Three adjoining, Grade II listed gasholders are being re-erected at a new location in King’s Cross.
The 60m diameter gas holders form the basis of a new residential development and when finished will have a block of flats within each ring. They differ from other holders as they are grouped together and are structurally linked by a 12 column “core” at the centre.
The three storey, 34m high structures were first erected in 1860 but were taken down in 2001 and then refurbished over a two-year period by Shepley Engineering.
Bourne Construction Engineering is now re-erecting the 123 columns – 41 per level. Due to their potentially brittle nature, the columns are transferred from horizontal to vertical using a bespoke element called a “rocket launcher”. The first level has been erected and work on the second level is currently underway.
Bourne Construction Engineering contracts manager Colin Hillier-Daines said that the team faced some interesting challenges when designing the erection process to connect the columns. “When first erected in 1860, small children were sent up inside the column to bolt-up the various connections, obviously HSE dictates we can no longer do this,” he said. “So in usual engineering style, we started with a plywood mock-up to figure out how to overcome this.
“Various tools were developed to hold and locate the bolts during erection.”
To ensure that the columns can withstand the lifting process, each column is load tested using a specially installed “lifting collar” and then “hanging weight” tested, prior to installation.