Analysis Of Flexural Capacity Of Prestressed Concrete Continuous Short Rib T-beam

The emergence of prestressed concrete short rib T-beam is mainly used to replace the hollow slab beam as a new upper bearing structure.The main reason why it can replace the hollow slab is that the structure of the short rib T-beam can overcome the defects of the hollow slab,such as hinge crack,bearing void,water accumulation in the slab.etc.However,there are few engineering cases of short rib T-beam at home and abroad,so the bearing capacity of short rib T-beam needs further analysis.In order to study the bearing capacity and failure mode of the prestressed concrete continuous short rib T-beam,the 32m prestressed concrete continuous short rib T-beam is taken as the prototype and the 4:1 scale ratio is used to make the scale test beam.Through the static load test of the scale beam,the failure mode and the mechanical change of the mid span section of the short rib T-beam are studied.Using,ABAQUS finite element software,a reduced scale plastic damage model is established and compared with the static load test results.The nonlinear finite element model of 32m original beam is established,and the factors affecting the bearing capacity of prestressed concrete continuous short rib T-beam are analyzed.The main research results are as follows:(1)The undamaged bearing capacity of concrete short rib t is mainly in the elastic stage.When the cracks appear in the beam body,it indicates that the beam body enters the elastic-plastic stage.In this stage,the rigidity damage of the beam body is the most serious and the damage parts are mainly in the mid span area and the negative bending moment area.When the rigidity damage of the beam body reaches a certain degree,the beam body enters the final failure stage.(2)By comparing the finite element calculation results of the reduced beam with the static load test results,it can be concluded that the midspan deflection curve is in good agreement with 94%,and the tensile stress curve of the main reinforcement at the lower edge is also in good agreement.At the same time,the initial crack position and crack distribution area of the finite element model beam and the test beam are also in good agreement.(3)Increasing the ratio of initial prestress and prestress can significantly improve the serviceability limit load of prestressed continuous short rib T-beam:the influence of the change of height coefficient of compression zone on the bearing capacity can be divided into two cases.When the height coefficient of compression zone increases due to the increase of tension bar,the ultimate load of bearing capacity and the serviceability limit load of beam can be significantly increased;when the compression bar decreases,the ultimate load of bearing capacity can be significantly increased When the height coefficient of compression zone increases,it has little effect on the ultimate load of bearing capacity and the ultimate load of normal use;the change of concrete strength grade has little effect on the bearing capacity of beam.