The Study Of Mechanical Properties Of High-pier Large-span Continuous Rigid Frame Bridge

The continuous rigid frame bridge has advantages of continuous beam and T-rigid Frame. Piers, beams and foundation are combined together to bear a various of loads. It has small size on dimensions, large clearance under the bridge, wide vision and with more good technical and economic natures. It is one of the most competitive bridge at present.The paper takes a high-pier large-span continuous rigid frame bridge which is named Hong Qi Bridge. Many mechanical properties are studied.Three structure internal force states of Hong Qi Bridge construction stage are analyzed. The structure internal force state of maximal cantilever state, the structure internal force state of side span closure state and the structure internal force state of the entire bridge state are analyzed, the position of the maximum force of structure internal force of continuous rigid frame bridge are attained. According to the position of maximum force of piers and girders are combined together in Hong Qi bridge, an finite element model is built and the local stress is analyzed, stress distribution situation is checked and the recommendations is given.It is been analyzed that the main beam under shear lag effect on box girder of Hong Qi Bridge, the stress distribution of the calculated sections is obtained under dead load. Three bar simulation method and space finite element method are compared. The shear lag effect coefficient views are obtained.The dynamic characteristics of the Hong Qi Bridge is analyzed, the natural frequency of the bridge is given, the different modes are analyzed and the dynamic characteristics of the bridge is obtained. According to high pier feature of Hong Qi Bridge, the buckling stability analysis of the bridge structure is necessary. The four typical construction stages buckling stability is preliminary analyzed and its stability safety factor are calculated, that is the highest pier buckling stability analysis, the maximum cantilever buckling stability analysis, side span closure buckling stability analysis and the full bridge closure stability analysis. It is the most unsteady state that the maximum cantilever state.As the high-pier large-span continuous rigid frame bridge is built in earthquake-prone mountainous southwest region, the design of the bridge is equivalent to the seismic intensity 7 under the force of the earthquake. So earthquake response analysis is very important. Earthquake response analysis, which is included response spectrum analysis and time history analysis, obtain the maximum value of the two results used for seismic analysis, seismic forces obtained control of bridge piers should be designed to conclusion.According to the structure feature of the Hong Qi Bridge in the paper, DoctorBridge, Midas and Ansys finite element software is used to establish two-dimensional or three-dimensional, beam or shell, the partial or the full bridge finite element model to calculate. AntoCAD, Origin graphics processing software are also used. The results of these calculations are analyzed to study the mechanical properties of the Hong Qi Bridge. The study also has the reference value for the analysis of mechanical properties of the similar engineer.