EIR/202600506384 · FOI/EIR · partially withheld
Transport Scotland - M8 woodside viaduct works queries: EIR release
Information requested
The following information on the woodside viaduct works:
1. How much this has cost.
2. How late has the work run over from original work date stated.
3. When it will be finished (actual date) please.
4. How much all the extra work has cost from the original project price.
5. And why the overrun of works (please be accurate) I mean the course of all the extra time and money.
Response
As the information you have requested is 'environmental information' for the purposes of the Environmental Information (Scotland) Regulations 2004 (EIRs), we are required to deal with your request under those Regulations. We are applying the exemption at section 39(2) of the Freedom of Information (Scotland) Act 2002 (FOISA), so that we do not also have to deal with your request under FOISA.
This exemption is subject to the 'public interest test'. Therefore, taking account of all the circumstances of this case, we have considered if the public interest in disclosing the information outweighs the public interest in applying the exemption. We have found that, on balance, the public interest lies in favour of upholding the exemption, because there is no public interest in dealing with the same request under two different regimes. This is essentially a technical point and has no material effect on the outcome of your request.
To aid my response I have answered your questions in the order you requested.
Q1. How much this has cost.
A1. To date the project cost stands at £125 million. A cost range of £126 - £152 million for completion of the temporary propping was announced in May 2024.
Q2. How late has the work run over from original work date stated.
A2. In March 2021, the works were projected to complete in late 2023, making them up to 4 years late based on the revised programme dates announced in August 2025 of completion in the second half of 2027. However, it should be noted that the dates announced in 2021 represent the project’s anticipated timelines at that time, based on limited information, and did not reflect the huge scale of the project now underway.
Q3. When it will be finished (actual date) please.
A3. It is not possible to give a precise date as there are many factors influencing completion of a complex construction project. The activities required for completion are programmed with anticipated durations for each activity. A risk analysis is then performed with completion dates calculated for various scenarios. This gives a range of dates with the earliest based on a very optimistic scenario and the latest based on the most pessimistic scenario. From this information, and past experience, judgement is used to select the most likely range of completion dates. Based on this, the current expected completion date for the temporary propping works on the eastbound carriageway, allowing all eastbound lanes to reopen, is in the Autumn of 2026 and the latter half of 2027 for the westbound carriageway.
To stay up to date with the projects progress please refer to these links - Amey website - SW Trunk Roads - and the Transport Scotland FAQs, with announcements made on the Transport Scotland website - News | Transport Scotland
Q4. How much all the extra work has cost from the original project price.
A4. Due to the urgent nature of the works, the original price was based on limited information. It is therefore not directly comparable with the complex works that are actually required. The original estimate of £33.6 million, confirmed in a previous EIR in September 2021, only allowed for steel props on the existing foundations of the viaducts. The currently estimated costs, including extensive groundworks and utility diversions, are within a range of £126 - £152 million. The early estimate also excluded risk allowances and other commercial costing mechanisms such as Optimism Bias, which are included in the current projections.
Q5. And why the overrun of works (please be accurate) I mean the course of all the extra time and money.
A5. As described above the early estimates were based on simply installing steel props under the bridge, resting on existing foundations. As the investigation and design work progressed, it became clear that the majority of the foundations were not suited for this purpose and extensive groundworks, including piling, was required to extend existing foundations, and others had to be strengthened.
A consequential impact of this was that many buried services had to be diverted, which is an expensive and lengthy process determined by the utility owner. Other services required expensive protective measures.
Ultimately each support location has required a bespoke design, taking all constraints into consideration, rather than a standard design for each location. This significantly increases design time and also has an impact on construction time and costs.
Detailed consultation and tunnel impact assessments were also required in relation to piling works near the subway tunnels which run under the western end of the viaducts, to ensure these were not damaged by the works. This was completed before piling commenced near the tunnels and ground vibration monitoring was installed to protect the tunnels. However, an existing sewer, adjacent to the subway tunnels, was found to be in a different location than expected. The impact of this is that the sewer has to be diverted, a major operation in itself but complicated by its proximity to the subway tunnels.
Further detailed consultation and tunnel impact assessment is required for this, in addition to an enhanced ground monitoring system.
There have been other smaller impacts related to consistent supply of materials and fabrication of steelwork, as well as availability of specialist contractors but the issues described above have had the greatest impact.
About FOI
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Contact Please quote the FOI reference Central Correspondence Unit Email: contactus@gov.scot Phone: 0300 244 4000 The Scottish Government St Andrew's House Regent Road Edinburgh EH1 3DG
Detected exemption language
We are applying the exemption at section 39(2) of the Freedom of Information (Scotland) Act 2002 (FOISA), so that we do not also have to deal with your request under FOISA. This exemption is subject to the 'public interest test'. Therefore, taking account of all the circumstances of this case, we have considered if the public interest in disclosing the information outweighs the public interest in applying the exemption. We have found that, on balance, the public interest lies in favour of upholding the exemption, because there is no public interest in dealing with the same request under two different regimes.
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