| With the rapid development of building industry, the demand of building formwork for concrete construction is very large. At present, plywood for concrete form is common formwork in Construction. Greatly using of plywood for concrete form as wood material, it is not only waste forest resources, but also harm on environment, developing new materials and style of building formwork is extremely urgent. The Wood-Plastic Composite (WPC) has been made by waste materials including plastics and wood off-cut and a series advantages including uncomplicated manufacture process and low cost, which provides a new way for development of building formwork.According to analysis on application of existing formworks, this paper presented a new type of WPC formwork, which makes full use of the advantage of driving for WPC with environmental protection and low cost, Based on experimental research and numerical simulation, investigations on physical and mechanical of WPC formwork were made systematically and provides useful theoretical reference for the popularization and application of the new type of WPC formwork. The main researches and results of this thesis are as follows:(1) According to the norm, the physical properties of PE, PP and PVC three kinds of WPC building formwork material were investigated by tests, including water ratio, tensile strength, bending strength and elastic modulus of materials, and Based on the experimental data, WPC solid-core formwork was studied. The results show that Wood-PVC formwork with higher strength and modulus satisfy the engineering requirements; under the same bearing capacity situation, Wood-PVC solid-core formwork has best mechanics properties and smallest designed thickness.(2) Three hollow-core formwork of WPC were designed Based on Wood- PVC (rectangle-hole, squaree-hole, circular-hole respectively). Using the finite element software ANSYS, analysis of bearing capacity and deformation of hollow-core formwork of WPC were studied. The results show that bearing capacity of hollow-core formwork of WPC satisfies requirements, the dimensional change significantly affects load carrying capacity and deformation of formwork; the support spacing of hollow-core formwork should be controlled below 400mm and within 300mm, saving the cost of the squared timbers.(3) In order to reduce the volume of the hollow-core formwork of WPC, this paper adopts the finite element optimal module in ANSYS programs to optimize the dimensions design, optimum design result was given. The results show that the First- method was recognized as the most accurate. On the premise of meeting the requirements of stress and distortion, optimum design size is 5mm×12mm×32mm×25mm×1200mm, mechanics properties of formwork is more reasonable after Optimizing, structural of formwork not only safety, but also keeping cost saving.(4) According to the norm, steel-structure WPC formwork was designed, based on theoretical approach of combination principle, deflection value was calculated under different load combination. Calculating outcomes displayed that deflection value were controlled in 3mm, when load values was below 70 KN/m2.Steel-structure WPC formwork has good mechanical properties and is quite qualified for the formwork construction.(5) Based on the evaluation principle for techno-economy of construction, three different formworks were make economic analysis. The results revealed that because of the excellent mechanical properties and low material cost, Wood-PVC formwork had the lowest prices. It was good for replacing bamboo (wood) plywood, wood formwork, and other solid-core formwork, while the price was low. During the building construction in northern winter, using Wood-PVC formwork, as compared with plywood, could achieve savings of about 50%, and it could save cost effective thermal-insulating. When the template engineering have strict requirement for steel formwork, it can use steel-structure WPC formwork, because the cost is not expensive after recovery conversion. |
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