Trial panels as bench marks
An essential part of the preconstruction programme of any contract involving visual concrete should be the building of a large sample or full-size mock-up of a section of the structure.
Ideally, the sample should be built on site by the contractor. It may be used to verify the construction methods, the suitability of the reinforcement detailing, the formwork, the concrete, and any awkward junctions or features which could possibly give rise to problems. It should include a horizontal and a vertical construction joint.
The construction sample will be a test of the designer’s foresight as well as of the contractor’s ability. It is therefore important for both parties to appreciate the need for full cooperation well in advance. As the main purpose of the sample is to ‘uncover any unexpected difficulties’ which may arise in construction, it should be built as early as possible in order to allow for revisions. The sample must be specified and included in the bill of quantities.