The Design And Study Of Continuous Girder Bridge Transformed From Simply-Supported Structure

With the development of science and technology and communication, due to their convenient construction, economical cost, reasonable force character and comfortable driving, pre-stressed continuous beam bridge have made a rapid progress in recent years, and become one of the most competitive bridge types. Among the several kinds of regular construction methods of beam bridge, the method of the simply supported-continuous construction is a kind of effective and economical one, compared with the pre-stressed continuous beam bridge, its cost is much lower, and it is a kind of more excellent construction methods. It overcomes the fracture of the joint only with the ordinary steel, and the non-harmony issue of the strain and stress between the structures under different force. It also strengthens the stress store of the joint between the beams, and assures the continuous and whole capability of the bridge.There are many structural patern in simple-supported systems into continuous system because of the diffrence in section forms and continuous fashion. This paper analyse the peculiarity of various section form. To provide different section forms that are the same with different spans by comparing the peculiarity of structural resisting and economy about different section forms and then provide more theoretical basis for optimize design and decreasing cost. The plan layout about the deck and the setting mode about overtake high are usually the design difficulties. This paper summarize some different manipulating basis under the different cases according to practice experience and then widen the apply range of simple-supported systems into continuous system.A simulation method of three dimensional structure of prestressed bridge upper structure is introduced by using the three dimensional finite element analysis program Midas. As an example, the simulative processes of a prestressed concrete bridge, which was transformed from simple-supported systems into continuous system, were presented according to its real constructing courses and using status.According to the Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts ( JTG D62-2004 ),this paper carry on many checking computations :the checking computations of resisting load abilities about the positive sections and the resisting crack checking computations under enduring status and normal service limit state, the checking computations about deflection and the vertical stress checking computations under enduring status and normal service limit state, the main compressive stress and main tensile stress calculations under service phase and maximum tensile stess checking computation about steel at tensile location, the checking computation during the construction. The results are describe as follows: the carrying capacity checking computation about resisting bending at positive section and resisting shear at skew sections and the resisting crack checking computation of the long or short term effect combination, the checking computation about deflection and the stress at permanence and transitoriness status and the maximum tensile stress about prestressed steels and so on, all checking computation accord with the cord specification. There are comparative main tensile stress over the piers and this result can not cater into the prestressed specification value in code. But the result will cater into the code specification if calculating and designing according to reinforced concrete elements. The paper analyse the carrying load peculiarity about both the single line supports and double line supports. At last provide the construction technics and notice iterms about simple-supported systems into prestressed continuous system.