Many of us still remember that fateful day: on the morning of 26 May 2016, twenty pieces of scaffolding that were being hoisted into the air fell onto the construction site of the former VROM ministry building in The Hague. After falling 60 m, they landed on the construction site, killing a woman who was passing by at the time. This was not the first accident where public safety was threatened in the area around a construction site. However, it did prompt the immediate drafting of new national guidelines governing safety on demolition and construction sites (Landelijke Richtlijn Sloop- en Bouwveiligheid). But what does this mean in practice for construction in a busy and crowded area like Zuidas?
Clearing public areas
‘If anything is accidentally dropped, it creates risks for the public area around the work site’, explains Cees Bruijns, consultant and technical project manager at the City of Amsterdam. ‘The aim is to keep those risks to a minimum. In an area as densely built-up as Zuidas, it’s far from easy ensuring that space is kept clear of the public. You can’t just close a cycle path for months. If it’s impossible to close off the public space, we work with the contractor and commissioning authority to identify equivalent measures for guaranteeing public safety.’
Safety zone
This can sometimes be quite a puzzle, as Martin Brouwer, Zuidasdok’s integrated safety manager, knows only too well. For the regeneration of Amsterdam Zuid station, the De Nieuwe Meer and Amstel interchanges and the construction of the future motorway tunnel, we are always building close to the A10 and the tracks. It is simply impossible to keep closing them at the drop of a hat or for long periods. ‘Imagine that you have a crane that needs to lift a sheet pile 30 m long. You can then calculate what’s known as the safety zone’, says Brouwer. ‘If it’s impossible to immediately close the public area within that zone, the question is: could we perhaps use shorter sheet piles or a different material? Can we make technical changes to improve safety? Temporarily fencing off a metro platform? Or working at a different time? You have to tailor your approach to the situation. Zuidasdok makes use of external hoisting and lifting experts when preparing, customising, executing and supervising works.’
Social disruption
Max Hermans, safety manager for the regeneration of Amsterdam Zuid station, explains how this tailored approach to work happens: ‘When deciding what measures are needed, we take such issues as social disruption into account. If closing the public space – in our case, the tracks or the road – is unacceptable, the contractor will work out how it’s possible to work safely, by taking additional measures based on risk analysis.’ Examples of additional measures include fall protection, a protective structure, an auxiliary structure or a temporary support structure. ‘We make an internal assessment of the proposed measures before putting them to the Environment Service (Omgevingsdienst). Only when they give their approval, is it possible for us to start work.’
State of the art
When approving and supervising lifting works, the Environment Service also pays close attention to another new guideline, introduced in 2020. This focuses specifically on foundation works in the public environment. Brouwer: ‘This guideline has not yet been made law, but is the state of the art in construction. For example, it’s useful in calculating very specifically how far a piece of foundation or machinery might fall, and therefore in determining the size of the safety zone and measures to be taken.’ Hermans adds: ‘For the regeneration of the station, we’ve had to apply some measure or other to guarantee safety during lifting on an almost daily basis. Because we’re often repeating the same work, we’ve built up quite a library that we can now rely on. Examples include rotating piles and inserting sheet piles: we have some good methods, backed up by technical evidence, on how we can achieve that safely if the safety zone cannot be completely cleared of the public.’
Working at height
For Zuidasdok, foundations are being inserted into the ground endlessly, but for the construction of housing and office buildings, we regularly need to work at heights in Zuidas. There is also a set repertoire for that, as Bruijns confirms. ‘When you’re increasing the height of the building, you don’t put five cranes around the building to hoist the façade. In that case, we say: put the cranes inside and work from the inside-out.’ Other methods also include protection against falls – such as adding an extra rope when hoisting a sheet pile – or putting a crash deck in place. The aim of a crash deck is to protect passers-by from falling objects up to 5 kg in weight, such as a hammer. But what do you do if you have to lift a concrete pile that weighs two tonnes? Bruijns: ‘We then see if it’s possible to work with a series of brief stops. When the hoisting takes place, we temporary close the footpath, cycle path or road and there are traffic controllers on hand to keep everything running smoothly.’
No compromising on safety
Bruijns does not think that the measure involving brief stops is ideal. ‘When the new courthouse was being built, there was a requirement to keep the cycle path open. So we applied the brief stops method: several times a week, the cycle path closed for around 15 minutes. That itself can lead to different safety issues because people start walking or cycling across a crowded road surface to reach their destination. Obviously, we want a situation that’s as stable as possible – but if we closed every public area where we’re building, it’d be impossible to get around Zuidas anymore.’ Bruijns believes that there is still plenty of work to be done when it comes to safety awareness: ‘Many accidents are caused by people’s behaviour. The situation in and around a construction site has to be orderly and straightforward. That’s why it’s good that there are standard guidelines and that the Environment Service approves construction plans in advance. We simply can’t compromise on safety.’
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