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Grimshaw designs barn-like vents for HS2 tunnel


Grimshaw has revealed its designs for a new barn-like vent shaft serving HS2’s proposed 10 mile-long Chiltern tunnel

The single-storey, zinc-clad building at Chalfont St Peter is the first of four similar head house structures, which will provide ventilation and emergency access to the high-speed rail line’s twin tunnels 60m below.

The project has been drawn up by HS2’s main works contractor, the Align joint venture team, which is made up of contractors Bouygues Travaux Publics, Sir Robert McAlpine, VolkerFitzpatrick, design giant Jacobs, engineers and project managers Ingerop-Rendel, landscape architect LDA, and Grimshaw.

According to the consortium, the structure ’takes its inspiration from the style of local barns and other agricultural buildings’ and its ’pre-weathered grey zinc roof will age naturally over time, without loss of robustness or quality, while the whole structure will sit on a simple dark-blue brick base’.

Diane Metcalfe, associate principal at Grimshaw, said the scheme had been ’sensitively designed to complement the rural character of the Chilterns’.

She added: ’The position and orientation of the head house buildings are located to conceal them within the landscape and form a courtyard similar to local farmyard arrangements.

’The pitched roof, zinc-clad buildings are a modern interpretation of the local agricultural and industrial vernacular. Design proposals are a result of close and collaborative engagement with the Area of Outstanding Natural Beauty review group.’

July 2020 chalfont st peter 3d pdf ventilation shaft grimshaw

July 2020 chalfont st peter 3d pdf ventilation shaft grimshaw

The project includes bird boxes, reptile basking banks, a grass snake laying heap and a hibernaculum, while material excavated from the shaft will be used to create most of the landscaping to avoid putting extra lorries onto local roads.

HS2 project client director Rohan Perin said: ’Once construction is complete, the head house at Chalfont St Peter will be one of very few structures of the Chiltern tunnel that will be visible to residents living nearby. That’s why it’s critical that we get the design right.’

The plans for the head house went on public display yesterday today (23 July) through a month-long virtual engagement event.

Elsewhere on the £106 billion HS2 rail link, Grimshaw continues to work on plans for Euston Station and the Curzon Street terminus in central Birmingham.


Project data

Location – Chalfont St Peter
Local authority – Buckinghamshire Council
Type of project – High Speed Rail
Client – HS2
Architect – Align D (Grimshaw)
Landscape architect – Align D (LDA)
Planning consultant - Align D
Structural engineer - Align D
M&E consultant - Align D
Quantity surveyor - Align
CDM adviser - Align D
Lighting consultant - Align D
Main contractor - Align
Funding – HM Government, as part of the HS2 project
Tender date – C1 MWCC contract awarded July 2017
Start on site date – below ground works 2020, headhouse 2023
Completion date - 2024
Contract duration - To be confirmed
Gross internal floor area – approx. 450m2
Form of contract and/or procurement - NCE
Annual CO2 emissions - To be confirmed
Total cost – not available for headhouse


Readers' comments (3)

  • Apart from the head houses themselves (agricultural in form but seemingly not in detail or 'cost engineering' terms) the function of the other bits and pieces in the compounds is unclear, given the poor quality of the drawing.
    To be really critical, could not standard open vented cattle shed design have been taken for the external shell enclosing the vent / access / escape shaft, with security provided internally?
    The whole HS2 project is open to criticism for cost increases that fuel attempts to stop it dead in its tracks, and these proposals can surely be questioned for not using a real low cost agricultural building to encase the specialist superstructure of the head shaft.

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  • all that effort into the design and they still have to put an ugly fence around it... surely that could of been designed out

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  • Industry Professional

    It needs a Ha - Ha!
    Not a funny ha ha but the landscape kind

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