Gilbert-Ash Constructs Mayhew Theatre at the UK Foreign & Commonwealth Office

Author: Christopher Dollard

Gilbert-Ash is an award-winning UK construction firm that’s completed high-profile and prestigious construction projects, ranging from hotels and offices to foreign embassies and consulates, in 40 countries over the course of 30 years. With offices in London and Belfast, they are often contracted by the UK Foreign & Commonwealth Office due to their expertise and high-quality construction. They recently constructed the Diplomatic Teaching Academy in the Foreign & Commonwealth Office in London, officially opened by Prince William.

The Diplomatic Teaching Academy, formally named as the Mayhew Theatre after Cecily Mayhew, the first female diplomat from Britain, is a parabolic glass, steel, and wood structure that had to be built in the courtyard of the UK Foreign & Commonwealth Office in London - meaning that the steel superstructure needed to be lifted by crane into the courtyard located 90 meters away from road access and with only five metres of clearance on any side, which is quite a delicate operation.

For this project, Gilbert-Ash needed to operate within tight and sensitive spaces. They also had to complete an intricate and highly modern building with very strict geometrical design specifications. Fortunately, they invested in the Leica BLK360 imaging laser scanner, a crucial piece of technology that helped them achieve success with the Mayhew Theatre, which won a 2019 Construction Excellence Award.

Advanced Technology Required for Complex, High-Profile Construction

Gilbert-Ash, as indicated by their successful record, has always been up to the challenges of high-profile construction work. However, the Mayhew Theatre design and construction process required advanced technology due to the complex challenges noted above.

“The superstructure of the building was a cantilevered hyperbolic paraboloid top ring beam with a zinc roof - which was referred to as the Pringle due to its shape - and within the building you had an elliptic paraboloid cedar slat ceiling,” said Paul McGeachy, Design Manager at Gilbert-Ash. For non-architects, that highly geometric language indicates that this is a complicated structure to build.

And yes, Pringles are hyperbolic paraboloid-shaped potato chips. To gain a sense for how complicated a “hyperbolic paraboloid” is, the New York Times published an article about supercomputers and mentioned Pringles, specifically how they are engineered: “Procter & Gamble even uses supercomputers to make sure that Pringles go into cans without breaking.”

Clearly, the Mayhew Theatre is a complex structure that required impeccable precision at every stage of design and construction, and the hyperbolic paraboloid zinc roof, not unlike a Pringle fitting into a can, needed to fit into the courtyard without damage to the Foreign & Commonwealth Office, a Grade 1 Listed Heritage building. If Pringles require supercomputers to fit into cans, then Gilbert-Ash certainly required a BLK360 to build the Mayhew Theatre successfully.

You can even view a detailed description and diagram of how the theatre was constructed in Construction Manager Magazine here.

Gilbert-Ash Invests in Leica BLK360 to Create 3D Models

At the start of the project, McGeachy and Graeme Gourley, Senior Estimator, realized that they needed to have extremely precise measurements of their construction plans for the theatre. They had already had some experience with digital construction and reality capture tools, but McGeachy came across the BLK360 and thought it might be the right fit for their portfolio of technology.

“I was at a digital construction fair, checking out the different stalls, and I came across the Leica stand. A spokesman talked me through it and gave me a demonstration,” said McGeachy. “At that point, it was easy to identify that this would be a good addition to our digital construction tools.”

However, because of the space constraints of the job site, the complicated design, and work with subcontractors, it wasn’t possible to simply start work there and adapt the design as work progresses. Instead, Gilbert-Ash decided to start building the steel superstructure off-site in order to determine on-site dimensions.

“Everything had to be meticulously thought out off-site by using digital construction methods,”
said Gourley. “We pre-erected the theatre to determine the size of the glass before it was manufactured and sent to site.”

“For us to set-out dimensions on site, the only way we could see to do that was to capture it in 3D,” said McGeachy. They then used the BLK360 to scan the superstructure and determine precise dimensions, which they could then use to order other materials, like glass and wood components. The accurate point cloud data captured by the BLK360 enabled Gourley’s team to begin their entire design process with precision that helped ensure accuracy during every step of construction.

“We’re one of the first people in Northern Ireland to invest in the Leica BLK360. We use that to capture our 3D point cloud data,” said McGeachy. “With the 3D models we had developed, we could easily identify clashes between all three disciplines and hold workshops with sub-contractors to develop methods for changes to the design.”

Design and Construction Workflow for a Hyperbolic Paraboloid

After capturing the superstructure, McGeachy used several workflows to process the data and create 3D models with Autodesk Revit, ReCap Pro & Mobile, and Navisworks. He was then able to develop the existing Revit model and dimensioned AutoCAD drawings, and the steel subcontractor was able to successfully design the steel structure, framing, and connections using Tekla Structures software.

“You’ve got these very complex geometric shapes, and it makes it even more complicated when they’re relying on and interacting with each other in this design,” said McGeachy. Because of the variety of materials and shapes in the theatre’s design, Gilbert-Ash relied on essential data from the BLK360 to inform all 3D modelling needed to ensure successful completion of the Mayhew Theatre.

“The Leica BLK360 has basically transformed the way we complete our projects, and it’s made a huge difference to us, especially with the coordination of subcontractors,” said Gourley. “Design clashes can be identified earlier, and the client can get a better sense of what they’re getting earlier on in the project."

With such a complicated structure being built for such a prominent location, purpose, and client, the BLK360 helped Gilbert-Ash to continue their successful relationship and award-winning work with the UK Foreign & Commonwealth Office. We look forward to seeing how Gilbert-Ash incorporates 3D laser scanning into their future projects.