Super Long Pile Foundation Trestle Bridge And Construction Platform Study On Mechanical Properties Of Structure

In recent years,a large number of temporary trestle bridges and construction platforms for super-long pile foundations have been used in the construction of large-scale cross-sea bridge projects.With the application of super-long pile foundations in these temporary structures,the pile sinking process has been caused.The safety of structural bearing capacity,and the application of these super-long pile foundations will continue to study the influence of mechanical characteristics,influencing factors,and sensitivities of temporary trestle bridges and construction platform structures.These problems determine the length of the long-pile trestle bridges.Reliability and safety of the construction platform.In this paper,taking the temporary bridge and construction platform for the construction of the Changjiang Five Bridge as an example,the ABAQUS finite element software was used to simulate the 55 m steel pipe pile sinking process,and the displacement penetration method was used in the process of the piling.The analysis of the maximum Mises stress and the vertical stress change law was performed;then the Midas/Civil finite element software was used to calculate the mechanical state of the super-long pile foundation trestle and the construction platform under the loads of wind,water flow,large-scale heavy-duty transport vehicles and their combined effects.Finally,the pile foundation scheme of the super-long steel pipe piles of the trestle bridge was discussed.The sensitivity of the pile length,pile diameter,wall thickness,and spacing between the piles of the pile to the mechanical performance of the lower structure of the trestle bridge was analyzed.The main findings of the paper are as follows:1)During the process of sinking,55 m steel pipe piles have a positive correlation with the maximum Mises stress of the pile and the depth of soil penetration.The maximum Mises stress and vertical stress of the pile have a negative correlation with the pile diameter and wall thickness.2)The mechanical properties of the Beierliang and steel-pipe piles on the trestle are mainly designed by the 300 t heavy-duty vehicle shield truck vehicle load control.Except for the belei beam,the simulation of the structural components of the construction platform satisfies the mechanical performance requirements under any working conditions.By analyzing the maximum combined stress and maximum shear stress under the most unfavorable working conditions of the bereal beam structure of the trestle bridge and the construction platform and the top beam of the trestle pile,the increase of the number of belle blades and the distribution of the encrypted horizontally distributed beam stiffened plate are proposed.Spacing and other suggestions.Under the basic combination of the most unfavorable load conditions,the first-order critical load factor(K)of the over-long pile foundation trestle and the construction platform is greater than 4,the structural safety and stability meet the specification requirements,and the super-long steel of the trestle bridge and the lower part of the construction platform The depth of the pipe pile foundations was reviewed and the results of the rechecks met the requirements.3)The super-long pile foundation in the trestle bridge adopts double-row piles,but there is great room for optimization;the effect of the length of the pile foundation,pile diameter and wall thickness on the mechanical properties of the substructure is: displacement value and combined stress value of steel pipe piles With the increase of the pile length,the stability of the trestle has an adverse effect.With the increase of pile diameter and wall thickness,the displacement value and combined stress value of the steel pipe pile are reduced,and the stability of the trestle is increased;The spacing between the link and the bracing or reducing the number of both will have an adverse effect on the mechanical properties of the super-long pile foundation structure.The above research results have important guiding significance for improving the construction design of the project and ensuring the structural safety of the trestle bridge and the construction platform.At the same time,the suggestions in the article also provide reference value for the design and construction of similar projects in the future.