The Study On Construction Monitoring And Prestress Loss Of The Deck-Type Beam-Arch Combination Bridge

In recent years,the beam-arch combination bridge are favored in urban bridge applications because of its strong adaptability to its foundation,large span,beautiful shape and so on.As one of the beam-arch combination bridge,the control section strain and deformation of deck-type prestressed concrete beam-arch combination bridge were collected and analyzed when the construction was carried out by the full-frame method.Which can correctly guide the bridge construction and ensure the construction quality.In addition,the formula of total prestress loss of the bridge in current norms is partial calculation method,of which the process is more complex and the empirical coefficients are more,Therefore it is necessary to change the way of thinking and make full use of the collected data during bridge construction and late monitoring,and carry out the study on simplified calculation method of stress comprehensive loss under the condition of monitoring.This article relies on the project "Construction Monitoring of Bridge on Fengqiao Road and across Cihu River in Ma’anshan ",and the quality of the whole process of the bridge construction was controled by the field measurement and modeling analysis.Furthermore,a simplified calculation formula which can estimate the comprehensive loss of prestressed bridge quickly in different time was proposed on the basis of the monitoring data of the main control section.The main works were as follows:1.According to the design drawings and construction scheme,the full-bridge finite element model is established by Midas Civil,and theoretical calculation is made on the beam-arch combination bridge.According to the calculation results,the control section is selected and the measuring points are arranged,thus the construction monitoring scheme is proposed.While the construction process is instructed and the quality and safety of the bridge are controlled in accordance with the monitoring scheme.2.The monitoring data is processed,the temperature error is eliminated,and the change of the force state during the bridge construction is analyzed through the data comparison of the relevant measuring points.The reliability of the theoretical model is proved by comparing the measured value and the theoretical value of the two bridges,while the reason of the error is analyzed.3.For the deck-type beam-arch combination bridge,the theoretical analysis and the simplified calculation of the structural calculation model,the cross-deflection formula under the joint action of self-weight and prestress is put forward,and then a simplified calculation method for calculating the prestress loss directly by mid-span deflection and cross-sectional strain is deduced.4.Based on the bridge monitoring data of this paper,the simplified calculation method,the Chinese normative method and the American normative method are used to calculate the prestressed loss of the bridge respectively.The results of this method are between the two countries,so it is proved that the calculation method has high accuracy,Can be used as a basis for rapid estimation of the comprehensive loss of prestressed bridge of the same type.