HS2’s Delta Junction, located north-east of Birmingham, represents one of the most intricate and concentrated areas of construction on the high-speed rail network. It’s being delivered by Balfour Beatty VINCI (BBV), HS2’s construction partner in the Midlands. Within this triangular section of the route, BBV is constructing a complex series of individual structures, including the Birmingham Spur Dive-Under, a 400m long concrete box structure designed to allow one railway line to pass under another instead of crossing at the same level.
The primary engineering challenge lies in the structure's scale. The main walls of the Dive-under stand at 11m tall, a considerable height that places increased pressure on the formwork system during the concrete pour.
To solve this, BBV is using PERI VARIO Girder Wall formwork. Unlike standard pre-built panel systems, VARIO is assembled from individual steel walers, timber girders, and a plywood face. This component-based approach allows for a tailored and strengthened shutter design.
Formwork, scaffolding, and construction accessories
The integrated approach extends beyond the formwork itself. Access platforms required for reinforcement steel fixing on the tall walls isprovided by PERI UP Flex Modular Scaffolding and the designs for the formwork and the access scaffold were coordinated between PERI’s internal engineering teams before delivery to site, ensuring a clash-free solution.
"One of the benefits for the customer is that they're not having to go to three different suppliers for accessories, scaffolding, and formwork," Biggs notes. "Internally, our teams can coordinate with one another to make sure one system doesn't clash with the other. That’s another advantage."
This is further demonstrated in the construction of the large base slabs. Here, in areas of congested reinforcement where traditional timber-based methods would be difficult and time-consuming, the team is using the BECOSTOP permanent stop end system. The steel mesh holds the concrete during the pour but is left in situ.
More than a supplier
The decision to partner with a specialist supplier for this integrated package stems from a long-term relationship established several years ago.
"I think it's a combination of factors," Biggs states when asked how PERI secured a collaboration with BBV. "It's PERI's capability to deliver big projects, whether that's from a service point of view, the ability to deal with large volumes, the range of systems we've got, or the quality and familiarity of the equipment. We've also appointed a full team of engineers and a project manager to ensure the delivery goes smoothly. It’s all about providing a complete solution."
As work continues on the dive-under, the project stands as a clear case study in how a coordinated, single-source solution partner for formwork, access, and engineering design can effectively de-risk and streamline construction on the most complex of civil engineering schemes.
