Research On Bearing Layout Of Special-shaped Continuous Box Girder Bridge

With the development of highway interchange and urban interchange,in order to make the bridge structure smooth,usually a large number of special-shaped bridges are required to be designed as transition bridges for the main bridge connecting ramps.Because of the special of this type of bridge structure,it will appear widening and bending.It is more complicated in mechanical properties than ordinary linear box girder bridges,and its spatial force characteristics are more obvious.The complexity adds some difficulties to the design of the bridge.At present,there are some serious problems in the bridge safety caused by the erroneous arrangement of the bearing of the special bridge caused by the unreasonable arrangement of the bearings,lateral displacement of the beam,and overturn of the beam.In view of these problems,it has good theoretical value and practical engineering significance to study the effect of the arrangement of shaped bridge bearings on the reaction forces of the shaped bridge bearings and the internal force of the bridge structure.In this paper,taking the right eighth main line box girder bridge in an interchange project as the engineering background,the solid element model of the special box girder bridge is established by Midas / FEA software,and the influence of different support arrangements on the stress of the special box girder bridge is analyzed.The main contents and conclusions of the study are as follows:1.In order to explore the influence of the restraint arrangement of the bearings on the forces of the special-shaped continuous box girder bridge,the differences between the internal force of the beam bridge structure and the reaction forces of the bearings under the four restraint arrangements are analyzed and compared,and the restraint arrangements of the bearings are obtained.Based on the change of the influence of the structural force,the constraint layout of the support of the special beam bridge was proposed.2.In order to investigate the influence of the lateral spacing of the supports on the forces of the special continuous box girder bridge,the differences between the internal force of the beam bridge structure and the vertical reaction forces of the supports under different lateral spacing solutions of the supports were compared and analyzed,and the lateral spacing of the supports was obtained The effect of the change on the stress on the structure of the special-shaped bridge is changed.The optimal lateral distance of the supports at each fulcrum of the special-shaped continuous box-girder bridge is given.3.Analyzed the stress condition of the special-shaped box girder bridge under the design load limit state,the design normal use state and the condition limit state.The results show that the special-shaped box girder bridge has a higher ultimate bearing capacity and safety.The comparative analysis of various working conditions has obtained the safety range of the lateral spacing of the bearings of the bridge widening section under three extreme conditions.