23 March 2022
The Rehabilitation of Side Path Road Project has experienced significant delays. One of the critical success factors was the design life of the road to be 20 years. This was predicated on the assumption that materials that can be produced locally would be readily available on-Island and of the appropriate quality to construct a flexible road pavement (a bituminous carriageway).
Over the last few months we have been working with the Contractor and quarry owners on supplying the correct grading of aggregate required for the road base in accordance with the specifications. As we progressed into Contract 3, which involves the laying of the road base, no material has yet been produced that complies with the road base specification. The quality of the road base is a key component in achieving the required performance (and design life) for the road.
All construction contracts under the Economic Development Investment Programme (EDIP) include construction site trials to establish if proposed materials, plant, equipment and workmanship, are fit for purpose and capable of producing the quality of work required in accordance with all aspects of the specification and programme.
Progress of the site trials has proven what is working and what isn’t. With the completion of additional sieve analysis and quality checks the supply of appropriate and specified materials is unlikely to be achieved due to:
- The current road base production is not to the required specification (insufficient fines in the crushed aggregate grading)
- The stone chippings for the surface dressing layers (6mm and 10mm chippings) have not yet been produced to the required specification
- Damage to the historic walls (a significant collapse) has occurred above the Brow, due to the construction plant required and used (particularly the vibrating roller) but also the grader and the pneumatic tyred roller
- Lack of foundations for most of the length of the historic wall along Side Path Road (as is now visible following excavation and disposal of the existing road material) makes further significant damage to the historic walls highly likely
- Site trials to select the type of bitumen emulsion to be used for the surface dressing layers and site trials of surface dressing and slurry seal operations cannot be undertaken until acceptable road base material and stone chippings can be produced.
If the above issues are not addressed, and we continue to proceed with a bituminous road construction, we will be faced with the following issues:
- The 20-year design life will be reduced
- The performance of the road pavement will be compromised, resulting in premature deformation (cracking and rutting) leading to premature potholing of the carriageway
- There will be a shorter period to the first maintenance intervention, and higher maintenance costs generally
- There will be significant health and safety risks for the site workforce during construction as well as people and properties below Side Path Road
- There will be significant risk of widespread damage to historical assets.
With immediate effect, no further construction works are being undertaken on Side Path Road until repairs to the historic wall above the Brow is completed, and until satisfactory site trials have been undertaken. No works can proceed until the road base can be produced to the satisfaction of the Engineer.
Given the above issues Side Path Road will remain closed for the foreseeable future.
St Helena Government will be discussing possible options early next week and the public will be informed accordingly. One of the options being considered is constructing a concrete road instead of a bituminous road.
#StHelena #SidePathRoad #EDIP
23 March 2022