The Incremental Launching Method with a Floating Support of Metal Combined Bridge Superstructures

Purpose: To consider the necessity of applying the erection technology of metal combined superstructure in the form of a lattice truss with a triangular lattice and a rigid bottom chord with driving underneath single span bridges by the incremental launching method with the use of floating support. To show the significance and efficiency of this method. To give the sequence of the main installation operations. To draw a general scheme of launching. To outline the procedure for checking the superstructure at all stages of erection. To show the method of checking the floating support according to two groups of limit states. Methods: Comparison of incremental launching using a floating support with incremental launching using auxiliary supports, as well as construction of the span on falsework. Analysis of the stress values obtained during the inspection of the superstructure at all stages of erection, as well as of the analytical expressions of the floating support inspection methodology. Results: The advantages of the incremental launching with the use of floating support in comparison with other types of installation of metal combined superstructure are specified. The main operations and features of metal combined superstructure erection are outlined. The general scheme of installation of facilities is given on the example of construction of the highway bridge over the river Psezuapse, as well as comments on the verification of the metal combined superstructure are given. The basic formulas for checking the floating support are expressed. Practical significance: Features and advantages of this method of installation of metal combined superstructure will simplify the construction of single-span bridges with the superstructure of this kind, as well as increase the economic efficiency of such projects. The method of floating support testing can be recommended for practical use.