Research On The Effect Of Transverse External Prestress For Steel-Concrete Composite Bridge Decks

Steel grid and concrete composite bridge deck has the properties of high strength, light structure, etc, and has extensive application prospect in engineering practice. For non-prestressed steel grid and concrete composite bridge deck, on the one hand, large width results in its increased stress and deflection; on the other hand, during the stage of applying wet concrete, the steel girders accumulate a great deal of extra initial stress, resulting in higher stress level in use stage. Application of transverse externally prestress on steel girders, can improve stress level of steel girders, decrease deflection of composite bridge deck and ease construction, and has practical significance for construction of this kind of bridge in the future.In this dissertation, steel and concrete composite bridge deck is classified and the structure characteristics and advantages of the steel grid and concrete composite bridge deck are detailed. Reasons of applying transverse externally prestressed steel beams on steel grid and concrete composite bridge deck are described, and the calculating formulas of transverse external prestress loss are given. At last, numerical simulation analysis on steel grid and concrete composite bridge deck is conducted using the single variable method by the finite element software ANSYS.The main analysis content are: In steel and concrete composite bridge deck, the effect of different linear transverse externally prestressed steel beams on deflections and stresses of steel grid and concrete composite bridge deck is analyzed. In steel and concrete composite bridge deck, the effect of different numbers of transverse externally prestressed steel beams on deflections and stresses of steel grid and concrete composite bridge deck is analyzed. In use stage of steel and concrete composite bridge deck, the layout form and numbers and separation distance of transverse externally prestress are analyzed, and reference values are given. Prestress stress increment and the limit bending bearing capacity of combination single beam are discussed, proposing a number of steel beams are equivalent to one single steel beam according to the stiffness and moment of inertia in the steel and concrete composite bridge deck, turning steel grid and concrete form to steel and concrete single beam form in calculating.