Tài liệu Field evaluation of composite materials for bridge strengthening

FIELD EVALUATION OF COMPOSITE MATERIALS FOR BRIDGE STRENGTHENING by ALEXIS ANDRES LOPEZ-INOJOSA A DISSERTATION Presented to the Faculty of the Graduate School of the UNIVERSITY OF MISSOURI-ROLLA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY in CIVIL ENGINEERING 2006 Antonio Nanni, Advisor Genda Qhen John Myers Cesar Mendoza K. Chandrashekhara Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI N um ber: 3229186 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. ® UMI UMI Microform 3229186 Copyright 2007 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Copyright 2006 Alexis Lopez-Inojosa All Rights Reserved Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. PUBLICATION DISSERTATION OPTION The present dissertation has been prepared in the form of five technical papers for publication. The first paper “Field Validation of FRP Strengthening Technologies on Five Reinforced Concrete Bridges,” pages 79 through 99, has been accepted for publication in the ACI Journal Concrete International: Design and Construction. The second paper “Validation of FRP Composite Technology Through Field Testing,” pages 100 through 115, has been published in the World Conference on Nondestructive Testing, Montreal, Canada. August 30- September 3, 2004. The third paper “Strengthening of a Reinforced Concrete Bridge with Externally Bonded Steel Reinforced Polymer (SRP),” pages 116 through 136, has been submitted to the Journal Composites Part B: Engineering (Elsevier). The fourth paper “Bonded and Mechanically Fastened FRP Strengthening Systems: A Case of Study,” pages 137 through 162, has been accepted for special publication of ACI committee 440: 7th International Symposium on Fiber Reinforced Polymer Reinforcement for Reinforced Concrete Structures (FRPRCS-7), to be held in New Orleans, Louisiana, November 9, 2005. The fifth paper “Moment Redistribution in Continuous Reinforced Concrete Slabs Strengthened with Carbon NSM Bar,” pages 163 through 187, has been submitted to the Journal Composites Part B: Engineering (Elsevier). Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. iv ABSTRACT This dissertation document consists on five technical papers, compiling the results of the research done on two projects related to the uses of FRP materials on the strengthening RC bridges structures. Four papers are related to the first project “Validation of FRP Composite Technology Through Field Testing,” and one paper to the second project “Moment Redistribution on Composite-Strengthened RC Slabs.” The work of the first project focuses on field validation of five variances of FRP techniques for strengthening of concrete bridges. Fundamental issues related to bridge strengthening with composites are identified and studied, in particular those associated to construction, analysis and design, load testing, load rating and monitoring. One of the intellectual merit of the present dissertation consist of development of materials and construction specifications, a comprehensive document developed to make the technology of composite available to bridges owners and intended to be used in future FRP-related projects. These specifications cover material and construction requirements for strengthening RC bridges with composites materials and cover the phases of concrete repairs, surface preparation, material specification, storage, handling, installation process, for five technologies used in the project. The work of the second project is focuses on analytical and numerical work to discuss if moment redistribution can be neglected in Reinforced Concreted (RC) flexural slabs strengthened with externally-bonded carbon FRP system. Two 22-ft continues slabs were tested to validate the model. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. v ACKNOWLEDGMENTS The author wishes to express his sincere appreciation and gratitude to his advisor Dr. Antonio Nanni for the opportunity to work under a high performance and professional team. Also, to Dr. Shamsher Prakash for his appropriate and disinterested advise. Special thanks are given to his partner Estela Melian and to his colleagues and friends: Dr Nestore Galati, Eli Hernandez, William Otero, Abigayle Sherman, Gayle Spitzmiller, Jason Cox, Travis Hernandez, Silvia Rocca, Marta Matana, Jess Moss and Wesley Merkle for their cooperation, friendship and help. The author is grateful to the University of Missouri-Rolla (UMR) for the opportunity to pursue PhD studies. Also, to Missouri Department of Transportation (MoDOT), to the Center for Infrastructure Engineering Studies (CIES) at UMR and to the University Transportation center (UTC) at UMR for their financial support. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS Page PUBLICATION DISSERTATION O PT IO N ..........................................................................iii ABSTRACT .............................................................................................................................. iv ACKNOWLEDGMENTS............................................................................................................v LIST OF ILLUSTRATIONS..................................................................................................... xv LIST OF T A B LE S.................................................................................................................... xix SECTION 1. INTRODUCTION......................................................................................................1 2. DESCRIPTION OF THE FIELD VALIDATION PR O JE C T............................. 2 2.1. BACKGROUD AND DESCRIPTION............................................................2 2.2. LOAD TESTING AND MONITORING.........................................................5 2.2.1. Load Testing............................................................................................5 2.2.2. Fiber Optic...............................................................................................6 2.2.3. Crack S ensor.......................................................................................... 7 2.2.4. Installation Criteria for FRP to be Used for Strengthening.............. 7 2.2.5. Delamination and Substrate C ondition............................................... 8 2.2.6. Microwave Near-Field N D T ................................................................ 9 3. MATERIALS AND CONSTRUCTION SPECIFICATIONS............................10 3.1. CONCRETE R E PA IR .................................................................................. 10 3.1.1. Site D em olition.................................................................................. 10 3.1.1.1. General requirem ents.......................................................... 10 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. vii 3.1.1.2. Submittals................................................................................ 10 3.1.1.3. Dust and debris control......................................................... 11 3.1.1.4. Protection................................................................................11 3.1.1.5. Execution................................................................................. 11 3.1.2. Deck Repairs........................................................................................12 3.1.2.1. Description of work................................................................12 3.1.2.2. Locations................................................................................. 12 3.1.2.3. M aterials.................................................................................. 13 3.1.2.3.1. Cementitious patch material................................. 13 3.1.2.3.2. A ggregate................................................................14 3.1.2.3.3. Reinforcing b a rs.....................................................14 3.1.2.4. Equipm ent...............................................................................14 3.1.2.5. Construction m ethod............................................................. 15 3.1.2.6. Surface preparation.................................................................16 3.2. MANUAL LAY-UP CARBON/EPOXY FRP L A M IN A TE.................. 17 3.2.1. G eneral....................................................................................................18 3.2.2. Delivery, Handling and Storage..........................................................20 3.2.3. Products................................................................................................. 21 3.2.3.1. Carbon fabric.......................................................................... 21 3.2.3.2. Epoxy prim er/sealer.............................................................. 22 3.2.3.3. Epoxy putty surface/void filler.............................................22 3.2.3.4. Epoxy saturant........................................................................ 23 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. viii 3.2.4. Execution...............................................................................................23 3.2.4.1. Concrete repair.......................................................................23 3.2.4.2. Surface preparation................................................................ 23 3.2.4.3. Carbon manual lay-up laminate installation.......................25 3.2.4.3.1. Application of filler/surface.................................27 3.2.4.3.2. Application of carbon fiber sheet........................ 27 3.2.5. Rework and Repairs............................................................................. 29 3.2.6. Acceptance Testing.............................................................................. 30 3.3. NEAR SURFACE MOUNTED COMPOSITE BAR SYSTEM ............. 31 3.3.1. G eneral................................................................................................... 31 3.3.2. Delivery and Storage............................................................................ 33 3.3.3. Products................................................................................................. 34 3.3.3.1. Carbon/epoxy FRP bars.........................................................34 3.3.3.2. Epoxy adhesive system..........................................................35 3.3.3.2.1. Epoxy adhesive.......................................................35 3.3.3.2.2. UV protection.........................................................36 3.3.4. Execution...............................................................................................36 3.3.4.1. Concrete repair.......................................................................37 3.3.4.2. Surface preparation................................................................ 37 3.3.4.3. Carbon bar installation............................................................. 38 3.3.5. Rework and Repairs............................................................................. 40 3.4. BONDED CARBON/EPOXY PRE-CURED LAMINATE .....................41 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ix 3.4.1. G eneral................................................................................................... 41 3.4.2. Delivery, Handling and Storage..........................................................43 3.4.3. Products.................................................................................................44 3.4.3.1. Carbon/epoxy FRP pre-cured lam inate.............................. 44 3.4.3.2. Epoxy prim er/sealer.............................................................. 45 3.4.3.3. Adhesive..................................................................................45 3.4.4. Execution...............................................................................................46 3.4.4.1. Concrete repair.......................................................................46 3.4.4.2. Surface preparation................................................................ 46 3.4.4.3. Pre-cured CFRP laminate installation.................................47 3.4.5. Rework and Repairs............................................................................. 50 3.4.6. Acceptance Testing.............................................................................. 51 3.5. STEEL REINFORCED POLYMER LAMINATES ................................52 3.5.1. G eneral................................................................................................... 52 3.5.2. Delivery and Storage............................................................................ 54 3.5.3. Products................................................................................................. 55 3.5.3.1. Steel cord lam inates.............................................................. 55 3.5.3.2. Epoxy resin............................................................................. 55 3.5.4. Execution...............................................................................................56 3.5.4.1. Concrete repairs.......................................................................... 56 3.5.4.2. Surface preparation................................................................ 56 3.5.4.3. Steel reinforced polymer laminate installation...................57 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. X 3.5.5. Rework and Repairs............................................................................. 61 3.5.6. Acceptance Testing.............................................................................. 61 3.6. MECHANICALLY FASTENED FRP LA M IN A TE...............................62 3.6.1. G eneral................................................................................................... 62 3.6.2. Delivery and Storage............................................................................ 64 3.6.3. Products.................................................................................................65 3.6.3.1. FRP strip..................................................................................65 3.6.3.2. Epoxy adhesive system..........................................................65 3.6.3.3. Fasteners..................................................................................66 3.6.4. Execution...............................................................................................66 3.6.4.1. Surface preparation................................................................ 66 3.6.4.2. Mechanically fastened FRP lam inate..................................66 3.6.5. Rework and Repairs............................................................................. 68 4. DESCRIPTION OF MOMENT REDISTRIBUTION PR O JEC T.....................69 5. LAYOUT OF THE DISSERTATION.................................................................. 71 5.1. PA PER S............................................................................................................71 5.2. APPENDICES.................................................................................................. 74 6. CONCLUDING REM A RK S..................................................................................75 BIBLIOGRAPHY.......................................................................................................................77 PAPER 1. FIELD VALIDATION OF FRP STRENGTHENING TECHNOLOGIES ON FIVE REINFORCED CONCRETE BRIDGES.............................................79 ABSTRACT...................................................................................................... 79 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. xi INTRODUCTION.............................................................................................80 DESCRIPTION OF THE PR O JEC T............................................................. 80 BRIDGE ANALYSIS AND COMPOSITE REINFORCEMENT D ESIG N ............................................................................................................. 81 CONSTRUCTION............................................................................................84 Surface Preparation............................................................................. 87 Inspection During Construction........................................................89 LONG TERM M ONITORING.......................................................................91 NDT M ONITORING....................................................................................... 92 CONCLUSIONS...............................................................................................92 ACKNOWLEDGMENTS................................................................................94 REFERENCES.................................................................................................. 94 2. VALIDATION OF FRP COMPOSITE TECHNOLOGY THROUGH FIELD TESTING .................................................................................................. 100 A bstract............................................................................................................ 100 Introduction......................................................................................................100 FRP M aterial....................................................................................................103 Critical Issues on FRP Strengthening........................................................... 104 Fiber Alignment................................................................................... 105 Optimal Surface Roughness................................................................106 Detection of Debonding...................................................................... 108 Strain M easurement.............................................................................110 Degree of Resin C uring...................................................................... 110 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Cracking................................................................................................ I l l Long-term Global Performance......................................................... I l l Results and Discussion................................................................................... 112 Conclusions......................................................................................................112 Acknowledgments...........................................................................................113 References........................................................................................................ 113 3. STRENGTHENING OF A REINFORCED CONCRETE BRIDGE WITH EXTERNALLY BONDED STEEL REINFORCED PO L Y M ER ................... 116 ABSTRACT.....................................................................................................116 INTRODUCTION...........................................................................................116 BRIDGES DESCRIPTION .......................................................................... 118 BRIDGE ANALYSIS AND SRP REINFORCEMENT DESIGN 119 INSTALLATION OF SR P.............................................................................123 Surface preparation.............................................................................123 Reinforcement installation................................................................124 LOAD RATING.............................................................................................. 124 LONG-TERM PERFORMANCE.................................................................125 CONCLUSIONS............................................................................................. 126 ACKNOWLEDGMENTS..............................................................................126 REFERENCES................................................................................................ 127 4. BONDED AND MECHANICALLY FASTENED FRP STRENGTHENING SYSTEMS: A CASE STUDY..........................................137 SYNOPSIS.......................................................................................................137 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. INTRODUCTION...........................................................................................138 BRIDGES DESCRIPTION AND OBJECTIVES.......................................140 BRIDGE ANALYSIS AND ENTERNAL REINFORCEMENT D ESIG N ........................................................................................................... 142 INSTALLATION OF EXTERNAL REINFORCEMENT........................ 145 Surface preparation.............................................................................145 Reinforcement installation................................................................145 LOAD RATING.............................................................................................. 146 FIELD VALIDATION AND FEM ANALYSIS.........................................147 CONCLUSIONS............................................................................................. 150 ACKNOWLEDGMENTS..............................................................................151 REFERENCES................................................................................................ 152 5. MOMENT REDISTRIBUTION IN CONTINUOUS REINFORCED CONCRETE SLABS STRENGTHENED WITH CARBON NSM BARS ..................................................................................................................... 163 ABSTRACT.....................................................................................................163 INTRODUCTION...........................................................................................164 VARIABLES INFLUENCING M R ............................................................. 166 MR IN THE ACI C O D E................................................................................167 ELEMENTS STRENGTHENED WITH F R P ............................................ 169 NEAR SURFACE MOUNTED CARBON FRP BAR SY STEM 171 DECREASE OF DUCTILITY DUE TO FRP REINFORCEMENT 172 NUMERICAL PREDICTION AND EXPERIMENTAL TE ST ...............173 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. xiv Test R esults.........................................................................................176 SUMMARY AND CONCLUSIONS........................................................... 176 REFERENCES................................................................................................ 178 APPENDICES A. CONSTRUCTION REPORT: STRENGTHENING OF BRIDGE P-0962..................................................................................................................... 188 B. DVD: INSTALLATION PROCESS FOR FIVE VARIATIONS OF COMPOSITE MATERIALS.......................................................................... 206 V IT A .......................................................................................................................................... 208 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. XV LIST OF ILLUSTRATIONS Figure Page 2.1. Manual Lay-up FRP Laminates and FRP NSM B ars................................................ 3 2.2. Adhered Pre-cured FRP Laminates.............................................................................. 3 2.3. Mechanically Fastened FRP Lam inates.......................................................................4 2.4. Steel Reinforced Polym ers............................................................................................ 4 2.5. Load Testing Using Surveying E q u ip m en t................................................................ 6 2.6. Fiber Optic Sensors Installation....................................................................................6 2.7. Microwave Image of a D isbond....................................................................................9 2.8. Automated Scanner........................................................................................................ 9 6.1. Flowchart for the Organization of the D issertation...............................................76 PAPER 1 1. Approach to One of the Strengthened Bridges.............................................................97 2. Manual Lay-up FRP Laminate for Shear U -w raps..................................................... 97 3. Adhered Pre-cured FRP Laminate Installation............................................................97 4. Near Surface Mounted Bars Installation.......................................................................97 5. Mechanically Fastened FRP Laminate Installation..................................................... 98 6. Manual Lay-up SRP Laminate....................................................................................... 98 7. Surface Preparation by Sandblasting............................................................................. 98 8. Environmental Pollution C ontrol...................................................................................98 9. Load Testing Using Surveying Equipm ent.................................................................. 99 10. Longitudinal Deflection Before and After Strengthening........................................ 99 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. xvi PAPER 2 1. Representation of FRP M aterial................................................................................... 104 2. Fiber Misalignment Detection...................................................................................... 106 3. Roughness Surface.........................................................................................................108 4. Intentional Delaminations on FRP Lam inates........................................................... 109 5. Load Testing....................................................................................................................112 PAPER 3 1. Fabric Made of Steel Cords...........................................................................................129 2. Lateral View of Bridge P 0 9 6 2 ..................................................................................... 129 3. Cross Section of the Bridge...........................................................................................129 4. Truck Loads HS20-44 and 3 S 2 .................................................................................... 129 5. Internal Strain and Stress Distribution for a Rectangular Section Under Flexural at Ultimate S tage............................................................................................130 6. Illustration of Dimensional Variables Used in Shear Strengthening....................... 130 7. Flexural SRP Strengthening Layout Detail and MomentsforInternal Girders.... 131 8. Shear SRP Strengthening Layout Detail and Shear for Internal G irders................132 9. Surface Preparation........................................................................................................133 10. Cutting the Cord T ape................................................................................................. 133 11. Application of Epoxy R esin....................................................................................... 133 12. Installation of SRP by Manual Lay-up Procedure.................................................. 134 13. Full Impregnation of S R P ...........................................................................................134 14. U-Wraps for Shear Reinforcement.............................................................................134 15. Static Load Test............................................................................................................ 135 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. xvii PAPER 4 1. Side View of the Bridge Y-0298 in Pulaski County, M O.........................................155 2. Areas of Deck with Major Concrete Deterioration on both Sides of the Bridge ..155 3. Geometry of the Bridge................................................................................................. 156 4. FRP Materials Used in Strengthening System ........................................................... 157 5. MF-FRP System for the Strengthening of the Major Deteriorated Areas.............. 157 6. Strengthening Layout of the Bridge Y-0298.............................................................. 158 7. Installation of Manual Lay-up Lam inates...................................................................158 8. Application of the MF-FRP Strengthening System .................................................. 159 9. Instrumentation to Monitor Displacements and Strains............................................160 10. FEM Model for the Bridge Y-0298........................................................................... 160 11. Composite Reinforcement in FEM M odel............................................................... 161 12. Experimental and Analytical Displacement Prior to Strengthening..................... 161 13. Experimental and Analytical Displacement after Strengthening.......................... 162 14. Strain in the MF-FRP Lam inates...............................................................................162 PAPER 5 1. Representation of Continuous Beam under Distributed L o a d .................................181 2. Idealized Moment-Curvature Relationship.................................................................181 3. Strain Diagram for Reinforced C oncrete....................................................................181 4. Moments Variation for Continuous Elements............................................................ 182 5. Permissible Moment Redistribution According ACI 3 1 8 -0 2 .................................. 182 6. Moment-Curvature Relationship for FRP-Strengthened Section.............................182 7. Moment Curvature Relation under Elastic and Nonlinear Behavior for Strengthened and Unstrengthened FRP Sections......................................................183 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. xviii 8. Ultimate Net Tensile Strain vs. Amount of Steel Reinforcement p/pb...................183 9. Decrease of Net Tensile Steel Ultimate Strain with FRP Reinforcement.............. 184 10. Geometry and Cross-section Details of the Slabs................................................... 184 11. Setup of the Specimen................................................................................................. 184 12. Applied Force vs. Displacement for Numerical Prediction and Test.................... 185 13. Negative Moment vs. Applied Force for Elastic Prediction and Test...................185 14. Moment Redistribution vs. Applied Force............................................................... 186 15. Variation of the Ratio Negative Moment over Positive Moment for Elastic Prediction and Experim ent...................................................................... 186 16. Forces between the NSM Bar and the Adhesive......................................................187 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. xix LIST OF TABLES Table Page 2.1. Project Expected D eliverables......................................................................................4 3.1. Mechanical Properties for Carbon F abric................................................................. 21 3.2. Mechanical Properties for Prim er/Sealer.................................................................. 22 3.3. Mechanical Properties for Putty Surfacer................................................................. 23 3.4. Mechanical Properties for Epoxy Saturant................................................................ 23 3.5. Mechanical Properties for Epoxy A dhesive.............................................................. 35 3.6. Mechanical Properties for FRP B ars.......................................................................... 35 3.7. Epoxy Resin B inder..................................................................................................... 36 3.8. Carbon Pre-cured Laminates....................................................................................... 45 3.9 Mechanical Properties for Primer................................................................................ 45 3.10. Mechanical Properties for A dhesive........................................................................46 3.11. Mechanical Properties for Steel Cord Laminates................................................... 55 3.12. Mechanical Properties for Epoxy Resin.................................................................. 56 3.13. Fiber Composite FRP Lam inates............................................................................. 65 3.14. Mechanical Properties for Epoxy Adhesive System ...............................................66 PAPER 2 1. Bridge P-0962 in Dallas County, MO...............................................................................102 PAPER 3 1. Properties of SRP constituent m aterials...................................................................... 136 2. Design values for flexure and shear SRP reinforcement...........................................136 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.