Study On Static Behavior And Model Test Scheme Design Of Steel-Concrete Segment Of Hybrid Girder Rigid Frame-Continuous Railway Bridge

The hybrid girder technique has been outstanding since its appearence for its great technical and financial performance.Therefore it has been gradually applied in railway bridge construction in China.As for railway bridge with medium and large span,beam bridge is still the mainstream.Now there are few examples of railway hybrid girder rigid frame-continuous bridge.The main span of Hangzhou-Wenzhou Railway Bridge is 216 m and the design speed is160 km/h,which will become the first railway box hybrid girder rigid frame-continuous bridge in China.The steel-concrete segment is posterior-plate-type with cells,and it’s the essential part of the bridge,either the key point of the project.Taking Hangzhou-Wenzhou Railway Bridge as the engineering background,mechanical behavior is analyzed and test program is designed to explore the performance of the joint section.The main research contents and results are as follows:(1)The stress distribution and section properties of joint section of Hangzhou-Wenzhou Railway Bridge are obtained through ANSYS.It turns out that under the most disadvantage condition,the joint section is under pressure with low stress level;The steel-concrete segment can transmit force smoothly and has a specific transmission path;The distribution of stiffness is smooth along the joint section,and the deformation is uniform and continuous.(2)According to the parameter analysis,as for joint section of large-span rigid frame bridges,the thickness of the posterior bearing plate should be 40-60 mm,the length of the embedded section of steel beam should reach at least 2 m,improving the efficiency of force transmission only by increasing the stiffness of the shear connector is not recommended,the thickness of top and bottom plate of steel beam should be 20 ～ 24 mm,the failure of the nail will increase the stress of the bearing plate and the other nails,so the safety of the nail should be ensured in design.(3)The loading test scheme is designed on the basis of finite element analysis to verify the calculation.The selected similarity ratio of the model is 3:10.Through finite element analysis of the test model,it is concluded that the stress level and distribution between the test model and the original segment model are identical,which means the two are in good equivalence.