Widening of Reinforced Concrete Bridges Extension of Pier

Preparing to load PDF file. please wait...

0 of 0
100%
Widening of Reinforced Concrete Bridges Extension of Pier

Transcript Of Widening of Reinforced Concrete Bridges Extension of Pier

Syracuse University
SURFACE

Dissertations - ALL

SURFACE

December 2019
Widening of Reinforced Concrete Bridges – Extension of Pier Cap Beams with CFRP Composites
Cheng Tan Syracuse University

Follow this and additional works at: https://surface.syr.edu/etd Part of the Engineering Commons
Recommended Citation Tan, Cheng, "Widening of Reinforced Concrete Bridges – Extension of Pier Cap Beams with CFRP Composites" (2019). Dissertations - ALL. 1106. https://surface.syr.edu/etd/1106
This Dissertation is brought to you for free and open access by the SURFACE at SURFACE. It has been accepted for inclusion in Dissertations - ALL by an authorized administrator of SURFACE. For more information, please contact [email protected]

ABSTRACT
Increase in traffic load dictates widening highway bridges rather than construction of new bridges, as it offers an economical solution. Highway bridge widening is usually accomplished by the construction of additional new bridge piers, however, large amount of construction work and extensive use of heavy plant and machinery could result in very high cost. For limited widening of bridges, e.g. addition of one driving/emergency lane, extension of the pier cap beam offers an attractive solution. Due to additional load resulting from the widened bridge, strengthening of extended cap beams may be needed. In addition, depending on the strength of the existing pier column, limited strengthening of the column will probably be needed.
This research project presents a bridge cap beam extension and reinforcing system, which is considered an alternative of constructing new piers for bridge widening projects. Experimental results and numerical modeling of quarter-scaled reinforced concrete hammerhead non-prismatic pier cap beams, extended on verges and reinforced with different CFRP systems are presented, followed by development of a practical analytical model. In addition, a column strengthening system, which provides a continuous load path to transfer additional moment to the foundation, was presented in this study.
The experimental work was to investigate the structural performance of this particular type of beams with different reinforcing systems, such as concrete jacket, CFRP sheets and pre-saturated CFRP laminates with various anchor systems. Thirteen pier cap beam specimens were tested to evaluate the effect of the reinforcing systems on ultimate strength, stiffness and ductility. In addition, five full-scaled rectangular RC columns strengthened with either concrete jacket or vertical CFRP plates were tested under cyclic loading, flexural and cyclic performance of strengthened columns, and strain distribution on CFRP composites were investigated.

A numerical study based on finite element modeling was performed to investigate the failure mechanism of tested beams. A 3-D finite element model was developed and verified against experimental results. A good agreement between finite element results and experimental results was achieved in terms of failure mode, ultimate capacity and load-deflection response.
The experimental work and finite element results demonstrated the feasibility of proposed cap beam extension system. All of the tested reinforcing systems are effective in improving flexural strength of the extended cap beams. Among the investigated reinforcing systems, the fully wrapped CFRP sheet offers the most efficient solution for proposed system. Based on these observations, an iterative based simple practical analytical model was developed to predict the ultimate capacity of extended cap beams with CFRP reinforcing systems. A few design and construction recommendations are presented at the end of the dissertation.

Widening of Reinforced Concrete Bridges – Extension of Pier Cap Beams with CFRP Composites
by Cheng Tan M.S. Syracuse University, 2015 B.S. Nanjing Forestry University, 2013
Dissertation Submitted in partial fulfillment of the requirements for the degree of
Doctor of Philosophy Civil Engineering.
Syracuse University December 2019

Copyright © Cheng Tan 2019 All Rights Reserved

ACKNOWLEDGEMENT
The research presented in this dissertation was sponsored by Shandong Luqiao Group Co., Ltd. I would like to express my deepest appreciation and gratitude to my advisor, Dr. Riyad Aboutaha, for the patient guidance and mentorship he provided to me, all the way from when I was first starting my graduate study, through to completion of this degree. I would also like to express my sincere thanks to my oral exam committee members, Dr. Shobha Bhatia, Dr. Dawit Negusssey, Dr. Eric Lui, Dr. Baris Salman and Dr. Wanliang Shan. Thank you for serving on this oral exam committee, and for your encouragement, constructive and insightful comments and suggestions. I’m grateful to my industrial collaborators. Faculty and students in Shandong University and Shandong Jiaotong University provided great help conducting the experimental tests. I also extend my gratitude to members from Shandong Luqiao Group and Shanghai Horse Construction, who provided me help on testing materials. I would like to thank my colleagues and friends in Syracuse for their continued support. They offered me a wonderful memory during my study in Syracuse. Last but not least, I would also love to express my sincere gratitude to my wife Jia Xu and my family for all the support, understanding, encouragement, and love throughout this research.
v

TABLE OF CONTENTS
Abstract........................................................................................................................................... i Acknowledgement ......................................................................................................................... v Table of Contents ......................................................................................................................... vi List of Figures.............................................................................................................................. xii List of Tables ............................................................................................................................... xv Chapter 1 Introduction................................................................................................................. 1
1.1 Background ........................................................................................................................... 1 1.1.1 Bridge Widening............................................................................................................. 1 1.1.2 Proposed Bridge Pier Cap Beam Extension and Reinforcing System............................ 1 1.1.3 Numerical and Analytical Solutions............................................................................... 3
1.2 Objective and Scope .............................................................................................................. 4 1.3 Outline of the Dissertation .................................................................................................... 5 Chapter 2 Literature Review ....................................................................................................... 7 2.1 Introduction ........................................................................................................................... 7 2.2 Bridge Widening and Strengthening ..................................................................................... 8
2.2.1 Conventional Bridge Widening Practices....................................................................... 8 2.2.2 Bridge Widening without Additional Piers .................................................................... 9 2.2.3 Shear Behavior between Old and New Concrete ......................................................... 11 2.2.4 Closure Slabs ................................................................................................................ 12 2.2.5 Concrete Jacket............................................................................................................. 12 2.2.6 Steel Post-tensioning .................................................................................................... 13 2.3 CFRP Strengthened RC Beams ........................................................................................... 14 2.3.1 Strengthening Scheme and Efficiency.......................................................................... 15 2.3.2 Bond Strength between CFRP and Concrete................................................................ 17
2.3.2.1 Bonding mechanism............................................................................................... 17 2.3.2.2 Bonding agent ........................................................................................................ 19 2.3.2.3 Anchorage system .................................................................................................. 20 2.3.3 CFRP Post-tensioning System...................................................................................... 20 2.3.4 Flexural Strength Prediction Models ............................................................................ 22 2.3.4.1 ACI 440.................................................................................................................. 22 2.3.4.2 FIB Bulletin 14 ...................................................................................................... 23
vi

2.3.4.3 Teng’s model ......................................................................................................... 24 2.3.4.4 Al-Zaid’s Model..................................................................................................... 27 2.4 Deep Beams......................................................................................................................... 28 2.4.1 Strengthening of RC Deep Beams................................................................................ 28 2.4.1.1 Fiber modified concrete ......................................................................................... 28 2.4.1.2 Special detailing of steel reinforced concrete ........................................................ 29 2.4.1.3 Post-tensioning....................................................................................................... 29 2.4.1.4 Externally bonded CFRP composites .................................................................... 29 2.4.2 Analytical Model of RC Deep Beams .......................................................................... 30 2.4.2.1 Modified Compressive Field Theory ..................................................................... 30 2.4.2.2 Strut-and-tie model ................................................................................................ 31 2.4.2.3 CFP model ............................................................................................................. 32 2.4.2.4 Other models .......................................................................................................... 34 2.4.3 FRP Reinforced RC Deep Beams................................................................................. 35 2.4.3.1 FRP reinforcing bars .............................................................................................. 35 2.4.3.2 Externally bonded CFRP laminates ....................................................................... 36 2.5 Numerical Modelling of CFRP Strengthened RC Members............................................... 37 2.5.1 Concrete Model ............................................................................................................ 38 2.5.1.1 Discrete crack model.............................................................................................. 38 2.5.1.2 Smeared crack model ............................................................................................. 38 2.5.1.3 Concrete models in ABAQUS ............................................................................... 39 2.5.2 Bond Modelling ............................................................................................................ 40 2.5.2.1 Lu’s model ............................................................................................................. 40 2.5.2.2 Cohesive elements ................................................................................................. 42 2.5.2.3 Damage plasticity model........................................................................................ 43 2.5.2.4 Intermediate crack debonding................................................................................ 43 2.5.2.5 Concrete cover separation...................................................................................... 44 2.5.3 Numerical Solution Methods........................................................................................ 45 2.5.3.1 Dynamic approach ................................................................................................. 45 2.5.3.2 Limit analysis......................................................................................................... 45 2.5.3.3 XFEM .................................................................................................................... 46 2.5.4 Applications of FEM on FRP Strengthened Beams ..................................................... 47 2.5.4.1 Strengthening scheme and efficiency .................................................................... 47 2.5.4.2 Initially damaged beams ........................................................................................ 48
vii

2.5.4.3 Long-term effect .................................................................................................... 49 2.5.4.4 High temperature behavior .................................................................................... 50 2.6 RC Columns under Cyclic Loading .................................................................................... 50 2.6.1 Seismic Behavior of RC Columns................................................................................ 50 2.6.2 FRP Strengthened RC Columns ................................................................................... 51 2.7 Summary ............................................................................................................................. 53 Chapter 3. Experimental Phase (Cap Beams) .......................................................................... 54 3.1. Introduction ........................................................................................................................ 54 3.2. Specimen Description ........................................................................................................ 54 3.2.1 Materials ....................................................................................................................... 57 3.2.1.1 Concrete ................................................................................................................. 57 3.2.1.2 Steel........................................................................................................................ 57 3.2.1.3 CFRP system.......................................................................................................... 57 3.2.2 Detailing of Specimens................................................................................................. 58 3.2.2.1 Dimension and steel reinforcement ....................................................................... 58 3.2.2.2 Reinforcing scheme ............................................................................................... 61 3.2.3 Specimen Fabrication ................................................................................................... 63 3.2.3.1 Extension casting ................................................................................................... 63 3.2.3.2 Application of reinforcing system ......................................................................... 67 3.3. Test Setup ........................................................................................................................... 68 3.3.1 Loading Procedure........................................................................................................ 68 3.3.2 Instrumentation ............................................................................................................. 69 3.3.3 Data Acquisition ........................................................................................................... 69 Chapter 4. Experimental Results (Cap Beams) ....................................................................... 70 4.1. Introduction ........................................................................................................................ 70 4.2. Test Results ........................................................................................................................ 70 4.2.1 PB1 (REF) .................................................................................................................... 70 4.2.2 PB2 (REFD) ................................................................................................................. 72 4.2.3 PB3 (P1L1A0) .............................................................................................................. 74 4.2.4 PB4 (P1L1A2) .............................................................................................................. 76 4.2.5 PB5 (P1L1A6) .............................................................................................................. 78 4.2.6 PB6 (P2L1A8) .............................................................................................................. 81 4.2.7 PB7 (P1L2A6) .............................................................................................................. 83 4.2.8 PB8 (P2L2A8) .............................................................................................................. 85
viii

4.2.9 PB9 (S8) ....................................................................................................................... 87 4.2.10 PB10 (CJS8) ............................................................................................................... 89 4.2.11 PB11 (P1L1A8S) ........................................................................................................ 91 4.2.12 PB12 (P1L1A8ρ1)....................................................................................................... 93 4.2.13 PB13 (P1L1A8ρ2)....................................................................................................... 96 4.3 Effect of Variables on Extended Beams.............................................................................. 99 4.3.1 Dowel Bars ................................................................................................................... 99 4.3.2 Anchorage System ...................................................................................................... 100 4.3.3 Amount of CFRP Reinforcement ............................................................................... 102 4.3.4 Location of CFRP Reinforcement .............................................................................. 104 4.3.5 Amount of Original Shear Reinforcement.................................................................. 105 4.3.6 CFRP Sheets versus Pre-saturated CFRP Plates ........................................................ 106 4.3.7 Concrete Jacket........................................................................................................... 107 4.3.8 Coupler Properties ...................................................................................................... 108 4.4 Summary ........................................................................................................................... 108 Chapter 5 Experimental Phase (Columns) ............................................................................. 110 5.1 Introduction ....................................................................................................................... 110 5.2 Specimen Description ....................................................................................................... 110 5.2.1 Materials ..................................................................................................................... 112
5.2.1.1 Concrete ............................................................................................................... 112 5.2.1.2 Steel...................................................................................................................... 112 5.2.1.3 CFRP system........................................................................................................ 112 5.2.2 Detailing of Specimens............................................................................................... 112 5.3 Test Setup .......................................................................................................................... 113 5.3.1 Loading Procedure...................................................................................................... 113 5.3.2 Instrumentation ........................................................................................................... 115 5.3.3 Data Acquisition ......................................................................................................... 115 5.4. Test Results ...................................................................................................................... 116 5.4.1 C1 (REF)..................................................................................................................... 116 5.4.2 C2 (CJ)........................................................................................................................ 118 5.4.3 C3 (REF2)................................................................................................................... 120 5.4.4 C4 (FRP1)................................................................................................................... 122 5.4.5 C5 (FRP2)................................................................................................................... 124 5.5 Evaluation of Test Results................................................................................................. 126
ix
SystemsAdditionBridgeModelSolution