Purpose : For Decision
Date: 10 SEPTEMBER 2002
Title: MILITARY ROAD – STABILISATION OF AFTON DOWN AND THE REALIGNMENT OF CARRIAGEWAY AT SHIPPARDS CHINE
To inform members of the current situation of progress with the stabilisation of Afton Down and the realignment of Shippards Chine, Military Road.
Members will be aware that following a lengthy process of negotiations with English Nature, The National Trust and a subsequent planning process, approval was granted in principle for the stabilisation of Afton Down and the realignment of carriageway at Shippards Chine. A design was prepared by the Councils consultant, High Point Rendel and tenders invited for the works to be returned in September 2001. Tenders were submitted by Keller Ground Engineering and AMEC Capital Projects Ltd. in the sum of £4,001,793.73 and £4,957,767.47 respectively. The Council had received an award from GOSE in the sum of £2,000,000 to secure this project.
The consultant’s estimate prior to tender stage was in the sum of £2,500,000. Following the receipt of tenders, a meeting was held with officers of High Point Rendel and both contractors to discuss possible ways forward. Both contractors put forward their proposals which would endeavour to reduce the cost of the works.
Of the two, AMEC proved to be more favourable and stated that an element of their tender covered the risk of undertaking the works in this location. It was decided that AMEC was the preferred contractor and subsequent negotiations with them followed with regard to their proposals. They suggested that a trial be undertaken at Afton Down to assess the suitability of the ground with regard to a piling operation and to ascertain the amount of voids that exist in the chalk. In addition, it was proposed that tests would be undertaken on a method of ground anchorage. This trial was undertaken between the 30 April and the 31 May 2002 and proved very successful. Based upon the results of this trial, AMEC prepared a report detailing their findings. A subsequent meeting was held with officers, High Point Rendel and AMEC on the 31 July 2002 where AMEC’s proposals were discussed.
Based on these trials, our consultants are now proposing an alternative design which would enable the works to be undertaken in a more efficient and cost effective way and which would reduce the budget figure for the works at Afton Down to some £2,300,000, plus £600,000 for the carriageway realignment at Shippards Chine. However, this estimate does not include for a number of possible risk items which are currently under discussions with AMEC. It is probable that any costs arising from these as yet unquantified risks could be accommodated on a shared basis.
Clearly the trials already completed at Afton Down have allowed our consultants to make a robust assessment of the likely risks in carrying out these works but we are still in discussions with the contractor to try to clarify the impact of any additional risks on the final costs of the works.
Our consultants have also advised that considerable savings could be made with regard to the proposed realignment of the Military Rd at Shippards Chine if these works were carried out by as part of a separate contract that did not require the specialist equipment and specialist techniques required for the works at Afton Down.
It is therefore intended to progress to these works as a separate contract probably as an early part of the 2003 to 2004 Capital Programme.
High Point Rendel are currently undertaking a re-design of the scheme at Afton Down which includes the proposals as put forward by AMEC and these are to be completed by the end of August. As part of the planning consent, there is a requirement that these works must be decommissioned after 50 years and AMEC are giving consideration to their proposals for this.
It is anticipated that the final design of these works can be completed and accepted during week ending 8 September and that a further verbal report can be made to the Executive on 10 September on the progress of the design and costs implications of the agreed design
In order to reduce the potential risks it is imperative that the stabilisation element of these works is carried out under the most favourable ground conditions which are likely to be at the end of the summer and before any prolonged periods of high rainfall and It is most desirable for the works to be started as soon as possible say at the end of September or as soon as practically possible.
From the original budget of £2,000,000 design costs and the costs of the extensive grouting and stablisation costs so far undertaken reduce the remaining 2002 to 2003 capital budget provision for the works to some £1,775,000 leaving a budget shortfall of some £1,225,000. This consists of £625,000 shortfall on the stabilisation works plus £600,000 for the carriageway realignment at Shippards Chine. As mentioned above, it is also possible that there could be additional costs for items of risk.
The works are expected to be carried out over the period October 2002 to March 2003 and it is considered that additional funding for the works programmed and certainly the final payment for the works will not be required until 2003 /2004.
It is suggested that the £1,225,000 shortfall be first call from the 2003/2004 Capital Budget.
Contact point: Mr Nick Gallin, Senior Maintenance Engineer - ☎ 823777
M J A FISHER
Corporate and Environment Services
Portfolio Holder for Transport