Cladding tolerances

■ Manufacturers may say that their glazed systems can only

Deflection may affect cladding or glazing in the following ways:

■ When a slab deflects, the load on the central fixings will be relieved and shed to outer fixings.

accommodate deflection as low as 5 mm.

There should be open discussions between the designers for the various elements to determine the most cost-effective way of dealing with the interaction of the structure and cladding.

References

1 BRITISH STANDARDS INSTITUTION. BS EN 1992-1-1, Eurocode 2: Design of concrete structures. General rules and rules for building. BSI, 2004.

2 MOSS, R M & BROOKER, O. How to design concrete structures using Eurocode 2: Beams. The Concrete Centre, 2006.

3 MOSS, R M & BROOKER, O. How to design concrete structures using Eurocode 2: Slabs. The Concrete Centre, 2006.

4 MOSS, R M & BROOKER, O. How to design concrete structures using Eurocode 2: Flat slabs. The Concrete Centre, 2006.

5 NARAYANAN, R S & BROOKER, O. How to design concrete structures using Eurocode 2: Introduction to Eurocodes. The Concrete Centre, 2005

6 BRITISH CEMENT ASSOCIATION. Early striking and improved backpropping. BCA, 2001. (Available from www.concretecentre.com)

7 PALLETT, P. Guide to flat slab formwork and falsework. Construct, 2003

8 THE CONCRETE SOCIETY. Technical report No. 58 Deflections in concrete slabs and beams. The Concrete Society, 2005.

9 GOODCHILD, C H & WEBSTER, R M. Spreadsheets for concrete design to BS 8110 and EC2, version 3. The Concrete Centre, 2006. 10 BRITISH STANDARDS INSTITUTION. BS 8110-1. Structural use of concrete - Code of practice for design and construction. BSI, 1997.

Acknowledgements

The content of this publication was produced as part of the project 'Eurocode 2: transition from UK to European concrete design standards'. This project was part funded by the DTI under the Partners in Innovation scheme. The lead partner was the British Cement Association. The work was carried out under the guidance of the Concrete Industry Eurocode 2 Group, which consists of representatives from:

Alan Baxter and Associates • Arup • British Cement Association • British Precast • Building Research Establishment • Clark Smith Partnership • Concrete Innovation and Design • Construct • Department for Trade and Industry • Office of the Deputy Prime Minister • The Concrete Centre • The Concrete Society • Quarry Products Association.

0700 4 500 500 or 0700 4 CONCRETE

[email protected]

For more information on Eurocode 2 and other questions relating to the design, use and performance of concrete contact the free National Helpline on:

Published by The Concrete Centre

Riverside House, 4 Meadows Business Park, Station Approach, Blackwater, Camberley, Surrey GU17 9AB

The Concrete Centre7

www.concretecentre.com

Ref: TCC/03/23 ISBN 1-904818-33-1

First published May 2006, revised December 2006 © The Concrete Centre™ and British Cement Association

All advice or information from The Concrete Centre is intended for those who will evaluate the significance and limitations of its contents and take responsibility for its use and application. No liability (including that for negligence) for any loss resulting from such advice or information is accepted by The Concrete Centre or its subcontractors, suppliers or advisors. Readers should note that publications from The Concrete Centre are subject to revision from time to time and they should therefore ensure that they are in possession of the latest version. This publication has been produced following a contract placed by the Department for Trade and Industry (DTI); the views expressed are not necessarily those of the DTI.

The Concrete Centre"

Introduction to Eurocodes

Location

Original

Amendment

Table 5, rows 3,5,7 & 9

1.5 Qk

1.5c Qk

Page 6, Item 13 in left hand column

The punching shear checks are carried at 2d from the face of the column-

The punching shear checks are carried out at 2d from the face of the column—

Getting started

Location

Original

Amendment

Table 6, row 3

0.900 Gl + 0.100 Ql

0.090 Gl + 0.100 Ql

Table 10, notes

a is the axis distance (see Figure 4) Note 3 added:

hs is the slab thickness, including non-combustible flooring

Table 8, row 9

Car park elements subject to airborne chlorides only

Elements subject to airborne chlorides only

Slabs

Location

Original

Amendment

Table 3, note 2

F is the total design ultimate load, l, is the effective span

F is the total design ultimate load, l, is thespan

Table 3, new note 4

-

Based on 20% redistribution at support and no decrease in span moments

Table 4, values for K'

% redistribution

K

% redistribution

K

Q

Q.2Q5

Q

Q.2QSa

5

Q.193

1Q

Q.1S2a

1Q

Q.1SQ

15

Q.16S

15

Q.1óó

2Q

Q.153

2Q

Q.151

25

Q.137

25

Q.136

3Q

Q.12Q

Table 4, new key

a It is often recommended in the UK that K'should be limited to 0.168 to ensure ductile failure

Table 5, 6

0.954

0.950!

Figure 3, box 5 from top of diagram

cts may assumed to be 310 MPa

cts may be assumed to be 310 MPa

Figure 5, heading

Basic span-to-depth ratios

Basic span-to-effective-depth ratios

Figure 5, Note 2

-

K = 0.4 for cantilevers

Figure 5, Note 4

I = K d

11 | 1.5^/fckp 0 | V^cîT 1 p' + (p-p') + 12 0

I = K d

11 + ^Vwo +f iy (p-p') 12 Vpo _

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Page 1 of 4

The Concrete centre*

The Concrete centre*

Page 5 'Design for shear'

It is not usual for a slab to contain shear reinforcement, therefore it is only necessary to ensure that the concrete shear stress capacity without shear reinforcement (vRd,c - see Table 7) is less than applied shear stress (vEd = VEd /(bd ))•

It is not usual for a slab to contain shear reinforcement, therefore it is only necessary to ensure that the concrete shear stress capacity without shear reinforcement (vRd,c - see Table 7) is more than applied shear stress (vEH = VEd /(bd)).

Page 6 'Ribbed or waffle slabs'

Current practices for determining forces in ribbed and waffle slabs may also be used for designs to Eurocode 2. Where a waffle slab is treated as a two-way slab refer to previous section. Where it is treated as a flat slab reference may be made to How to design concrete structures to Eurocode 2: Flat slabs4

Current practices for determining forces in ribbed and waffle slabs may also be used for designs to Eurocode 2. Where a waffle slab is treated as a two-way slab refer to previous section, but note that their torsional stiffness is significantly less than for a two-way slab and the bending moment coefficients may not be applicable. Where it is treated as a flat slab reference may be made to How to design concrete structures to Eurocode 2: Flat slabs4

Page 7 'Maximum spacing of reinforcement'

For slabs 200 mm thick or greater reference should be made to section 7.3.3 of the Code or Chapter 2, originally published as Getting started5.

For slabs 200 mm thick or greater the bar size and spacing should be limited to control the crack width and reference should be made to section 7.3.3 of the Code or Chapter 2, originally published as Getting started5.

Beams

Location

Original

Amendment

Table 2, row 5

bmin in column C = 300

bmin in column C = 200

Table 3, row 3

0.900 Gl + 0.100 Ql

0.090 Gl + 0.100 Ql

Table 4, values for K'

% redistribution

K

% redistribution

K'

0

0^05

0

O.ZOS3

5

0.193

10

0.1SZa

10

0.1 SO

15

0.168

15

0.166

Z0

0.153

Z0

0.151

Z5

0.137

Z5

0.136

30

0.1Z0

Table 4, new key

a It is often recommended in the UK that K'should be limited to 0.168 to ensure ductile failure

Figure 5, box 2

vEd = shear stress at d from face of support

vEH = design shear stress

Figure 5

0 - 0.5 sin-1| VEd I |0.18fCk(1 - fck /250) J

0- 0.5 sin-1| VEd I 10.20fck(1 - fck / 250)J

Figure 5

Asw VEd bw s 0.9 dfywd cot 0

Asw VEd bw s fywd cot 0

Figure 5, add title to x-axis

-

Percentage of tension reinforcement

(As,req'd/bd)

Figure 7, heading

Basic span-to-depth ratios

Basic span-to-effective-depth ratios

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Page Z of 4

The Concrete Centre"

The Concrete Centre"

Figure 7, Note 4

I = K d

11 | 1.5^/fckp 0 | V^cîT 1 p' + (p-p') + 12 0

I = K d

11 + ^Vwo +f iy _ (p-p') 12 Vpo _

Figure 7, note 1

-

Delete note

Figure 14

For flange in tension: Vrd = 0.16 fCk (1- fck/250)

For flange in tension: Vrd = 0.195 fck (1- fck/250)

Figure 14

For flange in compression: Vrd = 0.195 fck (1- fck/250)

For flange in compression: Vrd = 0.160 fck (1- fck/250)

Table S

fck

VRd.max (when cot O = 2.5)

fck

vRd,max

Flange in tension

Flange in compression

Flange in tension

Flange in compression

2Q

2.94

3.59

2Q

3.59

2.94

25

3.6Q

4.39

25

4.39

3.6Q

28

3.98

4.85

28

4.85

3.98

3Q

4.22

5.15

3Q

5.15

4.22

32

4.46

5.44

32

5.44

4.46

35

4.82

5.87

35

5.87

4.82

4Q

5.38

6.55

4Q

6.55

5.38

45

5.9Q

7.2Q

45

7.2Q

5.9Q

5Q

6.4Q

7.8Q

5Q

7.8Q

6.4Q

Location

Original

Amendment

Table 3, heading

, using method A

Figure 4

MoE

Moe

Page 6

An/2 = (NEd - fcd b dc)/[(osc - OtYc]

Asn/2 = (NEd - fcd b dc)/(osc - 0

Page 6

Asn/2 = Area of reinforcement required to resist axial load

Asn = Area of reinforcement required to resist axial load

Page 6

Asm/2 = [M - fcd b dc (h/2 - dc/2)] [(h/2 - dc/2)(osc - ost)Yc]

Asm/2 = [M - fcd b dc (h/2 - dc/2)] [(h/2 - dc/2)(osc - o*)]

Page 6

Asm/2 = Area of reinforcement required to resist axial load

Asm = Area of reinforcement required to resist axial load

Page 8 'spacing requirements for columns'

Add to final paragraph: No bar should be further than 150 mm from transverse reinforcement (links) in the compression zone

Foundations

Location

Original

Amendment

Table 4, row 3

1.Q Gk

11 Gk

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Page 3 of 4

How to design concrete structures using Eurocode 2 O)

EfTQ ta The Concrete Centre"

Flat slabs

Location

Original

Amendment

Table 3, Note 4

Based on 15% redistribution at supports and no decrease in span moments

Based on 20% redistribution at supports and no decrease in span moments

Table 4, values for K

% redistribution

K'

0

0.205

5

0.193

10

0.180

15

0.166

20

0.151

25

0.136

% redistribution

K'

0

0.208a

10

0.182a

15

0.168

20

0.153

25

0.137

30

0.120

Table 4, new key a It is often recommended in the UK that K'should be limited to 0.168 to ensure ductile failure

Figure 3, box 4 from top of diagram

Determine Factor 2 (F2) Where the slab span exceeds 7 m and it supports brittle partitions, F2 = 7//eff Otherwise F2 = 1.0

Determine Factor 2 (F2) Where the slab span exceeds 8.5 m and it supports brittle partitions, F2 = 8.5/ leff

Otherwise F2 = 1.0

Figure 4, Note 3

Table 7

fck

^rd,max

20

3.31

25

4.05

28

4.48

30

4.75

32

5.02

35

5.42

40

6.05

45

6.64

50

7.20

fck

^rd,max

20

3.68

25

4.50

28

4.97

30

5.28

32

5.58

35

6.02

40

6.72

45

7.38

50

8.00

Deflection calculations

Location

Original

Amendment

Figure 5, box 5, item 2

(200 MPa)

(200 GPa)

\\tccdata\tcc\Users\OBrooker\For KMS\How to errors v4.doc Revision 4/23 March 2007

Page 4 of 4

How to design concrete structures using Eurocode 2

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