Research On Construction Monitoring And Optimization Technology Of Basket-type Concrete-filled Steel Tube Arch Bridges

The basket-type concrete-filled steel tube(CFST)arch bridge is one of the most competitive bridge types owing to its various advantages,such as beautiful shape,light weight,large stiffness and good spanning capacity.An increase in span of the basket-type CFST arch bridge can lead to complicated construction technology and difficult construction correspondingly.Therefore,the importance of construction monitoring and control is gradually highlighted.A basket-type CFST arch bridge over Beijing-Shenyang high speed railway is taken as the engineering background in this paper.The construction process is monitored and controlled,the identification,adjustment and optimization of internal force of the derrick in construction stage are studied,and the removing process of the supports onto the arch rib is optimized.The main research contents are as follows:(1)The characters of basket-type arch bridge and the importance of bridge construction monitoring and controlling are briefly introduced.The advantages and characteristics of basket-type concrete-filled steel tube arch bridge are summarized,and some domestic basket-type concrete-filled steel tube arch bridges that have built in recent years are listed.The importance of construction monitoring and control in the complex bridges is expounded.(2)The method of bridge construction monitoring and controlling is summarized;According to the actual situation and characteristics of the bridge,the bridge construction monitoring content was drawn up;A formal analysis method and a finite element software Midas Civil were carried out to study the each construction stage of the basket-type concrete-filled steel tube arch bridge over Beijing-Shenyang high speed railway.Based on the analysis of the field monitoring data and the theoretical data,the mechanical characteristics of main girder and arch rib are studied.(3)The frequency method and the jack determination method are combined to study the internal force identification of the construction and adjustment of cable phase of the bridge,and the influence matrix method is used to adjust internal force of derrick of the bridge.The existing derrick cable force optimization methods are simply summarized;By the method of constrained minimum bending energy,the internal forces of the into bridge phase derrick are optimized.(4)The impact of the removing sequence of arch rib scaffold on the basic structural stress and line shape is studied.According to the actual situation,several removing plans of the temporary supports onto the arch rib are proposed.Through the scaffold removing process simulation with finite element software Midas Civil,a suitable plan for this bridge frame scheme is proposed.