Engineering The Leadenhall Building

The Leadenhall building opened in mid-2014 and is one of the most iconic buildings here in London. At 225 metres tall it currently sits as the 4th tallest building in London, however, this list seems to be changing on a daily basis! It’s known as ‘The Cheesegrater’ because of its sloped facade, we’ll get into why it’s sloped later.

Here at Yuanda, we’re extremely proud to have played a part in the Leadenhall Building. There were a number of engineering challenges that needed to be overcome on its facade, so today I sat down with Brian Quinn (Yuanda Engineer) to run through some of the complexities on this project.

Leadenhall Building Design

Firstly, let’s take a look at the designers and the project team that came up with this unique design. The Leadenhall Building was designed by Rogers Stirk Harbour + Partners with to have unique facade angled at a slope of 10 degrees. The reason for this slope is rather unique. As part of a planning requirement in central London, there are specific sightlines that must be maintained. One such sightline is the view of the dome of St. Pauls Cathedral.

By tapering the building back it appears as though the building is leaning away from the dome of St. Pauls cathedral, thus, maintaining the sightline from Fleet Street (to the West).

Image source

Facade Engineering Challenges (Interview)

This week we sat down with Brian Quinn from the Yuanda engineering department to dive into some of the details of this groundbreaking project.

How long have you been with Yuanda and what is your current role?

I’ve been with Yuanda since 2011 and am now a Senior Engineer (Engineering Team Lead).

Which projects have you worked on?

Full projects: Leadenhall, Indescon (that’s beautiful), Newington Butts, Harbour Central, and now Nine Elms Square.

Can you tell us some interesting facts about The Leadenhall Building?

• It is known informally as The Cheesegrater because of its distinctive wedge shape similar to that of the kitchen utensil with the same name.
• This project was a major challenge for all departments of the Yuanda family. This was due to the size of the building, very fine tolerances and movements, the large number of unique facade systems and its many interfaces (especially with the exposed steelwork details).
• The walkway gratings between the double skin were fabricated from individual aluminium strips that were welded together. These walkways were also designed to work for us to transfer wind loads from the outer skin to resist the lateral loadings.
• It has many complicated exposed brackets, where our attention to detail was relentless.
• It has pig nose stainless steel fixings, I’ll leave you to google that one!

What was unique about the façade?

First and foremost, the sheer amount of exposed detail. We basically had to break the facade into 3 key parts:

• The offices with the double skin façade,
• The North Core with the lifts and services risers (yellow steelwork),
• The zone forming the link between the two parts.

Oh also, there were the lower levels around the entrance area surrounding the external escalators. This was comprised of a different system too.

Main façade (sloping) is a double skin façade – inner façade stands on the relevant floor, while the outer laminated glass façade is supported from steel hangers.  The hangers span 7 floors if I recall correctly, with the mega hangers at the building corners.

The facades to the North Core (where you have the yellow steelwork) are very slim profiles, with special details including exposed brackets, elements with motorised louvres in the middle of glass panels.

Simply put it was a very unique facade. Truly one of a kind!

What were some of the challenges you had at TLB?

• For me, it was my first project in the façade industry and was not an easy one to start on.  It was a case of sink or swim, but by keeping my head above the water, with the help of my amazing colleagues, it gave me a good base education for future projects.
• It was non-stop attention to detail and the feeling of always being late.
• Aside from the many complicated systems, designing the brackets and calculating the load on them was always a challenge.
• The steel hangers on the outer skin of the double-skin façade support 7 levels of elements, with the hangers supported from cast steel brackets at the tops.

It was such a complex and unique project that they filmed an entire documentary on the construction process.

Extreme Engineering Leadenhall Building Documentary

If you’re interested in seeing the construction process that was involved in making this, we’ve included an embedded full version of the construction documentary below. The Leadenhall building is an icon of modern engineering and we’re glad to have helped make it happen.