Elephant and Castle: Case Study Transcript

Conquip was approached to design and deliver the temporary works and propping solutions for this project.

Excavation at Elephant and Castle is a large, complex scheme. Sequencing and methodologies often change as work progresses, so we have to adapt our designs while excavation is already underway. This requires being proactively involved in all site meetings, because once the work starts, it can’t stop. Our focus is to collaborate with our clients and continuously feed back to our design teams to improve what we offer.

Conquip and Morrisroe, along with Multiplex, worked together to ensure we had the most efficient design possible. The site presents a huge number of ground engineering complexities — Network Rail boundaries, a London Underground station just meters from the site, and the Bakerloo line running directly underneath.

To manage the high loads and limit deflection, we used a double-stacked waler beam. Normally, this would require extra props or extending the double waler beyond its needed length. Instead, we developed a two-to-one transition piece, maintaining continuity in strength across the section. This is especially useful for complex or uneven shapes, like those on this site.

One of the things that sets Conquip apart is the speed at which they can deliver bespoke items. If something needs adapting, their in-house teams can design, manufacture, and deliver it directly to site, preventing downtime.

The basement at Elephant and Castle is almost split in two. Most of the project has a two-story basement for the three ready towers and the university block, but the London Underground box has a five-story deep basement. The two-story basement presented logistical challenges — deliveries needed to continue, and construction had to proceed simultaneously with the top-down slab at level B2. The central area is a five-story section, which required careful planning around a transfer structure above the Bakerloo line.

To develop the right propping scheme across all three areas, we worked closely with Conquip and KDL. We started working with Conquip early in the design stage, which allowed us to value-engineer the propping requirements, reducing the number of props needed. This improved buildability and maximized the efficiency of the props.

The proprietary system reuses existing steel, making it sustainable. On this project, we were also able to incorporate Morrisroe’s own equipment, further enhancing sustainability. Fewer props mean fewer deliveries, fewer collections, and less waste overall.

The design collaboration has been excellent. The Conquip team is approachable and always willing to provide solutions on the spot. The quality of work on site has been second to none. Program outputs have been met reliably — props are always delivered and installed on time, allowing excavation to proceed without delays. This efficiency has been a major benefit to the project.