Gas holders are obsolete features of town and city landscapes across the UK.
Whilst a few have been saved or repurposed the majority have either been demolished or are scheduled to be demolished. Nearly 200 of these icons of British industry have been earmarked for demolition since 2013.
Andun have been completed a number of demolition engineering projects on gas holders from London to Liverpool.
These have included a range of different gas holder designs including MAN, spiral guided, column guided, above ground, below ground and Wiggins.
Common Gas Holder Demolition Engineering Challenges
Due to their location in urban environments there can be a number of demolition engineering challenges to mitigate prior to demolition.
These can include access constraints, latent defects and the proximity of the gas holder to live rail environments or high pressure gas pipelines.
Outlined below are two demolition engineering case studies from gas holders Andun have worked on in recent years.
Wiggins Gas Holder Demolition Oxted
This project involved crane positioning, finite element analysis (FEA) and demolition engineering for the demolition of a Wiggins type gas holder, positioned adjacent to the main Victoria railway line.
The proposed scheme required the design of crane positions for a LTM 1100 (100Te) crane to allow the removal of the roof in sections by a man in basket. Consultation with network rail was required due to the proximity with the rail line to London Victoria.
The demolition commenced with the removal of the roof sections, the sections were cut and dropped within the remaining structure.
The back section of the structure was initially inaccessible using the proposed crane position so the cutting sequence had to be carefully planned to allow the front of the structure to be reduced in height to get the boom of the crane into place to reach the rear of the holder.
This sequencing had to be thoroughly assessed during the FEA analysis.
The roof trusses were then sequenced to be cut and dropped to ensure a gradual and controlled demolition/drop into the centre of the remaining structure.
Southall MAN Gas Holder Demolition
MAN gasholder demolition on a site located next to a long term Heathrow parking site, the Great Western Main Line and surrounded by high pressure gas mains.
MAN (Maschinenfabrik Augsburg Nürnberg) are a type of gas holder that utilises a piston that controls the pressure and floats above the gas.
Andun provided the following on the project
- Demolition engineering sequence
- Temporary bridge design for heavy plant access over high pressure gas mains
- Crane rail design
- Crane design
The demolition was carried out with custom cranes (previously designed by Andun) running on a series of crane rails. The crane rails span from node to node on the holder roof. The crane rails were an engineering exercise as they had to be man handleable, yet strong enough for the span, and carry the loads from the crane.
The cranes work around the structure sequentially removing panels, which are lowered directly to ground level..
Once the structure is reduced in height to around 40m the works are completed using high reach excavators for speed.