Study On The Stress Characteristics And Parameter Sensitivity Of The Bottom Basket-tied Arch Bridge

With the rapid development of large and medium-sized urban Bridges in China,the underside basket-tied arch bridge,as a non-thrust girder arch composite system bridge,has absolute advantages when the elevation of the bridge is strictly limited,the clearance requirements are high under the bridge and the span is 60?200m.This bridge type has been widely used and developed in modern city branch river bridge,which has the characteristics of strong adaptability to the foundation,large span ability and unique and beautiful appearance.With the increase of span length and the complication of structure form,it is very important to study the mechanical properties of structure deeply.Based on the research results at home and abroad,the research was carried out with the 84m basket-type tip-arch bridge of Guitang river in Changsha as the engineering background,and the following research results were obtained:(1)The finite element calculation model of the Guitang river bridge is established by using the finite element analysis software Midas/Civil,and the modeling method of this type of bridge is studied,including the establishment of node units,the selection of materials,the application of load and the simulation of construction stage.The static characteristics of the bridge under the limit of load-bearing capacity and the limit of normal operation are studied.The static load test was completed.(2)Through the finite element numerical analysis method,the system research concrete-filled basket structure static characteristic of arc bridge system with structural design parameters:the rise-span ratio,arch rib and collar beam stiffness ratio,the influence law of different arrangement derrick,get components change with structural parameters control section internal force and the change law of internal force distribution,size and the reasonable value range of the structure parameters is presented.(3)Two kinds of stability theories of Bridges and analysis methods of structural stability are summarized and expounded.The effects of structural design parameters,such as horizontal support form,sagittal span ratio,arch rib stiffness,arch rib inclination Angle,and derrick arrangement,on the overall stability of the structure are studied in detail,providing reference for the design and construction of the same type of engineering.(4)Through the state into a bridge structure are affected by the parameter sensitivity study:the characteristics of component materials for bulk density,stiffness and temperature sensitivity of environment parameter to forecast deviation,found the influence concrete-filled basket arc bridge components into the state of the bridge main material parameters,so that we can from the Angle of construction strictly control the construction quality,to ensure the bridge internal force and linear to meet the design requirements.