1 introduction to eurocodes
TRANSCRIPT
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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
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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
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4 storey RC frame braced and unbraced exercise
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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
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Composite prestressed inverted tee beam exercise
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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
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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.
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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
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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.
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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
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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
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Influences durability, e.g. cover to bars for certain
exposure 30 >> 40 mm
BS EN 1991 Actions on Structures
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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
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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
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EC2 does not give helpful design procedures,
e.g. beam design or column charts
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The Concrete Centre,
UK EC2 Design Guides
do it for us, presenting
the design in a similar
manner to methods
used in BS8110
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The Concrete Centre, UK EC2 Design Guides
e.g. beam design procedure
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The Concrete Centre, UK EC2 Design Guides
e.g. deflection control by span/depth ratio
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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.
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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
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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