THE UNIVERSITY OF MANITOBA FACULTY OF GRADUATE STUDIES STRUCTURAL HEALTH MONITORING OF THE GOLDEN BOY BY BOGDAN ANDRES BOGDANOVIC A Thesis/ Practicum submitted to the Faculty of Graduate Studies of The University of Manitoba in partial fulfilment of the requirements of the degree of MASTER OF SCIENCE BOGDAN ANDRES BOGDANOVIC @ 2OO4 DEPARTMENT OF CIVIL ENGINEERING WINNIPEG, MANITOBA JULY 2OO4 THE UNTYERSITY OF MAI\IITOBA FACTJLTY OF GRÄDUATE STIIDIES ***** COPYRIGHT PERMISSION STRUCTURAL HEALTH MONITORING OF THE GOLDEN BOY BY BOGDAN ANDRES BOGDANOVIC A ThesislPracticum submitted to the Faculty of Graduate Studies of The University of Manitoba in partial fulfillment of the requirement of the degree of MASTER OF SCIENCE Bogdan Andres Bogdanovic @ 2004 Permission has been granted to the Library of the University of Manitoba to lend or sell copies of this thesis/practicum, to the National Library of Canada to microfilm this thesis and to lend or sell copÍes of the film, and to University MicrofïIms Inc. to publish an abstract of this thesis/practicum. This reproduction or copy of this thesis has been made available by authority of the copyright o\ilner solely for the purpose ofprivate study and research, and may only be reproduced and copied as permitted by copyright laws or with express written authorization from the copyright owner. Abstract ABSTRACT The elaborate inspections performed on civil structures tend to be very time and cost consuming. lt is somewhat difficult to asses the damage or deterioration by visual inspection and may perhaps lead to the sudden demise of the structure. The Golden Boy statue was faced with this problem. Through an extensive inspection of the statue's shaft, it was determined that the diameter of the shaft had reduced by approximately 10% due to corrosion. A wind tunnel test and theoretical analysis of the statue demonstrated that for a hundred year wind the steel shaft would reach approximately 91% of its ultimate strength. To avoid this sudden collapse, the Golden Boy was removed from the top of the legislature's dome and the shaft was replaced. ln addition, sensors were installed on the shaft of the Golden Boy as a mean to asses the behaviour and condition of the structure in the future. lt provides an effective and cost effective method for condition assessment and Structural health monitoring (SHM). This thesis presents the installation of sensors, the key elements of a successful SHM system and an in-depth processing and interpretation of the SHM data. A mathematical model and theoretical analysis of two diagnostics tests are also presented. The accuracy of the diagnostic tests and model is demonstrated by comparing the behaviour of the analysis of the strain gauge data collected. The strain gauge data records only the dynamic and thermal strains of the statue due to the wind and temperature, respectively. The analysis consist of removing the ii Abstract thermal strains and obtaining the dynamic strains due to the wind action experienced at that instant. The diagnostic tests are determined by two different types of theoretical approaches which are able to set some kind of confidence in the data. The results are compared to one another as a result of the maximum gust of wind intensity during some time frame. The diagnostic test of the accelerometer at high wind velocity ranging from 3OKm/hr to the maximum of S9Km/hr, demonstrates an average increase of 9% in maximum strain when compared to the strain gauge analysis results. The diagnostic test of the wind meter shows a quite higher average increase of 35%. The diagnostic tests demonstrate an alternative way to establish the structural movement of the Golden Boy, should the strain gauges malfunction. The analysis provides some guidelines for what is expected for maximum strain during a typical windy day (max. gust velocity) and allows for a simplified formula to predict the maximum boundary strain limits for different winds. The natural frequency of 3 Hertz is verified by both theoretical analysis of the mathematical model and the Fast Fourier Transform (FFT) of the live data sensor (Accelerometer). lt establishes the main criterion of the statue being in great health as well as set the limit for the future if the natural frequency changes. All findings are based on the early stage of the SHM process. This work will serve as the initial starting point and foundation for the long term and continuous monitoring of the Golden Boy. The data collected has shown the reliability of the instrumentation and SHM system. Furthermore, the study has produced observation and recommendation for future work in the SHM of the Golden Boy. iii Acknowledqements ACKNOWLEDGEMENTS This research project was carried out under the direct supervision of Dr. Aftab. A. Mufti. The author wishes to express his gratitude to Dr. Aftab A. Mufti for his academic support, guidance and advise as well as experience and knowledge throughout the investigation. Appreciation is extended to the technical assistant of Mr. Moray Mcvey, Mr. Grant Whiteside and Chad Klowak for their Laboratory assistance and the installation of all sensors devices for the SHM process of the Golden Boy. The author wishes to thank Ms. Liting Han and Mr. Gregory Page for all their assistance in the civionic and computer aspect of the project, respectively. Their expertise and knowledge in the field of electrical and computer web designing is very essential part in the remote monitoring process. The evolution of "ClVlONlCS" continues to expand in ways unimaginable for Engineers. Also recognise the helpful advise in writing and editing the report by Dr. Ashutosh Bagchi and as well as his guidance, advise and expertise Knowledge in the field of Structural Health monitoring. Gratitude is extended to Dillon Consulting Engineer, Mr. Bob Wiebe, Government Service Engineer, Mr. Mike Hawrylak and Legislative Building Superintendent, Mr. Todd Mickalash for their constant guidance, patients, concerns and assessment on the SHM aspects at the Legislature Building. Finally, the author wishes to express his sincere gratitude to his parents and son Colton for their support throughout my studies and also for their strength, support and encouragement throughout this project. iv Acknowledoements CONTRIBUTION TO SHM KNOWLEDGE The following involvement was obtained through the SHM of the Golden Boy project: o The implementation and contribution of Civionics which includes the combination of two different disciplines, electrical and civil engineering. The execution of instrumentations preparation and installation. The contribution to the SHM system. The contribution to designing the web site for continuous monitoring of different projects around the lSlS Canada Network. The implementation of the mathematical model. The implementation of the data collecting, data retrieval, data processing and data interpreting for the analytical part of the SHM project. The correlation and comparison of the theoretical model analyses to the actual live data recorded. Table of Contents TABLE OF CONTENTS ABSTRACT il ACKNOWLEDGEMENTS IV TABLE OF CONTENTS VI LIST OF FIGURES LIST OF TABLES XIV I.INTRODUGTION I 1.1. PROBLEM I 1.2. OBJECTIVES 3 1.3. SCOPE 4 2. BACKGROUND 2.1 . MANITOBA LEGISLATURE BUILDING 6 2.2.THE GOLDEN BOY STATUE 9 2.3. STRUCTURAL CONCERNS 12 2.4. STRUCTURAL HEALTH MONTTORTNG (SHM) 17 2.5. CtVtONtCS t9 3. INSTALLATION OF THE SHM SYSTEM 20 VI Table of Contents 3.1 . RESTORATION PROCESS 20 3.2. THE CIVIONICS SYSTEM 2t 3.2.1. PRrpnRnroru or ITSrRUMENTS 24 3.2.2. I¡rsrRuro¡r PRocrss 27 3.2.2.1. Rosette Strain Gauges and Thermocouples 29 3.2.2.2. Fibre Bragg Grating Sensors 3l 3.2.2.3. Accelerometers 32 3.2.2.4. Electrical Box 35 3.3. STRUCTURAL HEALTH MONITORING PROCESS 35 3.3.1. lrusrRuïoN oF THE SHM CorurRoL RooM 36 3.3.2. SrRucrunRL HEALTH MoITIIToRIIIG SYSTEM 40 3.3.2.1. Acquisition of Data 4l 3.3.2.2. Communication of Data 42 3.3.2.3. lntelligent Processing of Data 42 3.3.2.4. Storage of Processed Data 44 3.3.2.5. Retrieval of Data 45 3.3.3. DnrR AcoursrroN (DAO) Sysruu 45 3.3.4. Wee BRsEo MoNrroRrNc 48 3.3.5. lrusrRuroN oF THE UIIRR Sorrrrc Wlr.ro SrrusoR 49 3.4. LOCATION OF SENSORS 53 3.4.1 . DRvne¡o lrusrnu¡¡rruTATroNS 55 3.4.2. Role or CrvroNrcs Spgcrncnrorus 56 4. THEORITICAL ANALYSIS 57 4.1. STRUCTURAL MODEL 57 vil Table of Gontents 4.2. NOTATION AND S¡GN CONVENTION 6t 4.3. STATIC ANALYSIS 62 4.4. STRESSES o5 4.4.1. AxrRl SrRrss 65 4.4.2. BENDTNG Srnrss 66 4.4.3. SHeRR SrRrss 67 4.4.4. Con,rarNro SrRrsses 68 4.4.4.1. Mohr's Circle Representation 70 4.5. STRAIN 7l 4.6. WIND LOADING or 100 YEAR wrND sroRM (NBCC,1995) 72 4.7. DYNAMIC ANALYSIS 78 4.7.1. FRrr VraRAroÌ.r 79 4.7 .2. EourvRlerur Srrrrrurss 82 4.7 .3. Foncro VTBRATToN 84 4.7 .4. No¡rprRroorc ExcrtRt¡otrr 86 5. PROCESSING AND INTERPRETING THE SHM DATA 89 5.1. WIND RETRIEVAL INFORMATION CENTRE 90 5.2. STORAGE, RETRIEVAL AND MODIFICATION OF DATA 93 5.3. ANALYSIS OF THE STRAIN GAUGE DATA 95 5.4. ANALYSIS OF THE ACCELEROMETER DATA 99 5,4.1 . A¡IRI-ysIs RESULTS 100 5.4.2. NuveRrcRl Rrsulrs r02 5.5. DIAGNOSTIC DYNAMIC ANALYSIS AND RESULTS t02 5.5. 1 . NRruRru FRrougtr¡cv 103 viii Table of Gontents 5.5.2. DyNAMrc ArrrRr-ysrs o¡r Wr¡ro MEreR DRIR 106 5.5.2.1. Matlab Program 109 5.5.2.2. Numerical Results r12 5.5.2.3. Effect of Damping ll3 5.6. DISCUSSION AND COMPARISON 115 5.7. SIMPLIFIED FORMULA 122 6.