Reinforced Concrete – Design to SANS 10100-1:2000

TABLE OF CONTENTS

MODULE 1 INTRODUCTION

1.1 SYMBOLS .1.1

1.2 MATERIALS 1.5

1.2.1 Concrete 1.6

1.2.2 Reinforcing steel 1.6

1.2.3 Cover .1.7

1.2.3.1 Durability 1.7

1.2.3.2 Fire resistance 1.8

1.2.3.3 Practical considerations 1.8

1.3 LOADS 1.9

1.3.1 Dead loads 1.9

1.3.1.1 Unit weight .1.9

1.3.2 Live loads

1.3.2.1 Floor loads .1.10

1.3.2.2 Roof loads 1.11

1.3.3 Loading patterns .1.11

1.3.3.1 Uniformly distributed 1.11

1.3.3.2 Point 1.12

1.3.3.3 Triangular and trapezoidal 1.12

1.3.4 Unit conversions .1.13

1.3.5 Continuity effects .1.13

1.4 LIMIT STATES DESIGN 1.14

1.4.1 Limit states approach .1.14

1.4.1.1 Ultimate limit state 1.14

1.4.1.2 Serviceability limit state 1.15

1.4.2 Limit state equation .1.15

1.4.3 Partial factors 1.15

1.4.3.1 Load factors 1.16

1.4.3.2 Resistance factors 1.17

MODULE 2 ANALYSIS OF BEAMS AND FRAMES

2.1 ARRANGEMENT OF LOADS 2.1

2.2 CONTINUOUS BEAMS 2.2

2.2.1 Moment distribution 2.2

2.2.1.1 Example 2.1 (moment distribution) 2.4

2.2.2 Redistribution of moment 2.6

2.2.2.1 Example 2.2 (redistribution) 2.7

2.2.3 Analysis coefficients 2.10

2.2.3.1 Example 2.3 (analysis coefficients) 2.11

2.3 RIGID FRAMES 2.13

2.3.1 Simplification into sub-frames 2.13

2.3.1.1 Vertical load only 2.13

2.3.1.2 Vertical and lateral loads 2.14

2.3.1.3 Example 2.4 (sub-frame analysis) 2.15

MODULE 3 BEAMS

3.1 FLEXURE 3.1

3.1.1 Rectangular beams 3.1

3.1.1.1 Example 3.1 (moment of resistance) 3.7

3.1.1.2 Example 3.2 (area of tension reinforcement) 3.10

3.1.2 Rectangular beams doubly reinforced 3.11

3.1.2.1 Example 3.3 (area of compression reinforcement) 3.14

3.1.3 Flanged beams 3.16

3.1.3.1 Effective flange width 3.16

3.1.3.2 Flexural strength 3.17

3.1.3.3 Example 3.4 (area of tension reinforcement) 3.19

3.1.4 Nominal reinforcement and spacing of bars 3.20

3.1.4.1 Minimum area of tension reinforcement 3.21

3.1.4.2 Minimum area of compression reinforcement 3.22

3.1.4.3 Maximum area of reinforcement 3.22

3.1.4.4 Additional reinforcement in deep beams 3.22

3.1.4.5 Minimum reinforcement in flange 3.23

3.1.4.6 Minimum spacing of all bars 3.23

3.1.4.7 Maximum spacing of bars in tension 3.25

3.1.4.8 Choice of reinforcing bars 3.26

3.1.5 Curtailment 3.27

3.1.5.1 Anchorage length 3.28

3.1.5.2 Simplified rules 3.29

3.1.6 Design flowchart for flexure 3.31

3.2 SHEAR .3.33

3.2.1 Sections un-reinforced for shear .3.33

3.2.2 Sections reinforced for shear 3.34

3.2.2.1 Stirrups 3.35

3.2.2.2 Inclined bars 3.36

3.2.3 Nominal Reinforcement and spacing of bars 3.37

3.2.3.1 Minimum area of stirrups .3.37

3.2.3.2 Maximum spacing of stirrups 3.37

3.2.3.3 Stirrups for compression reinforcement .3.37

3.2.4 Other considerations 3.38

3.2.4.1 Concentrated load close to support .3.38

3.2.4.2 Practical fixing .3.38

3.2.4.3 Anchorage of stirrups .3.39

3.2.4.4 Curtailment .3.39

3.2.4.5 Local bond 3.39

3.2.5 Design flowchart for shear 3.40

3.2.6 Example 3.5 (shear reinforcement) 3.40

3.3 TORSION 3.43

3.3.1 Torsional shear stress 3.43

3.3.2 Reinforcement .3.44

3.3.2.1 Links 3.44

3.3.2.2 Longitudinal bars .3.45

3.4 COMBINED SHEAR AND TORSION 3.45

3.4.1 Example 3.6 (combined shear and torsion) 3.46

3.5 DEFLECTION 3.49

3.5.1 Rectangular beams .3.49

3.5.2 Flanged beams 3.51

3.5.3 Example 3.7 (deflection) .3.52

3.6 DESIGN EXAMPLE .3.55

MODULE 4 SLABS

4.1 INTRODUCTION .4.1

4.2 ANALYSIS .4.2

4.2.1 One-way spanning .4.3

4.2.2 Two-way spanning .4.3

4.2.2.1 Simply supported unrestrained slabs 4.4

4.2.2.2 Restrained slabs 4.5

4.2.3 Flat slabs 4.6

42.3.1 General configuration 4.6

4.2.3.2 Division of panels .4.7

4.2.3.3 Analysis .4.8

4.3 DESIGN FOR FLEXURE 4.11

4.3.1 Reinforcement 4.11

4.3.2 Nominal reinforcement and spacing of bars 4.12

4.3.2.1 Minimum area of tension reinforcement 4.12

4.3.2.2 Minimum spacing of bars 4.12

4.3.2.3 Maximum spacing of bars 4.12

4.3.3 Placement and curtailment of bars 4.12

4.3.3.1 One-way spanning slabs 4.13

4.3.3.2 Two-way spanning slabs 4.13

4.3.3.3 Flat slabs 4.14

4.4 DEFLECTION 4.15

4.4.1 One-way spanning slabs 4.15

4.4.2 Two-way spanning slabs 4.15

4.4.3 Flat slabs 4.16

4.5 DESIGN FOR SHEAR 4.16

4.5.1 Beam shear 4.16

4.5.2 Punching shear 4.17

4.5.2.1 Point load on solid slabs 4.17

4.5.2.2 Flat slabs 4.19

4.6 DESIGN EXAMPLES 4.19

4.6.1 Simply supported slab 4.19

4.6.2 Restrained slab 4.24

4.6.3 Flat slab 4.27

4.7 OTHER SLAB SYSTEMS 4.35

4.7.1 Rib and hollow block 4.35

4.7.2 Coffer or waffle 4.36

4.7.3 Voided construction 4.37

4.7.4 Permanent formwork 4.37

4.7.5 Ribbed beam 4.38

MODULE 5 STAIRS

5.1 LOADING 5.1

5.1.1 General 5.1

5.1.2 Imposed load 5.1

5.1.3 Dead load 5.2

5.2 ANALYSIS 5.2

5.2.1 Effective span 5.2

5.3 DESIGN 5.3

5.3.1 Longitudinally spanning 5.3

5.3.1.1 Example 5.1 (longitudinally spanning stair) 5.4

5.3.2 Laterally spanning 5.7

MODULE 6 COLUMNS AND ARCHES

6.1 INTRODUCTION .6.1

6.2 BRACING 6.1

6.3 EFFECTIVE HEIGHT .6.2

6.3.1) General method .6.2

5.3.2 Rigorous method 6.3

6.3.3 Nomograph 6.4

6.4 SLENDERNESS .6 5

6.4.1 Limits .6.6

6.4.2 Example 6.1 (slenderness classification) 6.7

6.5 DESIGN AXIAL LOAD 6.8

6.6 DESIGN MOMENT .6.9

6.6.1 Additional Moments in slender columns 6.9

6.6.2 Uni-axial bending .6.11

6.6.2.1 Braced slender columns .6.11

6.6.2.2 Unbraced slender columns .6.13

6.6.2.3 Short columns .6.14

6.6.3 Bi-axial bending 6.14

6.6.4 Example 6.2 (design moment) .6.15

6.7 LONGITUDINAL REINFORCEMENT 6.17

6.7.1 Derivation of design equations 6.17

6.7.1.1 Full compression .6.18

6.7.1.2 Partial compression .6.19

6.7.2 Design charts 6.20

6.8 OTHER CONSIDERATIONS 6.28

6.8.1 Minimum area of main reinforcement .6.28

6.8.2 Maximum area of main reinforcement .6.28

6.8.3 Minimum requirement for links .6.28

6.9 EXAMPLE 6.3 (reinforcement) .6.29

MODULE 7 FOUNDATIONS

7.1 INTRODUCTION .7.1

7.2 ISOLATED BASES .7.1

7.2.1 Base dimensions 7.2

7.2.2 Bending .7.2

7.2.2.1 Layout of reinforcement 7.3

7.2.3 Shear 7.3

7.2.3.1 Beam shear 7.3

7.2.3.2 Punching shear 7.4

7.2.4 Example 7.1 (centric axial load) 7.4

7.2.5 Example 7.2 (centric axial load and applied moment) 7.8

7.3 COMBINED BASES 7.13

7.3.1 Base dimensions 7.13

7.3.2 Bending 7.14

7.3.3 Shear 7.14

7.3.4 Example 7.3 (rectangular combined base) 7.14

7.4 STRAPPED BASES 7.22

7.4.1 Base dimensions 7.23

7.4.2 Bending 7.23

7.4.3 Shear 7.23

7.4.4 Example 7.4 (strapped base) 7.24

MODULE 8 RETAINING WALLS

8.1 TYPES 8.1

8.1.1 Gravity 8.1

8.1.2 Cantilever 8.1

8.1.3 Counter-fort or buttress 8.1

8.2 COMPONENTS OF A RETAINING WALL 8.2

8.3 MODES OF FAILURE 8.2

8.3.1 Overturning 8.2

8.3.2 Sliding 8.3

8.3.3 Soil failure 8.3

8.3.4 Fracture of elements 8.3

8.4 SOIL PARAMETERS 8.4

8.4.1 Angle of internal friction 8.4

8.4.2 Soil density 8.4

8.4.3 Sliding friction coefficient 8.4

8.4.4 Maximum ground pressure 8.4

8.5 APPLIED PRESSURES 8.4

8.5.1 Active soil pressure 8.4

8.5.2 Passive soil pressure 8.5

8.5.3 Surcharge pressure 8.5

8.5.4 Water pressure 8.5

8.5.5 Resulting pressure distribution 8.6

8.6 DESIGN APPROACH 8.8

8.7 EXAMPLE 8.1 (cantilever retaining wall) 8.10