Research On Effect Of Stirrup Reinforcement Ratio On High Temperature Shear Behavior Of Reinforced Concrete Continuous Beam

With the development of the economy and the rapid increase in high-rise buildings,the number of building fires has increased year by year.RC continuous beams are the most widely used in actual building structures.However,there are few studies on the fire resistance of RC continuous beams under high temperature in China.Especially the research on shear performance of RC continuous beams at high temperatures has not been reported so far.In this paper,the nonlinear finite element model of RC continuous beam under fire is established.The validity of the model is verified by the test results.The influence of the hoop ratio on the shear performance of RC double-span and threespan beams under different fire conditions is studied.And compared with the shear performance of the RC simply supported beam under fire.The main contents and conclusions of the research are as follows:1)According to the ISO834 standard heating curve,the RC continuous beam with three sides is heated,the temperature field of the beam section is symmetrically distributed,and the temperature difference between the non-fire surface and the fire surface is large.The difference between the lowest temperature and the highest temperature is about 900 ° C.Thermal stress is generated inside the beam,which intensifies the strength of the material and the beam shear bearing capacity.2)Using the thermal coupling model of RC continuous beam,the influence of stirrup ratio on the shear performance of the double-span beam and the three-span beam under different fire conditions is analyzed.The fire resistance of RC continuous beam under shear failure at high temperature is exponentially related to the hoop ratio of the beam.When the hoop ratio is increased to a certain extent,the shear resistance of the beam is no longer significantly promoted.3)By comparing the shear performance of simply supported beam and continuous beam under high temperature,it is found that the failure characteristics of double-span continuous beam and simply supported beam are brittle failure,but the deformation deflection of continuous beam is larger and the inflection point is not obvious,In comparison with the simply supported beam,the destruction process is relatively slow and ductile.Figure 86;Table 14;Reference 56...