The Structural Eurocodes

UK Building Regulations and Supporting

Standards

Dr David Moore

Director of Engineering

BCSA

Russian Delegation, BCSA 26th Sept 2011

Content

• Building Regulations

• Approved Document A

• Eurocodes

• Design guides

• Execution Standards

The Building Regulations 1965

The Building Regulations 1965

The building shall be constructed so that the

combined dead, imposed and wind loads are

sustained and transmitted by it to the ground:

a) Safely; and

b) Without causing such deflection or deformation

of any part of the building, or such movement of

the ground as will impair the stability of any part

of another building.

Approved Document A

The Structural Eurocodes What are they?

EN 1990, Eurocode - Basis of structural design

EN 1991, Eurocode 1 - Actions on structures

EN 1992, Eurocode 2 - Design of concrete structures

EN 1993, Eurocode 3 - Design of steel structures

EN 1994, Eurocode 4 - Design of composite steel & concrete structures

EN 1995, Eurocode 5 - Design of timber structures

EN 1996, Eurocode 6 - Design of masonry structures

EN 1997, Eurocode 7 - Geotechnical design

EN 1998, Eurocode 8 - Design of structures for earthquake resistance

EN 1999, Eurocode 9 - Design of aluminium structures


Each Eurocode has several parts:

• EN 1993-1, General & rules for buildings

• EN 1993-2, Steel bridges

• EN 1993-3, Towers, masts & chimneys

• EN 1993-4, Silos, tanks & pipelines

• EN 1993-5, Piling

• EN 1993-6, Crane supporting structures

And each part can have several sub-parts…


• EN 1993-1-1, General rules

• EN 1993-1-2, Fire design

• EN 1993-1-3, Cold-formed

• EN 1993-1-4, Stainless steels

• EN 1993-1-5, Plated structures

• EN 1993-1-6, Shell structures

• EN 1993-1-7, Trans. loaded plates

• EN 1993-1-8, Joints

• EN 1993-1-9, Fatigue

• EN 1993-1-10, Toughness

• EN 1993-1-11, Tension components

• EN 1993-1-12, High strength steels

And each sub-part has its

own National Annex!


EN 1990

EN 1991

EN 1994 EN 1993 EN 1992

EN 1999 EN 1995 EN 1996

EN 1998 EN 1997

Safety, serviceability

and durability

Actions on structures

Design and detailing

Geotechnical and

seismic design


Product Standards

Execution Standards

Designation Materials Elements Testing

Testing Installation Assembly Manufacture

Design Rules


Published by BSI

a) BSI title page

b) BSI National Foreword

c) EN title page

d) EN text

e) EN Annex(es)

f) BSI National Annex

(May be a separate document)

NB. The EN parts are reproduced

without any alterations

a

b

c

d

f

e


The criticality of the National Annex

• Allows for differences in:

– Geography, climatic conditions

– Level of safety, durability, economy

• NA contains:

– Nationally determined parameters

– Country specific data (e.g. wind „maps‟)

– Decisions on application of informative annexes

– References to NCCI

It cannot modify the content of the EN Eurocode text in any way


NCCI – Non Contradictory Complementary Information

• Fills in the gaps in the Eurocodes:

• Steel NCCI all on www……….

The Structural Eurocodes Why have they been developed?

To:

• Eliminate technical obstacles to trade

• Harmonise technical specifications

• Improve functioning of EU market

• Increase EU competitiveness

The Structural Eurocodes When will they have to be used?

Estimated programme:

• All Eurocodes & NAs are published

• BS 5950 etc withdrawn in March 2010

Government policy is still unclear:

• PPD for public works after 2010

• UK Building Regulations?

– No update of AD ‟A‟ until 2013

– BS 5950 still referenced

– Letter from Secretary of State?

The Structural Eurocodes How are they different?

• Code drafting by committee!

• Cultural changes:

– Greater use of first principles

– Greater use of FE analysis

– Better knowledge of maths

• Increased number of documents

– E.g. Steel composite bridge design

• 5 to BS 5400

• 14 to Eurocodes


Principles & Application Rules:

• Principles:

– General statements for which there is no alternative

– Identified by the letter „P‟, & Use the word „shall‟

– Fundamental requirements

• Application Rules:

– Generally recognised rules that comply with the „Principles‟

– Use words such as „should‟, „may‟, „can‟

– Alternative rules are permitted

(But must offer equivalent safety, serviceability & durability)


Terminology:

• “Action” - load or imposed displacement

• “Verification” - check

• “Resistance” - capacity (in terms of strength)

• “Execution” - construction / fabrication

Notation (Subscripts):

• “Ed” = design value of effect of actions (e.g. NEd = axial force)

• “Rd” = design value of the resistance

(e.g. NRd = resistance to axial force)


Member sign convention:

• As per software packages – less potential for error!

• x-x axis along the member

y y y y

y y

z

z

z

z

z

z

v

v

u

u

The Structural Eurocodes Where can I find help?

From the steel construction industry

• Involved in drafting the Eurocodes

• Published ENV guidance documents

• Involved in drafting the UK NAs

• Started latest guides over 5 years ago

A lot of history

A lot of expertise


Initial suite of technical guidance from Corus / BCSA / SCI:

Steel Building Design:

• Introduction to the Eurocodes

• Concise Eurocodes

• Design Data

• Medium Rise Braced Frames

• Worked examples – Open sections

• Worked examples – Hollow sections


Steel Building design:

Introduction to the Eurocodes



Concise Eurocodes

•



Design Data

•



Medium Rise Braced Frames

•



Worked examples – Open sections

•



Worked examples – Hollow sections

•

• Old Standards • BS 5950 Part 2

• National Structural Steelwork Specification 5th ed

• New European standards • BS EN 1090-2

• National Structural Steelwork Specification 5th ed( CE Marking)

Execution/Fabrication Standards

• Constructor responsibility

– Manufacturer‟s declaration of conformity

– Warranty that product meets the specification

• Safety critical products

– Must have suitable FPC

– FPC needs to be certified by a Notified Body

– Linked to Execution Classes [EXC]

• Welding is a special process

– Reliance on the “system” and the “personnel”

– Competent welders and inspectors required

– Competent welding coordinator

Principles – EN 1090-2

• Covers all fabricated steelwork from Purlins to Portal Frames including Bridges

• Components made from:

– Hot-rolled steel

– Cold-formed steel

– Flat products (plates, sheet and strip)

– Bars, castings and forgings

• Applies to:

– Series production (Purlins, sheets, decking etc)

– Bespoke structures

– Components made from kits of parts

Scope – EN 1090-2

• Execution class is at the heart of:

– BS EN 1090-2

• Execution Class is a design issue

• Can apply to the whole structure, part of the

structure or specific details

• A single structure may include several Execution

Classes

Execution Classes

• Recommendations for determining Execution

Class are given in BS EN 1090-2.

• There are four Execution Classes:

– Execution Class 1 „Lowest‟

– Execution Class 2

– Execution Class 3

– Execution Class 4 „Highest‟

Execution Classes

• Execution Class should be selected on the

following three conditions:

– The consequence of a structural failure

(Consequence Class)

– The type of loading (Service Category)

– The processes used for the work and the

required quality level of the component

(Production Category)

Selection of Execution Classes

Execution Classes

Consequence

Class

CC1 CC2 CC3

Service categories SC1 SC2 SC1 SC2 SC1 SC2

Production

categories

PC1 EXC1 EXC2 EXC2 EXC3 EXC3a EXC3a

PC2 EXC2 EXC2 EXC2 EXC3 EXC3a EXC4

EXC4 should be applied to special structures or structures with extreme

consequences of a structural failure as required by national provisions

Example

• 10 storey office

• Subject predominantly to static loading

• S275 steel

• Some welded components

Consequence Class – CC2

Service Category – SC1

Production Category – PC1

Determination of Execution Classes - Example

Execution Classes - Example

Consequence

Class

CC1 CC2 CC3

Service categories SC1 SC2 SC1 SC2 SC1 SC2

Production

categories

PC1 EXC1 EXC2 EXC2 EXC3 EXC3a EXC3a

PC2 EXC2 EXC2 EXC2 EXC3 EXC3a EXC4

EXC4 should be applied to special structures or structures with extreme

consequences of a structural failure as required by national provisions

UK Building Regulations and Supporting

Standards

Dr David Moore

Director of Engineering

BCSA

Russian Delegation, BCSA 26th Sept 2011

The Structural Eurocodes

Documents

Transcript of The Structural Eurocodes