Silvertown Tunnel in depth

13/06/2019 |

Now that the winners of Transport for London's (TfL) £1bn Silvertown Tunnel project - procured through a Design, Build, Finance and Maintain contract - have been announcedHighways speaks to TfL to find out more about this flagship scheme.

1) The financial risk for construction and an initial maintenance period will sit with the private sector rather the public sector. How long does the consortium's 'initial maintenance period' last?

Once completed, the consortium will operate the tunnel for 25 years. Riverlinx will be incentivised to ensure that the tunnel is open and operating smoothly at the most busy periods. Under the terms of the agreement signed, TfL will only start paying for the tunnel once it is operational, limiting its financial exposure on this project. Responsibility for the tunnel will then pass to TfL after the 25 years.

2) Are you building a digital twin of the tunnel for future maintenance support?

TfL has set high level requirements in relation to asset and information management to encourage innovation and high standards of future maintenance. The details of how this is to be delivered are for the consortium to agree and develop. 

We would be happy to share more information this work once the Riverlinx team mobilises and begins this process later this year.

3) Are you using the heat generated from drilling to power anything? This was discussed for Crossrail but never happened in the end, we understand.

We are not intending to do this. Due to the large diameter and shallow depth of these tunnels under the river, and the nature of road traffic, the heat that might be generated from this project does not justify the investment required to install equipment to recover it.

4) What are you doing with the waste materials?

A comprehensive waste management plan will now be developed by Riverlinx to detail how waste will be managed through construction. We have set high level requirements on Riverlinx through the Project Agreement to ensure proper application of the waste hierarchy and mitigate the environmental impacts of construction. For example we will require that 100% of suitable excavated materials and at least 55% of all materials by weight will be transported by river.

5) Do you know what drilling machines will be used yet?

We expect that an Earth Pressure Balance (EPB) type Tunnel Boring Machine will be used to construct the main tunnel drives. The actual machines however will be procured by Riverlinx.

6) How many people will be involved in construction?

The exact details of the workforce will further detailed with Riverlinx through the next stages but we anticipate that at peak roughly 1,000 people will be involved in construction. We have committed to employing at least 25% of the workforce from the local community, as well as to creating apprenticeships and training opportunities.

7) What percentage of the cost allows for optimism bias?

The financial risk for construction and maintenance sits with Riverlinx; however we have worked closely with tenderers during the procurement process to ensure appropriate allowances have been made for risk and other factors.

8) To avoid the issues that Crossrail saw, will you be changing any of the ways information is passed between the consortium, TfL and the mayor, and then made public?

Riverlinx will be fully responsible for design, construction and maintenance and everything that is required to integrate the various sub-contracts they will establish to deliver the scheme. The financial risk for this also sits with Riverlinx who are not paid until the tunnel is open and meets out quality standards.

Despite this, we have set a number of requirements on Riverlinx to record and report information on construction performance. This will cover progress as well as environmental performance, community engagement and other related matters. As the Riverlinx team mobilise over the course of this year, we will be working closely with them to finalise the details of how we will report this information between Riverlinx, TfL, the mayor and the public.

9) What is the design life of the asset?

The tunnel has a design life of 120 years although certain equipment or elements of it will need to be replaced, renewed and maintained within that timeframe.

10) Is the tunnel being designed to support future connected or autonomous vehicles? If so in what way?

Although the technology/infrastructure that might be required to support this is still somewhat uncertain, we have made provision for ‘dark’ fibre cables and spare cable capacity to be installed throughout the tunnel to allow future installation during the maintenance period. This gives us flexibility to respond to future requirements as and when we might require them.

Highways InProfile

latest magazine issue
Highways jobs

Senior Transport Planner

£47,532 - £50,574
Royal Greenwich is a borough synonymous with first class modern services Greenwich, London (Greater)
Recruiter: Royal Borough of Greenwich

Technician - Highway Inspector

Grade 8 £28,797 - £30,708 per annum (Pay Award Pending)
Within the Highways Maintenance Team we are looking for an enthusiastic, customer focused and experienced person to join the Service Derbyshire
Recruiter: Derbyshire County Council

Waste Recycling Operative

£25,584 to £27,269, Grade 5
An opportunity exists in the Council’s Street Scene Services for a Waste Recycling Operative. Wakefield, West Yorkshire
Recruiter: Wakefield Council

Project Delivery Senior Team Leader

£74,480 - £85,964
Are you an experienced Chartered Civil Engineer (or equivalent professional qualification) Glasgow City
Recruiter: Transport Scotland

Assistant Traffic Management Technician - WMF2104e

£25,584 - £25,992
Westmorland and Furness Council is seeking an organised and enthusiastic individual to join our South Lakeland team Kendal, Cumbria
Recruiter: Westmorland and Furness Council

Bulky Operative

£25,584.00 - £27,269.00, Grade 5, 37 hours, Permanent.
An opportunity exists in the Council’s Street Scene Services for a Bulky Operative Wakefield, West Yorkshire
Recruiter: Wakefield Council

Project Delivery Team Leader

£57,710 - £71,842
Are you an experienced Chartered Civil Engineer (or equivalent professional qualification). Glasgow City
Recruiter: Transport Scotland

Traffic Management Officer - WMF2102e

£37,035 - £37,938
This is a key role supporting the delivery a wide range of traffic and road safety schemes. Kendal, Cumbria
Recruiter: Westmorland and Furness Council

Shared Service Manager (Waste) North Herts Council

£52000 - £61000 per annum
Shared Service Manager (Waste) North Herts CouncilNorth Herts CouncilPermanent, Full Time£52,866 - £61,866 per annum, plus car allowance (pay award pe England, Hertfordshire, Letchworth Garden City
Recruiter: Essex County Council

Street Scene Protection Officer - Braintree District Council

£30000 - £34000 per annum
Street Scene Protection Officer - Braintree District CouncilBraintree District CouncilPermanent, Full Time£30,313 to £34,612 per annumLocation
Recruiter: Essex County Council

Traffic Management Officer - WMF2102e

£37,035 - £37,938
This is a key role supporting the delivery a wide range of traffic and road safety schemes. Kendal, Cumbria
Recruiter: Westmorland and Furness Council

Assistant Traffic Management Technician - WMF2104e

£25,584 - £25,992
This is a key support role, helping to deliver a wide range of traffic and road safety schemes across South Lakeland. Kendal, Cumbria
Recruiter: Westmorland and Furness Council

Flood Risk Engineering and Strategy Officer

£49,764 - £55,623
In line with our One Coventry Values, we want to ensure that our communities are represented across our workforce Coventry, West Midlands
Recruiter: Coventry City Council

Senior Integrated Transport Officer

£34,324 - £37,529
Are you an experienced transport planning professional ready to influence strategic policy and drive real change Matlock, Derbyshire
Recruiter: Derbyshire County Council

Street Cleansing Operative

£25,584.00 to £27,269.00, Grade 5
An opportunity exists in the Council’s Street Scene Services for a Street Cleansing Operative Wakefield, West Yorkshire
Recruiter: Wakefield Council

Highways Gully Operative

£25,584.00 to £27,269.00, Grade 5
Are you a hard-working looking for career in highway maintenance? Wakefield, West Yorkshire
Recruiter: Wakefield Council

Roadworker Trainee LGV Driver (3 Posts)

Grade 6 £25,183 - £25,638 per annum (Pay award pending)
We’re looking for Roadworker/trainee LGV drivers to be part of our team undertaking major highway, bridge and related construction and reconstruction Derbyshire
Recruiter: Derbyshire County Council

Engineer

£44,430 - £51,663
This post is within the Highways Design and Delivery Team. London (Greater)
Recruiter: Tower Hamlets London Borough Council

Highways Policy and Procedures Officer - WMF3011e

£37,035 - £37,938
This is an exciting opportunity to support the Asset Manager in developing policies and procedures Cumbria / Various
Recruiter: Westmorland and Furness Council

Civil Enforcement Officer - WMF3013e

£27,711 -£28,624
Are you seeking an active and challenging role, part of a friendly and welcoming team? Cumbria / Various
Recruiter: Westmorland and Furness Council
SUBSCRIBE NOW

Latest Video

Subscribe to Highways today to ensure you keep your finger on the pulse of everything happening in the UK road network throughout the year.

SUBSCRIBE NOW