Assessment Methods Of Bridge Security Based On Effective Prestressed Detection

Prestressed steel beam is the key force elements of the prestressed concrete bridge structure and the stress state determines the overall performance of the structure. Prestress loss directly affects the bridge deformation, structural strength and service life. Detection on the effective prestressed steel beam, assessment and safety checking of prestressed concrete bridges have important practical significance, so the article starts of this topic.The studies in this paper rely on west transportation construction projects of the country "medium and large span prestressed concrete bridge detection technology" cited prestressed tendons along the distribution of research results to carry out the applied research. In the real bridge reserved measuring point, using horizontal displacement increment detection method measure the current effective pre-tension of the steel beam to calculate the measured effective prestress. Analysis numerical model of the real bridge and calculate the design value of effective prestress steel beam. Through the effective real value of testing and design of the comparative analysis to determine the losses and structural safety of current stage prestressed steel beam. Calculate steel beam stress along the boundary value in volatility (0,10.0], combining steel beam effective prestressed frictional distribution rule and distribution pattern to judge index delta steel beam bridge means obeying distribution patterns,and the ratio is about 0.93,Simulate the distribution of the effective prestressed steel beam and calculate the main force of steel beam bridge, and prove the prediction of the effective prestressed steel beam along the correctness of the distribution. State according to the design from the top to bottom edge of the main beam of concrete stress distribution has been sampled in accordance with prestressed steel beam measured to calculate the current phase of the upper and lower edge of the main beam of concrete stress. With the growth of operating time,the upper edge of the main girder concrete compressive stress increases, the lower edge of the compressive stress decreases, and the speed is slow down after. Effective prestressed steel beam decreases, the speed has became slow gradually.Bridge in the operational phase by the combined effects of a variety of complex factors, especially the loss of prestress effects, and to ensure the bridge safety. The spatial model is used in this paper, considering the comprehensive various factors to check of the safety. From the theoretical analysis results, crack may appear in the operation of this bridge after 30 years and suggestions on reserve pipeline in such places with external prestressing tendons or adding prestressed tendons.