| As a new type of green,environmentally friendly,and construction efficient building formwork,aluminum alloy formwork has been gradually promoted by the government.However,the initial investment cost of aluminum alloy formwork is high,only in large projects and super high-rise projects because of low cost amortized to reflect the advantage.In order to reduce the investment cost of aluminum alloy formwork and expand their promotion scope,it is necessary to conduct research on the optimization design of aluminum alloy formwork.Carbon Fiber Reinforced Polymer(CFRP)has the advantages of high specific strength and specific stiffness.This paper combines CFRP and aluminum alloy formwork to produce CFRP-Aluminum alloy formwork.By utilizing the reinforcement effect of CFRP,the amount of aluminum alloy used is reduced to cut material cost while ensuring the flexural properties.This article conducted uniaxial tensile tests on aluminum alloy and CFRP-aluminum alloy specimens,and the stress-strain curves and mechanical properties of the materials were obtained;Secondly,the normal use state and ultimate limit state flexural tests of 21 formwork specimens were carried out with the CFRP reinforcement position,the number of CFRP layers on the side ribs and whether the end of side ribs CFRP is anchored as parameters.The mechanical properties of specimens were obtained,and the influence of different parameters on the flexural properties of specimens was discussed.Finally,using finite element software for parameter expansion analysis and optimizing the design of the formwork specimens,a high-performance and low-cost CFRP aluminum alloy formwork design scheme was obtained.The main conclusions were as follows:(1)Under the normal use state,all specimens met the specification requirements for stiffness and strength of the formwork.Strengthening the side ribs of the specimen with CFRP can effectively inhibit the development of midspan deflection.Increasing the number of layers of CFRP or installing anchor measures at the end of CFRP cannot improve the flexural performance of the specimens.(2)Under ultimate limit state,the ultimate bearing capacity,initial flexural stiffness and specific energy absorption of the specimens with CFRP reinforced side ribs are increased by 36%,28%,and 30%respectively,but the deflection coefficient decreased by 8%.With the increase of the number of CFRP layers on the side ribs,the ultimate bearing capacity and initial stiffness of the specimens increased,but the increase amplitude was not proportional to the number of CFRP layers.The anchorage measures at the end of the CFRP of side rib had little effect on the flexural properties of specimens.(3)According to the finite element extension parameter analysis,the initial flexural stiffness and ultimate bearing capacity of specimens significantly reduced by decreasing the thickness of side ribs.The closer the bolt hole is to the face plate,the greater the initial flexural stiffness and ultimate bearing capacity of the specimen.When the longitudinal ribs were removed,the ultimate bearing capacity of the specimens decreased obviously.The thickness of longitudinal rib and crossing rib had the least influence on the flexural properties of specimens.(4)Compared with the original aluminum alloy formwork,the optimised CFRP-aluminum alloy formwork specimen had a 24.4%reduction in aluminum alloy usage,a cost reduction of RMB 20.7/m~2,a 13.5%increase in initial stiffness and a 28.9%increase in ultimate bearing capacity,with good overall performance.In this paper,the flexural properties and failure mechanism of CFRP-aluminum alloy formwork were clarified through experiments and numerical simulation.The results obtained have certain reference value for the optimization design of aluminum alloy formwork. |
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