SPATA Intro to Eurocode 2 4 Oct 2012

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SPATA Training 4 Oct 2012 - Eurocode 2 1

Introduction to Eurocode 2

SPATA Training4 October 2012

Charles Goodchild

BSc CEng MCIOB MIStructE

The Concrete Centre

2

•Setting the scene for the Eurocodes,

• their format,

• their hierarchy,

• how they interact.

• An overview of Eurocode 2,

• highlighting changes from and

• comparing it to BS8110

• How it all fits together.

Outline

3

Setting the scene

Eurocodes are being/ will be used in:

• EU countries

• EFTA Countries

• Malaysia

• Singapore

• Vietnam

• Sri Lanka

• Others?

CEN National Members

Austria Belgium

Cyprus Czech Republic

Denmark Estonia Finland

France Germany Greece

Hungary Iceland Ireland

Italy Latvia Lithuania

Luxembourg Malta The

Netherlands Norway

Poland Portugal Romania

Slovakia Slovenia Spain

Sweden Switzerland

United Kingdom

4

EN 1990Basis of Design

EN 1991Actions on Structures

EN 1992 ConcreteEN 1993 SteelEN 1994 CompositeEN 1995 TimberEN 1996 MasonryEN 1999 Aluminium

EN 1997Geotechnical

Design

EN 1998Seismic Design

Structural safety, serviceability and durability

Design and detailing

Geotechnical & seismic design

Actions on structures

Eurocode Hierarchy

5

• 58 Parts to Eurocodes plus National Annexes

• Culture shock / steep learning curve

• New symbols and terminology

• Affects all materials

• Confusion over timescales

• Costs:

◦ Training

◦ Resources

Challenges of the Eurocodes

6

BS 8110 and all old structural design British Standards have now been ‘withdrawn’. There will be a period of co-existence between our current codes and the Eurocodes.

DCLG letter: “Building Control will continue to consider the appropriate use of relevant standards on a case by case basis….. [The ‘traditional’] British Standards may not necessarily be suitable ….. in the medium and long term.”

DCLG 2012 Consultation document – Eurocodes only in AD A by 2013?

Insurers? Large projects? International projects?

Scottish Technical Handbook: ‘The structural design and construction of a building should be carried out in accordance with the following Structural Eurocodes’.

Eurocodes: Timescales

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Eurocodes: Timescales

Highways:

HA IAN 124/11 July 2011

3 Implementation

“Unless otherwise agreed with HA Project Sponsors/Project

Managers and the Technical Approval Authority (TAA),

Eurocodes must be used for the design of new and

modification of existing highway structures (including

geotechnical works), . . . .”

8

• Most of Europe using the same basic design codes:◦ Increased market for UK consultants◦ Increased market for UK manufacturers◦ Reduced costs when working in several European

markets◦ Greater transferability of highly skilled staff◦ Greater understanding of research, proprietary products

etc. ◦ Reduce software development costs

• Technically advanced codes

• Logical, organised to avoid conflicts between codes

Opportunities

9

Each Eurocode Contains:

a. National front cover

(e.g. Eurocode 2)Format of the Eurocodes

10



b. National forward

Format of the Eurocodes

11



b. National forward

c. CEN front cover


12



b. National forward

c. CEN front cover

d. Main text and annexes (which must be as produced by CEN)


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b. National forward

c. CEN front cover

d. Main text and annexes (which must be as produced by CEN)

e. Annexes - can by normative and/or informative


National Annex(NA).


15

• Values of Nationally Determined Parameters (NDPs)

(NDPs have been allowed for reasons of safety, economy and durability)

• Example: Min diameter for longitudinal steel in columns

min = 8 mm in text min = 12 mm in N.A.

• The decision where main text allows alternatives

• Example: Load arrangements in Cl. 5.1.3 (1) P

• The choice to adopt informative annexes

• Example: Annexes E [Strength class for durability] and J [particular detailing rules] are not used in the UK

• Non-contradictory complementary information (NCCI)

• TR 43: Post-tensioned concrete floors – design handbook

The National Annex provides:

16

+ PDs

+ NA + NA

+ NAs

+ NA

+ NAEN 1990Basis of Design

EN 1991Actions on Structures

EN 1992 ConcreteEN 1993 SteelEN 1994 CompositeEN 1995 TimberEN 1996 MasonryEN 1999 Aluminium

EN 1997Geotechnical

Design

EN 1998Seismic Design

Structural safety, serviceability and durability

Design and detailing

Geotechnical & seismic design

Actions on structures

Eurocode Hierarchy

These

affect

concrete

design

17

• BS EN 1990 (EC0): Basis of structural design

• BS EN 1991 (EC1): Actions on Structures

• BS EN 1992 (EC2): Design of concrete structures• BS EN 1993 (EC3): Design of steel structures

• BS EN 1994 (EC4): Design of composite steel and concrete structures

• BS EN 1995 (EC5): Design of timber structures

• BS EN 1996 (EC6): Design of masonry structures

• BS EN 1997 (EC7): Geotechnical design

• BS EN 1998 (EC8): Design of structures for earthquake resistance

• BS EN 1999 (EC9): Design of aluminium structures

The Eurocodes

EurocodeBasis of structural design

EN 1990 provides comprehensive information and guidance for all the Eurocodes, on the principles and requirements for safety and serviceability.

It gives the safety factors for actions and combinations of action for the verification of both ultimate andserviceability limit states.

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Published 27 July 2002

Says that structures are to be designed, executed and maintained so that, with appropriate forms of reliability, they will:

• Perform adequately under all expected actions

• Withstand all actions and other influences likely to occur during construction and use

• Have adequate durability in relation to the cost

• Not be damaged disproportionately by exceptional hazards

Eurocode: BS EN 1990 (EC0):Basis of design

Eurocode – EC0Representative value of an action

Design value of an action = Fd

= F Frep

= F ( FK )where

FK = the characteristic value of actionFrep = FK - is the representative value = Four values, namely, 1.0 or 0 or 1 or 2

Qk = Characteristic Value (of a variable action)0 Qk = Combination Value1 Qk = Frequent Value2 Qk =Quasi-permanent Value

Greek Alphabet

The ULS is divided into the following categories:

EQU Loss of equilibrium of the structure.Ed,dst ≤ Ed,stb

STR Internal failure or excessive deformation of thestructure or structural member.

Ed Rd;

GEO Failure due to excessive deformation of the ground.

FAT Fatigue failure of the structure or structural members.

Eurocode – EC0Ultimate Limit State – Categories

23

Generally for one variable action: 1.25 Gk + 1.5 Qk

Provided:1. Permanent actions < 4.5 x variable actions2. Excludes storage loads

Eurocode: ULS Actions

Design values of actions, ultimate limit state – persistent and transient design situations (Table A1.2(B) Eurocode)

Comb’tion

expression

reference

Permanent actions Leading

variable

action

Accompanying variable

actions

Unfavourable Favourable Main(if

any)

Others

Eqn (6.10) γG,j,sup Gk,j,sup γG,j,inf Gk,j,inf γQ,1 Qk,1 γQ,i Ψ0,i Qk,i

Eqn (6.10a) γG,j,sup Gk,j,sup γG,j,inf Gk,j,inf γQ,1Ψ0,1Qk,1 γQ,i Ψ0,i Qk,i

Eqn (6.10b) ξ γG,j,supGk,j,sup γG,j,inf Gk,j,inf γQ,1 Qk,1 γQ,i Ψ0,i Qk,i

Eqn (6.10) 1.35 Gk 1.0 Gk 1.5 Qk,1 1.5 Ψ0,i Qk,i

Eqn (6.10a) 1.35 Gk 1.0 Gk 1.5 Ψ0,1 Qk 1.5 Ψ0,i Qk,i

Eqn (6.10b) 0.925x1.35Gk 1.0 Gk 1.5 Qk,1 1.5 Ψ0,i Qk,i

24

Load arrangements to EC2

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Load arrangements to EC2alternative to UK NA

26

Characteristic combination (Normally used for irreversible limit states)

Gk,j + Qk,1 + 0,IQk,I

Frequent combination (Normally used for reversible limit states)

Gk,j + 1,1Qk,1 + 2,IQk,I

Quasi-permanent combination (Normally used for long term effects and appearance of the structure)

Gk,j + 2,IQk,I

Eurocode: SLS Actions

27

EurocodeEurocode: SLS Actions -

28

Eurocode: Annex A

Action 0 1 2

Category A: domestic, residential areas 0.7 0.5 0.3

Category B: office areas 0.7 0.5 0.3

Category C: congregation areas 0.7 0.7 0.6

Category D: shopping areas 0.7 0.7 0.6

Category E: storage areas 1.0 0.9 0.8

Category F: traffic area(vehicle weight < 30 kN)

0.7 0.7 0.6

Category G: traffic area(30 kN < vehicle weight < 160 kN)

0.7 0.5 0.3

Category H: roofs 0.7 0 0

Snow (For sites located at altitude H <1000 m asl)

0.5 0.2 0

Wind loads on buildings (BS EN 1991-1-4) 0.5 0.2 0

29










The Eurocodes

30

Eurocode 1 has ten parts:

• 1991-1-1 Densities, self-weight and imposed loads

• 1991-1-2 Actions on structures exposed to fire

• 1991-1-3 Snow loads

• 1991-1-4 Wind actions

• 1991-1-5 Thermal actions

• 1991-1-6 Actions during execution

• 1991-1-7 Accidental actions due to impact and explosions

• 1991-2 Traffic loads on bridges

• 1991-3 Actions induced by cranes and machinery

• 1991-4 Actions in silos and tanks

Eurocode 1: Actions

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Eurocode 1 Part 1-1: Densities, self-weight and imposed loads

• Bulk density of reinforced concrete is 25 kN/m3

• The UK NA uses the same loads as BS 6399

• Plant loading not given

Eurocode 1

32










The Eurocodes

33

Date UK CEB/fib Eurocode 2

1968 CP114 (CP110 draft) Blue Book (Limit state design)

1972 CP110 (Limit state design) Red Book

1975 Treaty of Rome

1978 Model code

1985 BS8110 Eurocode 2 (EC)

1990 Model Code

1993 EC2: Part 1-1(ENV) (CEN)

2004 EC2: Part 1-1 (EN)

2005 UK Nat. Annex.

2006 BS110/EC2 PD 6687

2010 EC2 Model Code 2010

Eurocode 2 is more extensive than old codes

Eurocode 2 is less restrictive than old codes

Eurocode 2 can give more economic structures [?]

Eurocode 2: Context

34

• Code deals with phenomenon, rather than element types so Bending, Shear, Torsion, Punching, Crack control, Deflection control (not beams, slabs, columns)

• Design is based on characteristic cylinder strength

• No derived formulae (e.g. only the details of the stress block is given, not the flexural design formulae)

• No ‘tips’ (e.g. concentrated loads, column loads, )

• Unit of stress in MPa

• Plain or mild steel not covered

• Notional horizontal loads considered in addition to lateral loads

• High strength, up to C90/105 covered

• No materials and workmanship

• Part of the Eurocode system

Eurocode 2 & BS 8110 Compared

35

Concrete properties (Table 3.1)

• BS 8500 includes C28/35 & C32/40

• For shear design, max shear strength as for C50/60

Strength classes for concrete

fck (MPa) 12 16 20 25 30 35 40 45 50 55 60 70 80 90

fck,cube (MPa) 15 20 25 30 37 45 50 55 60 67 75 85 95 105

fcm (MPa) 20 24 28 33 38 43 48 53 58 63 68 78 88 98

fctm (MPa) 1.6 1.9 2.2 2.6 2.9 3.2 3.5 3.8 4.1 4.2 4.4 4.6 4.8 5.0

Ecm (GPa) 27 29 30 31 33 34 35 36 37 38 39 41 42 44

fck = Concrete cylinder strength fck,cube = Concrete cube strength fcm = Mean concrete strength fctm = Mean concrete tensile strength Ecm = Mean value of elastic modulus

Eurocode 2

36

Product form Bars and de-coiled rods Wire Fabrics

Class

A

B

C

A

B

C Characteristic yield strength fyk or f0,2k (MPa)

400 to 600

k = (ft/fy)k

1,05

1,08

1,15 <1,35

1,05

1,08

1,15 <1,35

Characteristic strain at maximum force, uk (%)

2,5

5,0

7,5

2,5

5,0

7,5

Fatigue stress range

(N = 2 x 106) (MPa) with an upper limit of 0.6fyk

150

100

• In UK NA max. char yield strength, fyk, = 600 MPa• BS 4449 and 4483 have adopted 500 MPa

Reinforcement properties (Annex C)

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Extract BS 8666

38

Nominal cover, cnom

Minimum cover, cmin

cmin = max {cmin,dur; cmin,b ; 10 mm}

Axis distance, aFire protection

Allowance for deviation, ∆cdev

bond ≡durability as per BS 8500

10 mm

Tables in Section 5 of part 1-2

Eurocode 2 - Cover

39

BS EN 1992-1-1 & Cover

Minimum cover, cmin = max {cmin,b; cmin,dur ;10 mm}

cmin,b = min cover due to bond (= )

cmin,dur = min cover due to exposure – see BS 8500 Tables A3, A4, A5 etc

a AxisDistance

Reinforcement cover

Axis distance, a, to

centre of bar

a = c + m/2 + l

Scope

Part 1-2 Structural fire design gives several methods for fire engineering

Tabulated data for various elements is given in section 5

BS EN 1992-1-2 Structural Fire Design

EC2 - Cover

41

Provides design solutions fire exposure up to 4 hours

The tables have been developed on an empirical basis confirmed by experience and theoretical evaluation of tests

Values are given for normal weight concrete made with siliceous aggregates

No further checks are required for shear, torsion or anchorage

No further checks are required for spalling up to an axis distance of 70 mm

For HSC (> C50/60) other rules apply

Section 5. Tabulated data

Part 1-2 Fire: Section 5.

42fi = NEd,fi/ NRd or conservatively 0.7

Part 1-2 Fire Section 5. Tabulated data

Columns: Method A

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Standard fire

resistanceMinimum dimensions (mm)

Possible combinations of a and bmin

where a is the average axis

distance and bmin is the width of be am

Web thickness bw

R 30

R 60

R 90

R 120

R 180

R 240

bmin= 80a = 15*

bmin= 120a = 25

bmin= 150a = 35

bmin= 200a = 45

bmin= 240a = 60

bmin= 280a = 75

16012*

20012*

25025

30035

40050

50060

45035

55050

65060

50030

60040

70050

80

100

110

130

150

170

Part 1-2 Fire Section 5. Tabulated data

Continuous Beams

44

For grades of concrete up to C50/60,

εcu= 0.0035; = 1 ; = 0.8 ;

fcd = cc fck/ c = 0.85 fck/1.5 = 0.57 fck fyd = fyk/1.15 = 435 MPa

Derived formulae include:

z/d = (1 + (1 + 3.529K)0.5] / 2 (where K = M/bd2fck)

As = MEd/(1.15 fykz )

K’ = 0.207 ( = 1. But UK best practice limits x/d to 0.45 max

which in turn limits K’ to 0.167)

Eurocode 2 - Flexure

The following flowchart outlines the design procedure for rectangularbeams with concrete classes up to C50/60 and grade 500 reinforcement

Determine K and K’ from:

Note: =1.0 means no redistribution and = 0.8 means 20% moment redistribution.

Beam doubly reinforced –compression steel needed

Is K ≤ K’ ?

Beam singly reinforced

Yes No

ck

2 fdbM

K 21.018.06.0'& 2 K

Carry out analysis to determine design moments (M)

It is often recommended in the UK that K’ is limited to 0.168 to ensure ductile failure

K’

1.00 0.208

0.95 0.195

0.90 0.182

0.85 0.168

0.80 0.153

0.75 0.137

0.70 0.120

EC2 - FlexureDesign Flowchart

Calculate lever arm z from:

* A limit of 0.95d is considered good practice, it is not a requirement of Eurocode 2.

*95.053.3112

dKd

z

Check minimum reinforcement requirements:

dbf

dbfA t

yk

tctmmin,s 0013.0

26.0

Check max reinforcement provided As,max 0.04Ac (Cl. 9.2.1.1)

Check min spacing between bars > bar > 20 > Agg + 5Check max spacing between bars

Calculate tension steel required from:zf

MA

yd

s

EC2 - FlexureFlow Chart for singly reinforced section

*.. dKd

z 950533112

EC2 - Flexureessential design by hand

435 MPa = 500/1.15 =

where K = M/bd2fck

z = d x z/d

As = MEd/fydz

Check min reinforcement provided As,min > 0.26(fctm/fyk)btd (Cl. 9.2.1.1)

Check max reinforcement provided As,max 0.04Ac (Cl. 9.2.1.1)Check min spacing between bars > bar > 20 > Agg + 5

Check max spacing between bars

48

Strut inclination method

cotswsRd, ywdfz

s

AV

21.8 < < 45

Eurocode 2 – Beam shear

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Eurocode 2 vs BS8110: Shear

Shear reinforcement

density

Asfyd/s

Shear Strength, VR

BS8110: VR = VC + VS

Test results VR

Eurocode 2:

VRmax

Minimum links

Less links!(but more critical)

Safer!

EC2 - ShearDesign Flow Chart for Shear

Yes (cot = 2.5)

Determine the concrete strut capacity vRd when cot = 2.5vRd = 0.138fck(1-fck/250)

Calculate area of shear reinforcement:Asw/s = vEd bw/(fywd cot )

Determine vEd where:vEd = design shear stress [vEd = VEd/(bwz) = VEd/(bw 0.9d)]

Determine from: = 0.5 sin-1[(vEd/(0.20fck(1-fck/250))]

Is vRd > vEd?No

Check maximum spacing of shear reinforcement :s,max = 0.75 dFor vertical shear reinforcement

51

We can manipulate the Expressions for concrete struts so that

when

vEd < vRd,cot =2.5,

then

cot = 2.5 ( = 21.8°)

and

Asw/s = vEd bw/(fywd.2.5)

fck

MPa

vRd cot = 2.5

MPa

20 2.5425 3.1028 3.4330 3.6432 3.8435 4.1540 4.6345 5.0850 5.51

ShearEurocode 2 – Beam shearessential design by hand

52

The deflection limits stated to be:

• Span/250 under quasi-permanent loads to avoid impairment of appearance and general utility

• Span/500 after construction under the quasi-permanent loads to avoid damage to adjacent parts of the structure.

Deflection requirements can be satisfied by the following methods:

• Direct calculation (Eurocode 2 methods considered to be an improvement on BS 8110) .

• Limiting span-to-effective-depth ratios

Eurocode 2 – Deflection

53

Is basic l/d x F1 x F2 x F3 >Actual l/d?

Yes

No

Factor F3 accounts for stress in the reinforcementF3 = 310/s ≤ 1.5

where s is tensile stress under characteristic load orAs,prov/As,req’d

Check complete

Determine basic l/d including K for structural system

Factor F2 for spans supporting brittle partitions > 7mF2 = 7/leff

Factor F1 for ribbed and waffle slabs onlyF1 = 1 – 0.1 ((bf/bw) – 1) ≥ 0.8

Increase As,prov

or fck

No

Eurocode 2 – Flow chart for L/d

54

Basic span/effective depth ratios

20.5

Percentage of tension reinforcement (As,req’d/bd)

Sp

an t

o d

epth

rat

io (

l/d)

Structural system

K

Simply supported

1.0

End span 1.3

Internal span 1.5

Flat slab 1.2

Cantilever 0.4

fck = 30,

= 0.50%

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EC2 Columns: Design moments

1st order moments:

M01 = Min {|Mtop|,|Mbottom|} + ei Ned

M02 = Max {|Mtop|,|Mbottom|} + ei Ned

where

ei = Max {Io/400, h/30, 20}

(20 mm usually critical)

For stocky columns:

Design moment, MEd = M02

56

For Slender columns,

MEd = Max[M02, M 0e +M2,M01 + M 2/2]

Where

M2 = nominal 2nd order momentM2 = NEd e2 where e2 = fn(deflection)

There are alternative methods for calculating

eccentricity, e2, for slender columns

Actions

Effective length, l0

First order moments

Slenderness,

Slenderness limit, lim

Is lim?Yes

No

Design Moments MEd

Slen-

der

Calculate As

Detailing

M0e M0e + M2

EC2 Columns: Slenderness (7)& 2nd order moments

57

Slenderness = l0/i

where

l0 = Effective length,

= Fl

. . . . . of which more later (or use BS8110 factors!}

Actions


First order moments

Slenderness,


Is lim?Yes

No

Design Moments, MEd

Slen-

der

Calculate As

Detailing

EC2 Columns: Slenderness & 2nd order moments: Slenderness

i = radius of gyration= (I/A)

For a rectangular section, = 3.46 l0 / h

For a circular section, = 4 l0 / h

58

Actions


First order moments

Slenderness,


Is lim?Yes

No

Design Moments, MEd

Slen-

der

Calculate As

Detailing

l0 = l l0 = 2l l0 = 0,7l l0 = l / 2 l0 = l l /2 <l0< l l0 > 2l

2

2

1

1

45,01

45,01

k

k

k

kF = 0,5

Braced members:

Unbraced members:

k

k

k

k

kk

kk 2

21

1

21

21

11

11;101maxF =

M

EC2 Columns: Slenderness (2)& 2nd order moments: Effective length & F

F

59

1.02

bl

El

E

kb

c

c

I

I (From PD 6687: Background paper to UK NA)

Where:

Ib,Ic are the beam and column uncracked second moments of area

lb,lc are the beam and column lengths

k = relative stiffness= ( / M) (E / l)

Actions


First order moments

Slenderness,


Is lim?Yes

No

Design Moments, MEd

Slen-

der

Calculate As

Detailing

EC2 Columns: Slenderness (3)& 2nd order moments: Effective length & F

F: working out k (each end)

(From Eurocode 2)

Alternatively...

60

Slenderness = l0/i

Actions


First order moments

Slenderness,


Is lim?Yes

No

Design Moments, MEd

Slen-

der

Calculate As

Detailing

EC2 Columns: Slenderness (4) & 2nd order moments: Effective length : F from k

1.02

bl

El

E

kb

c

c

I

I

ki = relative stiffnesseach end

F

l0 = Fl

And

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Allowable Slenderness

lim = 20ABC/n

where:A = 1 / (1+0,2ef)

ef is the effective creep ratio;

(if ef is not known, A = 0,7 may be used)

B = (1 + 2) = Asfyd / (Acfcd)

(if is not known, B = 1,1 may be used)

C = 1.7 - rm

rm = M01/M02

M01, M02 are first order end moments,

M02 M01(if rm is not known, C = 0.7 may be used)

n = NEd / (Acfcd)

Actions


First order moments

Slenderness,


Is lim?Yes

No

Design Moments, MEd

Slen-

der

Calculate As

Detailing

EC2 Columns: Slenderness (5)& 2nd order moments: Allowable Slenderness

62

Actions


First order moments

Slenderness,


Is lim?Yes

No

Design Moments, MEd

Slen-

der

Calculate As

Detailing

105 kNm 105 kNm 105 kNm

-105 kNm 105 kNm

rm = M01/ M02

= 0 / 105

= 0

C = 1.7 – 0

= 1.7

rm = M01/ M02

= 105 / -105

= -1

C = 1.7 + 1

= 2.7

rm = M01/ M02

= 105 / 105

= 1

C = 1.7 – 1

= 0.7

lim = 20ABC/n

EC2 Columns: Slenderness (6)& 2nd order moments: Allowable Slenderness & C

63

If Slenderness > Allowable slendernessThen include nominal 2nd order moment, M2

M2 = NEd e2 where e2 = fn(deflection)There are alternative methods for calculating

eccentricity, e2, for slender columns

Actions


First order moments

Slenderness,


Is lim?Yes

No

Design Moments MEd

Slen-

der

Calculate As

Detailing

M0e M0e + M2

EC2 Columns: Slenderness (7)& 2nd order moments

64

Eurocode 2: Column design

So we haveNEd and MEd !!!!

If using column charts we want:NEd/bhfck and MEd/bh2fck

from which we get: Asfyk/bhfck

65

Eurocode 2: Column design

Asfyk/bhfck = 1 ≡ As/bd = 6%

for C30/37 concrete and B500 steel

The design value of the ultimate bond stress, fbd = 2.25 12fctdwhere fctd should be limited to C60/75

1 =1 for ‘good’ and 0.7 for ‘poor’ bond conditions2 = 1 for 32, otherwise (132- )/100

a) 45º 90º c) h > 250 mm

h

Direction of concreting

300

h


b) h 250 mm d) h > 600 mm

unhatched zone – ‘good’ bond conditionshatched zone - ‘poor’ bond conditions


250


EC2 – Detailing: Ultimate bond stress

08/10/2012


lbd = α1 α2 α3 α4 α5 lb,rqd lb,min

However:

(α2 α3 α5) 0.7

lb,min > max(0.3lb; 15, 100mm)

EC2 – Detailing:

Design Anchorage Length, lbd

EC2 – Detailing: Alpha values

• For members without shear reinforcement this is satisfied with al = d

a l

Ftd

a l

Envelope of (M Ed /z +NEd)

Acting tensile force

Resisting tensile force

lbd

lbd

lbd

lbd

lbd lbd

lbd

lbd

Ftd

“Shift rule”

• For members with shear reinforcement: al = (MEd/z) + 0.5VEd Cot

But it is always conservative to use al = 1.125d

EC2 – Detailing Curtailment of reinforcement

70

BS EN 1990 BASIS OF STRUCTURAL

DESIGN

BS EN 1991 ACTIONS ON STRUCTURES

BS EN 1992DESIGN OF CONCRETE

STRUCTURESPart 1-1: General Rules for

StructuresPart 1-2: Structural Fire Design

BS EN 1992Part 2:

Bridges

BS EN 1992Part 3: Liquid

Ret. Structures

BS EN 1994Design of

Comp. Struct.

BS EN 13369Pre-cast Concrete

BS EN 1997GEOTECHNICAL

DESIGN

BS EN 1998SEISMIC DESIGN

BS EN 13670Execution of Structures

BS 8500Specifying Concrete

BS 4449Reinforcing

Steels

BS EN 10080Reinforcing

Steels

Eurocode 2: relationships –

BS EN 206Concrete

NSCS

DMRB?

NBS?

Rail?

CESWI?

BS EN 10138Prestressing

Steels

71

Specifications

BS EN 13670

72

BS EN 13670 & NSCS

New Types of Finish

Hierarchy of Tolerances

Includes NA

Types of Finish as BS EN 13670

Hierarchy of Tolerances

Green Issues

BS EN 13670

08/10/2012


73

BS EN 1990 BASIS OF STRUCTURAL

DESIGN

BS EN 1991 ACTIONS ON STRUCTURES

BS EN 1992DESIGN OF CONCRETE

STRUCTURESPart 1-1: General Rules for

StructuresPart 1-2: Structural Fire Design

BS EN 1992Part 2:

Bridges

BS EN 1992Part 3: Liquid

Ret. Structures

BS EN 1994Design of

Comp. Struct.

BS EN 13369Pre-cast Concrete

BS EN 1997GEOTECHNICAL

DESIGN

BS EN 1998SEISMIC DESIGN

BS EN 13670Execution of Structures

BS 8500Specifying Concrete

BS 4449Reinforcing

Steels

BS EN 10080Reinforcing

Steels

Eurocode 2: relationships –

BS EN 206Concrete

NSCS

DMRB?

NBS?

Rail?

CESWI?

BS EN 10138Prestressing

Steels

74

Eurocode 2 & the UK – what does it mean?

A paper by Moss and Webster (BS8110 vs EC2, TSE 16/03/04)

concluded:·

• big impact

• learning curve

• not wildly different from BS8110 in terms of the design approach.

• similar answers

• marginally more economic.

• less prescriptive and more extensive than BS8110

• gives designers the opportunity to derive benefit from the

considerable advances in concrete technology over recent years

• believe that after an initial acclimatisation period, EC2 will be

generally regarded as a very good code.

75

Flat slabs: Economic depths

150

200

250

300

350

400

450

500

4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0

SPAN, m

SLAB D

EPT

H,

mm

IL = 5 kN/m2

To BS8110 incl 1.5 SDL IL = 2.5 kN/m2

To BS8110 incl 1.5 SDL

To EC2

EC2: up to 25 mm shallower @ 9 m

EC2: up to 15 mm shallower @ 6 m

Rev’d 12 May 10

To BS8110

5 to 7 % savings?

76

Concise Eurocode 2RC Spreadsheets

‘How to’

compendium

www. eurocode2.info

ECFE – scheme sizing

Worked Examples

Properties

of concrete

Technical publications (CCIP)

Scheme design

Precast Design Manual

Precast Worked Examples

Concise Eurocode 2 for Bridges

77

Concise Eurocode 2

Clarity

Clear references

Comment

Design aids

78

‘How to’ compendium

08/10/2012


79

Spreadsheets to BS EN 1992-1-1 (and UK NA) TCC11 Element designTCC12 Bending and Axial ForceTCC13 Punching ShearTCC14 Crack WidthTCC21 Subframe analysisTCC31 One-way Solid Slabs (A & D)TCC31R Rigorous* One-way Solid SlabTCC32 Ribbed slabs (A & D)TCC33 Flat Slabs (A & D) (single bay)TCC33X Flat Slabs. Xls (whole floor)TCC41 Continuous beams (A & D)TCC41R Rigorous* Continuous BeamsTCC42 (β) Post-tensioned Slabs & Beams (A & D)TCC43 Wide Beams (A & D)

Spreadsheets

TCC51 Column Load Take-down & DesignTCC52 Column Chart generationTCC53 Column DesignTCC54 Circular Column DesignTCC55 Axial Column ShorteningTCC71 Stair Flight & Landing – SingleTCC81 Foundation PadsTCC82 Pilecap Design

80

Design GuidanceNew Concrete Industry Design Guidance is written for Eurocode 2

• TR 64 Flat Slab

• TR43 PT

• TR58 Deflections

Text books

81

Introduction to Eurocode 2

Charles Goodchild,

BSc CEng MCIOB MIStructE

The Concrete Centre

www.concretecentre.com

www.eurocode2.info

Documents

SPATA Intro to Eurocode 2 4 Oct 2012