Brentford Waterfront Block B and C Temporary Works Design

Beta Scope

Beta Design Consultants scope covers temporary works design for 3 Blocks:

3D Geotechnical Analysis.
Design of Temporary Works to satisfy CATIII checking.
Full BIM modelling of Temporary works for clash checking.
Design of connections of temporary works to the capping beam.
Design of thrust blocks used to restrain the raking props.
The preparation of the detailed fabrication drawings.
The detailing of all embedded plates including the rebar bending schedules.

Background

Beta Design Consultants was commissioned by Lomas Steel Structures to design the temporary works for the basement excavation of Blocks B and C of the mixed-use development at Brentford Waterside.

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. A mix of raking props and diagonal props were considered.

Idea Statica was used to design all connections and achieve maximum standardisation possible to reduce cost of fabrication and time of installation.

Tekla Structures was used to model all the steel structure as well as to model the rebar on the embedded plates.

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.