Research On The Construction And Control Of Large-span Continuous Rigid Frame Bridge

With the rapid development of our national transportation and the improvement of bridge building technology, the bridge building turns out to be more large-span and high-tech, and prestressed concrete continuous rigid bridge holds a dominant position for its advantage of high strength, crisp lines, simple and quick construction, and strong leaping ability during the 100-300m span bridges. Large-span prestressed concrete continuous rigid bridge construction usually adopts symmetric cantilever casting method and is a complicate construction process, during which the actual state of the bridge turns out to be an aberration from the theoretical calculation state due to many identified and unidentified influencing factors. Therefore, the bridge construction controlling is indispensable in order to guarantee the quality and security of bridge building, to ensure the alignment and structural internal forces of continuous rigid bridge meet the designed requirement and to make actual state of continuous rigid conform to the designed state as much as possible.In the first place, based on the project of Liang-Ji Canal Bridge on the highway from Jinan to Heze, the content, method and basic principle of large-span continuous prestressed concrete rigid bridge construction is expounded, and a suitable construction control program is given in this paper. By establishing calculating model for Liang-Ji Canal Bridge construction, the construction process is analyzed and the change in stress and displacement of key cross-section is controlled effectively and is compared with actual measured results, during which reliable data is provided to construction control work.In the second place, linear forecast focus of the construction process is discussed and grey theory and Kalman filtering theory are introduced. What is more, in order to control the construction process of Liang-Ji Canal Bridge, prediction model is established to forecast the adjusted deflection value of the main beam, which is proof that Kalman filtering grey predictive value is closer to the actual value.At last, a brief introduction of basic concept of temperature field and basic calculating principle of temperature effect is given. Based on the actual measured data, the temperature field of box beam and temperature effect is simulated by bridge finite element software, which helps to analyze the change of deflection and stress brought by temperature difference during cantilever construction and to draw the relevant conclusions.