Annual inspection v structural appraisal – what is the difference?
The physical integrity of a sports ground is key throughout its lifespan. To help maintain this, the Guide to Safety at Sports Grounds (Green Guide) recommends the following:
- A detailed, annual inspection of all structures, installations and components (Section 5.12 of the Green Guide).
- A detailed structural appraisal carried out at regular intervals (every six to ten years) (Section 5.13 of the Green Guide).
As there is often confusion between what constitutes an annual inspection and what is involved in a structural appraisal, the below sets out to explain the differences.
In essence, an annual inspection is a more straight forward visual, non-intrusive inspection of all structures, installations and components in the ground. Whereas a structural appraisal is a more detailed and often intrusive inspection which may include comprehensive review and testing of structural elements.
Annual inspections are a critical way of identifying and addressing potential structural issues before they become a problem. They must be carried out by competent persons with the appropriate qualifications and experience. This should be a person who meets with the definition of competence as set out in the Green Guide and may include in this case a chartered building engineer, surveyor or a structural engineer.
Prior to the start of the annual inspection, the competent person should obtain a set of the sports ground’s structural layout plans, where available. This allows the engineer or surveyor to:
- understand the structural configuration and layout of the sports ground;
- identify critical areas for inspection;
- identify the allowable imposed loads, in order to assess the usage and possibility of overloading; and
- verify if unauthorised addition or alteration works that affect the structure of the building have been carried out.
It should be noted that in the case of sports grounds that do not possess original architectural drawings, the annual inspection may still be carried out but clearly due diligence should be undertaken by the competent person in the assessment and reporting of all elements of the inspection. In these cases the interpreting of the report will be greatly enhanced by photographic evidence, where appropriate.
During the inspection the competent person is expected to carry out, as a minimum, a visual inspection of:
- the condition of the structure of the sports ground, to identify any obvious structural defects such as signs of structural distress and deformation or material deterioration.
- whether loading on the various structural elements is as was originally intended and that no unauthorised adaptations have occurred which could impact upon the design loading of the elements.
If there are no signs of any structural deterioration or defects, the visual inspection should suffice and unless the competent person otherwise advises, no further action needs to be taken.
If, on the other hand, signs of significant structural deterioration or defects are present, the competent person should make a professional assessment of the deterioration or defect and recommend appropriate actions to be taken. Such actions may involve repair works or full structural investigation/analysis to parts or whole of the sports ground.
A documented report should be compiled on any defects identified and include a rating of urgency for the responsible person at the venue to develop a scheduled programme of repair to address the recommendations of the report.
A structural appraisal is a more detailed and rigorous test of the sports ground, conducted every six to ten years, as recommended by the Standing Committee for Structural Safety (SCOSS) and must be carried out by a competent Chartered Engineer (as outlined in Section 5.13 of the Green Guide).
The structural appraisal would be greatly assisted by the availability of full detailed drawings of the sports ground but, as described above, in the case of older sports grounds which may not benefit from such drawings the structural appraisal may still be carried out but clearly due diligence should be undertaken by the competent person in the assessment and reporting of all elements of the inspection. In these cases the interpreting of the report will be greatly enhanced by photographic evidence where appropriate.
The scope of the full structural appraisal includes:
- obtaining information relating to the design, construction, maintenance and history of the building;
- assessing the structural adequacy of the ground by checking the structural plans and calculations and reconstructing the structural plans if they are not available;
- carrying out tests on the materials used and structural elements of the ground;
- carrying out load tests on parts of the building as necessary;
- recommending appropriate safety precautionary and remedial measures to restore the structural stability and integrity of the structure.
Criteria for detailed structural appraisal should take account of:
- load factors used in the original design
- the degree of redundancy present
- the risk of disproportionate collapse
- the consequence of failure
- the requirements of the certifying authority, where appropriate.
Unlike the visual and non-intrusive annual inspection, the structural appraisal should provide detailed evidence of the continuing satisfactory performance of the existing structural components and expected life cycle of the structural elements under examination.
For example, where the visual annual inspection may identify that steelwork is rusting, the structural appraisal would require remedial action such as the wire brushing or sand blasting of steelwork to appreciate the amount of delamination the rust has caused and whether the amount of remaining steel section would support the combination of required loading (i.e. dead load, imposed load, wind load).
Another example would be, where the visual annual inspection may identify a crack in a wall, the structural appraisal would require further investigation such as holes bored in the wall for endoscopes or video cameras to check for the potential cause of the cracking.
Every structural appraisal should conclude with a report setting out the brief, details of the inspection carried out, the detailed and evidenced findings, conclusions and any recommendations arising which should be set against a time period for attention.
The recommendations from this report must be actioned by the sports ground within appropriate timescales identified in the report.