Force Analysis of Open Web Triangular Area of Ganxi Super Bridge during Construction
Ganxi Super Bridge is an open web continuous rigid frame bridge with a main span of 300 m,and the upper chord box girder in the open web triangular area adopts the post support of a few telescopic columns with the hanging basket for suspension casting.The lower chord box girder adopts the full cable-stayed buckle method with a hanging basket for suspension casting.To analyze the force characteristics of the temporary structural system in the triangular area during the construction process using this method,the force variation law during the construction process of the temporary structural system in the triangular area was summarized to verify the effectiveness of the construction method,and the optimal time to remove temporary buckle cables and support columns was proposed.The finite element structural analysis software was used to simulate the entire bridge construction process.The results show that the force of the structure meets the specification requirements by using this construction method.During the construction of the triangular area,the upper and lower chord box girders constructed are mainly compressed,and there will be a temporary and slight tension state during this period affected by the concrete pouring of the next section,column roof support,buckle cable tensioning,and other processes.When the closure of the triangular area is completed,the section of the box girders is mainly compressed,and there is slight tension in some parts.After the closure of the whole bridge,the box girders in the triangular area are in the full compression state,and the compressive stress increases significantly compared with the closure state in the triangular area.After the removal of temporary cables and columns,the upper and lower chord box girders have obvious stress redistribution,but they are still in a full compression state.The peak value of temporary cable force appears before the closure of the triangular area.After the closure of the triangular area,it generally shows a downward trend and rises near the demolition.During the construction process,the support force of the rear temporary column generally shows a downward trend,and the front column shows an upward trend.The support force of the column near the demolition is greatly improved.After comparison,it is recommended to remove the column first and then the buckle cable after the closure of the whole bridge.
Ganxi Super Bridgeopen web continuous rigid frame bridgetriangular areatemporary buckle cablesupport columnforce analysis
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