| Structural safety problems will inevitably occur in the operation process of traditional Bridges.Special appearance inspection is usually used to obtain some structural characteristics to judge the problems.However,it is not sufficient to infer the overall state through a single inspection structure,which has great limitations.It will also cause sudden bridge diseases that can not be found in time,and will also be affected by the professionalism of inspection personnel.Therefore,it is necessary and of great significance to study the corrosion characteristics of the main cable by means of main cable ventilation test,which can provide long-term anticorrosion data for the maintenance of similar old Bridges in the future.At present,some progress has been made in main cable anticorrosion.However,due to the large amount of effective information hidden in the data collected by the dehumidification system that has not been mined and utilized in time,accurate and effective data processing of the main cable dehumidification system needs to be focused on.In order to ensure the safe operation of the suspension bridge,the data collected by the main cable dehumidification system can be analyzed and the dehumidification status of the main cable can be evaluated,so as to give timely warning information to the main cable.It provides a new idea for improving the design of air supply mode of bridge main cable,and speeds up its own information acquisition and research and judgment of the healthy development trend of bridge,so as to further promote the comprehensive development of bridge technology.Based on the preventive maintenance test of cable system protection of suspension bridge of Huangpu Bridge,this paper carries out the following research:(1)Collect and summarize the development of bridge acquisition and monitoring system at home and abroad,and summarize the data processing and analysis methods in the latest time.Analyze the necessity of main cable corrosion mechanism,main cable anti-corrosion development system,composition of main cable dehumidification system and significance of main cable ventilation test in bridge operation state.Taking Huangpu Bridge as the research object,the field test study of main cable ventilation was carried out,including the whole test overview monitoring content,test purpose,theoretical basis,selection of test section,layout of monitoring points,selection of monitoring equipment and technical parameters.(2)Using software MATLAB to write programs to process data,including abnormal data elimination,data omission completion,redundant data smoothing,etc.,combined with3 σ x criteria,Grubbs criteria,estimation and comparison method,etc.Combined with field tests,abnormal temperature data and pressure data of the main cable were processed,and data were preprocessed in the early stage,which greatly improved the efficiency of data analysis.Abnormal data value processing methods,Lagrange interpolation,Newton interpolation and other methods were used to complete the missing data of main cable pressure.The temperature distribution characteristics are obtained by smoothing the temperature data of main cable by sliding average method and weighted sliding average method.The dehumidification state assessment of the main cable of Huangpu Bridge includes the detection of temperature and humidity,pressure,flow and other data,and explores the relationship between temperature and humidity.Further study on the relationship between air supply flow,exhaust flow and pressure shows that the best range is when the intake pressure is 1000-1500 Pa,the air supply flow of the intake clip is 25 ～ 35 m3/h,and the dehumidification distance should be controlled around 120-150 m.It is concluded that the main cable has different temperature differences in both vertical and vertical directions.When conducting temperature analysis,it is necessary to consider not only the overall temperature rise and fall characteristics of the external environment,but also the differences of local points of the main cable. |
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