Altrad RMD Kwikform complete complex formwork for HS2 Phase One

The company came across a number of challenges on the project (Photo: Altrad RMD Kwikform)

Altrad RMD Kwikform (ARMDK) recently engineered a complex formwork shutter for client Kilnbridge Construction Services Limited, to construct the Fixed Buttresses piers within tight cofferdam constraints on the Colne Valley Viaduct, being constructed by Align JV as part of HS2 Phase One.

The key formwork challenges on this project were the complex shape, reuse on 8.5m and 7.5m high piers, the required finish combining plain and textured surfaces and the limited access says Altrad RMD Kwikform.

ARMDK worked closely with their customer to provide a flexible solution that was efficient to use. It consisted of 79 unique quadrilateral panels ranging in weight from 82kg to 1550kg that were bolted together at the changes in direction of the pier.

The panels were designed as composite two-way spanning structures with folded horizontal channels and vertical flats. The completed structure utilised 20mm ties and hoop action to contain the significant concrete pressures. The vertical concrete loads from the arch were resisted by a specially designed support structure.

The company said that due to limited access and mechanical lifting options an innovative solution had to be developed to strike the equipment. ARMDK designed the support frame with special wedges which when struck lowered the frame onto integral wheels and allowed it to be rolled out leaving the panels held in place by the tie bars. A special full-width lifting beam, featuring a rotating circular tube was then used to lower the panels to the ground.

Andrew Jones, Chief Engineer at ARMDK, said, “The expertise of our engineers is highlighted with this project, they had to work to tight time constraints, delivering the extremely complex solution with many challenges in the process. This was a completely bespoke solution that showcases our complex formwork capabilities, and we are delighted with the end result.”