Use of modal flexibility method to detect damage in suspended cables and the effects of cable parameters

Modal flexibility is a widely accepted technique to detect structural damage using vibration characteristics. Its application to detect damage in long span large diameter cables such as those used in suspension bridge main cables has not received much attention. This paper uses the modal flexibility method incorporating two damage indices (DIs) based on lateral and vertical modes to localize damage in such cables. The competency of those DIs in damage detection is tested by the numerically obtained vibration characteristics of a suspended cable in both intact and damaged states. Three single damage cases and one multiple damage case are considered. The impact of random measurement noise in the modal data on the damage localization capability of these two DIs is next examined. Long span large diameter cables are characterized by the two critical cable parameters named bending stiffness and sag-extensibility. The influence of these parameters in the damage localization capability of the two DIs is evaluated by a parametric study with two single damage cases. Results confirm that the damage index based on lateral vibration modes has the ability to successfully detect and locate damage in suspended cables with 5% noise in modal data for a range of cable parameters. This simple approach therefore can be extended for timely damage detection in cables of suspension bridges and thereby enhance their service during their life spans.

[1]  H. F. Zhou,et al.  Modal Flexibility Analysis of Cable‐Stayed Ting Kau Bridge for Damage Identification , 2008, Comput. Aided Civ. Infrastructure Eng..

[2]  Dyab Khazem,et al.  Main Cable Corrosion Monitoring for Suspension Bridges Using a Nondestructive Sensing System , 2012 .

[3]  Charles R. Farrar,et al.  Comparative study of damage identification algorithms applied to a bridge: I. Experiment , 1998 .

[4]  Yi-Qing Ni,et al.  DYNAMIC ANALYSIS OF LARGE-DIAMETER SAGGED CABLES TAKING INTO ACCOUNT FLEXURAL RIGIDITY , 2002 .

[5]  Najib Bouaanani.  Numerical investigation of the modal sensitivity of suspended cables with localized damage , 2006 .

[6]  Hiroshi Zui,et al.  Practical Formulas for Estimation of Cable Tension by Vibration Method , 1980 .

[7]  David P. Thambiratnam,et al.  Vibration Characteristics of Shallow Suspension Bridge with Pre-tensioned Cables , 2005 .

[8]  A. K. Pandey,et al.  Damage Detection in Structures Using Changes in Flexibility , 1994 .

[9]  José Turmo,et al.  Linear vertical vibrations of suspension bridges: A review of continuum models and some new results , 2010 .

[10]  Yl L. Xu,et al.  Modal analysis of tower-cable system of Tsing Ma long suspension bridge , 1997 .

[11]  David P. Thambiratnam,et al.  Development of a vibration based method to update axial shortening of vertical load bearing elements in reinforced concrete buildings , 2013 .

[12]  A. K. Pandey,et al.  Experimental verification of flexibility difference method for locating damage in structures , 1995 .

[13]  Taehyo Park,et al.  Estimation of cable tension force using the frequency-based system identification method , 2007 .

[14]  Billie F. Spencer,et al.  Damage localization under ambient vibration using changes in flexibility , 2002 .

[15]  David P. Thambiratnam,et al.  Vibration based structural damage detection in flexural members using multi-criteria approach , 2009 .

[16]  Ahmet E. Aktan,et al.  Bridge-condition assessment by modal flexibility , 1994 .

[17]  Jean-Claude Golinval,et al.  Structural damage localization by combining flexibility and stiffness methods , 2005 .

[18]  Jan Ming Ko,et al.  Modal sensitivity analysis of Tsing Ma Bridge for structural damage detection , 2000, Smart Structures.

[19]  Charles R. Farrar,et al.  Computation of structural flexibility for bridge health monitoring using ambient modal data , 1996 .

[20]  Bijan Samali,et al.  Application of the modified damage index method to timber beams , 2008 .

[21]  S. Law,et al.  Structural Damage Detection from Modal Strain Energy Change , 2000 .

[22]  E. Parloo,et al.  Sensitivity-based operational mode shape normalisation: Application to a bridge , 2005 .

[23]  Filippo Ubertini,et al.  Eigenproperties of suspension bridges with damage , 2011 .

[24]  Hezhen Yang,et al.  Modal Strain Energy Decomposition Method for Damage Localization in 3D Frame Structures , 2006 .

[25]  Hyung-Jo Jung,et al.  Modal flexibility-based damage detection of cantilever beam-type structures using baseline modification , 2014 .

[26]  S. S. Law,et al.  DAMAGE LOCALIZATION BY DIRECTLY USING INCOMPLETE MODE SHAPES. TECHNICAL NOTE , 2000 .