Research On Identification Of Damaged Hanger And The Sections Of Anchoringcables Of Suspension Bridges Based On Monitoring Of Strain

The research object of this paper is a suspension bridge which prototype background is Humen Bridge located in Guangdong province of China.The health monitoring method of the main cable and the hangerwas studied in the following steps. The finite element model of the bridge was established first And then, based on the benchmark of the finite element model of Humen Bridge and the hypothesis of linear relationship, the damage of the cable was monitored according to the strains under under different working conditions. The results of the analysis prove that the damage of the hanger and anchorage region of the main cable can be effectively identified using the hypothesis of linear relationship. Therefore, this method is reliable for the health monitoring of the main cable and the hanger of the suspension bridge. The main research content of this paper includes the following aspects:(1) Humen Bridge was taken as the research object and itsfinite element model was established according to the existing data of Humen Bridge. And then, the finite element model was modified based on the designed cable force value and bridge type.Benchmark model of finite element for Humen Bridge was obtained subcequently so thatthe calculated results could be used in the Structural health monitoring.(2) Based on the benchmark modelof Humen Bridge, the finite element simulation was carried out The monitored variable was the strain of the main cable and the hangermand. Firstly, under the situation ofdifferent kinds of combinations and amouts of damages, the cable strain was calculated which was used in Structural health monitoring.Thenthe linear relationship between the health of the cable anchorage zone and the derrick with the strain was verified based on the hypothesis of linear relationship. Data showed that the linear hypothesis was acceptable when the setted damage degree was not larger than 30%. It could be said that the damage of the main cable anchorage zone and the derrick could be expressed in the linear relationship equations.(3) Based on the above theory of linearity hypothesis, identification method of cable (mian cable and hanger) damage was studied. Because the linear relationship is approximate, so the healthy state of main cable and the hangermand couldnot directly solving through the linear equations. Thus this paper used multi-objective optimization algorithm to solve the noninferior solution of cable damage vector and thenidentified the damages of the main cable and the hangerunder different combinations.The research results show that the damages of the cable anchorage zone and the hanger can be identified wellbased on the linear relationship and the multi-objective optimization algorithm, including the number of the damaged cables, the location of the damage, and the degree of the damage.