Application Of Parameter Sensitivity Analysis In Construction Monitoring Of Prestressed Concrete Continuous Beam Bridges

With the vigorous development of China's civil engineering industry,the construction technology of concrete bridge structure is gradually improved,the prestress technology is popularized and applied in the process of bridge construction,and the prestress concrete continuous beam bridge has become one of the most commonly used bridge types due to its unique advantages.There are many construction techniques for prestressed concrete continuous beam bridge,such as full support,push up method and cantilever method,among which cantilever method is the most complex and difficult to control.In order to ensure the safety of bridge construction,it is necessary to identify the sensitivity of the influencing parameters of the construction process and study the main influencing factors,so as to carry out efficient construction monitoring.This article first elaborated the construction monitoring content and method,and then to a super-large bridge(48 + 80 + 48)m three span prestressed concrete continuous girder bridge as the background,using the finite element software MIDAS/Civil to simulate the construction process,studies the structure internal force and deformation law in the process of bridge construction,and then by controlling the variable parameter sensitivity analysis of construction process,then studies the influence of the friction loss of prestress bridge structure,finally,the construction supervision of the bridge engineering monitoring means,the main conclusions are as follows:1.During the cantilever construction,due to the action of prestressing force,all beam sections are in the state of compression,and the stress variation range from the cantilever root to 1/2 of the cantilever length is large,and then gradually tends to be gentle.2.During the cantilever construction,during the early casting,the vertical displacement of the beam section is small and tends to be stable;when the cantilever length exceeds 1/2 the total length of the cantilever,the vertical displacement value changes greatly and the amplitude gradually increases.3.Through sensitivity analysis of various parameters,the degree and degree of influence of concrete bulk density,concrete elastic modulus and prestressed load on the internal force and deformation of the main beam during construction is obtained.4.Through the study of friction test,the actual friction parameters are obtained.The structure analysis method is used to get the modified model can better reflect the actual construction conditions.5.Based on the analysis of the monitoring results of the continuous beam bridge,the theoretical values calculated by the model after parameter modification can better reflect the stress and deformation of each stage of construction,and effective construction monitoring can provide guarantee for the safety and quality of construction.