Brentford Waterfront Block K Temporary Works Design

Beta Scope

Our scope comprised the following:

Temporary works design for the basement excavation.
Full BIM modelling of the basement and temporary works for clash checking.
Design of connections of temporary works to the capping beam.
Detailing and shop drawings for temporary works.

Background

Beta Design Consultants provided the temporary works design for the basement excavation of Block K of Brentford Waterfront redevelopment project.The development will develop the waterfront and this specific block would provide commercial space and 66 residential units.The site was particularly interesting as it is located close to the River Brent joining point with the River Thames. The tidal changes in the River Thames affect the water table level and the site is mainly alluvium soils overlaying the London clay.This lead to high lateral loads on the basement retaining walls.

Beta Solution

Beta Design Consultants carried out a 3D geotechnical analysis to confirm loading on the walls and establish the optimum layout for the temporary props. Initially, a mix of raking props and diagonal props were considered. However, to improve access and reduce need for reliance on thrust blocks, it was decided to rely on temporary props at capping beam level. The changes in the capping beam level necessitated the introduction of strategically positioned temporary waling beams in a couple of locations to avoid clashes. Known clashes were resolved by introducing splices to allow the removal of the props following ground floor curing.

Practical Details

Beta modelled the permanent works including the basement walls (sheet piles with capping beams), the basement slab and ground floor slab and all RC walls and columns. This allowed us to share with our clients BIM Level 2 model (IFC format) for clash checking. The advantage included ability to detect clashes early and solve them. Another advantage was the ability to modify the model when the capping beam was built. Following a site survey, we were able to revise our model to reflect the dimensions of the actually built permanent works rather than the design dimensions. This resulted in revised lengths and angles for temporary works. This update was essential prior to fabrication to ensure fit up and reduce misfit forces. So it is essential for speed of installation and for safety.