Continuous dynamic monitoring of a lively footbridge for serviceability assessment and damage detection

This paper aims at analyzing the feasibility of applying a vibration based damage detection approach, based on Principal Components Analysis (PCA), to eliminate environmental effects using the large amount of high quality data continuously collected by the dynamic monitoring system of Pedro e Ines footbridge since 2007. Few works describe real data, regularly collected along several years by reliable continuous dynamic monitoring systems in bridge structures. One main contribution is to show a large difference between making academic research based on numerical simulations or limited experimental samples, and making validity tests of innovative procedures using large high quality databases collected in real structures. The monitoring system, installed with the only initial objective of checking the efficiency of vibration control devices used to mitigate lateral and vertical vibrations, was therefore further developed for research purposes by implementing LabVIEW based automated signal processing and output-only modal identification routines, that enabled the analysis of the correlation of modal estimates with the temperature and the vibration level, as well as the automatic tracking of modal parameters along several years. With the final purpose of detecting potential structural damage at an early stage, the Principal Components Analysis (PCA) was employed to effectively eliminate temperature effects, whereas Novelty Analysis on the residual errors of the PCA model was used to provide a statistical indication of damage. The efficiency of this vibration based damage detection approach was verified using 3 years of measurements at Pedro e Ines footbridge under operational conditions and simulating several realistic damage scenarios affecting the boundary conditions. It is demonstrated that such a dynamic monitoring system, apart from providing relevant instantaneous dynamic information, working as an alert system associated to the verification of vibration serviceability limits, can also serve as an effective tool for long term bridge health monitoring.

[1]  Douglas C. Montgomery,et al.  Introduction to Statistical Quality Control , 1986 .

[2]  Filipe Magalhães,et al.  Online automatic identification of the modal parameters of a long span arch bridge , 2009 .

[3]  A. R. Flint,et al.  Planning and implementation of the structural health monitoring system for cable-supported bridges in Hong Kong , 2000, Smart Structures.

[4]  Yi-Qing Ni,et al.  Correlating modal properties with temperature using long-term monitoring data and support vector machine technique , 2005 .

[5]  C. Heinmeyer,et al.  Human induced vibrations in footbridges. Design guidelines. , 2008 .

[6]  Gaëtan Kerschen,et al.  Structural damage diagnosis under varying environmental conditions—Part I: A linear analysis , 2005 .

[7]  Filipe Magalhães,et al.  Operational modal analysis for testing and monitoring of bridges and special structures , 2010 .

[8]  Filipe Magalhães,et al.  LabVIEW toolkits for output-only modal identification and long-term dynamic structural monitoring , 2010 .

[9]  G. De Roeck,et al.  Vibration based Structural Health Monitoring using output-only measurements under changing environment , 2008 .

[10]  Bart Peeters,et al.  Continuous monitoring of the Øresund Bridge: system and data analysis , 2009 .

[11]  Filipe Magalhães,et al.  Studies for controlling human-induced vibration of the Pedro e Ines footbridge, Portugal. Part 1: Assessment of dynamic behaviour , 2010 .

[12]  Joaquim Figueiras,et al.  Monitoring system for execution control applied to a steel arch footbridge , 2012 .

[13]  Guido De Roeck,et al.  EFFECT OF TEMPERATURE ON DYNAMIC SYSTEM PARAMETERS OF A HIGHWAY BRIDGE , 1997 .

[14]  Elsa Caetano,et al.  Assessment and control of human-induced vibrations in the new Coimbra footbridge , 2005 .

[15]  Filipe Magalhães,et al.  Vibration based structural health monitoring of an arch bridge: From automated OMA to damage detection , 2012 .

[16]  Wei Hu,et al.  Implementation of a dynamic monitoring system at coimbra footbridge , 2008 .

[17]  Hu Wei-Hua,et al.  Operational modal analysis and continuous dynamic monitoring of footbridges , 2011 .

[18]  Jyrki Kullaa,et al.  DAMAGE DETECTION OF THE Z24 BRIDGE USING CONTROL CHARTS , 2003 .

[19]  Elsa Caetano,et al.  Investigation on damage detection of footbridges using continuous dynamic monitoring data , 2011 .

[20]  John T. DeWolf,et al.  Effect of Temperature on Modal Variability of a Curved Concrete Bridge under Ambient Loads , 2007 .

[21]  Rolf G. Rohrmann,et al.  Structural causes of temperature affected modal data of civil structures obtained by long time monitoring , 2000 .

[22]  Bart De Moor,et al.  Subspace Identification for Linear Systems: Theory ― Implementation ― Applications , 2011 .

[23]  Hoon Sohn,et al.  Effects of environmental and operational variability on structural health monitoring , 2007, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[24]  Filipe Magalhães,et al.  Studies for controlling human-induced vibration of the Pedro e Inês footbridge, Portugal. Part 2: Implementation of tuned mass dampers , 2010 .

[25]  Paul Reynolds,et al.  Vibration serviceability of footbridges under human-induced excitation : a literature review , 2005 .

[26]  Keith Worden,et al.  DAMAGE DETECTION USING OUTLIER ANALYSIS , 2000 .

[27]  Hoon Sohn,et al.  An experimental study of temperature effect on modal parameters of the Alamosa Canyon Bridge , 1999 .

[28]  Guido De Roeck,et al.  One-year monitoring of the Z24-Bridge : environmental effects versus damage events , 2001 .

[29]  Filipe Magalhães,et al.  Dynamic monitoring of a long span arch bridge , 2008 .