Latest on Design Codes for Concrete
21 Aug 2018
Eurocode 2 - 1 - 1
The process to update the Eurocodes is underway. Earlier this year some 1800 ‘informal’ comments were made across Europe on a 2nd draft of a revised EN 1992-1-1. A 3rd draft was delivered by Project Team I in May 2018. The main changes being considered include: changing strength reduction factor acc which in HSC columns will be offset by an allowance for confinement; shear without shear reinforcement, which will be based on Critical Shear Crack Theory, which is more widely applicable; punching shear, which will have revised rules and perimeters; and lap lengths.
Meanwhile, other Project Teams have delivered first drafts of revision to EN1992-1-2 (Fire) and of new draft annexes for assessment, steel fibre reinforcement, FRP strengthening and stainless steel.
Relevant CEN TC250/SC2 committees are considering and working on these drafts. It will be a couple of years before more finalised drafts become available for public comment.
A revision to the current EN1992-1-2 (Fire), Annex C, Columns, is being finalised. This will replace the tables in the current Annex C.
Eurocode 2 - 4
The Eurocode for the design of fastenings in concrete is due to be published by BSI in October 2018. The document forms part of Eurocode 2 and will be known as “BS EN 1992-4, Eurocode 2 Design of concrete structures – Part 4: Design of fastenings for use in concrete”.
Previously anchors may have been designed to the methods according to a CEN Technical Specification CEN/TS 1992-4 Parts 1 - 5 covering the various anchor types: Headed fasteners, Anchor channels, Post-installed mechanical fasteners and Post-installed chemical systems.
The new full code of practice amalgamates, updates and supersedes these documents. The document will provide the formal design method for those required to comply with the Eurocodes. Before this can happen a UK National Annex will need to be published and it is planned that a draft for publication of the UK National annex is published shortly after the new code is available.”
The specification of concrete code BS 8500 is being amended to include three-part blends of cement such as Portland cement, ggbs and limestone fines or Portland cement, fly ash and limestone fines. These are low carbon cements which will improve the range of options available to designers, specifiers and producers.
These cements are widely used elsewhere in Europe and are covered by the European standard EN 197-1. Other cementitious binders such as natural pozzolana and natural calcined pozzolana (or metakaolin) are also to be included in the new amendment to BS 8500.
The new cements can be used in reinforced and mass concretes for exposure classes XC, XD, XS and XF and also for DC1 and DC2 classes for concretes in the ground. There are further durability tests being done for concretes in more aggressive ground conditions.
BS8666, Scheduling, dimensioning, bending and cutting of steel reinforcement for concrete is to undergo a general revision with work having just started. The sub-committee has enough to work on but if you have specific points you wish to make, please do so using preferably
https://standardsdevelopment.bsigroup.com/projects/9018-01628 by 23 September 2018.
Otherwise a commenting form may be downloaded from https://boss.cen.eu/formtemp/Commenting_Form.doc and submitted to the Committee Secretary Lyle.McMahon@bsigroup.com by 30th September.