First published 2017 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.

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The rights of Xavier Lauzin to be identified as the author of this work have been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.

Library of Congress Control Number: 2017939369

British Library Cataloguing-in-Publication Data
A CIP record for this book is available from the British Library
ISBN 978-1-78630-186-4

Table of Contents

Cover

Title

Introduction

1 Inspection of Structures: Methodologies

1.1. Bridges
1.2. Structures for the retention and transportation of liquids
1.3. Storage structures for petroleum products
1.4. Maritime structures
1.5. Silos
1.6. Gantry, metal hanger and high masts

2 Concept of Resistance of Materials: Application to Reinforced Concrete

2.1. General information on reinforced concrete
2.2. Concrete material
2.3. Steels
2.4. Concept of strength of materials

3 Pathology of Structures

3.1. Pathology of concrete structures
3.2. The pathology of masonry structures
3.3. The pathology of composite material structures

4 Techniques for Repairing Civil Engineering Works

4.1. Repair of concrete structures
4.2. Protection of concrete structure
4.3. Underground recovery

5 Inspection and Maintenance of Structures in the United States: Methodologies

5.1. Engineering structures
5.2. Storage structures for petroleum products

Appendices

Appendix 1: Examples of Diagnosis on a Drinking Water Storage Structure Based on the CEMAGREF Method
1. A1.1. Description of the structure
2. A1.2. Conditions for development of the structure
3. A1.3. Information relating to the inspection
4. A1.4. Inspection of the structure
5. A1.5. Summary
6. A1.6. Conclusion
7. A1.7. Supplementary material
Appendix 2: Examples of Diagnosis on a Petroleum Products Storage Tank According to the DT 92 Method
1. A2.1. Origin and extent of the mission
2. A2.2. Description of the structure
3. A2.3. Investigation method
4. A2.4. Nature of damages and explanations
5. A2.5. Executive summary of the condition of the structure and its evolution
Appendix 3: Examples of Diagnosis of a Marine Structure Using the CETMEF VSC Method
1. A3.1. Appendix 3a: Periodic detailed inspection of 2009 campaign
2. A3.2. Appendix 3b: Directory of pathologies
3. A3.3. Appendix 3c: Sclerometer indices
4. A3.4. Appendix 3d: results of pachometric tests on slabs
Appendix 4: Inspection Report “Gantries, Metal Hangers and High Masts”
1. A4.1. Identification
2. A4.2. General characteristics
3. A4.3. Life of the structure
4. A4.4. Conditions for access
5. A4.5. General information
6. A4.6. Annotation of findings
7. A4.7. Gantry
8. A4.8. Conclusions
9. A4.9. Actions to be taken
Appendix 5: Measuring Equipment
Appendix 6: Inspections of Bridges

Bibliography

Index

End User License Agreement

List of Tables

Introduction

Table I.1. Indicative design working life

1 Inspection of Structures: Methodologies

Table 1.1. Periodic inspections table
Table 1.2. Periodic detailed inspections table
Table 1.3. Exceptional inspections table
Table 1.4. Qualification level table
Table 1.5. Methodology for evaluating structures
Table 1.6. Stakeholder qualification levels
Table 1.7. Classification of damages table
Table 1.8. Classification of structures according to the level of danger
Table 1.9. Periodicity table according to DT92
Table 1.10. Corrosion sacrificial thickness according to EC3
Table 1.11. Evaluation of the mechanical state table
Table 1.12. Evaluation of the state table
Table 1.13. Actions to be taken table
Table 1.14. EN 1991-4: Appendix C
Table 1.15. Level of inspection table
Table 1.16. Class of structure table

2 Concept of Resistance of Materials: Application to Reinforced Concrete

Table 2.1. Strength and deformation characteristics for concrete
Table 2.2. Properties of reinforcement

3 Pathology of Structures

Table 3.1. Different types of cracks
Table 3.2. Causes of premature cracking
Table 3.3. Limiting values for exposure classes according to EN 206
Table 3.4. ISR: category of consequences
Table 3.5. Exposure classes
Table 3.6. Conditions to respect level of prevention
Table 3.7. Sensitive minerals table
Table 3.8. Concrete chemical analysis
Table 3.9. Concrete chemical parameters
Table 3.10. Different types of matrices
Table 3.11. Characteristics of different resins
Table 3.12. Chemical resistance of different resins
Table 3.13. Summary table of the advantages and disadvantages for each type of fiber
Table 3.14. Compatibility between resins and fibers
Table 3.15. Association matrix/fiber
Table 3.16. Chemical compatibilities and incompatibilities
Table 3.17. Energy from radiations
Table 3.18. Mechanical characteristics of single fiber

4 Techniques for Repairing Civil Engineering Works

Table 4.1. Mechanical characteristics of composite fabrics
Table 4.2. Comparison between reinforcement by bonded metal plates and CFT
Table 4.3. Advantages and disadvantages of the dry and wet methods
Table 4.4. Cement dosage at the manufacturing of the shotcretes according to their target use and the cement content of the concrete in place Adapted from the document by AFTES
Table 4.5. Table of characteristics for different mortars
Table 4.6. Table 3.4 from EN 1992-1-1

5 Inspection and Maintenance of Structures in the United States: Methodologies

Table 5.1. Degradation index of structures
Table 5.2. List of civil engineering works to be inspected according to the API 653

Appendix 1: Examples of Diagnosis on a Drinking Water Storage Structure Based on the CEMAGREF Method

Table A1.1. General description
Table A1.2. Accessibility
Table A1.3. Measured coatings and carbonation thickness
Table A1.4. Nature of defects
Table A1.5. State of structure

Appendix 2: Examples of Diagnosis on a Petroleum Products Storage Tank According to the DT 92 Method

Table A2.1. Notatio

Appendix 3: Examples of Diagnosis of a Marine Structure Using the CETMEF VSC Method

Table A3.1. Characteristics of the structure
Table A3.2. Measured covering
Table A3.3. Measured covering
Table A3.4. Measured covering
Table A3.5. State of structure

Appendix 5: Measuring Equipment

Table A5.1. List of measuring equipment

Appendix 6: Inspections of Bridges

Table A6.1. Details of annual inspection
Table A6.2. Details of triennal visit
Table A6.3. Details of specific visits
Table A6.4. Details of periodic detailed inspections
Table A6.5. Details of Initial detailed report
Table A6.6. Details of End of contractual warranty visits
Table A6.7. Details of Exceptional detailed inspections

List of Illustrations

Introduction

Figure I.1. Sequence of tasks required to guarantee the duration

1 Inspection of Structures: Methodologies

Figure 1.1. Organization chart of the principle of structure monitoring
Figure 1.2. Classification of structures
Figure 1.3. Retention basin of an oil storage tank
Figure 1.4. Detailed diagram of the retention basin wall
Figure 1.5. Detailed diagram of the tray of the basin bottom
Figure 1.6. Construction on ground reinforcements
Figure 1.7. Principle of the CSV method
Figure 1.8. Example of management (source: CETMEF). For a color version of this figure, see "http://www.iste.co.uk/Lauzin/engineering.zip
Figure 1.9.
Figure 1.10. For a color version of this figure, see http://www.iste.co.uk/Lauzin/engineering.zip
Figure 1.11. Silo forces
Figure 1.12. Opening of the skirt of the silo following the implementation of an internal lining
Figure 1.13. Vertical cracking of the skirt of the cylindrical silo
Figure 1.14. Classification of structures

2 Concept of Resistance of Materials: Application to Reinforced Concrete

Figure 2.1. Influence of creep on permanent deformation
Figure 2.2. Creep coefficient for concrete under normal environment conditions
Figure 2.3. Restraint factors for typical situations
Figure 2.4. Design stress-strain diagram for reinforcing steel
Figure 2.5. Force-sliding diagram
Figure 2.6. Stresses diagram of a section

3 Pathology of Structures

Figure 3.1. Mohr circles
Figure 3.2. Stresses diagram
Figure 3.3. Microcracks inside concrete matrix
Figure 3.4. Source: Annales ITBTP no. 536
Figure 3.5. Fatigue tests
Figure 3.6.
Figure 3.7. Autodesiccation of the cement paste as a function of the W/C ratio (source LCPC)
Figure 3.8. Example of cracking by plastic shrinkage
Figure 3.9. Diagram of the degradation of concrete and reinforcement corrosion
Figure 3.10. Diagram of the corrosion of steels: Pourbaix diagram for the Fe-H₂O system. Domain I: immunity domain in which iron does not corrode. Domain II: corrosion domain in which Fe²⁺ and FeOOH^– ions are formed. Domain III: passivity domain where iron coats itself in Fe₃O₄ or Fe₂O₃
Figure 3.11. Diagram of the kinetics of the behavior of reinforcements and concrete [TUU 82]
Figure 3.12. Diagram of carbonation of concrete
Figure 3.13. Evolution of the carbonation depth as a function of time [BAL 92]. Curves 1–5: CPJ-CEM II 32.5 concretes with fc₂₈ values of 20, 25, 30, 35 and 40 MPa
Figure 3.14. Comparison between the carbonation of ordinary concrete (C25/30) curve 2 and HP concrete (C60/75) curve 1
Figure 3.15. Influence of humidity on the progression of carbonation [WIE 84]. Curve 1: t = 20 °C and 65% RH (external atmosphere). Curve 2: t = 9 °C and 77% RH (external and under cover). Curve 3: t = 9 °C and 77% RH (external atmosphere under rain exposure). This experiment shows that the phenomenon of carbonation develops more deeply in concretes subjected to increased hygrometry than in others
Figure 3.16. Influence of the W/C ratio on carbonation depth [SKJ 86]. Curve 1: specimen preserved in its mold for 1 day and in water for 27 days. Curve 2: specimen preserved in its mold for 1 day. Carbonation depths are measured after 6 years of exposure
Figure 3.17. Influence of cement dosage and the curing time on carbonation depth. An increase in cement dosage is favorable for carbonation depth
Figure 3.18.
Figure 3.19. The walls after pouring and while undergoing reinforcement
Figure 3.20. Pachometer measures of cover
Figure 3.21. Ettringite formation (source: LCPC)
Figure 3.22. Ettringite formation
Figure 3.23. Three types of ettringite (Source: LERM)
Figure 3.24. Influence of the W/C ratio on sulfate attacks [OUY 88]
Figure 3.25. Influence of C₃A content on sulfate attacks
Figure 3.26. Examples of sulfate reactions on a mud tarpaulin (waste water plant)
Figure 3.27. Recording of temperature rises in a solid piece (4 × 5 × 6 m)
Figure 3.28. ISR on a river bridge pile
Figure 3.29. Level of prevention
Figure 3.30. Example: sulfate attack at the foot of the lifting screws of a waste water plant
Figure 3.31. 1991 LCPC Recommendations. For new works, refer to FD P18-542 “Alkali Reaction”
Figure 3.32. Concrete cracking (St Hyacinthe-Quebec retaining wall)
Figure 3.33. Alkali reaction in a retaining wall (St Hyacinthe-Quebec)
Figure 3.34. Burst cones for aggregates
Figure 3.35. Alkali-reaction from electron microscope
Figure 3.36. Alkali-reaction from chemical analysis
Figure 3.37. Concentration of free chlorides in function of the quantity of C3A
Figure 3.38. a) Solution containing 150 g/L Cl^– with W/C ratios of 0.71, 0.47 and 0.23. b) Solution at 30 and 150 g/L with a W/C value of 0.47
Figure 3.39. Influence of cover thickness on the life span of a structure
Figure 3.40. Concrete attacks by sea water
Figure 3.41. Diagram of the deterioration of concrete by sea water
Figure 3.42. Example of marine salt attacks
Figure 3.43. Total water and non-frozen water. The fraction of non-freezeable water (here 8%) can reach 20% in a fully hydrated cement paste
Figure 3.44. Influence of the radius of pores on the melting temperature
Figure 3.45. Contraction/dilatation in function of temperature
Figure 3.46. Influence of the number of freeze-thaw cycles on the speed of sound in concrete structures
Figure 3.47. Example of â€œfaienceâ€ of the plaster
Figure 3.48. “FaÃ¯ence” photo of the plaster
Figure 3.49. Horizontal cracks associated with the juxtaposition of different materials under the coating
Figure 3.50. Cracking of the coating at the connection between reinforced concrete structures and masonry filling
Figure 3.51. Cracking connected to the foundation mode on swelling soils
Figure 3.52. Example of a saber shot
Figure 3.53. Cracking of coating in masonry blocks that are insufficiently dry
Figure 3.54. Differential settlement cracking at buillding angle
Figure 3.55. Cracks at 45° under different loads
Figure 3.56. Lack of waterproofing in a buried construction
Figure 3.57. Picture of osmosis blistering
Figure 3.58. Delamination test under the effect of a distribution of bending stresses
Figure 3.59. Example of delamination by local buckling (composite materials document)
Figure 3.60. Different types of repartitions
Figure 3.61. Finite elements model of a tank
Figure 3.62. Stress diagrams
Figure 3.63. Stress diagrams in the semi-circular part
Figure 3.64. Pathology linked to a defect in characterization of stress at the foot and a defect in the use of tissues
Figure 3.65. Composite materials document
Figure 3.66. Assembly breakage

4 Techniques for Repairing Civil Engineering Works

Figure 4.1. Example of floor reinforcement
Figure 4.2. Document by J. Bresson
Figure 4.3. Bending moment in sheet metal (according to J. N. Theillout)
Figure 4.4. Evolution of the maximum shear stress ress as a function of overlap length (document by J. N. T Theillout)
Figure 4.5. Deformation diagram
Figure 4.6. Operating diagram according to J. Bresson
Figure 4.7. Example of pressurization of plates
Figure 4.8. Bonding of metal plates (document by SIKA)
Figure 4.9. Example of a behavior law for CFT (document by Freyssinet)
Figure 4.10. Example of the behavior law for a UD complex (carbon-epoxy)
Figure 4.11. Stresses diagram
Figure 4.12. Deformation and forces diagrams
Figure 4.13. Entrainment stress diagram
Figure 4.14. LCPC document with CFT
Figure 4.15. Comparison of reinforced concrete with 1 mm RPF and traditional methods
Figure 4.16. Confined parabola-rectangle diagram
Figure 4.17. Example of additional prestressing
Figure 4.18. Example of reinforcement of a sugar silo
Figure 4.19. Example of beam reinforcement
Figure 4.20. Silo reinforcement
Figure 4.21. Reinforcement 1: reinforcement for anchoring new reinforcement in existing concrete (connectors); Reinforcement 2: shear force transverse reinforcement (usually welded mesh); Reinforcement 3: longitudinal flexion bending reinforcements (usually bars); Point 4: welding points between existing and new reinforcement (solution to be justified); Point 5: concrete poured at the top of the beam (increase in inertia); Points 6 and 7: various drilling for the passage of new reinforcements
Figure 4.22. Principle of dry spraying
Figure 4.23. Wet method with dense flow
Figure 4.24. Wet method with diluted flow
Figure 4.25. Principle of concrete incorporation
Figure 4.26. Example of a particle size distribution according to P 95-102
Figure 4.27. Shotcrete
Figure 4.28. Failure of repair due to incorrect preparation of support
Figure 4.29. Shrinkage cracks before injection
Figure 4.30. Injected cracks
Figure 4.31. Principle of cathodic protection
Figure 4.32. Diagram of corrosion of reinforcements in a water reservoir
Figure 4.33. Trace of steel corrosion on a tank cover dome
Figure 4.34.
Figure 4.35. Tank cover dome after implementation of a cathodic protection
Figure 4.36. Example of und derground recovery on shallow foundations
Figure 4.37. Example of recovery by pile
Figure 4.38. Example of underground recovery by ground injection
Figure 4.39. Example of application of injection grout
Figure 4.40. View of a jet grouting column
Figure 4.41. Foundations of the Le Havre maritime station
Figure 4.42. Implementation of new piles

Appendix 1: Examples of Diagnosis on a Drinking Water Storage Structure Based on the CEMAGREF Method

Figure A1.1. Aerial view of site

Appendix 3: Examples of Diagnosis of a Marine Structure Using the CETMEF VSC Method

Figure A3.1. General view
Figure A3.2. Aerial view of site
Figure A3.3. Action of chlorides on a concrete structure

Appendix 4: Inspection Report “Gantries, Metal Hangers and High Masts”

Figure A4.1. Classification of structures

Introduction

An important factor in the design of new structures and repairs to existing structures is the expected service life.

In France, for major civil engineering works such as bridges, this duration is around 100 years (the British even go as far as 120 years).

For more modest structures such as water treatment plants, storage silos, etc., this duration was tacitly defined as around 50 years.

There are many factors that can influence this:

– the nature of the materials used in the construction (masonry, steel, concrete, wood, etc.);
– the quality of these materials (high-performance concrete, stainless steel, etc.);
– the constructive arrangements used (accumulation of water on metal structures, lack of encapsulation of steel in a reinforced concrete structure, etc.);
– quality of the execution (quality of the welding, implementation of concrete, etc.);
– monitoring and maintenance.

Within the context of the European Regulation for Calculation and Implementation, all these criteria have been taken into account when determining the duration of use of a structure.

This means that the design of the structures is obsolete if the maintenance conditions are not respected.

Let us recall section 2.4 of EN 1990:

“2.4 Durability

(1) The structure shall be designed such that deterioration over its design working life does not impair the performance of the structure below that intended, having due regard to its environment and the anticipated level of maintenance.
1. (2) In order to achieve an adequately durable structure, the following should be taken into account:
  - – the intended or foreseeable use of the structure;
  - – the required design criteria;
  - – the expected environmental conditions;
  - – the composition, properties and performance of the materials and products;
  - – the properties of the soil;
  - – the choice of the structural system;
  - – the shape of members and the structural detailing;
  - – the quality of workmanship, and the level of control;
  - – the particular protective measures;
  - – the intended maintenance during the design working life”.

The question also arises for repairs carried out on a structure: what life expectancy should they be given?

With regard to new structures, EN 1990 indicates the following durations in Table I.1.

Table I.1. Indicative design working life

Design working life category	Indicative design working-life (years)	Examples
1	10	Temporary structures^a
2	10–25	Replaceable structural elements, for example rolling beams, supporting devices
3	15–30	Agricultural structures and the like
4	50	Buildings and other structures
5	100	Monumental structures of buildings, bridges and other civil engineering structures

^aStructures or parts of structures that can be disassembled for reuse should not be considered as temporary.

In the section “Execution of concrete structures”, section 4.1 of EN 13670 also specifies the need for an inspection program:

“(5) This standard assumes that the structure after completion is used as intended in the design and submitted to planned inspection and maintenance necessary to achieve the intended design working life and to detect weaknesses or any unexpected behavior”.

This requirement implies providing access to the main structural elements at the design level.

Examples include:

– suspended bridges where replacement of the suspension has not been studied at design stage;
– water treatment plants for which it was not possible to empty the tanks (nonbypassable treatment line).

It also implies the need for a “state 0” during the reception for new constructions as well as a structure maintenance plan.

From this state, the sequence of tasks that is required to guarantee the duration of use of the structures is presented in the figure below:

**Figure I.1.** *Sequence of tasks required to guarantee the duration*

The purpose of this book is to create an inventory of the methodologies used for inspections of civil engineering structures and to present the elements that can serve as a basis for the diagnosis and maintenance program of concrete structures.

We present the main topics that the reader can deepen their knowledge of by reading the standards cited.

How to use this guide

For a better understanding of the methodology used, in the last part of each inspection methodology listed in Chapter 1 is a paragraph about “points of to look out for”, which refers to Chapter 3 for probable causes of the pathology and to Chapter 4 for the means of reinforcement that can be considered.

Chapter 2 gives the basic notions of resistance of the materials that are required for proper comprehension of the behavior of concrete and the interpretation of the observed disorders.

The examples in the Appendix are informative; they aim to show a type of connection in adequation with the inspected structure. They are purely formal.