| At present,the main way to solve all kinds of pipelines is to make them pass through the bottom of the beam,and the use of the beam belly holes to make all kinds of pipelines pass through the beam belly can avoid crowding the space under the beam,and can greatly reduce the total height and weight of the building with the same number of layers.Reactive Power Concrete(RPC)has the characteristics of high strength,high toughness and high durability,making RPC perforated beams superior to ordinary concrete perforated beams in terms of mechanical performance,which can effectively improve the bearing capacity and durability of concrete structures,reduce the building’s own weight and reduce material consumption.At present,the research on the flexural performance of RPC members is mainly carried out through experiments,while the results of finite element simulation are relatively few.In this paper,based on the flexural test beam model of RPC beam,ABAQUS finite element analysis software is used to conduct systematic numerical simulation research on the flexural performance of RPC beam with open holes.The influence of cavity parameters such as cavity shape,size,horizontal position and vertical position on flexural ultimate bearing capacity,failure form,deformation and ductility of RPC open beam under concentrated load is mainly discussed.By selecting the appropriate constitutive relationship and model parameters of reactive powder concrete and reinforcement,and using the method of setting nonlinear springs between reinforcement and concrete units to simulate the bond and slip phenomenon between reinforcement and concrete,a correct and reasonable finite element model is established,and the correctness of the finite element model is verified by comparing with the test results.On this basis,RPC open-porosity beams with different hole parameters are established.Through the analysis of the stress cloud diagram,damage cloud diagram,displacement cloud diagram and load-deflection curve of the simulation results,the influence law of different hole parameters on the ultimate bearing capacity,failure form,deformation and ductility of RPC open-porosity beams is summarized.And put forward the approximate calculation formula of the modified flexural bearing capacity of RPC beam with open holes.Through the analysis and research,the main conclusions are as follows:(1)RPC beams with open holes in the pure bend section of the beam have the same open hole area,and the difference in bending performance between round,square and rectangular beam is not obvious.Round beam has a relatively good performance in ultimate bearing capacity,and rectangular beam has an excellent performance in ductility.(2)In the pure bending section,the ultimate bearing capacity and ductility of the beam decrease with the increase of the aperture,and the deformation increases with the increase of the aperture.When the diameter of the opening hole does not exceed 60% of the section height,the weakening of the ultimate bearing capacity of the beam is less than 5%.(3)The effect of the hole on the ultimate bearing capacity,deformation and ductility of the open-hole beam is small in the tensile area of the concrete.When the opening position is offset to the compression zone,the effect on the ultimate bearing capacity,deformation and ductility of the open-hole beam is very obvious,especially the ductility of the open-hole beam is more serious.(4)When the hole is in the pure bend section,with the horizontal position of the hole moving to the loading point,the ultimate bearing capacity and ductility of the open beam will decrease slightly;When the horizontal position of the hole is located in the shear bend section,the bearing capacity and ductility of the beam with the open hole will be greatly decreased.According to the conclusions of the research,the reference suggestions are provided for the hole setting of RPC open-hole beam,and the theoretical support is provided for the application of RPC open-hole beam in practical engineering. |
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