Darran Leaver has been a Member of the Institution since 2005 and a practising structural engineer since 1998. Here he talks about his career and his work on the 6-9 Buckingham Gate development - a major refurbishment of four Grade II Listed Victorian houses, on a busy road opposite Buckingham Palace in London. The project has been shortlisted in The Structural Awards 2016 “Structural Heritage” category.
I have always had a talent and interest for technical design and my work experience was geared towards the construction industry, so the progression to a career as a structural engineer seemed the right one.
I’ve worked on a number of outstanding heritage projects during my career, the redevelopment of the Café Royal at Piccadilly being a source of particular pride. This saw a Grade II building of significant scale and heritage extensively redeveloped, with much of the building deconstructed and replaced in an intricate fashion. I was Technical Director for the delivery of the civil and structural services for this project and it was a real achievement. Others heritage projects I’ve worked on include No.5 St. James’s Square and The University Arms Hotel in Cambridge.
When approaching a heritage project it’s important to get a clear understanding of the developer’s ambitions and prepare a methodology which accommodates this, the contractor’s construction methodology, and respect for the original structure.
6-9 Buckingham Gate provided a number of unique challenges. Besides the presence of very sensitive neighbours (the Duchy of Cornwall on one side, and the Queen’s armed service response division on the other) we faced particular challenges in terms of the mobile ground where the building rests. The ground is subject to a continuous flow of water from an underground river, which made the piled foundations really problematic (a pile foundation is a column of concrete typically reinforced with steel bars).
To bore the hole for the pile required an auger (screw) – but if the auger doesn’t constrain the earth it extracts (by way of a casing projecting beyond the auger), the earth is merely replaced by earth pulled in by the water flow. To push the casing ahead of the auger required a good heavy piling rig – which we couldn’t use within the existing building!
In the end we used five different kinds of piling to accommodate the countless ground issues including secant piling, contiguous piling, crimped steel tubes, traditional deep underpinning and shallow underpinning.
As you might expect, to overcome the constraints of the site took lots of time, lots of commitment, enthusiasm, thinking outside the box, and discussion and experience. It was very satisfying and almost a relief to see the work completed and we’re delighted to see it considered for a Structural Award.
Learn more about The Structural Awards.