Research On Mechanical Properties And Design Method Of Prestressed Composite Continuous Slab

With the deepening of industrialization of construction,residential construction is gradually moving towards high production efficiency and high mechanization level.The assembled concrete structure can achieve factory production and assembly construction,so as to obtain ultra-high construction quality and efficiency,which is a good fit for this development trend.Therefore,prefabricated concrete structures are being promoted.Floor slab occupies a large proportion in the whole structure and the traditional construction technology of floor slab is complicated.Therefore,it is of great significance to study the new composite floor slab with high bearing capacity,high earthquake resistance,high construction speed and environmental protection.Secret spell prestressed composite floor is a new type of floor system,for the research of the floor system in the vertical load distribution features of the internal force and bending moment amplitude modulation factor selection,this paper has five pieces of pres tressed composite continuous plate and a simply-supported prestressed composite board to carry out the experimental study,the nonlinear finite element model is established and the prestressed composite continuous board and carries on the parameter analysi s,The selection range of moment amplitude modulation coefficient and the construction Design Suggestions of prestressed composite continuous plate are given.The details are as follows:(1)The flexural performance of three groups of prestressed composite continuous slabs(a total of five slabs)with the moment amplitude modulating coefficients of12.06%,17.21% and 22.83% respectively under vertical load was studied,and the failure modes and load-mid-span displacement curves of the composite slabs were analyzed.During the whole test process,there is no slip between the precast prestressed bottom plate and the post-cast concrete composite layer,and each prestressed composite continuous plate has bending failure,indicating that the precast prestressed bottom plate and the post-cast concrete composite layer can work together.It is suggested that the moment amplitude modulation coefficient of prestressed composite continuous plate should be controlled within 18% ～ 20%.(2)An experimental study on the bending performance of a single span prestressed composite slab under vertical load is carried out,and the experimental phenomenon and results of the single-span prestressed composite simply supported slab and prestressed composite continuous slab with the s ame reinforcement amount and structure are compared and analyzed.The results show that the prestressed bottom slab can effectively delay the cracking degree and increase the stiffness of composite slab.Compared with the single-span prestressed composite slab,the mechanical properties of prestressed composite continuous slab have been greatly improved,for example,the bearing capacity has been increased by 65.7%,the mid-span deflection under the same load has been significantly reduced,and the stiffnes s has been significantly increased.Therefore,made the single-span prestressed composite slab continuous can improve its stiffness and bearing capacity,and has good economy.(3)The finite element nonlinear model of prestressed composite continuous pla te is established and the correctness of the model is verified.The model is used to analyze the concrete thickness of bottom slab,concrete thickness of composite layer,length of reinforcement and amplitude modulation coefficient of bending moment of pre stressed composite continuous slab.Finally,the design suggestions of prestressed composite continuous plate are given.