Analysis On The Emptying And Bulging Tube Of Dumbbell Type Concrete-filled Steel Tube Concrete-Filled Steel Tube Arch Rib

As a composite structure,the concrete-filled steel tube has many advantages.At the end of the 20 th century,it has entered a rapid application development period in China.However,the emptying of the concrete-filled steel tubular arch ribs and the bulging tube will have an adverse effect on their application.In this paper,the analysis of the emptying and expansion of the concrete-filled steel tubular arch ribs is carried out with the aid of the emptying and drum samples.Based on the theory of plane strain,the theoretical formulas of tensile stress and void height at the interface between steel tube and concrete under axial compression,temperature and shrinkage are deduced,and the influence of each factor is quantitatively analyzed by example calculation.If no measures are taken under axial pressure and temperature,interface debonding is inevitable.The height of the interface under the effect of three factors is the same as the change law of tensile stress.The deflection stiffness of dumbbell-shaped concrete-filled steel tube(CFST)members with and without bonding was deduced and analyzed.An ANSYS model was established in connection with the detection of a concrete-filled steel-concrete arch bridge.The parameters affecting the mechanical properties of the structure were analyzed.The increase of the debonding rate of CFST arch ribs will lead to the decrease of its bending stiffness;the increase of the steel containing rate will compensate the reduction of the stiffness caused by the de-airing.There is no change in the structural mode characteristics of the concrete-filled steel tubular arch bridge in the absence of space,except that the natural vibration frequency of the structure is reduced.The removal of the void will reduce the ultimate bearing capacity of the structure and will advance into the plastic stage under load,affecting the performance.In the construction of dumbbell type concrete-filled steel tubular arch ribs,the ABQUS was used to simulate the different rib arching sequence,and the maximum stress and sectional deformation characteristics of the arch rib sections under various working conditions were analyzed.Analysis of bearing capacity of dumb-bell concrete filled steel tube.A load test was performed on the arch ribs of the bridge stage.Through the analysis of deflection and strain,it was found that the bending rigidity of the ribs of the arch ribs was reduced through the comparison of actual and theoretical calculations of modes and frequencies,and the overall stiffness of the structure was reduced.The vibration mode becomes more complicated,and the vibration type mutation point is easily formed at the disease position of the arch and rib tube.The emptying of steel pipe concrete arch ribs and the causes of the bulging were analyzed from the design to the later operation.The prevention and control measures for the evacuation and the bulging were carried out from several aspects including rib material,steel pipe structure,construction technology,and disposal methods.induction.This paper analyzes the problem of preventing the cracking of the tube during the filling of the concrete by adding a tie rod.The result shows that the maximum tension value of the rib cross section and the lateral deformation of the web can be effectively reduced by adding a vertical tie rod between the horizontal tie rod and the steel tube.