Study On The Construction Control Of Foshan Jiujiang Composite Cable-stayed Bridge

Composite cables-stayed bridge is one of the most competitive bridge types in long-span application which is advantageous in its fast construction, excellent span capacity, light self-weight, ease of construction and relative economical, etc. It has been widely applied recently in China. However, it is also a kind of highly statically indeterminate structure in design and construction, hence the final alignment and stress condition will be influenced by deviations of exerted force of the cables,erection level of segments, amount of loads and self-weight and so on. Additionally, the alignment of the composite cables-stayed bridge is difficult to be adjusted due to its specific construction method. As the segments are prefabricated before erecting in site, the allowable adjustment of angle and alignment are limited, thus a rigorous and successful control of construction is the guarantee of achieving design objective. Basing on Jiu Jiang Bridge, this thesis covers some key technical problems in control of construction of composite cables-stayed bridge.1,Assembled geometry and unstrained geometry of segmental bridge provide important information for fabrication and site construction, but there is some mistake about its application. The relationship and difference between assembled geometry and unstrained geometry are illustrated. Based on the compatibility between force and deformation, an approach to solving assembled geometry by iterating of construction sequence and to solving unstrained geometry by Tangent-Erection displacement was put forward in calculation of Jiu Jiang Bridge.2,Aiming at reasonable stress distribution of tower,main girder and concrete bridge slab, a spatial finite element model made up of 3-D spar element, beam element and elastic shell element is established. The nonlinear static analysis is performed by using ANSYS in order to model the real construction sequence and to get the distribution of internal force and stress, strain of the main girder and the concrete slab. Comparison between the result of calculation and the test result in site is also shown.3,It cannot be too much to focus on the test of the force of cables. Exact value of slope force is the basis of adjustment of the erection of segment in cables-stayed bridge construction. This thesis covers the theory and usage of frequency method and hydraulic pressure sensors in Jiu Jiang Bridge construction and testify that the frequency method is suitable for long slope while the hydraulic pressure sensors is suitable for short slope which is more stiffer.4,This thesis also tries to apply the parameter adjustment theory at the exerting of finishes construction step of Jiu Jiang Bridge. The Kalman filtering method is testified applicable in adjusting the parameter deviation.