Design of Prestressed Concrete to Eurocode 2 Second Edition
| Title |
|---|
| Design of Prestressed Concrete to Eurocode 2 Second Edition |
| Number of Page |
| 700 page |
| File Type |
| File Size |
| 9.5 MB |
1 Basic concepts 1
1.1 Introduction 1
1.2 Methods of prestressing 4
1.2.1 Pretensioned concrete 4
1.2.2 Post-tensioned concrete 5
1.2.3 Other methods of prestressing 6
1.3 Transverse forces induced by draped tendons 7
1.4 Calculation of elastic stresses 10
1.4.1 Combined load approach 10
1.4.2 Internal couple concept 12
1.4.3 Load balancing approach 13
1.4.4 Introductory example 13
1.4.4.1 Combined load approach 14
1.4.4.2 Internal couple concept 15
1.4.4.3 Load balancing approach 15
1.5 Introduction to structural behaviour:Initial to ultimate loads 16
2 Design procedures and applied actions 21
2.1 Limit states design philosophy 21
2.2 Structural modelling and analysis 23
2.2.1 Structural modelling 23
2.2.2 Structural analysis 24
2.3 Actions and combinations of actions 26
2.3.1 General 26
2.3.2 Load combinations for the strength limit states 29
2.3.3 Load combinations for the stability or equilibr/ium limit states 31
2.3.4 Load combinations for the serviceability limit states 32
2.4 Design for the strength limit states 33
2.4.1 General 33
2.4.2 Partial factors for materials 33
2.5 Design for the serviceability limit states 34
2.5.1 General 34
2.5.2 Deflection limits 35
2.5.3 Vibr/ation control 37
2.5.4 Crack width limits 37
2.5.5 Partial factors for materials 38
2.6 Design for durability 38
2.7 Design for fire resistance 40
2.8 Design for robustness 43
References 44
3 Prestressing systems 47
3.1 Introduction 47
3.2 Types of prestressing steel 47
3.3 Pretensioning 49
3.4 Post-tensioning 51
3.5 Bonded and unbonded post-tensioned construction 58
3.6 Circular prestressing 59
3.7 External prestressing 60
4 Material properties 63
4.1 Introduction 63
4.2 Concrete 63
4.2.1 Composition of concrete 64
4.2.2 Strength of concrete 65
4.2.3 Strength specifications in Eurocode 2 68
4.2.4 Deformation of concrete 73
4.2.5 Deformational characteristics specified in Eurocode 2 82
4.3 Steel reinforcement 87
4.3.1 General 87
4.3.2 Specification in Eurocode 2 88
4.4 Steel used for prestressing 91
4.4.1 General 91
4
.4.2 Specification in Eurocode 2 94
References 98
5 Design for serviceability 101
5.1 Introduction 101
5.2 Concrete stresses at transfer and under full service loads 102
5.3 Maximum jacking force 105
5.4 Determination of prestress and eccentricity in flexural members 106
5.4.1 Satisfaction of stress limits 106
5.4.2 Load balancing 114
5.5 Cable profiles 116
5.6 Short-term analysis of uncracked cross-sections 118
5.6.1 General 118
5.6.2 Short-term cross-sectional analysis 120
5.7 Time-dependent analysis of uncracked cross-sections 136
5.7.1 Introduction 136
5.7.2 The age-adjusted effective modulus method 136
5.7.3 Long-term analysis of an uncracked cross-section subjected to combined axial force and bending using AEMM 138
5.7.4 Discussion 156
5.8 Short-term analysis of cracked cross-sections 158
5.8.1 General 158
5.8.2 Assumptions 160
5.8.3 Analysis 160
5.9 Time-dependent analysis of cracked cross-sections 170
5.9.1 Simplifying assumption 170
5.9.2 Long-term analysis of a cracked cross-section subjected to combined axial force and bending using the AEMM 170
5.10 Losses of prestress 175
5.10.1 Definitions 175
5.10.2 Immediate losses 176
5.10.3 Time-dependent losses of prestress 181
5.11 Deflection calculations 187
5.11.1 General 187
5.11.2 Short-term moment–curvature relationship and tension stiffening 190
5.11.3 Short-term deflection 195
5.11.4 Long-term deflection 200
5.12 Crack control 208
5.12.1 Minimum reinforcement 208
5.12.2 Control of cracking without direct calculation 211
5.12.3 Calculation of crack widths 213
5.12.4 Crack control for restrained shrinkage and temperature effects 215
5.12.5 Crack control at openings and discontinuities 216
References 216
6 Flexural resistance 219
6.1 Introduction 219
6.2 Flexural behaviour at overloads 219
6.3 Design flexural resistance 222
6.3.1 Assumptions 222
6.3.2 Idealised compressive stress blocks for concrete 223
6.3.3 Prestressed steel strain components (for bonded tendons) 226
6.3.4 Determination of MRd for a singly reinforced section with bonded tendons 228
6.3.5 Determination of MRd for sections containing non-prestressed reinforcement and bonded tendons 232
6.3.6 Members with unbonded tendons 239
6.4 Design calculations 241
6.4.1 Discussion 241
6.4.2 Calculation of additional non-prestressed tensile reinforcement 242
6.4.3 Design of a doubly reinforced cross-section 245
6.5 Flanged sections 248
6.6 Ductility and robustness of prestressed concrete beams 254
6.6.1 Introductory remarks 254
6.6.2 Calculation of hinge rotations 257
6.6.3 Quantifying ductility and robustness of beams and slabs 257
References 260
7 Design resistance in shear and torsion 261
7.1 Introduction 261
7.2 Shear in beams 261
7.2.1 Inclined cracking 261
7.2.2 Effect of prestress 262
7.2.3 Web reinforcement 264
7.2.4 Design strength of beams without shear reinforcement 267
7.2.5 Design resistance of beams with shear reinforcement 268
7.2.6 Summary of design requirements for shear 273
7.2.7 The design procedure for shear 275
7.2.8 Shear between the web and flange of a T-section 281
7.3 Torsion in beams 282
7.3.1 Compatibility torsion and equilibr/ium torsion 282
7.3.2 Effects of torsion 284
7.3.3 Design provisions for torsion 285
7.4 Shear in slabs and footings 291
7.4.1 Punching shear 291
7.4.2 The basic control perimeter 292
7.4.3 Shear resistance of critical shear perimeters 294
7.4.4 Design for punching shear 296
References 307
8 Anchorage zones 309
8.1 Introduction 309
8.2 Pretensioned concrete: Force transfer by bond 310
8.3 Post-tensioned concrete anchorage zones 315
8.3.1 Introduction 315
8.3.2 Methods of analysis 319
8.3.3 Reinforcement requirements 325
8.3.4 Bearing stresses behind anchorages 326
8.4 Strut-and-tie modelling 342
8.4.1 Introduction 342
8.4.2 Concrete struts 343
8.4.4 Nodes 346
References 348
9 Composite members 351
9.1 Types and advantages of composite construction 351
9.2 Behaviour of composite members 352
9.3 Stages of loading 354
9.4 Determination of prestress 357
9.5 Methods of analysis at service loads 359
9.5.1 Introductory remarks 359
9.5.2 Short-term analysis 360
9.5.3 Time-dependent analysis 362
9.6 Flexural resistance 392
9.7 Horizontal shear transfer 392
9.7.1 Discussion 392
9.7.2 Design provisions for horizontal shear 394
References 398
10 Design procedures for determinate beams 399
10.1 Introduction 399
10.2 Types of sections 399
10.3 Initial trial section 401
10.3.1 Based on serviceability requirements 401
10.3.2 Based on strength requirements 402
10.4 Design procedures: Fully-prestressed beams 404
10.4.1 Beams with varying eccentricity 405
10.4.2 Beams with constant eccentricity 422
10.5 Design procedures: Partially-prestressed beams 432
Reference 440
11 Statically indeterminate members 441
11.1 Introduction 441
11.2 Tendon profiles 443
11.3 Continuous beams 446
11.3.1 Effects of prestress 446
11.3.2 Determination of secondary effects using virtual work 447
11.3.3 Linear transformation of a tendon profile 453
11.3.4 Analysis using equivalent loads 455
11.3.5 Practical tendon profiles 465
11.3.6 Members with varying cross-sectional properties 468
11.3.7 Effects of creep 470
11.4 Statically indeterminate frames 474
11.5 Design of continuous beams 478
11.5.1 General 478
11.5.2 Service load range: Before cracking 479
11.5.3 Service load range: After cracking 482
11.5.4 Overload range and design resistance in bending 483
11.5.5 Steps in design 486
References 499
12 Two-way slabs: Behaviour and design 501
12.1 Introduction 501
12.2 Effects of prestress 504
12.3 Balanced load stage 507
12.4 Initial sizing of slabs 509
12.4.1 Existing guidelines 509
12.4.2 Serviceability approach for the calculation of slab thickness 510
12.4.3 Discussion 514
12.5 Other serviceability considerations 516
12.5.1 Cracking and crack control in prestressed slabs 516
12.5.2 Long-term deflections 517
12.6 Design approach: General 519
12.7 One-way slabs 519
12.8 Two-way edge-supported slabs 520
12.8.1 Load balancing 520
12.8.2 Methods of analysis 522
12.9 Flat plate slabs 533
12.9.1 Load balancing 533
12.9.2 Behaviour under unbalanced load 535
12.9.3 Frame analysis 537
12.9.4 Direct design method 539
12.9.5 Shear resistance 540
12.9.6 Deflection calculations 541
12.9.7 Yield line analysis of flat plates 555
12.10 Flat slabs with drop panels 559
12.11 Band-beam and slab systems 560
References 561
13 Compression and tension members 563
13.1 Types of compression members 563
13.2 Classification and behaviour of compression members 564
13.3 Cross-section analysis: Compression and bending 566
13.3.1 Strength interaction diagram 566
13.3.2 Strength analysis 568
13.3.3 Biaxial bending and compression 579
13.4 Slenderness effects 580
13.4.1 Background 580
13.4.2 Slenderness criteria 584
13.4.3 Moment magnification method 585
13.5 Reinforcement requirements for compression members 591
13.6 Transmission of axial force through a floor system 591
13.7 Tension members 593
13.7.1 Advantages and applications 593
13.7.2 Behaviour 594
References 600
14 Detailing: Members and connections 601
14.1 Introduction 601
14.2 Principles of detailing 602
14.2.1 When is steel reinforcement required? 602
14.2.2 Objectives of detailing 603
14.2.3 Sources of tension 604
14.3 Anchorage of deformed bars 610
14.3.1 Introductory remarks 610
14.3.2 Design anchorage length 613
14.3.3 Lapped splices 617
14.4 Stress development and coupling of tendons 619
14.5 Detailing of beams 619
14.5.1 Anchorage of longitudinal reinforcement: General 619
14.5.2 Maximum and minimum requirements for longitudinal steel 623
14.5.3 Curtailment of longitudinal reinforcement 624
14.5.4 Anchorage of stirrups 625
14.5.5 Detailing of support and loading points 630
14.6 Detailing of columns and walls 634
14.6.1 General requirements 634
14.6.2 Transverse reinforcement in columns 635
14.6.3 Longitudinal reinforcement in columns 638
14.6.4 Requirements for walls 638
14.7 Detailing of beam–column connections 638
14.7.1 Introduction 638
14.7.2 Knee connections (or two-member connections) 639
14.7.3 Exterior three-member connections 642
14.7.4 Interior four-member connections 645
14.8 Detailing of corbels 646
14.9 Joints in structures 647
14.9.1 Introduction 647
14.9.2 Construction joints 648
14.9.3 Control joints (contraction joints) 649
14.9.4 Shrinkage strips 651
14.9.5 Expansion joints 652
14.9.6 Structural joints 652
References 654
Index 655
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