CEO’s Note · Figure 4.10 : Simplified detailing rules for slab Figure 4.11 : Rules for curtailment of reinforcement of slab Figure 4.12 : Types of flat slab Figure 4.13 : Flat

1

First of all, I would like to congratulate and express my deepest appreciation to the team on their hard work and contribution to this handbook.

Yung Kong Metal Works Co Bhd. (YKMW) has been in the steel wire production business since 1970. It started as a small factory along Abell Road, Kuching, Sarawak. Today, as one of the leading steel fabric manufacturers with its production plants located in Pending Industrial Estate, the company is equipped with automated welding machines with distinctive welding features.

YKMW had received its ISO 9002: 1994 award certification in 1999. Further improvements in its management system, it was also awarded the ISO 9001: 2000 Certification in 2001 and ISO 9001: 2015 in 2018. It has also been recognized by Malaysia certification body, SIRIM QAS Sdn. Bhd. (SIRIM) for its welded steel fabric certified to MS 145: 2001 in 2005. The company has succeeded to upgrade this certification to MS 145: 2006 in 2009 and furthermore MS 145: 2014 in 2018.

YMC Mesh Sdn. Bhd. has been one of the subsidiaries of YKMW Group since 2008. It supplies custom-made YMC welded steel fabric (YMC). It also provides fabric designed drawing and technical presentation as value-added services to customers.

YMC is one of the latest solutions for our construction industry. It is certified by SIRIM to MS 145: 2014 Steel Fabric for the Reinforcement of Concrete – Specification (Fourth Revision) and is recognized by Construction Industry Development Board (CIDB) Malaysia as a quality product for construction. This product and its manufacturing processes would be audited and tested by SIRIM yearly to ensure its compliance throughout the certification.

YMC is fabricated from a series of high-strength cold reduced steel wires arranged at right angles to each other and electrically resistance welded at all intersections in square or rectangular grids. This automated welding process employs the fusion of pressure and heat, which combines the intersecting wires into a homogenous section without losing the strength or area.

The welded intersections of YMC provide basic anchorage and further higher level of bonding is obtained by the positive rib profile on the wire. This will control and limit any development of crack line due to its close and consistent spacing of smaller wires.

This YMC technical handbook is mainly served for the purposes of 1) providing the latest industrial standard and information as reference for design engineers;2) providing the information as reference for the construction engineers in application; and3) as a reference material for our local college students especially from the school of structural and

civil engineering.

Finally, I hope that this technical handbook will benefit all parties both in academic and industry.

LOUIS HIIThe CEO of YKMW Groups

CEO’s Note

2

CEO’s Note .............................................................................................................................. 1

LIST OF TABLES .................................................................................................................... 5

LIST OF FIGURES ................................................................................................................... 6

LIST OF SYMBOLS ................................................................................................................. 7

CHAPTER 1: SPECIFICATION AND PRODUCT PROPERTIES1.1 Specification …............................................................................................................ 10

1.2 MS 146: 2014 ............................................................................................................. 10

1.2.1 Scope ............................................................................................................ 10

1.2.2 Chemical Composition ….............................................................................. 11

1.2.3 Quality of Finished Steel …............................................................................ 11

1.2.4 Tensile Properties …...................................................................................... 11

1.2.5 Fatigue Strength …........................................................................................ 12

1.2.6 Rebend Test ….............................................................................................. 12

1.2.7 Dimensions, Mass per Meter and Tolerances ............................................... 12

1.2.8 Surface Geometry ......................................................................................... 13

1.3 MS 145: 2014 ............................................................................................................. 15

1.3.1 Scope ............................................................................................................ 15

1.3.2 Fabric Reference ........................................................................................... 15

1.3.3 Chemical Composition .................................................................................. 17

1.3.4 Condition of Testing ....................................................................................... 17

1.3.5 Tensile Properties .......................................................................................... 17

1.3.6 Shear Force of Welded Joints ....................................................................... 17

1.3.7 Bend Performance ........................................................................................ 18

1.3.8 Dimensions and Tolerance ............................................................................ 18

1.3.9 Packing and Marking ..................................................................................... 20

CONTENTS

3

CHAPTER 2: DESIGN CONVERSION2.1 Substitution of Steel Reinforcement ........................................................................... 20

2.1.1 Conversion Formula ...................................................................................... 20

CHAPTER 3: DETAILING OF REINFORCEMENT3.1 Concrete Cover .......................................................................................................... 26

3.2 Spacing of Reinforcement .......................................................................................... 26

3.3 Bend ........................................................................................................................... 26

3.4 Anchorage .................................................................................................................. 27

3.4.1 Ultimate Bond Stress .................................................................................... 27

3.4.2 Basic Anchorage Length ............................................................................... 29

3.4.3 Design Anchorage Length ............................................................................. 31

3.4.4 Example of Anchorage Calculation ............................................................... 32

3.5 Lapping ....................................................................................................................... 33

3.5.1 Laps ............................................................................................................... 33

3.5.2 Laps for Welded Steel Fabrics Made of Ribbed Bars ................................... 34

3.5.2.1 Laps of the main reinforcement ....................................................... 34

3.5.2.2 Laps of secondary or distribution reinforcement .............................. 35

3.5.3 Type of Laps .................................................................................................. 36

3.6 Overhang .................................................................................................................... 37

CHAPTER 4: DETAILING OF MEMBERS AND PARTICULAR RULES 4.1 Solid Slab .................................................................................................................... 39

4.1.1 One-Way Spanning Slab ............................................................................... 39

4.1.2 Two-Way Spanning Slab ............................................................................... 42

4.1.3 Minimum Area of Reinforcement, As min ...................................................... 44

4.1.3.1 Minimum area for principal reinforcement ....................................... 44

4.1.3.2 Minimum area for secondary reinforcement .................................... 45

4.1.4 Maximum Area of Reinforcement, As max .................................................... 45

4.1.5 Spacing for Reinforcement ............................................................................ 45

4.1.5.1 Minimum spacing for reinforcement ................................................ 45

4.1.5.2 Maximum spacing for reinforcement ............................................... 45

4.1.6 Reinforcement at Free Edge ......................................................................... 46

4.1.7 Simplified Detailing Rules for Slab ................................................................ 47

4.1.8 Shear Reinforcement .................................................................................... 48

4

4.2 Flat Slab ...................................................................................................................... 49

4.2.1 Slab at Internal Columns ............................................................................... 52

4.2.2 Slab at Edge and Corner Columns ................................................................ 53

4.2.3 Punching Shear Reinforcement .................................................................... 53

4.3 Reinforced Concrete Wall ........................................................................................... 54

4.3.1 Load Bearing Wall (Shear Wall) .................................................................... 54

4.3.2 Non-Load Bearing Wall ................................................................................. 54

4.3.3 Vertical Reinforcement .................................................................................. 56

4.3.3.1 Maximum area of reinforcement ...................................................... 56

4.3.3.2 Minimum area of reinforcement ....................................................... 57

4.3.4 Horizontal Reinforcement .............................................................................. 57

4.3.4.1 Minimum area of reinforcement ....................................................... 57

4.3.5 Transverse Reinforcement ............................................................................ 57

4.4 Retaining Wall ............................................................................................................. 58

4.4.1 Vertical Reinforcement .................................................................................. 58

4.4.2 Horizontal Reinforcement .............................................................................. 59

4.5 Reinforcement for Pad Footing ................................................................................... 59

4.5.1 Fabric up to Depth of Footing ........................................................................ 59

4.5.2 Hook Fabric ................................................................................................... 60

4.6 Reinforcement for Drainage and Box Culvert ............................................................. 60

REFERENCE ........................................................................................................................... 63

ANNEX ..................................................................................................................................... 64

5

Table 1.1 : Industrial standards

Table 1.2 : Chemical composition in percentage

Table 1.3 : Characteristic tensile properties

Table 1.4 : Fatigue test condition

Table 1.5 : Mandrel diameter for rebend test

Table 1.6 : Nominal cross-sectional area and mass per meter

Table 1.7 : Tolerance on mass per meter

Table 1.8 : Ranges for the rib parameters

Table 1.9 : Characteristic relative rib area

Table 1.10 : Fabric reference

Table 2.1 : Substitution of fabric for high yield bars (fy,Bar = 500 MPa)

Table 3.1 (a) Minimum mandrel diameter to avoid damage of reinforcement for bar

Table 3.1 (b) Minimum mandrel diameter to avoid damage of reinforcement for welded bent reinforcement and mesh bend after welding

Table 3.2 : Values of α1, α2, α3, α4, α5, coefficients

Table 3.3 : Required lap lengths for secondary wires of fabric

Table 4.1 : Minimum percentage of reinforcement

LIST OF TABLES

6

LIST OF FIGURESFigure 1.1 : Rib geometryFigure 1.2 : Fabric notationFigure 1.3 : Product label of YMC Figure 3.1 : Typical bendsFigure 3.2 : Method of anchorageFigure 3.3 : Description of bond conditionsFigure 3.4 : Values of K for beams and slabs Figure 3.5 : Adjacent lapsFigure 3.6 : Lapping of welded fabricFigure 3.7 : OverhangFigure 4.1 : One-way spanning slab diagramFigure 4.2 : Load distribution for one-way spanning slabFigure 4.3 : One-way spanning slab fabric design layout (Bottom fabric)Figure 4.4 : One-way spanning slab fabric design layout (Top fabric)Figure 4.5 : Two-way spanning slab diagramFigure 4.6 : Load distribution for two-way spanning slabFigure 4.7 : Two-way spanning slab fabric design layout (Bottom fabric)Figure 4.8 : Two-way spanning slab fabric design layout (Top fabric)Figure 4.9 : Edge reinforcement for a slabFigure 4.10 : Simplified detailing rules for slabFigure 4.11 : Rules for curtailment of reinforcement of slabFigure 4.12 : Types of flat slabFigure 4.13 : Flat slab fabric design layout (Bottom fabric)Figure 4.14 : Flat slab fabric design layout (Top fabric)Figure 4.15 : Division of panels in flat slabFigure 4.16 : Effective width, be, of a flat slabFigure 4.17 : Punching shear layoutFigure 4.18 : Reinforced concrete wall cut sectionFigure 4.19 : Reinforced concrete wall fabric design layoutFigure 4.20 : Reinforced concrete retaining wall fabric Figure 4.21 : Fabric up to depth of footingFigure 4.22 : Hook fabric for footingFigure 4.23 : U-Bend fabricFigure 4.24 : L-Bend fabricFigure 4.25 : Closed drain Figure 4.26 : Box culvert

7

LIST OF SYMBOLSymbol Description Unit

Chapter 1Re Yield strength MPa

Rm Tensile strength MPa

Agt Percentage total elongation at maximum force %

Ø Nominal diameter of the reinforcement steel mm

h Rib height mm

c Transverse rib spacing mm

β Angle of transverse rib inclination degrees

α Transverse rib flank inclination degrees

An Nominal cross-sectional area mm2

Chapter 2As,Fabric Equivalent area of steel fabric mm2/mAs,Bar Area of steel bar mm2/mfy,Bar Yield strength of steel bar MPa

fy,Fabric Yield strength of fabric MPar Radius of steel bar mm

Chapter 3dg Maximum size of aggregate mm

Øm,min Minimum mandrel diameter mmØ Diameter mmd Distance mmfbd Ultimate bond stress N/mm2

lb Basic anchorage length mmlb,rqd Basic required anchorage length mmlb,min Minimum anchorage length mmlbd Design length mmp Transverse pressure MPal0 Lap length mm

As,Prov Area of steel fabric provided mm2/ms Spacing of wires mm

8

Symbol Description UnitChapter 4

ly Longer span mmlx Shorter span mm

As,min Minimum area of reinforcement mm2/mAsw,min Minimum area of a link leg for vertical punching shear

reinforcementmm2/m

As,max Maximum area of reinforcement mm2/mAs,vmin Minimum area of vertical reinforcement mm2/mAs,vmax Maximum area of vertical reinforcement mm2/mAs,hmin Minimum area of horizontal reinforcement mm2/m

Ac Gross area of concrete section mm2

At Top reinforcement area mm2

fctm Mean tensile strength MPafyk Characteristic yield strength of reinforcement MPafck Characteristic cylinder strength MPa

bt/be Effective width mmd Effective depth mmh Depth of slab mmL Effective length my Distance from the edge of the slab to the innermost face of

the columnmm

smax Maximum spacing mmα Inclination of the shear reinforcement °

VEd Shear force kNVRd,max’ Design value of the maximum shear force which can

be sustained by the member, limited by crushing of the compression struts

kN

sr Spacing of shear links in the radial direction mmst Spacing of shear links in the tangential direction mm

9

Chapter 1 SPECIFICATION AND PRODUCT PROPERTIES

Malaysia steel mills produce and supply several kinds of steel products for construction industry such as hot rolled bar and wire rod. Low carbon wire rod complying with MS 16120-2 is widely used by downstream factories in producing cold drawn bar and welded steel fabric.

The usage of welded steel fabric in construction industry is strictly controlled by Malaysian Government on its quality. Malaysian Standard MS 145: 2014 is the industrial standard to specify the properties and quality of welded steel fabric as the reinforcement of concrete. Furthermore, MS 146: 2014 controls the raw material used to fabricate this welded steel fabric complying with MS 145: 2014. The enforcement unit CIDB ensures only the certified products being used at construction sites. This chapter is mainly describing on the specifications and requirements of these Malaysian Standards, and the supporting notes to describe the properties of YMC (brand of YKMW) as a certified welded steel fabric.

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1.1 SPECIFICATION

Department of Standard Malaysia publishes specifications for steel bar and welded steel fabric. And the Standard and Industrial Research Institute of Malaysia (SIRIM) will audit and issue product certificates for the compliances. The appropriate Malaysian Standards are given in Table 1.1.

Table 1.1: Industrial standardsStandard Title

MS 146: 2014 Steel for The Reinforcement of Concrete – Welded Reinforcing Steel – Bar, Coil and Decoiled Product – Specification (Fourth Revision)

MS 145: 2014 Steel Fabric for The Reinforcement of Concrete – Specification (Fourth Revision)

Note 1.1 YMC is certified to MS 145: 2014 with license number PY007001. Yearly renewal of license is required and approval is subject to the result of audit and laboratory test conducted by SIRIM.

YMC is further recognized by CIDB as a quality product with registration number 1141119SR0015.

Note 1.2 Bar used for the fabrication of YMC is strictly complying with MS 146: 2014.

1.2 MS 146: 2014

1.2.1 Scope

This Malaysian Standard specifies requirements for ribbed weldable reinforcing steel used for the reinforcement of concrete structures. It contains provisions for three steel grades, all of 500 MPa characteristic yield strength, but with different ductility characteristics. The three grades are B500A, B500B and B500C.

Note 1.3 Bar quality of YMC is defined as cold worked ribbed bar grade B500A. Note 1.4 Rib pattern of bar with grade B500A is described in MS 146: 2014 as the

following. Bars shall have two or more series of parallel transverse ribs with the same angle of inclination and the same direction for each series.

Note 1.5 Annex 2: The difference between the reinforcing bars B500A, B500B and

B500C.

Example of rib pattern of grade B500A

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1.2.2 Chemical Composition

The values of individual elements and the carbon equivalent shall not exceed the limits given in Table 1.2.

Table 1.2: Chemical composition in percentageCarbon

max.Sulphur

max.Phosphorus

max.Nitrogen

max.Copper

max.Carbon

equivalentmax.

Cast analysis 0.22 0.05 0.05 0.012 0.80 0.50

Product analysis 0.24 0.055 0.055 0.014 0.85 0.52

1.2.3 Quality of Finished Steel

All bars shall be free from harmful defects which can be shown to adversely affect the mechanical properties of the steel. Rust, seams, surface irregularities or mill scale shall not be the cause of rejection provided the mass, dimensions, cross-sectional area and the mechanical properties of a hand wire brushed test specimen are not less than the requirements of this standard.

Therefore, any surface rust which remains on the fabric is not harmful but in fact will increase the bond and anchorage properties of fabric. Loose rust can be easily removed during handling and shaking of fabric.

1.2.4 Tensile Properties

MS 146: 2014 states the minimum requirements for characteristic tensile properties of bar used for welded steel fabric as described in Table 1.3.

Table 1.3: Characteristic tensile propertiesGrade Yield Strength

Re

(MPa)

Tensile/Yield Strength Ratio

Rm/Re

Total Elongation at Maximum Force

Agt(%)

B500A 500 1.05 2.5B500B 500 1.08 5.0B500C 500 ≥ 1.15, < 1.35 7.5

Note 1.6 Rm/Re characteristic is 1.02 for sizes below 8 mm. Note 1.7 Agt characteristic is 1.0 % for sizes below 8 mm. Note 1.8 The absolute maximum permissible value of yield strength is 650 MPa.

12

1.2.5 Fatigue Strength

Reinforcing bars shall be subjected to fatigue testing. When submitting to axial force controlled fatigue testing, using a stress ratio (σmax/σmin) of 0.2, and stress range as in Table 1.4, test samples shall survive five million stress cycles.

Table 1.4: Fatigue test conditionBar size, Ø

(mm)Stress range

(MPa)≤ 16 200

16 < Ø ≤ 20 18520 < Ø ≤ 25 17025 < Ø ≤ 32 160

> 32 150

1.2.6 Rebend Test

Bend the test piece through an angle of 90°, around a mandrel with a diameter not exceeding those specified in Table 1.5, age the test piece (refer to 1.3.4 Condition of Testing) and then bend back by minimum 20°. After the test, the specimen shall show no sign of fracture or cracks visible to a person of normal or corrected vision.

Table 1.5: Mandrel diameter for rebend testBar size, Ø

(mm)Maximum mandrel diameter

≤ 16 4Ø> 16 7Ø

1.2.7 Dimensions, Mass per Meter and Tolerances

The preferred nominal diameters (unit in mm) are 8, 10, 12, 16, 20, 25, 32 and 40. If bar is used for the manufacture of welded fabric in accordance with MS 145: 2014, then preferred nominal diameter shall include 6, 7 and 9 mm.

13

Table 1.6: Nominal cross-sectional area and mass per meterNominal diameter

(mm)Cross sectional area

(mm2)Mass per meter

(kg)6789

10121620253240

28.338.550.363.678.5113201314491804

1257

0.2220.3020.3950.4990.6170.8881.582.473.856.319.86

Table 1.7: Tolerance on mass per meterBar size, Ø

(mm)Tolerance on mass per meter

(%)Ø > 8 ± 4.5Ø ≤ 8 ± 6.0

Note 1.9 The preferred millimeter nominal sizes of bar for YMC fabrication are 6, 7, 8, 9, and 10.

1.2.8 Surface Geometry

Rib is the protrusion on the outside of the bar produced through cold rolled process. It benefits in enhancing the bond and anchorage characteristics of the bar, better consistent properties and ductility. It also helps to minimize the crack widths in concrete elements as the force is well distributed through bond effect of ribbed bar as compared to plain bar. The values for the spacing, height and rib inclination of transverse ribs shall be within the range given in Table 1.8.

Table 1.8: Ranges for the rib parametersRib height,

hRib spacing,

cRib inclination,

β0.03Ø – 0.15Ø 0.4Ø – 1.2Ø 35° – 75°

14

Figure 1.1: Rib geometry

The projection of the transverse ribs shall extend over at least 75 % of the circumference of the product, which shall be calculated from the nominal diameter. The transverse rib flank inclination α shall be greater than or equal to 45°, and the transition from the rib to the core shall be radiused.

Where longitudinal ribs are present, there height shall not exceed 0.10Ø, where Ø is the nominal diameter of the product.

Table 1.9: Characteristic relative rib areaNominal bar size, Ø

(mm)Relative rib area

Ø ≤ 6 0.0356 < Ø ≤ 12 0.040

Ø > 12 0.056

Note 1.10 Bar of YMC is certified for its rib pattern and unique bar marking which can be found on the surface along the bar.

Bar Mark Description

\ Y \ M \ C \ Brand\ 8 \ Bar size\ 1 \ Local manufacturing\ x \ Start of bar mark\ 9 \ Country code

\ 1 \ 5 \ Registration number of CIDB

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1.3 MS 145: 2014

1.3.1 Scope

This Malaysian Standard specifies requirements for sheets of factory-made machine welded steel fabric for the reinforcement of concrete, manufactured from ribbed bars conforming to MS 146: 2014.

1.3.2 Fabric Reference

The fabric reference has been reviewed from nominal size to steel area in MS 145: 2014.

Table 1.10: Fabric referenceMS 145: 2006 MS 145: 2014

Square meshA4 A63A5 A98A6 A142A7 A193A8 A252A9 A318

A10 A393A11 A475A12 A565A13 A664

Rectangular mesh Structural meshB5 B196B6 B283B7 B385B8 B503B9 B636

B10 B785B11 B950B12 B1131B13 B1328

16

Long meshC5 C196C6 C283C7 C385C8 C503C9 C636

C10 C785C11 C950C12 C1131C13 C1328

Small square mesh Wrapping meshD4 D126D5 D196D6 D283D7 D385D8 D503D9 D636

D10 D785D11 D950D12 D1131D13 D1328

Note 1.11 The preferred fabrics of YMC are stated as below.

Type Fabric Reference Pitch (mm)

A Square mesh 200 × 200

B Structural mesh 100 longitudinal bars spacing200 transverse bars spacing

D Wrapping mesh 100 x 100

Note 1.12 Custom-made YMC refers to the fabrics which are different in dimensions according to the designed structures. However, it complies with MS 145: 2014 in the aspects of size, pitch, cross-sectional area and mass.

Element Description

Longitudinal bar Diameter from 6 to 10 mm

Transverse bar Diameter from 6 to 10 mm

Fabric length Up to 6.0 m

Fabric width Up to 2.4 m

Overhang length From 75 mm to 2.0 m

17

1.3.3 Chemical Composition

The chemical composition of bars shall conform to the requirements of MS 146: 2014. Refer to Table 1.2 Chemical composition in percentage.

1.3.4 Condition of Testing

Test piece shall be in aged condition: heat the test piece to 100 °C, maintain at this temperature (± 10 °C) for a period of not less than 60 minutes (maximum 75 minutes) and then cool in still air to room temperature.

1.3.5 Tensile Properties

Refer to Table 1.3: Characteristic tensile properties.

Note 1.13 YMC is certified to grade B500A. Therefore, it shall comply with the requirements stated below.

YMC Yield StrengthRe

(MPa)

Tensile/YieldStrength

Ratio

Rm/Re

Total Elongationat Maximum

Force

Agt

(%)

Shear Force ofWelded Joints

(kN)

A142A193A252A318A393

500 – 650 500 – 650 500 – 650 500 – 650 500 – 650

1.02 1.021.051.051.05

1.01.02.52.52.5

3.534.816.287.959.82

B283B385B503B636B785

500 – 650 500 – 650 500 – 650 500 – 650 500 – 650

1.02 1.021.051.051.05

1.01.02.52.52.5

4.814.816.287.959.82

D503D636D785

500 – 650 500 – 650500 – 650

1.051.051.05

2.52.52.5

6.287.959.82

1.3.6 Shear Force of Welded Joints

MS 145: 2014 states that the shear force of welded joints in welded fabric shall not be less than

0.25 x Re x An Where

Re is the specific characteristic yield strength; and An is the nominal cross-sectional area of the larger bar of the welded joint.

18

The number of broken welds shall not exceed 4 % of the total number of cross welded joints in the sheet, nor exceed half the number of cross welded joints along any one bar.

Note 1.14 Note 1.13 describes the shear force of welded joints of YMC in minimum.

1.3.7 Bend Performance

Refer to 1.2.6 Rebend Test. The bend test shall be conducted on the thicker bar.

1.3.8 Dimensions and Tolerance

The pitch of longitudinal bars and transverse bars shall not less than 50 mm. The permitted deviation of welded steel fabric are:

(a) length and width: ± 25 mm or ± 0.5 % whichever is the greater;

(b) bar pitch: ± 10 mm or ± 5 % whichever is the greater; and

(c) overhangs: to be agreed at the time of enquiry and order. Note 1.15 Certified reference of YMC.

Reference Nominal Bar Size(mm)

Nominal Pitch(mm)

Steel Area(mm2/m)

Mass(kg/m2)

Longitudinal Transverse Longitudinal Transverse Longitudinal Transverse

Square mesh

A142A193A252A318A393

6789

10

6789

10

200200200200200

200200200200200

142193252318393

142193252318393

2.223.023.954.996.16

Structural mesh

B283B385B503B636B785

6789

10

77888

100100100100100

200200200200200

283385503636785

193193252252252

3.734.535.936.978.14

Wrapping mesh

D503D636D785

89

10

89

10

100100100

100100100

503636785

503636785

7.909.9812.3

19

Figure 1.2: Fabric notation

Key:

L Length of the longitudinal bar (which are not necessarily the longer bar) in the sheet

W Length of the transverse bar

O1 and O2 Overhangs of the longitudinal bar

O3 and O4 Side overhangs of the transverse bar

Pm Pitch of the longitudinal bar

Pc Pitch of the transverse bar

W

L

O1

O2

O3O4 Pc

Pm

20

1.3.9 Packing and Marking

The manufacturer shall ensure that each bundle of output is securely tied with not less than four binders, and shall attach to bundle a durable label with the following information:

(a) standard number, MS 145: 2014;

(b) the grade of fabric;

(c) the type of fabric;

(d) the name of fabric manufacturer;

(e) the dimension of fabric; and

(f) number of sheet.

Figure 1.3: Product label of YMC

21

Chapter 2 DESIGN CONVERSION

This chapter includes the substitution for steel reinforcement from conventional steel bar to welded steel fabric and shows the conversion formula. As we know, using welded steel fabric drastically speeds up the construction process. It is available in wide range of bar diameters each suited for a particular reinforcing design application. The conventional steel bar reinforcement can be substituted with welded steel fabric resulting in easier controls, increase speed of installation, reducing offcuts and wastage.

22

2.1 SUBSTITUTION OF STEEL REINFORCEMENT

Welded steel fabric is the product used to reinforce concrete in construction. Fabric is made up of high tensile steel bars which are welded together using the modern technology. This welded steel fabric is used as a substitution for the conventional method of reinforcement using steel bars. YMC is one of the local brands of welded steel fabric which supplies custom-made fabric for local construction industries.

2.1.1 Conversion Formula

Previously, according to MS 146: 2006, the high yield tensile bar is 460 MPa. By referring to the latest version of MS 146: 2014 (Chapter 1, Table 1.3: Characteristic tensile properties), the new high yield tensile bar is 500 MPa.

To determine equivalent fabric area, As,Fabric, the general conversion formula is defined below:

Where

As,Bar is the area of steel bar in mm2/m; fy,Bar is the yield strength of steel bar in MPa; and fy,Fabric is the yield strength of fabric in MPa.

Since the yield strength for high tensile bar and steel fabric are both 500 MPa, we can assume that:

As,Fabric = As,Bar Note 2.1 High yield bar, fy,Bar = 500 MPa Note 2.2 YMC welded steel fabric, fy Fabric = 500 MPa

Table 2.1 shows the conversions of common bar diameter and spacing for easy reference purpose. Suitable fabric reference could be selected from fabric table based on converted equivalent fabric area. The area of recommended fabric reference should be equal or greater than the equivalent fabric area.

As,Fabric = As,Bar ×fy,Bar

fy,Fabric

23

Table 2.1: Substitution of fabric for high yield bars (fy,Bar = 500 MPa)Bars Fabric

Nominal SizeØ

(mm)

Spacing

(mm)

Area of steelbar, As,Bar(mm2/m)

Equivalent fabric area, As,Fabric

(mm2/m)

RecommendedYMC Fabric Reference

8 100 503 503 B503 (B8), D503 (D8)

150 335 335 A393 (A10), B385 (B7)

200 251 251 A252 (A8)

250 201 201 A252 (A8)

300 168 168 A193 (A7)

10 100 785 785 B785 (B10), D785 (D10)

150 524 524 B636 (B9), D636 (D9)

200 393 393 A393 (A10)

250 314 314 A318 (A9), B385 (B7)

300 262 262 A318 (A9), B283 (B6)

12 150 754 754 B785 (B10), D785 (D10)

200 565 565 B636 (B9), D636 (D9)

250 452 452 B503 (B8), D503 (D8)

300 377 377 A393 (A10), B385 (B7)

16 300 670 670 B785 (B10), D785 (D10)

Note 2.3 Certified reference for YMC is shown in Chapter 1, Note 1.15.

To determine the area of steel bar, As,bar as stated in Table 2.1, the formula below is given:

Step 1: Area of steel bar, As,bar = πr2 Step 2: No.of bar per m = Step 3: Area of steel bar per m = As,bar × no.of bar per m

Where

π is 3.142; and r radius of steel bar.

Work example below shows the substitution from steel bar to welded steel fabric.

Parameter

Bar diameter 8 mm

Bar spacing 150 mm

1 metre run 1000 mm

π 3.142 - fy,bar 500 MPa

fy,fabric 500 MPa

1000(bar spacing)

24

Calculation

Area of steel bar = πr2 = 3.142 × ( )2 = 50.272 mm2 No. of bar per metre = = = 6.667 no.of bar/m

Area of steel bar per m

Equivalent area of fabric = As,bar × = 335 × = 335 mm2/m

Hence, the recommended YMC Fabric is A393 (A10) or B385 (B7).

1000150

500500

1 mbar spacing

82

fy,Barfy,Fabric

Area of steel bar × no.of bar per m= = 50.272 × 6.667 = 335.16 ~ 335 mm

2/m

25

Chapter 3 DETAILING OF REINFORCEMENT

This chapter will explain the detailing for the reinforcement. Reinforcement is important to resist internal tensile forces calculated from analysis. Also, reinforcement is provided in compression zones to increase the compression capacity, enhance ductility, reduce long term deflections, or increase the flexural capacity for beams. In addition, reinforcement is required to prevent excessive cracking resulting from shrinkage or temperature changes in restrained structural elements. It is important to provide the adequate area of reinforcement required to resist internal tensile or compression forces required to attain the design strength. The provided area of reinforcement is not fully effective unless it is fully developed, it may be developed by bending, anchorage, lapping and etc. In addition to provide the sufficient areas of reinforcement, good detailing should be done considering the overall structural integrity.

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3.1 CONCRETE COVER

As stated in Clause 4.4.1.1, MS EN 1992-1-1: 2010, the concrete cover is the distance between the surface of the reinforcement closest to the nearest concrete surface (including links and stirrups and surface reinforcement where relevant) and the nearest concrete surface. The nominal cover shall be specified on the drawings.

3.2 SPACING OF REINFORCEMENT

The spacing of bars shall be such that the concrete can be placed and compacted satisfactorily for the development of adequate bond. The clear distance (horizontal and vertical) between individual parallel bars or horizontal layers of parallel bars should be not less than the maximum of k1 x bar diameter, (dg + k2 mm) or 20 mm where dg is the maximum size of aggregate.

Where bars are positioned in separate horizontal layers, the bars in each layer should be located vertically above each other. There should be sufficient space between the resulting columns of bars to allow access for vibrators and good compaction of the concrete. Lapped bars may be allowed to touch one another within the lap length.

Note 3.1 Clause 8.2, MS EN 1992-1-1: 2010.

Note 3.2 The recommended value of k1 and k2 are 1 and 5 mm respectively.

3.3 BEND

The minimum diameter to which a bar is bent shall be such as to avoid bending cracks in the bar, and to avoid failure of the concrete inside the bend of the bar. In order to avoid damage to the reinforcement the diameter to which the bar is bent (mandrel diameter) should not be less than Øm,min (Refer Table 3.1).

Note 3.3 Clause 8.3 MS EN 1992-1-1: 2010.

Table 3.1 (a): Minimum mandrel diameter to avoid damage of reinforcement for bar

Bar size, Ø(mm)

Minimum mandrel diameter for bends, hooks and loops

≤ 16 4Ø> 16 7Ø

Note 3.4 Adapted from Table 8.1N MS EN 1992-1-1: 2010.

27

Table 3.1 (b): Minimum mandrel diameter to avoid damage of reinforcement for welded bent reinforcement and mesh bend after welding

Minimum mandrel diameter

5Ø For d ≥ 3Ø, use 5ØFor d < 3Ø or welding between the curved zone, use 20Ø

Note 3.5 The mandrel size for welding within the curved zone may be reduced to 5Ø where the welding is carried out in accordance with MS EN ISO 17660 Annex B.

Figure 3.1: Typical bends

or ord

Single Bend Double Bend

Transverse bar

Longitudinal bar

28

3.4 ANCHORAGE

Reinforcing bars or welded steel fabrics should be anchored so that the bond forces are safely transmitted to the concrete avoiding longitudinal cracking or spalling. Transverse reinforcement shall be provided if necessary. Method of anchorage are shown in Figure 3.2.

Note 3.6 Clause 8.4.1, MS EN 1992-1-1: 2010.

Figure 3.2: Method of anchorage

3.4.1 Ultimate Bond Stress The ultimate bond strength shall be sufficient to prevent bond failure. The design value

of the ultimate bond stress, fbd for ribbed bars as shown below:

fbd = 2.25η1 η2 fctd

Where

fctd is the design value of concrete tensile strength according to 3.1.6 (2)P. Due to the increasing brittleness of high strength concrete, fctk,0.05 should be limited here to the value for C60/75, unless it can be verified that the average bond strength increases above this limit.

η1 is the coefficient related to the quality of the bond condition and the position of the bar during concreting, η1=1.0 when ‘good’ conditions are obtained.

η1 = 0.7 for all other cases and for bars in structural elements built with slip-forms, unless it can be shown that ‘good’ bond conditions exist.

29

η2 is related to the bar diameter

η2 = 1.0 for Ø ≤ 32 mm

η2 = (132 – Ø)/100 for Ø > 32 mm

Figure 3.3: Description of bond conditions

Direction of concreting

a) and b) “good” bond conditions for all bars

c) and d) unshaded area: “good” bond conditions shaded area: deficient bond conditions

Note 3.7 Clause 8.4.2, MS EN 1992-1-1: 2010.

3.4.2 Basic Anchorage Length

The basic required anchorage length, lb,rqd, for anchoring the force As.σsd in a straight bar assuming constant bond stress equal to fbd follows from:

lb,rqd = (Ø/4)(σsd/fbd)

Where

σsd is the design stress of the bar at the position from where the anchorage is measured from.

Where pairs of wires/bars form welded fabrics the diameters, Ø should be replaced by the equivalent diameter Øn = Ø√2.

Note 3.8 Clause 8.4.3, MS EN 1992-1-1: 2010.

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3.4.3 Design Anchorage Length

The design anchorage length, lbd is:

lbd = α1 α2 α3 α4 α5 lb,rqd ≥ lb,min

Where α1,α2,α3,α4,α5 are coefficients given in Table 3.2

α1 is for the effect of the form of the bars assuming adequate cover α2 is for the effect of concrete minimum cover

α3 is for the effect of confinement by transverse reinforcement α4 is for the influence of one or more welded transverse bars (Øǀ > 0.6Ø) along

the design anchorage length, lbd α5 is for the effect of the pressure transverse to the plane of splitting along the

design anchorage length

The product (α2 α3 α5) ≥ 0.7 lb,min is the minimum anchorage length if no other limitation is applied:

- For anchorages in tension: lb,min > max {0.3lb,rqd ;10Ø;100 mm} - For anchorages in compression: lb,min > max {0.6lb,rqd ;10Ø;100 mm}

The tension anchorage of certain shape in Figure 3.2 may be provided as an equivalent

anchorage length, lb,eq. lb,eq is defined :

- α1 lb,rqd for shapes shown in Figure 3.2b to 3.2d - α4 lb,rqd for shapes in Figure 3.2e

Note 3.9 Clause 8.4.4, MS EN 1992-1-1: 2010.

C1

C

a

a) Straight bars cd = min (a/2, c1, c)

C1a

b) Bent or hooked bars cd = min (a/2, c1)

C

c) Looped bars cd = c

31

Table 3.2: Values of α1, α2, α3, α4, α5 coefficients

Influencing factor Type of anchorage Reinforcement barIn tension In compression

Shape of barsStraight α1 = 1.0 α1 = 1.0

Other than straight α1 = 0.7 if cd > 3Ø otherwise α1 = 1.0

α1 = 1.0

Concrete coverStraight α1 = 1-0.15 (cd - Ø)/Ø

≥ 0.7≤ 1.0

α2 = 1.0

Other than straight α1 = 1-0.15 (cd - 3Ø)/Ø≥ 0.7≤ 1.0

α2 = 1.0

Confinement by transverse

reinforcement not welded to main reinforcement

All types α3 = 1 - Kλ≥ 0.7≤ 1.0

α3 = 1.0

Confinement by welded transverse

reinforcement

All types α4 = 0.7 α4 = 0.7

Confinement by transverse

pressure

All types α5 = 1 - 0.04p≥ 0.7≤ 1.0

-

Note 3.10 Adapted from Table 8.2 MS EN 1992-1-1: 2010.

Where

λ (ΣAst - ΣAst,min)/As ΣAst cross-sectional area of the transverse reinforcement along the design

anchorage length, lbd ΣAst,min cross-sectional area of the minimum transverse reinforcement = 0.25 As

for beams and 0 for slabs

As area of a single anchored bar with maximum bar diameter

K values shown in Figure

p transverse pressure (MPa) at ultimate limit state along lbd

Figure 3.4: Values of K for beams and slabs

As Øt , Ast

K = 0,1

As Øt , Ast

K = 0,05

As Øt , Ast

K = 0

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3.4.4 Example of Anchorage Calculation

Parameter:

Concrete cover = 25 mm

fy = 500 N/mm2

fck,cube =30 N/mm2

Ø = 7 mm

As = 193 mm2 (A193)

No. of bar = 5

Assume bot area of rebar near support is 50% As

0.5As = 193 × 0.5 = 96.50 mm2 Fb = 0.87fy As = = 41.98 kN

From Table 3.1 (MS EN 1992-1-1: 2010),

fck,cube = 30 N/mm2, fctd = 1.8

η1 = 0.7

η2 = 1.0

Design value of the ultimate bond stress

fbd = 2.25η1 η2 fctd = 2.25(0.7)(1.0)(1.8) = 2.835 N/mm2

Design stress of bars σsd = = = 218.14 N/mm2

Basic required anchorage length lb,rqd = = = 673.27 mm

0.87 x 500 x 96.5103

Fbno. of bar × πr2

41.98 × 103

5 × π × 3.52

∅4( ) σsdfbd( ) ( )5 × 74 ( )218.142.835

33

Tension

α1 = 1 α2 = 1 - = 1 - = 1.043

cd = min = = 25 mm

α3 = 1 - Kλ = 1 - 0 = 1

α4 = 1

α5 = 1

lb,min = max = max = 100 mm/bar

Design anchorage length

lbd = α1 α2 α3 α4 α5 lb,rqd ≥ lb,min = (1)(1.043)(1)(1)(1)(673.27) = 702.22 mm (for 5 no.of bar) Hence, 1 bar length = = 140.44 mm ≥ lb,min = 100 mm

3.5 LAPPING

3.5.1 Laps

The detailing of laps between bars shall be such that:

(a) the transmission of the forces from one bar to the next is assured;

(b) spalling of the concrete in the neighbourhood of the joints does not occur; and

(c) large cracks which affect the performance of the structure does not occur.

Laps between bar should normally be staggered and not located in areas of high moments/forces. The arrangement of lapped bars should comply with Figure 3.4, as set out below:

(a) the clear distance between lapped bar should not be greater than 4Ø or 50 mm, otherwise the lap length should be increased by a length equal to the clear space where it exceeds 4Ø or 50 mm;

(b) the longitudinal distance between two adjacent laps should not be less than 0.3 times the lap length, l0; and

(c) in case of adjacent laps, the clear distance between adjacent bars should not be less than 2Ø or 20 mm.

0.15(cd - ∅ ∅

0.15(25 - (5 × 7))5 x 7

( )200 - 142( )a2 ,c1, c ,25,25

{ }0.3 ,10∅,100 mmlb,rqd5 { }0.3 ,10(7),100 mm673.275

702.225

34

When the provisions comply with the statement above, the permissible percentage of lapped bars in tension may be 100% where the bars are all in one layer. Where the bars are in several layers, the percentage should be reduced to 50 %.

All bars in compression and secondary (distribution) reinforcement may be lapped in the same location.

Note 3.11 Clause 8.7.2, MS EN 1992-1-1: 2010.

Figure 3.5: Adjacent laps

FsFs

Fs

Fs

Fs

Fs

a

l0

≤ 4Ø≤ 50 mm

≥ 20 mm≥ 2Ø

Ø

≥ 0,3l0

3.5.2 Laps for Welded Steel Fabrics Made of Ribbed Bars

3.5.2.1 Laps of the main reinforcement

Laps may be made either by intermeshing or by layering fabrics. For intermeshed fabric, the lapping arrangements for the main longitudinal bars should conform to Clause 3.5.1.

For layered fabric, the laps of the main reinforcement should be generally be situated in zones where the calculated stress in the reinforcement at ultimate limit state is not more than 80 % of the design strength. The permissible percentage of the main reinforcement that may be spliced by lapping in any section, depends on the specific cross-section area of the welded fabric provided (As/s)prov, where s is the spacing of wires:

(a) 100 % if (As/s)prov ≤ 1200 mm2/m

(b) 60 % if (As/s)prov > 1200 mm2/m

Note 3.12 Clause 8.7.5.1, MS EN 1992-1-1: 2010.

35

Figure 3.6: Lapping of welded fabric

Fs

l0

Fs

a) intermeshed fabric (longitudinal section)

FsFs

l0

b) layered fabric (longitudinal section)

3.5.2.2 Laps of secondary or distribution reinforcement

All secondary reinforcement may be lapped at the same location. The minimum values of the lap length, l0 are shown in the Table 3.3 below.

Table 3.3: Required lap lengths for secondary wires of fabricDiameter of secondary bar, Ø

(mm)Lap lengths

Ø ≤ 6 ≥ 150 mm; at least 1 wire pitch within the lap length

6 < Ø ≤ 8.5 ≥ 250 mm; at least 2 wire pitches8.5 < Ø ≤ 12 ≥ 350 mm; at least 2 wire pitches

Note 3.13 Clause 8.7.5.2, MS EN 1992-1-1: 2010.

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3.5.3 Type of Laps

Full yield strength lap - The most common type lapping used.

- Transfer the full yield strength of the reinforcement.

- Staggered arrangement is to avoid accumulation of laps.

Half yield strength - Half yield strength laps with overlap of only one cross weld are acceptable in side laps of one-way slab. This is commonly used in top (negative) reinforcement.

- Transfer half the yield strength of the reinforcement

- May be use for side laps across beams

Reversed or nested-in-plane lap - Particularly useful in situations of maximum stress to maintain the lapped reinforcement in the same plane

Flying ends lap - Alternative method in plane lapping where one sheet is provided with a lap length overhang without welded intersections

- The lap length is determined as for lapped bars (plain or deformed wires), and without welded intersection on lapped wires, the ultimate anchorage bond stress of fabric do not apply

Non-yield strength transfer splice lap - May be used for secondary direction lapping over beam or secondary direction lapping where splice transfer is not important

37

3.6 OVERHANG

Overhang refers to the distance between the tip of the wire and the first weld joint. Other than the overall dimensions and spacings of the wires that determine the overhang to be provided, the usage of the fabric also plays and important role in deciding the suitable length of overhang.

Figure 3.7: Overhang

Specified length of overhangs

38

Chapter 4 DETAILING OF MEMBERS AND PARTICULAR RULES

The detailing of members and particular rules is very important with regard to the safety, serviceability and durability. It should be consistent with the design models adopted. Therefore, the minimum areas of reinforcement are given in order to prevent brittle failure, wide cracks and to resist forces arising from restrained actions. This chapter includes the detailing of members and particular rules for solid slab, flat slab, wall and retaining wall. The application of welded steel fabric in pad footing and drainage also shown in this chapter.

39

4.1 SOLID SLAB

4.1.1 One-Way Spanning Slab

One-way spanning slab is a slab which is supported by beams on the two opposite sides to carry the load along one direction. In one-way spanning slab, the ratio of longer span (ly) to shorter span (lx) is equal or greater than 2, i.e. longer span (ly) / shorter span (lx) ≥ 2.

Figure 4.1: One-way spanning slab diagram

Figure 4.2: Load distribution for one-way spanning slab

A

C

B

Dly

lx

40

Figure 4.3: One-way spanning slab fabric design layout (Bottom fabric)

Bottom fabric

41

Figure 4.4: One-way spanning slab fabric design layout (Top fabric)

Top fabric

42

4.1.2 Two-Way Spanning Slab

When a reinforced concrete slab is supported by beams on all the four sides and the loads are carried by the supports along both directions, it is known as two-way spanning slab. In two-way spanning slab, the ratio of longer span (ly) to shorter span (lx) is less than 2, i.e. longer span (ly) / Shorter span (lx) < 2.

Figure 4.5 Two-way spanning slab diagram

Figure 4.6: Load distribution for two-way spanning slab

A

C

B

Dly

lxE F

43

Figure 4.7: Two-way spanning slab fabric design layout (Bottom fabric)

Bottom fabric

44

Top Fabric

Figure 4.8: Two-way spanning slab fabric design layout (Top fabric)

4.1.3 Minimum Area of Reinforcement, As,min

4.1.3.1 Minimum area for principal reinforcement

The minimum area of principal reinforcement in the main direction is shown below:

Where

fctm mean tensile strength;

fyk characteristic yield strength of reinforcement; and

bt effective width; and d = effective depth

As,min = 0.26fctmbtdfyk

45

Table 4.1: Minimum percentage of reinforcementfck fctm Minimum percentage

(0.26 fctm/fyk2)25 2.6 0.1328 2.8 0.1430 2.9 0.1532 3.0 0.1635 3.2 0.1740 3.5 0.1845 3.8 0.2050 4.1 0.21

Note 4.1 Adapted from Table 3.1, MS EN 1992-1-1: 2010.

Note 4.2 Assume fyk = 500 MPa

4.1.3.2 Minimum area for secondary reinforcement

Secondary transverse reinforcement of not less than 20 % As,min should be provided in one way slabs. In area of near supports, transverse reinforcement is not necessary where there is no transverse bending moment.

4.1.4 Maximum Area of Reinforcement, As,max

Outside lap locations, the maximum area of tension or compression reinforcement should not exceed As,max = 0.04 Ac.

4.1.5 Spacing for Reinforcement

4.1.5.1 Minimum spacing for reinforcement

The minimum clear distance between bars should be greater than:

(a) bar diameter;

(b) aggregate size plus 5 mm; and

(c) 20 mm.

4.1.5.2 Maximum spacing for reinforcement

For slab which is less than 200 mm thick, the following maximum spacing, smax,slabs rules are apply.

(a) For the principal reinforcement: 3h but not more than 400 mm.

(b) For the secondary reinforcement: 3.5h but not more than 450 mm.

46

The exception is in areas with concentrated loads or areas of maximum moment where the following applies.

(a) For the principal reinforcement: 2h but not more than 250 mm.

(b) For the secondary reinforcement: 3h but not more than 400 mm.

Where h = the depth of the slab

Note 4.3 Clause 9.3.1.1, MS EN 1992-1-1: 2010.

4.1.6 Reinforcement at Free Edge

Along a free (unsupported) edge, a slab should normally contain longitudinal and transverse reinforcement, generally arranged as shown in Figure 4.9. The normal reinforcement provided for a slab may act as edge reinforcement.

Figure 4.9: Edge reinforcement for a slab

Note 4.4 Clause 9.3.1.4, MS EN 1992-1-1: 2010.

4.1.7 Simplified Detailing Rules for Slab

The detailing rules are used for slabs in the following circumstances:

(a) The slabs are designed for predominantly uniform distributed loads.

(b) In the case of continuous slab, design has been carried out for the single load case of maximum design load on all spans and the spans are approximately equal.

h

≥ 2h

47

Figure 4.10: Simplified detailing rules for slab

Figure 4.11: Rules for curtailment of reinforcement of slab

Reinforcement formaximum hogging moment

Face of support100%

50%

0.30l

0.15l ≥ lbd

a) Continuous member, top reinforcement

b) Continuous member, bottom reinforcement

c) Simple support, bottom reinforcement

0.2l

40%

100%

Reinforcement formaximum sagging moment

Position ofeffectivesupport

Face ofsupport

lbd

100%

15%

0.3L 0.3L0.15L or45ø

50% As 100% As 40% As

48

4.1.8 Shear Reinforcement

A slab in which shear reinforcement is provided should have a depth at least 200 mm. The shear reinforcement should form an angle, α of between 45° to 90° to the longitudinal axis of the structural element. In slab, if |VEd| ≤ 13 VRd,max', the shear reinforcement may consist entirely of bent-up-bars or of shear reinforcement assemblies.

Where

VRd,max' is the design value of the maximum shear force which can be sustained by the member, limited by crushing of the compression struts; and

VEd is shear force

The maximum longitudinal spacing of successive series of links is given by

smax = 0.75d(1 + cot α)

Where

α is inclination of the shear reinforcement; and

d is effective depth.

The maximum longitudinal spacing of bent-up bars is given by

smax = d

The maximum transverse spacing of shear reinforcement should not exceed 1.5 d.

Note 4.6 Clause 9.3.2, MS EN 1992-1-1: 2010.

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4.2 FLAT SLAB

Flat slab is a reinforced concrete slab supported directly by concrete columns without the use of beams. Flat slab is defined as one sided or two-sided support system with sheer load of the slab being concentrated on the supporting column and a square slab called ‘drop panel’.

Figure 4.12: Types of flat slabFlat slab

Flat slab with column head

Flat slab with drop panel

50

Figure 4.13: Flat slab fabric design layout (Bottom fabric)

Bottom fabric

51

Figure 4.14: Flat slab fabric design layout (Top fabric)

Top fabric

52

A flat slab should be divided into column and middle strips as shown in Figure 4.15.

Figure 4.15: Division of panels in flat slab

lx > ly

ly/4 ly/4

ly/ 4

ly/ 4

Middle strip = ly /2

Middle strip = lx - ly /2

Column strip = ly /2

ly

4.2.1 Slab at Internal Columns

At internal columns, unless rigorous serviceability calculations are carried out, top reinforcement of area 0.5 At should be placed in a width equal to the sum of 0.125 times the panel width on either side of the column. At represents the area of reinforcement required to resist the full negative moment from the sum of the two half panels each side of the column. It is also advisable to apply this requirement to perimeter columns as far as is possible. At internal columns at least two bars of bottom reinforcement in each orthogonal direction should be provided and they should pass between the column reinforcement.

Note 4.5 Clause 9.4.1, MS EN 1992-1-1: 2010.

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4.2.2 Slab at Edge and Corner Columns

Reinforcement perpendicular to a free edge required to transmit bending moments from the slab to an edge or corner column should be placed within the effective width, be, shown in Figure 4.16.

Figure 4.16: Effective width, be, of a flat slab

Note: z can be > cz and y can be > cyb) Corner column

AA Slab edge

cyy

z

be = z + y/2

czA

Note: y can be > cyb) Edge column

cy

y

cz

A

be = cz + y

Note 4.6 y is the distance from the edge of the slab to the innermost face of the column. Note 4.7 Clause 9.4.2, MS EN 1992-1-1: 2010.

4.2.3 Punching Shear Reinforcement

Where punching shear reinforcement is required, it should be placed between the loaded area/column and kd inside the control perimeter at which shear reinforcement is no longer required. It should be provided in at least two perimeters of shear links. The radial spacing of the links of should not exceed 0.75d. The tangential spacing of the links should not exceed 1.5d within the 2d from the column face, and should not exceed 2d for any other perimeter. The distance between the face of the column and the nearest shear reinforcement should be less than 0.5d.

Note 4.8 From Clause 6.4.5 (4) MS EN 1992-1-1: 2010, the recommended value of k is 1.5.

54

Figure 4.17: Punching shear layout

Section A - A

The minimum area of a link leg for vertical punching shear reinforcement is:

1.5 Asw,min /(sr.st) ≥ 0.08 √fck/fyk

Where

sr is spacing of shear links in the radial direction; and

st is spacing of shear links in the tangential direction.

Note 4.9 Clause 9.4.3, MS EN 1992-1-1: 2010.

4.3 REINFORCED CONCRETE WALL

4.3.1 Load Bearing Wall (Shear Wall)

Load bearing wall carries loads imposed on it from beams and slabs above including its own weight and transfer it to the foundation. These walls support structural members such as beams, slabs and walls on above floors above.

4.3.2 Non-Load Bearing Wall

Non-load bearing walls only carry their own weight and does not support any structural members such as beams and slabs. These walls are just used as partition walls or to separate rooms from outside.

55

Figure 4.18: Reinforced concrete wall cut section

R.C. STRIP FOOTING

R.C. SLAB TO DETAIL

GROUND BEAM TOP LEVEL

125mm THK. R.C. WALL TO DETAIL

2 LAYERS YMC A8

125

R.C. WALL TO DETAILT10–200C/C E.F.STARTER BARS

400

(LAP

)

40065

0

75

56

Figure 4.19: Reinforced concrete wall fabric design layout

4.3.3 Vertical Reinforcement

4.3.3.1 Maximum area of reinforcement

The maximum nominal reinforcement area, As,vmax for columns and walls outside laps is 0.04Ac. However, this area can be increased provided that the concrete can be placed and compacted sufficiently.

57

4.3.3.2 Minimum area of reinforcement

The minimum area of vertical reinforcement in walls is given by: As,vmin = 0.002Ac. Half the area should be provided in each face. The distance between two adjacent vertical bars should not exceed the lesser of either three times the wall thickness or 400 mm.

Note 4.10 Clause 9.6.2, MS EN 1992-1-1: 2010.

4.3.4 Horizontal Reinforcement

Horizontal reinforcement running parallel to the faces of the wall (and to the free edges) should be at each surface. It should not be less than As,hmin.

4.3.4.1 Minimum area of reinforcement

The minimum area of horizontal reinforcement in walls is given by: As,hmin = 0.001Ac or 25 % whichever is greater. The spacing between two adjacent horizontal bars should not be greater than 400 mm.

Note 4.11 Clause 9.6.3, MS EN 1992-1-1: 2010.

4.3.5 Transverse Reinforcement

In any part of a wall where the total area of the vertical reinforcement in the two faces exceeds 0.02Ac, transverse reinforcement in the form of links should be provided in accordance with the requirements for columns which is the diameter of the bars of welded steel fabric for transverse reinforcement should not be less than 5 mm.

Where the main reinforcement is placed nearest to the wall faces, transverse reinforcement should also be provided in the form of links with at least of 4 per m2 of wall area.

Note 4.12 Transverse reinforcement need not to be provided where welded steel fabric and bars of diameter less than 16 mm are used with the concrete cover larger than 2Ø.

Note 4.13 Clause 9.6.4, MS EN 1992-1-1: 2010.

58

4.4 RETAINING WALL

A retaining wall is a structure designed and constructed to retain earth or other material in vertical (or nearly vertical) position at locations where an abrupt change in ground level occurs. It is to prevent retained earth from assuming its natural angle of repose. The retained earth exerts lateral pressure on the wall by stability analysis – overturn, slide and settlement. Therefore, the wall must be design to be stable under the effects of lateral pressure.

Figure 4.20: Reinforced concrete retaining wall fabric

4.4.1 Vertical Reinforcement

Where axial forces dominate, the minimum area of vertical reinforcement is 0.002Ac; half this area should be placed in each face. Outside lap locations, the maximum area of vertical reinforcement is 0.04Ac; this may be doubled at lap locations. The distance between two adjacent vertical bars should not exceed the lesser of either three times the wall thickness or 400 mm.

For walls with a high axial load, the main reinforcement placed nearest to the wall faces should have transverse reinforcement in the form of links with at least four per m2 of wall area. Where welded fabric and bars of diameter less than 16 mm are used with cover larger than 2Ø, transverse reinforcement is not required.

59

4.4.2 Horizontal reinforcement

The minimum area of horizontal reinforcement is greater of either 25 % of vertical reinforcement or 0.001Ac. However, where crack control is important, early age thermal and shrinkage effects should be considered. Where flexural forces dominate, these requirements may be relaxed to 20 % of the vertical reinforcement area.

4.5 REINFORCEMENT FOR PAD FOOTING

Foundations which carry and spread concentrated loads to the soil from superstructures is called pad footing. They are usually placed to transfer point loads from the column or framed structures and consists of a concrete block or concrete pad. The pads are usually placed at a shallow depth, but they can also be used as deep foundation depending on the loads to be transferred and condition of the subsoil. Pad footing may be square, rectangular or circular in shape. If the pad is subjected to a heavy loaded structure, the pad footing may be stepped. The loads from the structure are simply distributed by the pad to the bearing layer of soil. Below shows the footing using fabric reinforcement.

4.5.1 Fabric up to Depth of Footing

In this type of fabric, the bars are bent at ends up to a height of footing. The concrete cover is provided in all the sides of the footing.

Figure 4.21: Fabric up to depth of footing

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4.5.2 Hook Fabric

This type of fabric is adopted in low rise and also high-rise building. The footing is reinforced as grid and at the ends of the fabric, the bars are hooked. Bending the bars ends helps in the proper anchorage of reinforcement, where the hook length is 9Ø, Ø is the diameter of bar.

Figure 4.22: Hook fabric for footing

4.6 REINFORCEMENT FOR DRAINAGE AND BOX CULVERT

For drainage and box culvert, the cut to size fabric can be because it is easier to install and will minimize the installation time at the site. Below shows the figure of drainage and box culvert using cut to size fabric.

Figure 4.23: U-Bend fabric

U-Bend Fabric

61

Figure 4.24: L-Bend fabric

Figure 4.25: Closed drain

Width varies

L-BendFabric

Depthvaries

Additional tie bars for hunching to engineer's requirement

62

Figure 4.26: Box culvert

63

REFERENCES1. MS 145: 2014, Steel Fabric for the Reinforcement of Concrete – Specification (Fourth

Revision)

2. MS 146: 2014, Steel for the Reinforcement of Concrete – Weldable Reinforcing Steel – Bar, Coil and Decoiled Product – Specification (Fourth Revision)

3. MS EN 1992-1-1: 2010, Malaysia National Annex to Eurocode 2: Design of Concrete Structures – Part 1-1: General Rules and Rules for Buildings

4. The Concrete Centre, (2006). How to Design Concrete Structure using Eurocode 2. Retrieved from

https://greganagno.com/download/Reinforced%20Concrete/How%20to%20design%20concrete%20structures%20using%20Eurocode%202.pdf

5. Krishna (2017). Types of Reinforcement or Mesh used in Different Footings (Foundations). Retrieved from https://civilread.com/types-of-reinforcement-in-footings/

6. Farid, N.M. (2010). Reinforced Slab. Retrieved from https://www.slideshare.net/MatNik1/reinforced-slab

7. Ibrahim, I.S. (2017). Design of Retaining Walls. Retrieved from http://civil.utm.my/iznisyahrizal/files/2017/05/Lecture-5-Design-of-Retaining-Wall.pdf

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1. SIRIM certified wire rod as raw material of welded steel fabric

2. Drawing process to reduce size and rib wire rod to required bar size.

3. Electronically controlled welding process combines the intersecting wires into a homogenous section

ANNEX 1 PROCESS FLOW

65

4. Bending machine to bend the welded steel fabric

5. Sample will be taken during welding process for laboratory test on its properties

6. Output with unique label from production will be stored inside warehouse under the roof

7. Delivery and unloading of welded steel fabric at site

66

8. Formwork installation at site

9. Installation of welded steel fabric at site

10. Concreting of slab at site

67

ANNEX 2 THE DIFFERENCE BETWEEN THE REINFORCING BARS B500A, B500B AND B500C

Reinforcing Steel Type B500A B500B B500C

Surface Smooth, dented, ribbed Dented, ribbed Ribbed

Delivery form Rollers, bars, point welded reinforcement meshes, lattice girders

Rollers, bars, welded reinforcement meshes

Nominal diameter (mm) 4 – 16 6 – 50 6 – 50

Min. yield / yield strength Re (Mpa)

500 500 500 Re, act / Re, nom 28 mm: 145

Min. shear force - gepuntl.wap. Fs - lattice gripper Fw / d (kN)

0.25 x An x Re0.25 x Ao / bx Re, o / b or 0.6 x Ad x Re, d

0.25 x An x Re0.25 x Ao / bx Re, o / b or 0.6 x Ad x Re, d

0.25 x An x Renvt

Tolerance nominal diameter (%)

± 4.5 ± 4.5 ± 4.5

Chem. composition (mass%) C < 0.22, etc Ceq < 0.50

C < 0.22, etc Ceq < 0.50

C < 0.22, etc Ceq < 0.50

Min. relative opp. cross-rib (dent), fr / pf

d = 4.0 – 6.0: 0.039 d = 9.0 – 10.5: 0.052 d = 6.5 – 8.5: 0.045 d = 11.0 – 50: 0.056

a) Rm / Re1.03 and Agt 2.0 for diameters ≤ 5.5 mm

b) Agt for rolls + 0.5%

c) Rm / Re min. 1.13 and Agt 7.0% for diameters ≤ 12 mm

d) Maximum stress ripple 2σa at top tension 0.6Read (300 MPa) and 1 million voltage changes. For top welded reinforcement meshes B500B and B500C, 2σa is at least 100 MPa. For roll-oriented products, 2σa minus 100 MPa, unless a higher value (≤ 175 MPa) has been statistically demonstrated for the maximum diameter used and for the target machine (type).

e) In the case of lattice girders, the lower rods must comply with B500A and / or B500B with the fR / P requirement. The top bars and diagonals may be reinforcing bars with only the requirements of Re, d and the chemical composition.

f) For rolls fR (ribbed) + 15%, fP (dented) + 5%. No requirement for weakly profiled / dented reinforcing steel (lattice girders).

Source: www.betonstaal.nl/en/blog/reinforcing-steel-b500a-b-c-what-is-the-differencer/

68

ANNEX 3 PREFERRED RANGE OF DESIGNATED FABRIC TYPES GRADE B500A

ReferenceNominal Bar Size

(mm)Nominal Pitch

(mm)Steel Area(mm2/m)

Mass(kg/m2)

Longitudinal Transverse Longitudinal Transverse Longitudinal Transverse

Square mesh

A63A98

A142A193A252A318A393A475A565A664

456789

10111213

456789

10111213

200200200200200200200200200200

200200200200200200200200200200

6398

142193252318393475565664

6398

142193252318393475565664

0.991.542.223.023.954.996.167.468.88

10.42

Structural mesh

B196B283B385B503B636B785B950B1131B1328

56789

10111213

777888888

100100100100100100100100100

200200200200200200200200200

19628338550363678595011311328

193193193252252252252252252

3.053.734.535.936.978.149.44

10.8612.40

Long mesh

C5C6C7C8C9

C10C11C12C13

56789

10111213

555566888

100100100100100100100100100

400400400400400400400400400

19628338550363678595011311328

494949497171

126126126

1.932.613.414.345.556.728.449.8711.41

Wrapping mesh

D126D196D283D385D503D636D785D950D1131D1328

456789

10111213

456789

10111213

100100100100100100100100100100

100100100100100100100100100100

12619628338550363678595011311328

12619628338550363678595011311328

1.973.084.446.047.909.98

12.3214.9217.7620.85

YUNG KONG METAL WORKS CO BHD (10181-U)Lot 1144, Jalan Kemajuan, Pending Industrial Estate,

93450 Kuching, Sarawak, Malaysia.

Tel : 082-484 327 Fax : 082-337 177Email : [email protected] : www.ykmw.yungkong.my

YMC MESH SDN BHD (428424-P)Wisma Hii Yii Ngiik, 1st Floor, Lot 7573

Jalan Kwong Lee Bank, 93450 Kuching, Sarawak, Malaysia

Tel : 082-480 182Fax : 082: 483 177Email : [email protected] : www.ymc.yungkong.my