Differences between BS 8110 and Eurocode 2 (EC 2) based on design notations

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Reinforced concrete design (RCD) in Nigeria have been based on the British Standard (BS 8110). Recently, precisely in 2010, BS 8110 was due to be replaced by a unified code known as Eurocode 2 (EC 2) for the design of reinforced concrete structures among European Union (EU) members. The development of Eurocode began in 1975 and the code is claimed to be the most technically advanced structural codes in the world. One of the key purposes of the code is to facilitate professional services and materials exchange among EU members. Besides these, the code have many other advantages above BS 8110 which according to (Narayanan and Brooker, 2006) include:

1. More economical structures are produced with EC 2 than BS 8110

2. The codes are logical and organized to avoid repetition

3. They are less restrictive than existing codes

4. It is more extensive than existing codes

5. It would provide more opportunity for designers to work throughout Europe

Since BS 8110 is being replaced by EC 2, it is expedient that countries that have hitherto being using BS 8110 should also adopt EC 2 in order to enjoy developments in reinforced concrete design. The learning of a new code is a daunting task but one that can easily be achieved by hardwork and determination. To facilitate easier learning of the codes, it may be ideal to compare the two codes. To show where they relate and differ. With these, one who is already familiar with BS 8110 can easily key into the new code EC 2. There are many places where these codes differ but I would show one of the least among these which are differences in notations.

Important areas of significant differences

1. Loads in BS 8110 are now Actions in EC 2. Likewise, dead and live loads in BS 8110 are now permanent actions and variable actions in EC 2 respectively. Bending moments and shear forces in BS 8110 are now internal moments and internal stresses in EC 2 respectively.

2. BS 8110 contains separate chapters on the design of beams, slabs, columns, bases, etc. However, EC 2 divides the material on the basis of structural action, i.e. bending, shear, deflection, torsion, etc., which may apply to any element.

3. BS 8110 is based on characteristic cube strength while EC 2 is a based on characteristic cylinder strength at 28 days. Generally, cylinder strength is approximately 0.8 x cube strength.

4. Unlike in BS 8110, design rules in EC 2 are applicable to steel reinforcement with characteristic yield strength in the range of 400 – 600 N/mm². Round mild steel with characteristic strength of 250 N/mm² which found usefulness in BS 8110 cannot be used in EC 2.

5. In EC 2, the partial factor for ultimate limit states have a single value of 1.5 but in BS 8110, it is usually based on stress type under consideration.

Notations

The notations would be categorized based on geometric properties, bending terms, shear terms and compression terms.

Geometric properties

Bending Notations

Shear notations: These are applicable in shear checks for structural members

Compression notations: These notations are commonly employed in the design of compression members such as columns

Some Design Terms

References

Arya, C. (2009): Design of Structural Elements. Third Edition. Taylor & Francis

2 Park Square, Milton Park, Abingdon, Oxon OX14 4RN

Narayanan, R.S. and Brooker, O. (2006): How to design concrete structures using Eurocode 2: Introduction to Eurocodes. The Concrete Centre Riverside House, 4 Meadows Business Park, Station Approach, Blackwater, Camberley, Surrey GU17 9AB

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