FRP-strengthened RC Structures

Transcription

1 FRP-strengthened RC Structures J. G. Teng The Hong Kong Polytechnic University, China J. F. Chen The University of Nottingham, UK S. T. Smith The Hong Kong Polytechnic University, China L. Lam The Hong Kong Polytechnic University, China JOHN WILEY a SONS, LTD

2 Contents Preface Notation xi xiii 1 FRP Composites for Strengthening RC Structures Introduction Methods of Forming FRP Composites Mechanical Properties of FRP Composites Resins Comparison of Performance for Strengthening of Structures Partial Safety Factors Concluding Remarks 7 References 8 2 Bond Strength of FRP-to-concrete Joints Introduction Test Methods, Behaviour and Failure Mode Existing Bond Strength Models Empirical Models Fracture-mechanics-based Models Design Proposals Performance of Bond Strength Models Chen and Teng's Model Design Recommendation Conclusions 26 References 27 3 Flexural Strengthening of Beams Introduction Methods of Strengthening General 32

3 vi CONTENTS Failure Unstressed Soffit Plates End Anchorage for Unstressed Soffit Plates Prestressed Soffit Plates Additional Remarks Modes and Typical Behaviour Classification of Failure Modes Flexural Failure Shear Failure Plate-end Debonding Failures Intermediate Crack-induced Interfacial Debonding Other Debonding Failure Modes Other Aspects of Debonding U Strip End Anchorage Flexural Strength General Design Equations Presence of Preloading Interfacial Stresses General Approximate Analytical Solutions Finite-element Results Higher Order Analytical Solutions Remarks Plate-end Debonding Strength Models General Review of Debonding Strength Models Experimental Data Performance of Debonding Strength Models Smith and Teng's Model Strength Model for Intermediate Crack-induced Interfacial Debonding Design Conclusions Appendix A Appendix B General Intermediate Flexural Crack-induced Debonding Intermediate Flexural Shear Crack-induced Debonding Recommendation Critical Sections and Plate-end Anchorage Strength Check Partial Safety Factors Application of the Design Procedure to Indeterminate Beams

4 CONTENTS vii Shear-capacity-based Models Concrete Tooth Models Interfacial Stress-based Models 90 References 95 4 Shear Strengthening of Beams Introduction Methods of Strengthening Strengthening Schemes Selection of Strengthening Schemes Failure Modes General Shear Failure with FRP Rupture Shear Failure without FRP Rupture Shear Failure due to FRP Debonding Failures Near Mechanical Anchors Existing Research on Shear Strength Models Chen and Teng's Shear Strength Model General Expressions Shear Failure Controlled by FRP Rupture Shear Failure Controlled by FRP Debonding Design Recommendation General Equations Shear Failure Controlled by FRP Rupture Shear Failure Controlled by FRP Debonding Spacing Requirement for FRP Strips Strengthening Design for Indeterminate Beams Comparison with Experimental Observations Conclusions 130 References Flexural Strengthening of Slabs Introduction Methods of Strengthening General Simply Supported One-way or Two-way Slabs Cantilever Slabs Failure Modes and Typical Behaviour Cantilever Slabs and One-way Slabs Two-way Slabs Design Recommendation for One-way Slabs Design Recommendation for Two-way Slabs Flexural Strength by the Moment Coefficient Method 143

5 viii CONTENTS Flexural Strength by Yield Line Analysis Debonding Strengths Anchorage of FRP Strips/Sheets 5.6 Conclusions References 6 Strengthening of Axially and Eccentrically Loaded Columns 6.1 Introduction 6.2 Methods of Strengthening General Wrapping Filament Winding Prefabricated Shell Jacketing Comparison of Strengthening Methods Constructional Aspects Shape Modification 6.3 Failure Modes and Typical Behaviour of FRP-confined Concrete Columns Circular Concrete Columns Rectangular Concrete Columns Elliptical Concrete Columns 6.4 Compressive Strength of FRP-confined Concrete General Review of Strength Models Experimental Data Trends of Experimental Data Performance of Strength Models Lam and Teng's Model 6.5 Stress-Strain Behaviour of FRP-confined Concrete General Review of Stress-Strain Models Experimental Data Trends of Experimental Data Performance of Existing Stress-Strain Models Lam and Teng's Stress-Strain Model 6.6 FRP-confined Rectangular Concrete Columns General Existing Models Experimental Data Lam and Teng's Model 6.7 FRP-confined Elliptical Columns 6.8 Design Recommendation for Axially Loaded Columns

6 CONTENTS ix General Expression for the Axial Strength of FRP-confined Concrete Ultimate Strength of FRP-confined RC Columns under Axial Load Design Recommendation for Eccentrically Loaded Columns General Existing Studies on FRP-confined RC Columns under Eccentric Loads Ultimate Strength of FRP-confined RC Columns under Eccentric Loads Moment-Curvature Analysis of FRP-confined 204 RC Columns Typical Interaction Curves Conclusions. 206 References Seismic Retrofit of Columns Introduction Typical Failure Modes of RC Columns under Seismic Attack General Shear Failure Flexural Plastic Hinge Failure Lap Splice Failure Flexural Shear Failure of Columns with Longitudinal Reinforcement Cut-offs Footing Failure Methods of Retrofit FRP Jackets with Horizontally Oriented Fibres Longitudinal Bonding of FRP Flexural Ductility of Retrofitted Columns Ductility Factors Ductility of Retrofitted RC Columns Ultimate Conditions of Retrofitted Columns *" General Shear Failure Flexural Plastic Hinge Failure Lap Splice Failure Flexural Failure of Columns with Longitudinal FRP Design Recommendations General Shear Strength Flexural Plastic Hinge Confinement 232

7 x CONTENTS Lap Splice Clamping Detailing Considerations Conclusions 235 References 236 Index