Research on Damage Identification Method for Steel-concrete Composite Beams Based on Modal Curvature Difference
Under the fatigue loads and adverse environmental effects,the in-service steel-concrete composite beams may experience different forms of damage,resulting in a decrease in structural per-formance and resistant capacity.Therefore,necessary health detection and damage assessment are nee-ded.The modal curvature changes of steel-concrete composite beam before and after the damage of studs and steel girder were analyzed using ANSYS finite element model.Based on the difference of modal cur-vature,the studs damage and steel girder damage were identified.Finally,the identification method was verified through model experiments.The results show that,after the stud is damaged,the reverse slope of the modal curvature in the damaged area disappears,meanwhile the value of modal curvature differ-ence at two ends of the damaged area experience extreme points.The area where the reverse slope of the modal curvature disappears and the area between the extreme points of the modal curvature difference can be determined as the damage area of studs.After the steel girder is damaged,both the modal curva-ture and the modal curvature difference undergo sudden changes at the damage location,with the latter showing more significant changes.The modal curvature is affected by the spacing and path when picking the values.When the spacing between picking points is taken as the spacing between studs,the studs damage and steel girder damage can be effectively identified through different paths.The modal test results can verify the feasibility of the identification method by modal curvature difference,but the iden-tification accuracy is greatly affected by measurement errors.
steel-concrete composite beamdamage identificationmodal curvature differencemodal test
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