Research On Structure Stability And Construction Control Of Long-Span And Broad-Width Arch Bridge

With the rapid development in design, construction technology of the bridge structure in recent years, there have been many long-span arch bridges with artistic modeling and complex structure. Due to the increasing use of light weight and high strength materials in long-span arch bridge, the structure tends to be thin-walled and its mechanical property and structure stability problem becomes more and more important. The construction control of long-span arch bridge is more and more systematic.Based on a long-span and broad-width arch bridge in Dalian, this article has conducted the research and analysis of several aspects such as the static performance of the structure under various loads, the dynamic properties of the structure, the stability and its influencing factors of the structure and the construction control simulation. The main work and conclusions are as follows:(1) Established the whole bridge model by using the finite element software MIDAS/Civil, calculated the stress and deformation of the major structural components under different types of loads and load combinations. Under dead load, the maximum stress occured at the foot of the arch rib, the maximum displacement was located at the middle of main span. Temperature load had a certain impact on the stress state of arch rib and edge stringer. Wind load had a great impact on wind bracing. The stress state of major structural components met the strength requirement and had a certain safety margin.(2) Analyzed the dynamic properties of the bridge by using subspace iterative method. The basic vibration frequency was 0.751 Hz, which mean the structure belongs to the flexible bridge. The out of plane stiffness of the bridge was relatively small than the in-plane stiffness, and the torsional stiffness was relatively big. The vibration situations of arch rib and bridge deck system were basically the same.(3) Analyzed the elastic stability of the structure, showed that the bridge had a good stability. The stability coefficient under dead load and load combinations were large and met the requirement of specification. The instability was mostly in the form of out of plane instability, showed that the in-plane stability was better than the out of plane stability. Discussed the effect of the form and amount of wind bracing on stability, analysis showed that the stability coefficient of wind bracing in shape ‘mi’ is the highest, the stability coefficient increased with the increase of the number of wind bracing.(4) Discussed the effect of rigidity of the arch rib and wind bracing. The lateral flexural rigidity Izz had the greatest impact of stability coefficient, the vertical flexural rigidity Iyy had a small effect on stability coefficient, and the torsional rigidity Ixx basically had no influence on the coefficient.(5) The construction process was divided into 14 stages according to the construction scheme, and then simulated the construction process of the main span structure using the forward analysis method. Designed and simulated two kinds of suspender tensioning scheme, and analyzed the stress and deformation of main span arch rib and edge stringer in each construction stage, provided the basis for the construction control of the engineering.