Project overview
This project is a park of 20 pods in Ras Al Khaimah. Wrenze Steel carried out the structural design of the underground steel structures for the park, working for Armadilla as client and consultant.
The image shows a compact, curved pod clad in timber, with a glazed door opening onto a wooden deck.
Our scope
Our scope was the structural design of the underground steel structures. Steel below ground has a different set of design conditions from steel above it, and those shaped the work:
- Earth pressure. Walls and members below ground carry soil pressure from the side, as well as vertical loads from above.
- Loads from above. Anything on top, such as a pod, deck, people or finishes, has to be carried through the steel to its supports.
- Groundwater and buoyancy. Where water is present, a buried structure can be pushed upward, which has to be checked against the weight holding it down.
- Durability. Buried steel sits in contact with soil and moisture, so protective coatings and drainage details are part of the design.
Twenty units on one site means the design is repeated, so a clear, efficient typical design gives the biggest benefit.
The structure
Underground steel structures are less common than buried concrete, but steel offers advantages on a project like this. Steel frames are light, prefabricated off site and quick to install, which suits a site with many small, repeated units. They can be delivered as kits and bolted together in place, with less wet work on site.
The design challenge is that the structure is loaded from all sides. The soil pushes on the walls, the load from above presses down, and the base must spread the load into the ground. Members that would be simple beams above ground also take axial load and bending from soil pressure below ground, so each needs to be checked for the combination.
Connections in buried steel must be designed for the same combined loads and detailed so water cannot collect at joints.
Read about our structural steel design service, or request a quote for an unusual steel structure.
