A number of reports in recent years have tried to define the role of public sector projects in setting the standard for construction industry procurement.
It is useful to review Crossrail in that context.
The challenge is to combine good value with a collaborative culture that gets the best out of all players, particularly the supply chain.
At WestonWilliamson+Partners, our work includes commissions for two central stations: Paddington for the Costain / Skanska joint venture, employed through WSP Parsons Brinckerhoff, and Woolwich for Balfour Beatty, employed through Mott MacDonald.
We did the design, from concept to tender, for both stations working for Crossrail, and then as part of the Aecom team on Paddington and the Arup / Atkins team on Woolwich.
We were not novated but were chosen by each contractor to support them in what turned out to be winning bids.
Crossrail procurement has been described as detail and construct, in which the contractors take responsibility for completing the design.
“The ability to complete the negotiation of approvals with Crossrail and external stakeholders with a consistent team has been important”
The tender design, and in particular the overall civil engineering design (which perhaps has the biggest liabilities) remains the responsibility of Crossrail.
Although unconventional, the procurement has allowed for consistency of the architectural team throughout.
Both the Aecom and the Arup / Atkins teams have been retained as Crossrail’s designers.
Dividing responsibility for the design has allowed knowledge and expertise to pass to the contractor team while allowing Crossrail to retain key expertise themselves.
Both the projects have design sensitivities adjacent to Grade I-listed buildings, so ensuring design consistency has proved very useful.
Programme is critical across the whole project and the ability to complete the negotiation of approvals with Crossrail and external stakeholders with a consistent team has been important.
“Too often in projects like Crossrail there is a knowledge chasm between design and construction”
Established relationships between designers working each side of the contract has also been useful.
Too often in projects like Crossrail there is a knowledge chasm between design and construction where one team picks up the job cold.
Supply chain engagement
We generally prefer working on contractor-led teams during construction. This allows us to engage properly with the supply chain.
We were able to work with the Costain / Skanska JV and its subcontractor Byrne Bros to develop a structural precast formwork as part of the top-down slabs of Paddington station, which has led to significant programme and quality benefits while reducing the risks associated with the in-situ alternative.
The challenge with splitting the responsibility for design between client and contractor is that design change can be disruptive unless there is effective collaborative working.
Paddington was the first station Crossrail procured and Woolwich the last. We have noticed that over that time each subsequent contract is a little more refined and the amount of post-tender design change is reduced.
Hopefully these invaluable lessons can be used to inform the next generation of large infrastructure projects the UK seems set to procure.
Rob Naybour is a founding partner at WestonWilliamson+Partners