Eurocodes as European Standards for Design and Calculation of Construction

The EN Eurocodes are a set of European standards which provide common rules for the design of construction works, to check their strength and stability against live and extreme loads such as earthquakes and fire. 

With the publication of all the 58 Eurocodes parts in 2007, the implementation of the Eurocodes is extending to all European countries and there are firm steps towards their adoption internationally. The Commission Recommendation of 11 December 2003 stresses the importance of training in the use of the Eurocodes, especially in engineering schools and as part of continuous professional development courses for engineers and technicians, noting that they should be promoted both at national and international level.  

In light of the Recommendation, DG JRC is collaborating with DG ENTR and CEN/TC250 “Structural Eurocodes” and is publishing the Report Series ‘Support to the implementation, harmonization and further development of the Eurocodes’ as JRC Scientific and Technical Reports. Editorial work for this Report Series is assured by the JRC together with partners and stakeholders, when appropriate. The publication of the reports type 3, 4 and 5 is made after approval for publication from the CEN/TC250 Co-ordination Group.

Influence of temperature on toughness and risk of brittle fracture

Due to a significant decrease of toughness properties of structural steel with decreasing temperatures there is a risk that structural steel components may under low temperatures be susceptible to brittle fracture. EN 1993-1-10 provides a method to avoid such brittle fracture by an appropriate choice of steel grade.

The background of this method is a fracture mechanics safety assessment for a particular accidental scenario that includes extremely low temperatures, the presence of crack-like flaws at critical Hot-Spots, that have grown by fatigue effects, the presence of nominal stresses Ed, and of material properties as specified in EN 10025.

The purpose of this report is to adapt the method in EN 1993-1-10 used for normal steel structures to the specific case of steel components of structural bearings that are produced according to EN 1337 and are subject to specific design, fabrication and installation methods. In this adaptation the specific shapes of components generally machined from

plates and the particular loading and verification models for the design of the components have been taken into account, so that eventually selection tables as

in EN 1993-1-10 could be established. In case a Finite-Element analysis is applied in the design of the components of

bearings the appropriate method to determine the reference stress Ed is a Hot Spot-stress HS as defined by Dong.

For usual dimensions of bearings a simplified procedure is offered that refers to nominal values of bend,d as the surface stress from the linear bending theory.

A worked example illustrates the use of the simplified procedure.

Last year, German magazine Der Spiegel published an article about the collapse of old bridges in Germany - mostly due to heavy vehicles traffic - and the efforts made to reconstruct and modernise them. The reconstruction of the bridge "Demminer Strasse" in Neubrandenburg with ArcelorMittal beams shows that steel is an ideal bridge solution, providing a sustainable, quick and economic construction.

Composite solution for more resistant structures

To rebuild the bridge "Demminer Strasse" in Neubrandenburg, general contractor Matthäi Bauunternehmen Leezen opted for a filler beam deck solution. This kind of steel-concrete composite bridge is used for short and medium span superstructures with severe construction depth restrictions. The new two-span bridge has two separated decks for each traffic direction. It is built over railway tracks and provides further connections via the B96 road.

As ArcelorMittal Downstream Solutions successfully collaborated with Matthäi Bauunternehmen Leezen for a precedent bridge project in Schwerin, we won the contract in May 2016 and delivered H-profile wide flange beams in grade S355M with a profile depth of 900 mm each. Due to the closely spaced beams and prefabricated fibre-cement elements, which are placed on the lower flanges, no additional formwork or falsework for the concrete between the beams was needed. Thus, traffic interference below the new bridge was strongly reduced and expensive closure times for the railway line could be limited to only few nights.

Sustainable beams from Luxembourg

The 19 and 31-metre-long beams were produced by ArcelorMittal Europe – Long Products' mill in Differdange (Luxembourg). Afterwards, they were cut and welded with transversals (IPE 400 S235JR) by Downstream Solutions in Bad Oldesloe (Germany). The thermomechanical rolling process of the high quality S355M grade associated with the anti-corrosion coating applied on the beams will ensure the longevity of the structure.

The beams, like most of our steel beams used in bridge construction, were made of scrap. This once again demonstrates the sustainability of steel, which can be recycled infinitely many times while retaining its properties.

Downstream Solutions and ArcelorMittal Europe – Long Products coordinated their deliveries with the customer and Deutsche Bahn, ensuring that assembling of the beams could take place at night in July without any problems. The construction of the bridge will be completed in the first or second quarter of 2018.

Text: ArcelorMittal Europe - Flat Products

Photos: © Matthäi Bauunternehmen Leezen