Long-span Continuous Rigid Frame Bridge Strengthened By External Prestressing

As the hub of transportation, the bridge is an important project of the national economy and the people’s livelihood. However, because of the design, the concrete girder cracking, operation and economic development, material performance deterioration, resulting in worldwide, large span continuous rigid frame bridge deflection generally, so clear under torsion, find out the feasible methods are very important. This paper discusses the starting point of this paper.(1) Analysis of Large Span Continuous Rigid Frame Bridge Development Status and learn about the causes of the causes of deflection, and the status quo of the deflection research, analyzed the present research situation of deflection of the disease causes, both at home and abroad to identify seven causes launches the elaboration, and analysis of the continuous rigid frame bridge under the long-term deflection of control research. The purpose and significance of the study is to provide reference for future theoretical research.(2) Choose a representative of a continuous rigid frame bridge as the background, the engineering background, main technical index, load index are introduced, and for full bridge integral heating, temperature of 25 for the structure stress check calculation, it is concluded that the security and stability of the structure. After research on prestress loss of influence factors and the theoretical analysis, to model for the influence of the benchmark study on prestress loss of structure, refinement, respectively, of roof beam, the closure effect of beam and vertical prestress loss of 10%,20%, making deflection percentage line graph, to assess the sensitivity.(3) Analysis of external beam cloth beam and main points of design, reference to domestic and foreign related standards and commonly used external prestressed cable form, commonly used to block type, design of external beam, cloth beam, and support to block, anchor point, through in vitro simulated beam tension for 0.5,0.6,0.65,0.7 times the tensile stresses. Due to the change of stress and displacement of and to explore the effect of prestressing loss of structure. By studying the different thickness of the steering block, the influence of the weight change of the steering block on the deflection of the beam is simulated.(4) Consideration of external beam stress for 0.5,0.6,0.7 times the tensile force of three kinds of situation, on the pier by the different influences of the force and displacement analysis of external prestressed, horizontal displacement of the pier of the three conditions, carrying capacity limit state strength envelope, deflection and strain of, give some reference for practical engineering.