Standards for reinforcement

Standards relating to concrete reinforcing and prestressing are:

EN 10138 - Prestressing Steel

Prestressing steels is in four parts:

• EN 10138-1. Prestressing steels. General requirements 
• EN 10138-2. Prestressing steels. Wire 
• EN 10138-3. Prestressing steels. Strand 
• EN 10138-4. Prestressing steels. Bars 

These parts are currently under development.

EN 10080: Steel for the reinforcement of concrete, weldable, ribbed reinforcing steel 

BS EN 10080:2005

Weldable steel for the reinforcement of concrete has become subject to the European Standard, BS EN 10080. This standard went back and forth over many years seeking a pragmatic agreement amongst Europeans on how to standardise reinforcement. In other words, it has taken a long time to move from being a mandated standard (one that the European Commission asked CEN to prepare) to being a harmonised standard. In 2008 it had to be withdrawn as a harmonized standard because some countries legal requirements for additional properties of reinforcement were not met. However, it was implemented in the UK in late 2005 and its subsequent withdrawal has no effect on BS 4449 etc.

BS EN 10080:2005 gives no actual specification or figures; that is left to the National Standards.

Requires that technical classes should be specified by values of:

• R_e,               yield strength;
• R_m/R_e,          Ratio of tensile strength/Yield strength,
• A_gt,              Percentage total elongation at maximum force,
• R_e,act/R_e,nom    (where appropriate), Ratio of actual to specified value of yield strength, 
• fatigue strength, 
• bend performance, 
• weldability, 
• bond strength, 
• tolerances and 
• dimensions. 

It contains an informative Annex ZA, which describes how the standard may be used for the purposes of CE marking. Please note that the CE mark is not a quality mark. It merely identifies the product as complying with the essential requirement laid down by the European Commission in their 'mandate' to CEN. CE marking is not a requirement of BS 4449:2005 and reinforcement cannot be CE marked as the harmonised standard has been withdrawn.

BS EN ISO 17660: Welding of Reinforcing Steel

This standard has two parts:

• BS EN ISO 17660-1:2006. Welding. Welding of reinforcing steel - Load-bearing welded joints
• BS EN ISO 17660-2:2006. Welding. Welding of reinforcing steel - Non load-bearing welded joints 

BS 4449: 2005 Steel for the reinforcement of concrete weldable reinforcing steel, bar, coil and decoiled product

This was a full revision of the standard and defines three grades of reinforcement conforming to the now withdrawn BS EN 10080: B500A, B500B and B500C.  The characteristic yield strength is set at 500 MPa and the tensile properties and ductility of the three grades are described in Table 1.

Characteristic tensile properties

The three grades conform to the three recommended ductility classes in BS 1992-1-1:2004 (Eurocode 2). It should be noted that below 8mm diameter, reinforcing steel to BS 4449 does not comply to BS EN 1992-1-1 with respect to ductility. This is not the only occasion where BS 4449:2005 has had to take into account the requirements of BS EN 1992-1-1.  For instance, the scope of Eurocode 2 is limited to ribbed reinforcement with strengths between 400 and 600 MPa.  Hence, plain round bar, grade 250, was dropped from BS 4449 (its use in structural applications was in severe decline anyway: it is generally more expensive and there is no longer any advantage in bending radii in links etc). 

BS 4449:2005 uses the term 'bar' for ribbed reinforcing steel. The terms 'rod' and 'wire' should be restricted to describe reinforcing steel in coil, or wire in reinforced concrete products.

BS 4482: 2005 Steel wire for the reinforcement of concrete products - Specification

This standard incorporates plain, indented and ribbed wire, coiled or decoiled. Grade 250 has been incorporated. The characteristic strength of the high yield steel has been set at 500 MPa and the ductility aligned with B500A in BS 4449:2005, but no fatigue performance is specified. 

Most wire to BS 4482 is unlikely to comply with BS EN 1992-1-1. To avoid any confusion, any design to BS EN 1992-1-1:2004 should have reinforcement specified to BS 4449:2005. Similarly any fabric used for structural purposes should be manufactured to BS 4483 using material specified to BS 4449:2005.

BS 4483: 2005 Steel fabric for the reinforcement of concrete - Specification

Apart from wrapping fabrics D49 and D98, fabric will be made from and evaluated as BS 4449:2005 material. A requirement for the strength of welded joints in BS EN 1992-1-1 has necessitated the withdrawal of A98 and B196 and has increased the diameter of transverse bars in some other designated fabric types.

BS 5896:2012 High tensile steel wire and strand for the prestressing of concrete.  

This standard provides the requirements for uncoated high tensile strength steel wire and strand for prestressing concrete.  It can be used while EN10138 standards are in preparation.

BS 8666: 2005 Specification for scheduling, dimensioning, bending and cutting of steel reinforcement for concrete

The 2005 revision of this code was produced in order to comply with the anticipated implementation of EN 10800, and this revision incorporates:

• Shape codes available under BS EN ISO 3766:2003. 
• Revised notation in accordance with BS4449:2005  and BS EN 10080:2005. 
• Revisions to BS4449:2005 (including the omission of grade 250 reinforcement), BS4482:2005 and BS4483:2005. 
• The provisions of EN 1992-1-1 (including the preclusion of wire to BS 4482:2005 for use for structural purposes).  
• Measurement of properties of decoiled material 
• Inspection frequencies of component dimensions. 

BS 7123: Specification for metal arc welding of steel for concrete reinforcement

This standard has been withdrawn and reference should be made to BS EN ISO 17660.