Investigation And Testing Of Structures And Bridges

Contents

PREFACE 4

CHAPTER I. BASIC INFORMATION ON INVESTIGATION AND TESTING OF STRUCTURES AND BRIDGES 5 .

 

1. Subject, aim, tasks reasons and types of investigation and testing o

 

structures and bridges 5

 

1.1. General information on safety and durability of structures and the need of their experimental investigation 5

 

1.2. Subject and basic concepts 8

 

1.3. Aim and tasks of investigation and testing 9

 

1.4. Types of investigation and testing 10

 

2. ‘'Main stages and preliminary studies 11

3.2. In-situ inspection 15

 

3.3. Testing the quality of structural materials 18

 

3.4. Choice of structural members and locations for measurement and observation 19

CHAPTER II. METHODOLOGICAL CHARACTERISTICS OF

 

STATIC FULL-SCALE TESTS 21 . .

 

4. Static test schemes. Static test loads: types, requirements and sizes 21

 

4.1. General principles 21

 

4.2. Types of test schemes and characteristics 21

 

4.3. Types of test loads 22

 

4.4. Requirements to the test loads 24

 

4.5. Test load sizes 25

 

5. Location of test loads 27

 

5.1. Reinforced concrete slabs 28

 

5.2. Reinforced concrete beams 29

 

5.3. Reinforced concrete columns 31

 

5 4 Trusses and arches 33 , ,

 

6. Organization and performance of static test loads. Stages, degrees an

 

states. Signs of failure 33

 

6.1. Organization of test loads 33

6.2. Realization of test loadings 37

 

6.3. Signs of failure 40

 

7. Determination of positions, number and location of measuring instruments 41

 

7.1. General principles 41

 

7.2. Peculiarities in investigating total deformations 42

 

7.3. Investigating the formation and opening of cracks in reinforced concrete cross-sections 43

 

7.4. Peculiarities in investigating a one-dimensional stress state 44

 

7.5. Peculiarities in investigating a two-dimensional stress state 46

 

7.6. General principles for investigating a volume (3D) stress state 48

 

8. Effect of temperature and humidity on the tested structures and measuring instruments. Reduction of deformation 49

 

8.1. Effect of temperature variation 49

 

8.2. Effect of external humidity 54

 

9. Errors in measurements and estimating of the accuracy of results 54

 

9.1. Types of errors 54

 

9.2. Estimation of the accuracy of results 55

 

10. Experimental determination of rigidities, deflections and forces 59

 

10.1. Experimental determination of bending rigidities 59

 

10.2. Experimental determination of deflections in the theoretical computational schemes of the structures 60

 

10.3. Experimental determination of support moments in continuous and anchored beams and truss rods 62

 

11. Analysis, conclusions and assessment of the behaviour of statically tested structures: qualitative and quantitative indices and criteria 64

 

11.1. Qualitative analysis 64

 

11.2. Quantitative analysis 67

 

CHAPTER III. METHODOLOGICAL CHARACTERISTICS OF DYNAMIC FULL-SCALE TESTS 71

 

12. Dynamic full-scale tests. Aim, tasks, test loads and effects. Types of vibrograms and oscillograms 71

 

12.1. Significance, aim and tasks 71

 

12.2. Types of dynamic test loads 72

 

12.3. Realization of dynamic test loading 75

 

13. Experimental determination of dynamic parameters and characteristics76

 

13.1. Types of vibrograms and oscillograms 76

 

13.2. Initial analysis of vibrograms and oscillograms 79

 

13.3. Experimental determination of dynamic coefficients 80

13.4. Determination of natural frequencies 82

 

13.5. Determination of the damping coefficient and damping decrement83

 

14. Analysis, conclusions and assessment of the behaviour of dynamically tested structures and bridges 84

 

14.1. Assessment of the stress state and strength 84

 

14.2. Assessment of serviceability 85

 

15. Assessment of the effect of vibrations on production processes and humans Protection against harmful vibrations 86

 

15.1. Assessment of the effect on production equipment 86

 

15.2. Effect of vibrations on humans 87

 

15.3. Protection against harmful vibrations 88

 

CHAPTER IV. MODELING OF BUILDING STRUCTURES 91

 

16. Polarization optical structural modeling 93

 

16.1. General principles 93

 

16.2. Nature and principles 93

 

17. Physic-mechanical structural modeling 98

 

17.1. Nature and principles 98

 

17.2. Basic methodological issues 99

 

17.3. Types of scales and their determination 100

 

17.4. Characteristic numbers (invariants) 101

 

18. Brittle varnish coating technique 102

 

18.1. General information 102

 

18.2. Testing methodology 102

 

CHAPTER V. PRACTICAL METHODS FOR DIAGNOSTICS, INVESTIGATION AND NON-DESTRUCTIVE TESTING OF STRUCTURES AND BRIDGES 105

 

19. Mechanical methods for concrete NDT in structures by “partial local damages” 108

 

19.1. By cutting out of cores 108

 

19.2. By pulling out concrete rods 110

 

19.3. New methods “cut-and-puU” tests 110

 

20. Mechanical instrumentation (hardness) NDT methods 113

 

20.1. By plastic indentation 114

 

20.2. By elastic rebound 116

 

21. Physical NDT methods for diagnostics of structures and bridges 119

 

21.1. Method of ultrasonic resonance 119

 

21.2. Vibration method 121

 

21.3. Ultrasonic impulse method 123

21.4. Magnetic techniques for diagnostics and NDT 129

 

21.5. Radiometric techniques for diagnostics and NDT 130

 

21.6. Complex techniques for diagnostics and NDT of members and structures 131

 

22. Experimental determination of residual (initial) stresses 133

 

22.1. Character and occurrence 133

 

22.2. Experimental determination of residual stresses 135

 

CHAPTER VI. QUALITY AND RELIABILITY OF STRUCTURES

 

23. Types of defects and damages and their effect on the state of building structures and bridges 137

 

23.1. General principles and importance 137

 

23.2. Basic terms 137

 

23.3. Types of structural defects, damages and failures (DDF) 138

 

23.4. General conclusions from the analysis and recommendations 140

 

24. Reliability of building structures. Basic characteristics and inspection methods 141

 

24.1. General principles and terms 141

 

24.2. Determination of the reliability characteristics 142

 

24.3. Inspection methods 144

 

CHAPTER VII. EQUIPMENT AND INSTRUMENTATION FOR MEASURING MECHANICAL QUANTITIES IN INVESTIGATIONS AND TESTING 145

 

(S/Measuring instrumentation: basic requirements and classifications. Principles of measuring mechanical quantities 145

 

25.1. Requirements for instrumentation 145

 

25.2. Peculiarities and principles in measuring and determining ^ ipechanical quantities 147

 

(26. Typical instruments for measuring displacements and rotations 149 —26.1. Rod and lever deflectometers 150

 

26.2. Wire deflectometers 151

 

26.3. Dial gauges and deflectometer indicators 154

 

26.4. Hydrostatic and optical (geodetic) deflectometers and clinometers 155

 

/27. Mechanical and electrical instruments for measuring local and relative .... linear deformations 159

 

27.1. Mechanical lever strain gauges 159

 

27.2. Dial and dial-lever strain gauges 160

 

27.3. Electrical devices for measuring mechanical quantities 163 28. Recording devices, apparatuses and systems 168

28.1. Mechanical recording devices 168

 

• 28.2. Electric recording apparatuses and systems 169 29/Testing systems and equipment: test rigs, presses, jacks, dynamometers 172

 

29.1. Test rigs 172

 

29.2. Loading mechanisms and systems