Eleanor Street – Ventilation Shaft Formwork Design

Delivery of an alternative more efficient and effective formwork design at the Eleanor Street Crossrail ventilation shaft.

Contractor: Kilnbridge

Primary Contractor: BBMV / Crossrail

Scope of Work

The Eleanor Street shaft is a Crossrail ventilation shaft, it is deep going all the way down to the tunnels.  

The original design intended to permanently install a fabricated steel shutter system to enable concrete to be cast. 

The main challenge with this approach would be the access constraints and the fixings to keep the fabricated steel structure in place.

The shape to be cast included a square ring beam around the top of the shaft and a thinner flat slab.

As outlined in the drawings below displaying the original design intent from the client and the intended profile of the concrete to be poured (in pink)

Alternative Design Concept

After an initial review of the project, our engineering team identified a potentially more practical approach.

The client was receptive to an alternative design and the team developed a concept that would enable access to install a traditional timber shutter.

Design Solution

This concept was to install an anchor point into the core above the slab level. The deck system could then be lifted in and suspended from this bracket. 

The drawing below shows the detailed design solution provided. 

Successful Installation

By considering an alternative approach to the client’s initial design intent, the engineering team was able to develop and implement a more efficient and effective solution. 

The proposed design was accepted by the client and the platform proved to be an effective workspace for the team, enabling them to prepare the site for the concrete pour and complete the project as intended.

The images below illustrate the formwork placement in situ, with the timber shutter detailed to work around the system. 

Additional Resources

Review our webinar recordings for more case studies and a review of temporary works engineering.

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