Analysis Of Vertical Rotation Construction And Study On The Key Technical For CFST Arch Bridge

Concrete-filled steel tube (CFST) arch bridge has developed rapidly in China because ofits good performance, such as reasonable mechanical characteristics and strong crossovercapability, etc. At the same time, vertical rotation method has been widely adopted due to a lotof outstanding advantages, such as economic, safe and reliable and easy to operate, so thisconstruction technology of CFST arch bridge we hold has reached world advanced level.However, compared with the engineering practice, the theories about this kind of bridge arerelatively backward, such as any unified and complete technical specifications of CFST archbridge has not been promulgated until now. As a result, we can’t offer any applicableguidelines to this kind bridges’ construction in China, leaving construction risks. Therefore,studying on the key technical for vertical rotation construction is an urgent task. Taking ahalf-through CFST tied arch bridge with span arrangement (40m+200m+40)m as an example,mechanical behavior of the tower and other structure and pre-arch are analyzed using thefinite element method in this paper.1. Using the space frame to simulate the arch rib, accurate modal to simulate the verticalrotation process was established. To analyze the tower’s instability, the theory of elasticstability was employed to obtain the tower’s instability coefficients, instability modes andresponses when half-span arch ribs leaving from frameworks and closure. The resultsindicated that (1) adding lateral braces between the two towers and properly tensioning theback cable and installing lateral cables on the flank of two towers can prevent the risk oftowers’ stability failure;(2) the longitudinal displacement of towers’ top and the stress oftowers’ feet is the key point of construction monitoring and control in this stage;(3) using thefinite element method to analyze vertical rotation construction is reliable.2. Simulate the arch ribs and ear plate’s structure around the lifting point and analyzetheir stress distribution and deformation during the vertical rotation construction process,arriving some relevant conclusions, which can provide a reference for the design and furtherstudy of this force transmission structure.3. The factors considered in actual setting of pre-arch of arch bridge and the setting methods were systematically summarized. The analysis model of finite element method ofCFST arch bridge was established in this paper by using Midas/Civil and SAP based on theactual project and caculated it’s pre-arch.4. Pursue the unreasonable construction phases from the previous construction schemeusing calculating the pre-arch and study to improve. By Calculation and comparative analysis,the improving methods are presented. As a result, not only the force and deformation state ofthe ribes were improved, but also the pre-arch for the main arch of the bridge was effectivelyreduced.In this paper, by finite element analysis, some effective design measures to enhance thetower and lifting point structure were put forward to guarantee the safety of vertical rotatingconstruction. Studied the main arch pre-arch set problems and exploratory improved theconstruction scheme to reduce the pre-arch. Therefore, the study in the paper will not onlyensure the successful completion of the CFST arch bridge, but also provide some usefulguidance and reference to this kind bridges’ vertical rotation construction.