Construction Monitoring Of High-pier Large-span Box-girder Bridge With Continuous Rigid Frame And Curved Beams

Currently, many highways cross steep-terrained mountainouses and valleys in the southwest of China, which demands high-pier and large-span curved bridges with complicated filates to satisfy the need. Due to the influence of curvature, construction monitoring of curved beam bridges is much more difficult than that of straight bridges, however, relevant researches have never been made a lot abroad. Lahui viaduct, in terms of height, ranks number one in Guangxi Zhuang Automomous region and number two in Asia among curved beam bridges with same structure. Therefore, the research on it can be meaningful in academy and useful in practical engineering construction. This paper sets the8th main part of Lahui viaduct as an example, introduces the project of Liuzhai-Yizhou highway in Guangxi and carries out the research on construction monitoring of box-girder bridges with high piers and curved beam.After it takes concrete unit weight tests, the curve of elastic-modulus experiments and basket weight pressure tests and fixes period, technology and the temporary loads, simulation model of construction is finally builded via forward analysis method and Midas civil2010software.Have a long-term observation of the flunctuation value of stress and displacement of the T-shape cantilever before and after block pouring, prestressing elongation and closure as well as under different temperature-conditions.To define the main impact factors in different conditions by application of the model for dynamic simulation in construction and calculation of variable values in theory for each block in all conditions. Through sensitivity analysis of both stress and displacement, it is defined that loading errors at the stage of cantilever construction is caused by dead weight and prestressing force. Through sensitivity to parameter variations, it is determined that the error type of actual values and theoretical values.In view of the influence of temperature on bridge stress and distortion, linear-difference method is proposed to define theoretical values under the influence of measured temperature.Have a research on application of the mearsuement-errors recognition and grey theory in construction prediction. Based on the relevant coefficients of both theretical data and measured data, this paper preoposes a semiempirical and semi-theory formula for mearsuement errors and five calculation methods for prediction errors through grey system:the average value of the5lowest residual errors, the average value of the top5freguency of residual-error grades, the weighted average value of the prediction errors of adjusted values limited in apt interval, the weighted average value of the5lowest residual errors and the weighted average value of the data of the top5freguency of residual-error grades limited in apt interval.The analysis of the influence of high pier, settlement and distortion on the upper structure of bridge can provide relevant technical reference for similar studies in the future.