| In order to reduce life and property loss caused by accidents of concrete-filled steel tube arch bridge (CFST), it is very necessary to monitor and evaluate its health condition. The response parameters of the bridge, including strain, cable force and displacement, can reflect the health condition of the bridge. Sensors are the direct tools to obtain these parameters. Traditional sensors used in monitoring CFST arch bridge have exposed a lot of problems, such as poor durability and low accuracy of measurement, low sampling frequency, vulnerable to environmental factors. It urgent needs the latest sensor technology to solve these problems in bridge health monitoring. In this paper, based on the monitoring platform of a half-through steel tube arch bridge model, up-dated and developmental sensors technology were applied to the monitoring of testing bridge model, the main research work is as follows.(1) According to the experimental research and the general requirements of Outstanding Civil Engineer Platform of Zhejiang University, an experimental steel tube arch bridge model was designed to simulate the real bridge. The design concept, key technology, construction process and design details of steel tube arch bridge model were also introduced in details. Strength, stiffness and stability of the steel tube arch bridge model were analyzed(2) Static and dynamic behavior of steel tube arch bridge model was analyzed by finite element program. Theoretical internal force, stress and deformation of arch rib, longitudinal beam and crossbeam were calculated in completed bridge phase and moving vehicle loads condition. Frequency and vibration model of steel tube arch bridge model were obtained from finite element model. Buckling stability analysis verified its stability meet the requirements of the maximum testing load conditions.(3) Static and dynamic test of steel tube arch bridge model was carried on. By comparison between the theoretical value obtained from numerical simulation and the measured value, high precision, high sensitivity and not affected by electromagnetic interference of FBG strain sensors were verified. The measured results were in good agreement with the results obtained from numerical simulation about fundamental frequency. There is only4.1%error between them.(4) High order vibration mode’s influence on the dynamic response analysis of long-span arch bridge can not be ignored, It is necessary for large span arch bridge to be nonlinear time history analysis, Torsional vibration model of wind braces and rigid crossbeam around the longitudinal direction appeared in the first order vibration mode, So it is the key to select vertical stiffness of transverse connection component in CFST bridget for the design of long span arch bridge(5) Optical fiber sensors were used to test suspender cable force of steel tube arch bridge model. Test results shown that the optical fiber grating sensors have good linearity and can accurately measure cable force. Optical fiber sensors have high sampling rate, its sampling frequency can reach several thousand hertz. Optical fiber sensors can be well used to monitor suspender cable force of arch bridge on the condition of high-speed vehicle loads.(6) Machine vision displacement monitoring system which is based on correlative matching algorithm was used to monitor arch rib and longitudinal beam deformation. Through several test cases in different working distance and different angle, it indicated that dynamic displacement measurement of arch bridge model was come true at the precision of1/100millimeter; it has important application prospects in the deflection displacement of civil engineering structure monitoring. |
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