Interview | HS2 Ltd’s Howard Mitchell challenges the way construction productivity is measured

The week before NCE interviewed HS2 Ltd head of innovation Howard Mitchell, the government announced it was delaying parts of the High Speed 2 (HS2) project.

It said that the leg between Birmingham and Crewe along with work associated with the Euston Station terminus would be pushed back.

Several industry heavyweights have commented that this felt like a counter-intuitive move. Stretching a programme out could lead to a loss of momentum and increased costs.

Changes like this also create uncertainty for supply chains, threatening future business and investment plans. Innovation generally comes from companies at the tail end of these chains, so will there be a negative impact for them and for HS2’s innovation aspirations?

Mitchell gives a careful answer. “For my portfolio of innovation projects, we don’t see a particular impact,” he says. “It changes the nature of the activity. Maybe we are not going to focus on enabling works as much because we need to be digitising the design process.”

Innovation is not just identifying those areas we can improve but finding new ways of driving efficiency

Mitchell’s 200-strong portfolio is already demonstrating productivity improvements. Success stories include artificial intelligence (AI) that slashes programme durations; parametric analysis tools that speed up design decisions; and 3D printing of structures that takes hours rather than days. So far, his innovation programme has returned more than £200M in cost savings and 1.8M.t in carbon reductions for HS2.

Data from the Office of National Statistics shows that construction’s productivity, in terms of output per hour worked, has not changed much in the past 50 years. In fact, it has actually fallen by 7% since 1997.

But one of the challenges in measuring productivity in construction is that the range of activities involved is so varied, says Mitchell. “It is not just contractually complex, it is physically complex. We don’t have the ability to measure activities in the same way as we do in, say, a pharmaceutical-style environment,” he explains.

Aggregating data to produce broad brush productivity statistics loses all the success stories, he adds.

Triple baseline

HS2 measures its productivity against a triple baseline: “We drive all of our projects with a laser focus on the reduction of time, carbon and cost for the build and operation of HS2,” says Mitchell.

As well as measuring improvements against the overall project cost, budgets for each phase and costs of assets and activities, each innovation project is steered by a group of experts who can drill down into the detail.

“It is essential that we have client, contractors, academics and other experts at the table who take into consideration a number of different perspectives including where and how costs are incurred over the lifetime of the build and in operation.”

Although some of HS2’s productivity gains due to innovation can be expressed traditionally as higher output per hour, Mitchell is seeking completely different ways of doing things.

These could rip up programmes and sequencing altogether.

AI is being used to optimise scheduling for the Chiltern Tunnels

He explains: “Innovation is not just identifying those areas we can improve but finding new ways of driving efficiency as well as looking across to other industries and seeing how they have improved efficiencies.”

Making and measuring efficiency gains is simpler in the design phases, according to Mitchell.

“Architecture or design is naturally very predisposed to have a degree of digitalisation and therefore be highly efficient. Even within this area we are innovating,” he adds.

On site, productivity improvements are harder to come by. “You cannot digitise moving earth around,” says Mitchell. But, even here, some of his innovation portfolio is bearing fruit.

Digital time and motion

He picks out Sentry, which is akin to a digital time and motion study where videos of various activities are played back to those involved so that they can suggest ways they can improve.

After early resistance from some on site, Sentry has taken off, says Mitchell, with Balfour Beatty Vinci JV now using it across the programme.

“It’s the ultimate way to deliver innovation, using the pull from those people who are undertaking the activity,” he says, likening the practice to sportspeople watching back their game.

Perhaps more intriguing is the application of AI developed by Alice Technologies to optimise scheduling.

The Align JV, formed by Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick, has been using this on the Chilterns tunnels contract. The system looks at all the permutations of programming and sequencing and helps select the best.

It is incredible to think that years of operational and programming experience might be trumped by AI, but it is cutting programme times “very significantly” says Mitchell. Now other contractors are considering it, as is HS2 Ltd.

Mitchell also highlights the 3D printing of concrete structures in controlled environments next to sites. Skanska Costain Strabag JV is trialling ChangeMaker 3D’s Printfrastructure technology on drainage elements, creating huge productivity gains: one hour with a robot versus 40 hours and several workers.

Another concrete-related innovation, this time from a company called Cloud Cycle, uses a specific gravity sensor inside a concrete truck to automatically warn when the load goes out of tolerance. This will reduce waste, improve quality and reduce programme delays says Mitchell.

Carbon vs cost

With twin goals of cost and carbon reduction, there must sometimes be a tension between the two.

Often, the criticism of lower carbon technologies is that they increase capital cost to the point that they are unviable for the wider industry.

With a portfolio approach, Mitchell and his team can balance the two goals, he says, using discounted cash flow and discounted carbon calculation models to look at investment versus return to the programme.

Mitchell sees the race to net zero as a driving factor behind innovation and productivity gains and draws parallels with the energy and automotive sectors, where he worked before joining HS2 Ltd in 2019. “Those sectors have gone through significant shifts, moving from fossil fuel-driven systems towards renewables,” he says. “We, as HS2 Ltd,  are similarly  going through a major shift where carbon is incredibly high on the priorities of this organisation. And that’s driven a huge amount of innovation.”

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  1. Planning to fail.

  2. Stephen Trowbridge

    It’s a bit difficult to take an article seriously when it includes Grand Designs expressions like “the build” rather than Construction Project. What might be better a better measure is how many people are paid for by the contractors Prelims and on the client side reimbursable contracts from the various consultants. There are way too many people with little experience feeding off each other where there is a positive profit motive in not performing or delivering. We have turned failure into profit..

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