Decoding the Eurocodes

National Annex for Part 2 is now a draft for public comment

The long awaited draft UK National Annex for Eurocode 7 Part 2 (BS EN 1997-2) has been published by BSI.

The draft is open for comment until 31 May 2009.

The pieces of the jigsaw are finally coming into place...

UK National Annex update

Yet more UK National Annexes are available from BSI Online:

• Eurocode 3 Design of steel structures
  • A further five NAs are now published
• Eurocode 9 Design of aluminium structures
  • All five NAs are now published

There are now only 10 (out of 58) NAs waiting for publication ...

• Eurocode 3 Design of steel structures
  
  • NA to BS EN 1993-1-6 and -7 covering shells and plates
  • NA to BS EN 1993-3-1 and -2 covering towers, masts, and chimneys
  • NA to BS EN 1993-4-1, -2, and -3 covering silos, tanks, and pipelines
  • NA to BS EN 1993-5 covering sheet piling
  • NA to BS EN 1993-6 crane supporting structures
• Eurocode 7 Geotechnical design
  
  • NA to BS EN 1997-2. Ground investigation and testing

Yet more UK National Annexes are available from BSI Online:

• Eurocode 3 Design of steel structures
  • A further five NAs are now published
• Eurocode 9 Design of aluminium structures
  • All five NAs are now published

There are now only 10 (out of 58) NAs waiting for publication ...

• Eurocode 3 Design of steel structures
  
  • NA to BS EN 1993-1-6 and -7 covering shells and plates
  • NA to BS EN 1993-3-1 and -2 covering towers, masts, and chimneys
  • NA to BS EN 1993-4-1, -2, and -3 covering silos, tanks, and pipelines
  • NA to BS EN 1993-5 covering sheet piling
  • NA to BS EN 1993-6 crane supporting structures
• Eurocode 7 Geotechnical design
  
  • NA to BS EN 1997-2. Ground investigation and testing

Error in UK National Annex to Eurocode 7 Part 1

There is an error in the UK National Annex to Eurocode 7 Part 1, on page 16...

Table A.NA.17 gives the value of the partial factor on a permanent, unfavourable action as 1.335, when the correct value should be 1.35 (as in Eurocode 7 itself).

BSI-SCI 'user needs' workshop

I just got back from an interesting workshop, looking at how easy Eurocode 3 is to apply to the design of simple steel structures (column, beam, etc.). The workshop was run by the Steel Construction Institute on behalf of BSI.

Most of the attendees were new to the Eurocodes, but experienced steel designers. It was interesting to see that the problems that face geotechnical engineers in adapting to Eurocode 7 also face steel designers adapting to Eurocode 3. Terminology is different; concepts appears strange, but familiar; the outcome is about the same.

BSI publishes final National Annexes for Eurocode 2

British Standards Institution has completed the publication of all the National Annexes to Eurocode 2, the new concrete code. This means that the following Eurocodes are published in their entirety in the UK:

• EN 1990, Basis of structural design
• EN 1992, Design of concrete structures
• EN 1995, Design of timber structures
• EN 1996, Design of masonry structures

UK National Annex goes to the printers

It's finished! The text of the UK National Annex to EN 1997-1 has been finalised and the document is "with the printers". Maybe now people will start to pay attention to the new code and attempt to make the most of it.

I will post again when I know the physical publication date.

UK National Annex almost ready

BSI committee B/526 held its latest meeting in Chiswick today. The main item on the agenda was preparation of the UK National Annex to BS EN 1997-1. A draft of the NA was tabled and - apart from the section on pile design - agreed subject to minor corrections.

For pile design, Brian Simpson and I proposed a new set of model and resistance factors for design using ground parameters (and a corresponding set of correlation factors for design based on testing). The proposal took account of our greater confidence in calculations when they are supported by static load test results. In essence, the proposal leads to a low equivalent global safety factor when preliminary piles tests are scheduled; a moderate safety factor when only working pile tests are available; and a high safety factor when no tests are performed.

The framework for pile design that Brian and I tabled was accepted by the committee, subject to the numerical values of the factors being scrutinised and agreed with the Federation of Piling Specialists. Hopefully, this process will not take too long (watch this space for news) and we can publish the NA during the summer of 2007.

Work in progress: UK National Annex to EN 1997-1

I'm just back from the latest B/526 meeting, where we discussed comments received on the draft UK National Annex to Eurocode 7 Part 1. (For those of you who don't know, B/526 is the BSI committee responsible for producing and maintaining British Standards covering geotechnical engineering.) The hope was to publish the NA by the end of 2006.

The good news is that considerable progress was made sifting through the feedback received from this summer's public comment period. The bad news is we didn't have time to complete the job in one meeting.

As expected, the most time consuming issue was discussion of pile design. Eurocode 7 allows piles to be designed in two ways:

1. from test results, with calculated resistances modified by correlation factors that take account of the number of tests performed
2. from ground parameters, with resistances modified by a model factor that takes account of uncertainties in the calculation model

The "ground parameter method" appears to be the one favoured by UK piling engineers, but details of how this method should work are missing from Eurocode 7. The main issues are:

• should characteristic ground parameters X_k be selected as "cautious estimate" or "best estimate" values?
• should a model factor γ_Rd (as suggested by the code) or a correlation factor ξ (as used in the correlation factor method) be used to modify calculated resistances?
• at what stage in the calculations should the model factor appear?
• what value(s) should the model factor take?
• should there be different values of γ_Rd for different pile types (bored, driven, CFA)?
• should the partial factors for base resistance (γ_b) and shaft (γ_s) differ according to pile type (as they currently do in the code)?
• should the values of γ_Rd be incorporated directly into γ_b and γ_s so only one set of factors is used in calculations?
• how do the results of this method compare with traditional designs?

The current plan for resolving these issues is for a set of example calculations to be prepared for discussion at the next meeting of the Federation of Piling Specialists and for B/526 to decide on the issues above based on the feedback received.

If anyone wants to contribute to this process, please contact me for further info.

Spend euros, save pounds

Cost of puchasing EN 1997-1 from British Standard Online: £192
Cost of puchasing EN 1997-1 from UNI Store: €102 (= £70)
Cost of puchasing EN 1997-1 from pronorm: KR835 (= £70)

Underwhelmed by BSI e-learning site

British Standards Institution (BSI) has created a free "e-learning course to introduce the construction industry to the global benefits of using the structural Eurocodes".  The interactive conference can be found at www.bsi-global.com/eurocodes.

Having spent some time looking at the site, I wonder why BSI has wasted its money producing such a simplistic introduction to the Eurocodes. Do they think we are all morons? Web users want lots of information, quickly, and do not want to be spoon-fed largely irrelevant facts and figures about the codes. And on top of it all, you have to register to access the information! Don't bother.