Study On Mechanical Behavior And Green Construction Of Prefabricated Composite Slab Trestle Bridge

Trestle bridge is an important auxiliary building for bridge construction,its bearing capacity,stability,construction speed and other performance affect the overall success or failure of the project.The traditional trestle structure system has some shortcomings,such as complex construction procedures,large number of constructors,low stability of connection nodes,high uncertainty risk,poor monolithic stability,large energy consumption,and serious environmental pollution disturbance.There are few innovative designs of Trestle Structure System at home and abroad.Most of the trestle design still adopt the form of traditional structure system.In view of the shortcomings of the traditional trestle system,this paper puts forward a new structure system of trestle using composite structure,which makes full use of the advantages of high performance and predictability of composite structure,can reduce the construction process of trestle project,greatly improve the construction speed,reduce the risk of construction personnel,improve the mechanical stability of trestle structure,reduce the construction disturbance.The new structure system can solve the problems existing in the traditional structure system.In order to explore the applicability of the new trestle structure system,the paper gives the construction method of the new system,summarizes the load calculation of the trestle project,and deduces the calculation formula of the elastic bending capacity and the plastic bending capacity of the steel sandwich concrete composite slab.The common calculation method of bearing capacity of steel pipe pile is improved,and the calculation method of internal friction and increased friction of soil arch is put forward.The calculation is carried out by using the actual test data,and the results are compared.It is found that the accuracy of the improved calculation method of bearing capacity is 8%-15%higher than that of the standard calculation method.The load displacement function of small diameter steel pipe pile is derived by using parabolic load transfer curve.The ABAQUS finite element models of one span steel sandwich concrete composite slab and five span new structure system trestle are established respectively.The calculation results show that the theoretical value of bearing capacity calculation formula is in good agreement with the model calculation result,and the ratio of the theoretical value of plastic bending capacity formula to the finite element calculation result is 0.97.Increasing the thickness of steel plate,the thickness of concrete layer and the ratio of height to span can significantly increase the bearing capacity and rigidity of the composite slab.Under the adverse conditions,the ratio of the maximum normal stress to the allowable stress of the superstructure of the new trestle structure system is 0.75,and the deformation is small,and the structure system layout is reasonable.In order to systematically evaluate the energy consumption and environmental disturbance of trestle engineering,conform to the development trend of green building and green construction industry,a green construction evaluation system is established according to the engineering conditions,environment and requirements of trestle engineering,and the weight and evaluation criteria of indexes are determined,which can provide reference for the design and construction of green low-carbon trestle.