Research On Mechanical Performance Of Prestressed Concrete Continuous Beam-Steel Arch Composite Bridge

As a kind of composite system bridge,continuous beam arch bridge combines the mechanical characteristics of continuous beam bridge and one's of arch bridge,which has the advantages of long span,good stiffness and beautiful appearance.Therefore,it is widely used in municipal bridge and highway bridge construction.Because of the complexity of the construction technology and the trend of the increasing span of the continuous beam arch composite bridge,it is of great practical significance for the design and construction of this kind of bridge to study the mechanical performance of the composite system bridge and its influence factors.Based on the research results of previous scholars,this paper takes the Yanchuan Bridge project in Yanji City as the background,and uses the finite element software to analyze the performance of the prestressed reinforced concrete continuous beam-steel arch composite bridge.The research generally includes the following contents:(1)The bridge's general finite element software Midas Civil was adopted to study the effects of the overall and local difference in temperature on the bridge to establish a full-bridge spatial model.Study the influence of overall temperature difference and local temperature difference on the bridge;Arch ribs with different dip angles were constructed also by using software to study the effect of spatial arch ribs with an internal inclination of 0°?18° on the static force performance of the bridge.(2)Construction monitoring of the bridge,stress and line type control were done,and the measuring data of the stress and line type should be collected.Compared the measuring data with the theoretical data,the results show that the actual stress of the bridge is consistent with the model calculations,which provides technical support for the actual construction of the bridge.Completed the construction of bridge,load tests were carried out to verify the safety and practical performance of the bridge.The bridge structure safety should have sufficient safety reserves.(3)On the basis of comprehensive analysis of the main factors affecting the calculation of cable force of short hanger,the space model of single hanger is established by using finite element software ABAQUS.The calculation method of cable force of short hanger is discussed by considering the modified boundary condition,calculated length and flexural rigidity EI.The following research results have been achieved in this paper:(1)Temperature gradient effect of the bridge is significantly greater than that of the whole temperature difference effect the internal force generated by the whole temperature difference effect is 66.8%of that generated by the temperature gradient effect;the internal force of the 18 degree inclined arch rib is 28.8%higher than that of the 0 degree inclined parallel arch rib,and the force of the parallel arch rib is significantly better than that of the inclined arch rib.(2)The actual stress performance of Yanchuan Bridge during construction phase is in accordance with theoretical analysis,and the measured structural response after completion of the bridge is in accordance with theory and is less than theoretical calculation value,which indicates that the bridge structure is safe and reliable.(3)The force calculation is a relatively accurate calculation method.When the boundary is articulated,the calculated length is corrected to subtract half the length of the upper and lower anchoring sections,and the flexural rigidity of the suspender is 0.8EI,the calculated cable force is consistent with the actual situation of Yanchuan Bridge.For the maximum derivation is less than 3%,the calculation models meet the actual needs of the project.