| Green High-performance Fiber-reinforced Cementitious Composites(GHPFRCC)is made by replacing large amount of cement with industrial waste fly ash,and adding polyvinyl alcohol Fiber(PVA Fiber)and other materials on the basis of ECC material,which has not only excellent mechanical properties,but also has a brilliant performance on environmental protection and low carbon economy.By using methods of fire test and finite element simulation,this paper has studied factors which might influence the fire-resistance performance of GHPFRCC frame joints.The main contents are as follows:The first part mainly introduces the fire resistance tests of GHPFRCC frame beam-column joints.The fire resistance limit,temperature field and displacement changes are measured through the test,and the influence of axial pressure ratio and fire mode on the fire resistance of the joints are studied in combination.The second part mainly includes using ABAQUS software to carry out finite element simulation of frame beam-column joints.The finite element constitutive model is established,and then this part carries out fire simulation on the joint specimen with the effect of thermal mechanical coupling to obtain the fire resistance limit,temperature field change and beam end displacement change of the beam-column joint under high temperature.By using simulation to compare with the test results and to complete the results that have not researched in the test,the following conclusions are drawn as followed:(1)A complete GHPFRCC constitutive model is established in this paper,and comparative analysis is conducted from three aspects,including fire resistance limit,temperature field change,and beam end displacement change.The simulation results are ingood agreement with the test results.(2)The fire resistance limit is shorter with a greater axial pressure ratio of GHPFRCC specimen under the same conditions.The fire resistance of GHPFRCC specimens on three sides elevated temperature is about twice as high as that of specimens on four sides subjected to fire.(3)GHPFRCC specimens can bear greater axial load than C30 concrete specimens,and GHPFRCC specimen has excellent fire-resistance performance.However,the specimen is damaged more serious with higher axial load under elevated temperature,simultaneously,the degree of stirrup configuration has a certain impact on the damage of components after fire,and the phenomenon shows that tighter stirrup configuration leads to slighter damage when specimens subject to fire.(4)The fire mode has a great influence on the change of temperature field inside the component,while the axial pressure ratio has little influence on the change of temperature field under the same condition of being subjected to fire.(5)The displacement of the top of the column moves greater with the greater axial pressure ratio under the same conditions.However,under the same axial pressure ratio,the displacement of the top of the column is not affected obviously by the fire mode.In the earlier and middle stage of fire,the axial compression ratio has little effect on the displacement of beam end,and the gap is wide in the later stage of fire. |
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