Greenville is a special project in Leidsche Rijn, Utrecht. Heijmans was awarded the tender at the start of 2017. And around 1.5 years later, the first shovel went into the ground to mark the start of a 2.5-year construction period. Although this may seem like a long time, a lot of things must be taken into consideration when realising the building. Design manager at Heijmans, Rob Tolboom, explains what the construction phase will entail.
Underground car park
The first job was to construct an underground car park. Rob: “We have started to build the foundations in the meantime. A total of 616 piles will be driven into the ground, which amounts to around 9 or 10 a day. This means between 55 and 65 working days will be needed for pile-driving activities. Depending on the weather, we expect to complete these activities by the end of February 2019. In the meantime, we have already started to construct the support columns. These include the load-bearing beams in the cellar floor and cellar floor itself. The underground car park is expected to be ready around September. At that point, we will be almost a year down the line.”
The cellar is one of the most difficult parts of the whole construction process. Rob: “It can only be released by the fire brigade once the whole building has been completed. This means the cellar will still feature jack posts even when we have moved on to the last phase of construction. All escape routes from the cellar will only be safe once all installations are operational and the underground car park has been ‘released’ by the fire brigade; only then can we complete the handover. So there is a good chance that some homes will have been completed prior to this point.”
Building shell & prefabrication
“The shell for phase one (A/B in the image above) is expected to be ready by the end of 2019. We will immediately start façade-related activities once the first part of the shell has been realised. We will then continue on a phase by phase basis. When we start building the shell for the final phase, the first window frames will already have been installed for the first phase. This will allow us to streamline the process, thus cutting construction time and maximising efficiency during construction. For instance, interior walls will be realised when constructing the building shell. But we do face certain restrictions, for example, when halting bricklaying activities to wait for water to leak from poured concrete. In addition, the floors on each storey are different and we have a wide range of homes. This doesn’t make things any easier.”
Shortening the planning phase
“The underlying planning has been completed and we are now working on the finer details together with our partners. We are examining how our construction method can be modified so, for example, the cellar becomes operational much sooner. We are also examining possibilities for prefabricating certain building elements, including all planters. This will help to reduce activities at the construction site and create a bit of breathing space in our planning.”
What makes the process even more complicated?
“The first thing that springs to mind are the winter periods. We started construction activities in October 2018. This means freezing weather is just around the corner. When winter really kicks in, it will become a lot more difficult to pour concrete. As things stand, the planning contains two winter periods that will have an impact our timing.
Personnel shortages and long delivery times for materials in the whole construction sector are two additional factors that further complicate the construction process. And when you also consider our energy ambitions and the complex installations, it is easy to understand why we need so much time to realise this architectural masterpiece.
Greenville has placed great emphasis on quality, architecture and sustainability. We need until mid-2021 to realise this fantastic project, but people who are prepared to wait will be rewarded for their patience!”
Greenville reflected in a few figures:
10,000 m2 of interior walls
15,000 m2 of façades
16,000m2 of storey floors
5,500 m2 of cellar floor
5,500 m2 of ground floor surface
1,700 solar panels
4,140 m2 for framework
760,000 kg of reinforcements
1,800 m2 of natural stone