Quality starts in the design phase

Skanska’s rail projects are generally delivered through Network Rail frameworks under NEC design-and-build contracts, with the contractor committing commercially to a construction method, time, and programme at the end of the development phase. Aligning the design and construction approach before that point is therefore critical. “We’re trying to achieve a position where the construction method tracks alongside or even in advance of the design thinking.”

This means giving designers the information they need to develop solutions around construction requirements, while allowing construction teams to identify risks and constraints before they become site problems. Rather than waiting for a completed design before considering how it will be built, Skanska wants construction teams to be involved in developing the solution. 

Skanska has built this strategy around three key pillars: collaborative culture, progressive assurance, and construction integration.

Bringing teams together 

“We do a lot of work on culture early in projects, bringing teams together to ensure that the design solution is developed jointly by the construction and design teams. It’s about getting the right people involved and establishing the right method and the right design.” 

The ‘right design,’ he explained, means right for construction. “The design must meet the needs from a construction and commercial perspective. It’s a joint solution, and we need our construction teams to understand the design and to think early and in detail about how they want to build it.” 

That means asking fundamental questions during design: can it be constructed safely and correctly? Is the information sufficient to allow construction to commence? Has everything required been provided? And how will the work be phased and built? 

“To facilitate this, we’re defining deliverables and outputs for each team. This isn’t one-size-fits-all. It is based on risk and the complexity of the projects. So, for example, we don’t provide a 350-page constructability report for a small troughing, but some of the major stations will requires that level of detail.” 

Digital information is another important part of the process. Skanska aims to maintain a consistent work breakdown structure and design and construction packaging throughout the project, maintaining the same data structure from construction to handover. 

The system in practice 

“It’s a simple process in practice,” said David. “We request comments as we go along – through joint reviews, model reviews, or offline reviews – and address these proactively. The person who makes the comment is the person responsible for accepting when a comment is closed out.” 

Everything is captured in a central log, which supports assurance processes. “This log can be viewed by anyone. Everyone can see the comments raised, which helps to address some of the issues.” 

Case study – Euston Station 

To demonstrate what this collaborative approach looks like in practice, David used the example of a substation and cold store at Euston Station. Atkins led the initial design, with early contractor involvement from Skanska and key supply-chain organisations. As the project moved into detailed design, specialist suppliers took responsibility for elements including steelwork connections, cladding, MEP, and services fit out, while Atkins retained overall coordination. 

Installation models developed by subcontractors were federated by Skanska's digital team. These models allowed the teams to plan and design the work together, identifying and resolving issues ahead of installation. The models also provided the basis for joint reviews, with comments captured, assigned and closed out proactively.  

The approach incorporated progressive assurance. Information extracted from the models was used to set out foundations, steelwork and services accurately, while construction queries and routing issues were identified during design. This also helped the team address the potential risk of penetrations through the cladding, allowing testing and assurance to be undertaken during the design phase. 

The approach produced several significant benefits, including: 

• No changes from site during construction 
• 90% reduction in construction phase design support 
• All handback completed within four weeks 
• 50% reduction in as-built time 

Case study – Clifton Bridge 

In his second example, David used the 1960s post-tensioned box-girder Clifton Bridge in the Lake District to challenge the assumption that construction methodology must wait for detailed design. 

Skanska was appointed in October 2024 under a design-and-build contract for the bridge replacement, with construction beginning in early January 2025. The bridge was a 130m-long steel structure that needed to be moved approximately 50 to 60m, so the basic methodology could be established from the early design information. “We knew the requirement and the site constraints so there was no need to wait for the detailed design to decide on the construction method.” 

The original design called for an in-situ concrete deck, but because of a tight programme and a challenging location, the team changed to a precast deck solution. This reduced some of the risks associated with on-site concrete construction, but it required the precast units to be coordinated with the steelwork, with the bridge sections fabricated in Glasgow and the precast units produced in Belfast. 

Mott MacDonald led the design, with the supply chain was brought into the process through early contractor involvement, including the precast manufacturer and steelwork fabricator. The teams worked together during design to determine how the components would fit together and how the completed design would be assured. Digital modelling was used to examine tolerances and fit-up and identify potential problems before fabrication and installation.  

“Once we got on the site, we did a trial installation mock-up, allowing operators and installers to understand the positioning and working space and to verify the locations of the shear-stud pockets. Digital systems were also used to provide a single location for quality records and checks.”  

The project delivered several measurable benefits, including: 

• 25% reduction in concrete deck programme 
• Overall rework was less than 1% across the project.  
• The project achieved its programme in 17 months. 

Right first time 

“Quality starts in the design phase,” said David in closing. “It’s not a separate thing and it should be thought about early, just as much as safety or the environment. This is the culture we are pushing.”  

To achieve it requires a clear brief, detailed responsibility, collaborative design, and making designs buildable through early contractor engagement. “Ultimately, it’s about collaboration – the right people at the right time. As contractors, we need to think earlier, in detail, about the construction, and designers need to design to meet construction needs.”