Workshop on the Design of Reinforced and

Prestressed Concrete to EC2

Dr Kim S. Elliott

University of Nottingham

Kuala Lumpur : 26 27 March 2009

Johor Bharu : 30 31 March 2009

Workshop on EC2

Program Day 1

9.15 Lecture 1. Introduction to Eurocodes

9.35 Lecture 2. Loads, Actions and Combinations

10.30 Break

11.00 Lecture 3. Materials, Durability & Fire

11.30 Lecture 4. Reinforced Concrete: flexure, shear, deflection

12.45 Lunch

14.00 Lecture 5. Reinforced Concrete: compression, columns & walls

15.00 Break and set up classroom

15.15 4 storey RC frame exercise

4 storey RC frame braced and unbraced exercise

Workshop on EC2

Program Day 2

8.45 Lecture 6. Introduction to prestressed concrete & European

product standards

9.15 Lecture 7. Material, creep & losses, durability & fire

10.00 Break

10.30 Lecture 8. Prestressed flexure: service & ultimate

11.45 Lecture 9. Prestressed ultimate shear

12.30 Lunch

14.30 Lecture 10. Prestressed interface shear & deflection

15.00 Break and set up classroom

15.15 Composite prestressed beam exercise

Composite prestressed inverted tee beam exercise

The Eurocode Family

(57 all together)

BS EN 1990: Basis of design

BS EN 1991: Actions

BS EN 1992: Concrete

BS EN 1993: Structural steelwork

BS EN 1994: Composite steel and concrete

BS EN 1995: Timber

BS EN 1996: Masonry

BS EN 1997: Foundations

BS EN 1998: Seismic

BS EN 1999: Aluminium

Format of the Eurocodes

Each Eurocode contains:

National Foreword

Main text and Annexes (Normative and/or Informative)

National Annex (NA) provides :

- values of Nationally Determined Parameters (NDPs) boxed values- the decision where the Main text allows alternative

methods.

- the choice of Class where alternatives are given (e.g. to

allow for different environmental conditions)

- the choice of adopting Informative Annexes

Non-contradictory complementary information

NDPs have been allowed for reasons of safety, economy and

durability.

Mainly use the recommended value but- acc = 1.0 >> = 0.85 (used in fcd = acc fck/gm)

- flarge = 32 >> = 40 mm

- k1 to k6 changed moment redistribution limits

- gP,fav = 1.0 >> = 0.9 (g for prestress)

- additional requirements on span/depth l/d and crack wmax

Simplified load combinations

Use of BS 8500-1 (Concrete) for recommended concrete grade,

minimum cover, water/cement, cement content, types of cement

PD 6687 background to NA, e.g. on maximum areas, stability ties for progressive collapse are same as BS8110

Guidance on use of stainless steel, post-tensioned floors,

deflections, detailing.

Nationally Determined Parameters

BS EN 1990 Basis of structural designEurocode 0

Generally the structure shall be verified at:

Ultimate Limit State: Any condition that concerns the safety of people or structure

Loss of equilibrium (EQU); Internal failure or excessive

structural deformation (STR); Failure or excessive

deformation of ground (GEO); failure caused by time

dependent effects such as fatigue (FAT).

Serviceability Limit State: Corresponds to conditions in use of the structure. The limit state could be related

to cracking, deformation or vibration.

BS EN 1991 Actions on StructuresEurocode EC1

EN 1991-1-1 General actions- densities, self weight, imposed loads

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

EN 1991-1-3 Snow loads

EN 1991-1-4 Wind actions

BS EN 1991 Actions on StructuresEurocode EC1

EN 1991-1-5 Thermal actions

EN 1991-1-6 Actions during execution

EN 1991-1-7 Accidental actions

EN 1991-2 Traffic loads on bridges

EN 1991-3 Actions induced by cranes and machinery

EN 1991-4 Silos and tanks

Influences durability, e.g. cover to bars for certain

exposure 30 >> 40 mm

BS EN 1991 Actions on Structures

1: General 2: Basis of Design 3: Materials 4: Durability and cover to reinforcement 5: Structural analysis 6: Ultimate limit states 7: Serviceability limit states 8: Detailing of reinforcement and prestressing 9: Detailing of members and particular rules 10: Precast concrete elements and structures 11: Lightweight aggregate concrete structures 12: Plain and lightly reinforced concrete structures

BS EN 1992 : Concrete Structures

Eurocode EC2

EC2 Part 1-1 does not cover:

Resistance to fire

Particular aspects of special types of building (e.g. tall buildings)

Particular aspects of special types of civil engineering works (e.g. viaducts, bridges, dams, pressure vessels, offshore platforms or liquid retaining structures)

No-fines concrete and aerated concrete components, and those made with heavy aggregate or containing steel sections

EC2 does not give helpful design procedures,

e.g. beam design or column charts

The Concrete Centre,

UK EC2 Design Guides

do it for us, presenting

the design in a similar

manner to methods

used in BS8110

The Concrete Centre, UK EC2 Design Guides

e.g. beam design procedure

The Concrete Centre, UK EC2 Design Guides

e.g. deflection control by span/depth ratio

Related Standards

BS 8500-1, BS8500-2, EN 206

Complimentary British Standards for the specification of

cement and concrete.

BS10260: Specification for aggregates.

BS4449 / BS EN 10080

Specification for carbon steel for reinforcement was revised in

2006. It is complimentary to EC2 Annex C and the forthcoming

EN10080.

Major change is high tensile bar fyk = 500 N/mm2 (grade H)

3 classes of bar: A, B and C with increasing ductility, limiting

the amount of moment redistribution.

Related Standards

BS EN13670

Execution of concrete structures, replacing BS8110 Part 1,

Sections 6 and 7 on tolerances, workmanship, etc.

There is no equivalent guidance in EC2.

Other items without equivalence:

Lateral load distribution of point and line loads, e.g. 0.25L rule

Staircase reactions on landings

Design procedure for flexure, e.g. K = M/fcu bd2, and so on

Bending moment coefficients for beams and slabs, e.g. 0.071Fl

Conclusions

1. The family of Eurocodes is based on principles, rather than

methods

2. All materials are subjected to the same limit state regime

3. Format for all codes is : principles, materials, ultimate,

service, detailing

4. Materials may cross over, e.g. concrete and timber have the

same principles, load and material factors

5. UK has used back up from BS8110 and BS5950 to fill in

some of the missing gaps

6. Some data are hard to find, e.g. limiting x/d ratio for under-

reinforced beams