D&C offers many benefits to airside construction – if it’s done right. Joe Walsh explains how airport owners and contractors can get optimal results from using this type of contractual arrangement.

For many years, design and construct (D&C) has been the standard contractual model used for apartments, large commercial buildings, and road and rail projects. Now, it’s becoming more popular for airside construction projects. Previously, contractors received airside designs as a complete detailed design. But, under the D&C model, they receive a preliminary reference design with a contract to complete the design and construct the project.

D&C is a radical departure from the way airside projects traditionally work. And it can add real value from a procurement perspective, including:

  • Reduced risk for airport owners: D&C reduces risk for owners and increases the contractor’s risk because the contractor is a single point of responsibility for design and construction.
  • Construction efficiencies:  D&C allows the construction methodology to be more efficient in terms of the cost and time to build. For example, when contractors are involved in the design process, you get early market information about material and resource availability.
  • Buildability and value engineering: D&C ensures the design is assessed from the perspective of those carrying out the construction works, improving constructability, staging and sequencing. Problems can be identified, and de-risked or eliminated, ahead of time. Contractors can assess the practicalities of building the design, considering the availability of materials, construction methods, transportation logistics or site limitations.
  • Improved construction safety: The traditional model doesn’t have the contractor at the table early in the design piece. D&C, with Early Contractor Involvement (ECI), gets the constructor thinking early about safety as it relates to constructing the design.

However, to get these and other benefits, airport owners need to adapt their expectations and the way they engage with designers and contractors.

How to optimise D&C benefits

Now that alternative contractual models are being implemented, airport owners need to evolve their approach to procurement.

Protect quality with a robust Statement of Requirements

Your procurement strategy must safeguard quality. Otherwise, contractors may inadvertently compromise design to get a better commercial outcome. Runway and taxiway regulations are stringent. However, there are opportunities within the requirements to get an optimal operational solution whilst safeguarding for future developments. So, a contractor could ‘design to the max’ and achieve compliance but not deliver an optimal operational solution. A good example of this is the preliminary vertical alignment which is subsequently optimised to drive cut fill balancing requirements. While the output is compliant, it potentially results in a sub-optimal operational alignment, maximum grades and multiple grade changes.

To avoid giving contractors a commercial incentive to act contrary to the project’s best interests, runway owners and their designers need to set the rules of engagement by being clear in the Statement of Requirements about what is sacrosanct. That might be vertical alignments that are fixed as per the preliminary design.

Laser sharp Statements of Requirements avoid any grey areas in the tender situation, which is better for both parties. When everyone knows exactly what they’re quoting on, owners know they’re comparing apples with apples and get the quality outcomes they want. Equally, good contractors don’t lose out on jobs because a less experienced competitor is planning to design to the max thanks to a loop hole in the Statement of Requirements.

Build in enough collaboration time for designers and contractors

Most of the above benefits are derived from early collaboration between design engineers, the client and the contractor through ECI phases, which can unlock significant productivity and quality improvements. But airport owners need to recognise that effective collaboration takes time. ECI, as part of the procurement process, brings together people from diverse disciplines, who generally will not have worked together before. They also involve the co-ordination and integration of a great deal of complex information, procedures and systems.

It takes time to get all this sorted out: to build relationships, develop new understanding and gain trust. The longer a team works together, the higher the trust, the greater the understanding and the better quality the design output.

This is why it’s vital that timelines allow for designers to get early input from contractors and that respective programs are aligned to achieve the required outcomes. Otherwise, by the time contractors are up to speed – typically 5-6 weeks – and start to point out the value management or constructability aspects of the design, the input may be too late to capture in the design program. At this point, designers cannot back-track without impacting the program and the client incurring additional design costs.

Get contractors involved at the planning stage

In a highway D&C project, contractors aren’t typically brought in at the planning stage. But airside projects require more engineering input around staging and sequencing logic, geometrics, drainage, earthworks and utilities. To get engineers and contractors aligned, you need a joint planning effort, with sufficient time in the program to allow a ‘stop and discuss’ moment to capture and close out opportunities so they can be reflected in subsequent design iterations.

This requires flexibility in the procurement program. Owners need to be prepared to nail down final design resources and the program of deliverables after the contractor is on board and can have input into it. Once the contractor is appointed, the teams should sit down and agree on the combined program. Then – and only then – can it be resourced and timelines agreed with the airport owner. It’s well worth putting in the investment and time to get this right up front – otherwise, you run the real risk of being hit by program overruns and the impact of delayed deliverables.

Use emerging technologies to support collaboration

Airside projects can be highly complex in their design and construction, requiring both engineers and constructors to look at problems from each other’s respective positions. At Beca, we use a 3D virtual environment to model the site environment, so designers understand construction issues – and vice versa. For example, when you’re dealing with Airfield Lighting Equipment Rooms (ALERs), it is hugely beneficial to visualise this element in the model and thus enable both the designer and constructor to better understand the constraints and inform alternative approaches where relevant. This same approach is taken with new utilities and interfaces with storm water drainage infrastructure (a significant feature of any airfield design). Then, you can also use the model to explain the design change to the owner, so everyone has a shared understanding of the problem being faced and the reason for the amendment.

Create a collaborative environment

Collaboration doesn’t just happen. You have to get everyone’s buy-in. We start by holding meetings to talk about the coming challenges and agree on the culture and behaviours expected on the project. The resulting Team Charter often range from safety pledges – “Everyone goes home safe” – to collaborative behaviours – “Be honest and respectful when communicating” or “When something goes wrong, don’t appoint blame, solve the problem” or “Design decisions are agreed unanimously by the designers, contractors and owners”.


Airside projects are of a scale that can lend themselves to the D&C approach with ECI. We are working with airport owners and operators to successfully deliver to those new models, with excellent results. But, to get the most out of D&C, procurement strategies needs to change.

Airport owners should:

  • Safeguard quality upfront
  • Acknowledge the need for flexibility in timelines and resourcing needs
  • Enable Early Contractor Involvement
  • Explicitly enable collaboration