Insights 18th June 2024 Building Consultancy

The heavy battery burden of electric vehicles could be too much to bear for the UK’s 6,000 multi-storey car parks, so how can owners avoid collapse?

Ben Kearns, Partner and Head of Workman’s Venture Projects team, and James Edmonds, Director and Bristol office lead, at engineering consultancy Clarkebond, scope out the solutions in this article for EG.

The electric Hummer, first released by General Motors in April 2022, is colossal at more than four tonnes. The Mercedes EQV can tip the scales up to 2.9 tonnes, Jaguar Land Rover’s Range Rover weighs in at 2.5 tonnes, while Tesla’s top-selling Model Y is also a hefty 2.5 tonnes. That’s before the capacity of multiple people and their luggage are added.

For context, the humble Ford Cortina – the UK’s best-selling car of the 1970s – weighed in at a modest 980kgs. This was the kind of car the creators of multi-storey car parks (MSCPs) had in mind when they designed the structures in the 1960s and ’70s. Today, even a fully loaded internal combustion vehicle can weigh 2.5 tonnes, just in line with design loads of 2.5kN/m2 (to allow for dynamic effects) – (2.17kN/m2 x 1.15).

“Avoid partial collapse”

The Institution of Structural Engineers (IStructE) has warned that many car parks, especially the very old ones, may have to close “to avoid partial collapse” as electric cars become bigger, heavier, and more ubiquitous. In the last quarter of 2023, Chinese manufacturer BYD overtook Elon Musk’s Tesla to become the world’s largest maker of EVs, selling 526,000 to Tesla’s 484,000. Now, BYD is spearheading a massive onslaught on European and US markets, with 5,400 EVs already shipped to Dutch and German shores in Q1 this year.

To cope with the new weight loads, IStructE highlighted that there are a myriad of considerations the design of a modern car park needs to address, and safety must be paramount, particularly as selling petrol and diesel cars and vans will be banned in the UK by 2035.

Infrastructure review

Its guidance, Car Park Design, reflects the necessity of a new approach to internal layouts and other requirements for the structural design of car parks. Yet while the IStructE’s guidance sets out clear requirements for the design of new car parks to bear the loads presented by heavy EVs, the recommendations for older existing car parks are not as clear or far-reaching.

The IStructE states that car park owners should have their infrastructure reviewed by engineers to check if it needs to be strengthened, but pointed out that many owners may opt for imposing weight limits at their schemes, rather than paying for strengthening measures.

These measures could include allocating specific spaces for E-SUVs, limiting heavy vehicles to non-suspended slabs, only allowing access to vehicles below 2.5 tonnes, or increasing the size of individual spaces to reduce parking density.

The knock-on economic effect of these restrictions could be catastrophic for hard-pressed retailers who have barely recovered from the effects of the pandemic. Indeed, the last thing centre managers need is for shoppers to be deterred by problematic parking.

However, the alternative: strengthening structures to meet the new IStructE 3.0kN/m2 recommendation, is complex and costly, with intrusive works to add to the mix. What is clear is that almost all of the direct costs will be borne by infrastructure maintenance budgets – a prime reason to keep planned preventative maintenance (PPM) programmes well-managed and up to date.

Preventative maintenance

Add in inclement and extreme weather events – symptoms of climate change that EVs are designed to ameliorate – and the outlook is particularly threatening for the UK’s multi storey car parks, where exposed structural frames and floor slabs do not have the protection of enclosed external fabrics.

A diligent regime of pre-emptive inspections and repairs is required to help ensure existing load capacities are preserved, through identification and repair of concrete defects, corroded structural connections and movement joints. Owners can often fall into the mindset that a multi storey car park is an external environment, capable of withstanding all mother nature has to throw at it. This is a dangerous assumption, which must be avoided.

Policy for change

External influences could shift the situation: industry bodies such as the Energy and Climate Intelligence Unit (ECIU) have called for carmakers to produce smaller electric cars, after years of focusing on the most profitable SUVs. Similarly, they have suggested that governments should incentivise smaller cars through policies such as reduced taxes and parking charges. This would use fewer resources, limit carbon emissions, and make car park scrapes or collapse far less likely.

In the longer term, the assumption that electric cars will always be heavier is open to question. On average, EV batteries are packing twice as much energy into the same weight every decade. Batteries of the future are also predicted to be less flammable, reducing fire-risk inside MSCPs. In addition, there is the possibility that hydrogen or synthetic fuels, or other alternatives, could change the trend towards EVs, meaning MSCP owners would have the weight of worry lifted.

In the short term, however, it is simply good housekeeping to ensure that MSCPs are up to the task for which they were designed. Car park owners and operators have a vested interest in understanding the direction of the automotive sector, which is profitable and dynamic. The design and use of car parks will be forced down a road driven by consumer habits. Remaining informed, with disciplined maintenance regimes, will help ensure car park revenue regimes are not hindered, and that accessibility for customer footfall is not discouraged.

This article originally appeared in EG. 

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