in the process of construction.The concrete composite slab with precast prestressed key frame can reduce the wet operation and the manpower, and shorten the construction period, so that it can reduce construction cost.At the same time,the factory production and the mechanized production of the concrete composite slab with precast prestressed key frame effectively control the quality and improve the production efficiency,so it is conducive to energy conservation and environmental protection.The finite element analysis of the concrete composite slab with precast prestressed key frame by MIDAS/FEA program is conducted.The existence and the variation tendency of two-way effects under the loads in different conditions are researched by large numbers ofmodels,which provides a basis for the design and the engineering application of the concrete composite slab with precast prestressed key frame.In this paper, the research content is as follows:(1)Summarizes the theoretical research of prestressed precast composite plate.(2)Taking an example of the concrete composite slab with precast prestressed key frame whose span is 3600 mm,introduce the design process,the method, and the corresponding construction measures of this slab.(3)Establishing the finite element model of the concrete composite slab with precast prestressed key frame and the cast-in-place floor slab whose span is 3600 mm by MIDAS/FEA program,By comparing the regularities of distribution of the MISES stress of concrete, verified the existence and the variation tendency of two-way effects under the loads in different condition of the concrete composite slab with precast prestressed key frame,and ascertained the allocation proportion of the load in the direction of non prestressed and prestressed reinforcement of the concrete composite slab with precast prestressed key frame is 1:1.12.(4)Change the composite plate of four edges simply supported length ratio, analyze the stess of prestressed direction and none prestressed direction between the span of composite plate, analyze the change rule of stress between the prestressed direction and none prestressed direction, which on the surface of composite plate, determine the division of the one-way slab and the two-way plate boundaries, which was when the side length ratio is less than 2.2, use the two-way plate design, when the side length ratio greater than 2.2, use the one-way plate design.