This week’s blog is a little different to the norm. We invited an experienced structural engineer and member of SER’s Scottish Registration Board to provide some guidance on Typical Reinforcement Details, with a strong emphasis on what constitutes typical.
Typical reinforcement details
The Building (Procedure) Scotland Regulations 2004 require that an application for a building warrant must be accompanied by plans of sufficient detail for the Verifier to satisfy themselves that the work will comply with the Building Regulations, and must provide enough information to assist any site inspections that the Verifier wishes to make.
The Regulations also make clear that the Verifier has discretion over the extent to which information must be provided.
In order to provide further guidance on this matter BSD (in conjunction with SER and the Scottish Association of Building Standards Managers) produced two checklists within Annex A of their publication Procedural Guidance on Certification (including information to be submitted with a Building Warrant Application). The checklists are designed ‘to be used by applicants and their agents to check that the correct information has been assembled prior to the submission of the warrant application’. Both checklists show that typical reinforcement details crop up under a number of headings.
The purpose of this blog is to clarify what SER would interpret as being sufficient typical reinforcement information.
In putting together this blog, SER have noted that BSD also stated in Annex A that “details of construction including any frame and size and position of reinforcing material” must appear on the warrant plans.
Drawing information requirements
The size and position of reinforcement bars are critical to the structural performance of reinforced concrete members, and are generally determined as part of the normal design calculation process.
As such it is essential that the drawings provided as part of the warrant application replicate this information in a form that the Verifier can check. This would typically be as follows:
Beam and Columns
A cross section showing the main reinforcement and link bar arrangement for each size of section. Where reinforcement varies along the length of a member, more than one section may be necessary, such as the case for a beam with hogging forces.
Floor Slabs
A plan or section noting the spacing and sizes of bars on each face for each slab type or alternatively a note of the mesh type where this is used.
Retaining Walls
A cross section showing the spacing and position of bars in each face and the arrangement of steel at the stem and foundation junction at the base of the wall where continuity is often required.
Foundations
A typical cross section showing main reinforcement and link bar arrangements for each foundation type, or alternatively the mesh type and location.
Pile Caps
A cross section showing the main reinforcement, link bar arrangement and the position of any pile reinforcement projecting into the foundation for each pile cap type.
Tables and Schedules
Where section sizes are straight forward or repetitive, it can sometimes be beneficial to summarise the reinforcement requirements described above on a table or schedule added to the drawing. Provided that the table or schedule are accompanied by adequately notated plans, so that there is no ambiguity to the someone inspecting the works as to the size and position of reinforcement at any location, this would be an acceptable form of information.
Please note: The provision of reinforcement schedules such as the type normally produced for fabrication purposes are NOT required to comply with the above. Similarly detailed dimensioned reinforcement plans showing the actual location of curtailed reinforcement are not necessary for this purpose provided that the following information is included on the plans.
Further information
In all cases above the following additional information would be expected to be noted on the reinforcement drawings:
- Nominal cover requirements
- Grade and type of reinforcement or mesh type
- Minimum lap lengths for each size of bar or mesh type.
Audit rules
Under the current auditing rules, the following items would incur an Improvement Issue (1 point) due to the lack of reinforcement details:
B4.2 Substructure (including ground floor slab but excluding piling)
Deficiencies in the building warrant plans e.g. failure to identify foundation locations, dimensions, changes of level, material specification and typical reinforcement details.
B4.4 Earth Retaining Structures
Deficiencies in the building warrant plans e.g. failure to identify layout, level changes, dimensions, construction and typical reinforcement details.
B4.6 Superstructure – Principal load-bearing elements
Inadequate or insufficient details on the building warrant plans.
B4.8 Superstructure – Other elements
Inadequate or insufficient details on the building warrant plans.
We hope the information contained in this blog will be of assistance both during certification and at audit. This will be the first in a series of slightly more technical blogs written by SRB members over the coming months; if any of our members have any suggestions for future topics please let us know via [email protected] or @SER_Scotland.