Amstel junction: from investigations to design and construction

The reconstruction of the Amstel junction involves many different disciplines working together: Miltenburg’s infrastructure teams for the roads, as well as teams responsible for viaducts, bridges and traffic systems. Collecting relevant data for all these disciplines at the same time is a complex task. However, Miltenburg emphasises that it is worthwhile: ‘For road users in particular, it is better to bundle the various investigations and the associated disruption, rather than spreading them over a longer period.’

At the Amstel junction, we will modify sections of the A10 Zuid, A2 and A10 Oost. The asphalt used must not contain tar, as it includes substances that have been banned in road construction since 2001. We are therefore identifying sections of road surface that may contain tar. Miltenburg: ‘We already have a good understanding of where this occurs, based on previous core drillings to a depth of around 35 centimetres. However, there are gaps of up to half a kilometre between these earlier samples. To locate and remove tar even more precisely, we are now carrying out additional measurements using a mobile asphalt drill.’

At the same time, we are investigating the load-bearing capacity of the road surface through so-called structural drillings, reaching depths of around 60-70 centimetres. ‘This allows us to look beneath the 35-centimetre-thick asphalt to see what lies below’, Miltenburg explains. ‘In our case, this is usually sand.’ By means of penetration tests, we drill even deeper, up to around 40 metres below the road surface: ‘Using a special vehicle, we push a narrow steel rod with sensors into the ground. This measures resistance and soil strength. This allows us, for example, to determine the required pile lengths for the foundations of noise barriers.’

The three types of investigation mentioned above are only part of the picture. We will also dig test trenches to map cables and pipelines, as well as the presence of Japanese knotweed; we will carry out deflection measurements to assess the lifespan of the asphalt; and we will even conduct investigations in the river Amstel to test water quality and identify any remaining structures. In total, this amounts to more than 20 different investigations. Miltenburg: ‘And these are only the investigations needed for the provisional design, which we aim to complete by mid-October. From the second week of September, after the summer construction break, we will continue by monitoring the condition of existing structures, such as bridges. By then, we will have all the information we need to confidently start construction in 2028.’