Research On Construction Monitoring Technology Of Long Span CFST Arch Bridge

Concrete filled steel-tube(CFST) arch bridge is a new bridge-type in China in recent years with lots of advantages, such as good adaptability to the ground, good plasticity and toughness, light weight, high capacity, resistant to deformation, good economic performance and convenient to construction. However, The bridge-type development in the country a short time, there are many aspects of theory research can not keep up with the pace of practice. especially construction control technology research is not perfect relatively, to ensure structure line shape and structure stress of bridge in construction process that meet design specifications. This will keep abreast of the collar beam, arch rib and other stress state and deformation, to provide an early warning mechanism for the bridge construction, it can safely carry out construction and have very important significance.In this paper, engineering background choose Middle Route of South-to-North Water Transfer Project Weigangpu north I bid section across the canal under concrete steel tube tied arch bridge in Ye county, Henan. firstly, introduced the establishment of a full-bridge finite element model, carried out the construction process simulation analysis. Using reverse removedness calculation and formal installed calculation method to determine the ideal state of the construction phase of the bridge. Secondly, a detailed analysis researched the control technology of the bridge construction, the main content and obtained the following conclusions:(1) Introduced construction control basic theory, foundation and to achieve the desired effect, for practice in the actual project will lay a theoretical foundation.(2) analyzed the control technology of the collar beam, arch ribs lineshape and stress in construction process, and designed a monitoring program for the bridge, in the whole process of construction monitoring arch rib lineshape under the controllable range; box girder measured maximum compressive stress is 14.2Mpa, it does not produce tensile stress to meet the control objectives.(3) The hanger rod of tied Arch Bridge is critical force transfer components, the initial tension forces and cable force monitoring of the hanger rod given focus during construction. Introduced three methods of confirming initial tension forces and the basic principle of testing cable force by frequency method. Through adjusting the cable makes full bridge force distribution, the measured value and the target value of the error is less than 5%, to meet the requirements. By adjusting the cable hanger makes hanger force of the full bridge distribution, the measured value and the target value of the error is less than 5%, so it meet the requirements.As can be seen from the measured results of the whole construction process, Weigangpu north across the canal arch bridge that the girder and arch rib stress, line shape and hanger rod force were controlled better, them satisfied the design specifications and achieved satisfactory results.