Highlight in A16 near Terbregseplein

With the construction of a fly-over in the A16 at Terbregseplein, an infrastructural tour de force is taking place. For the first time in the Netherlands, the so-called ILM construction method is being applied here. This method ensures that traffic on one of the busiest highways in the Netherlands can continue as normal during the work.

The project creating a new connection between the A16 near Terbregseplein and the A13 near Rotterdam The Hague Airport is known as The Green Arch. Working on it are Besix, Dura Vermeer, Van Oord, TBI (Mobilis, CroonWolters & Dros), Rebel and John Laing. One of the components of this 11-kilometer-long new route on the north side of Rotterdam is the flyover. The fact that traffic is not hindered during the construction of this structure is thanks to the Incremental Launching Method (ILM), which is mainly used in mountainous areas. With this technique, the concrete shell of the new road surface is launched, so to speak. At a speed of 2 to 2.5 meters per hour, 820 meters of road surface are pushed into place.

Formwork and steel frame

Formwork specialist Doka Nederland was called in on this project to supply the formwork and steel frame on the pre-construction site for the ILM construction method. As a family company of Austrian origin, Doka has developed over 153 years into a globally active formwork company. The company has more than 7,300 employees spread over 160 branches in 60 countries on five continents. "Doka Netherlands can call on the enormous amount of specialized knowledge that has been built up over the years in Austria on the various formwork techniques and solutions from the branch in Oss and," says Director Hennie Roebroeks of the Dutch branch. Knowledge applied, for example, in the construction of the fly-over at the Terbregseplein near Rotterdam. 

The flyover consists of 2 road decks 410 meters long, resting on 20 piers. Each road deck consists of 17 segments with lengths ranging from 22 to 30 meters. Each deck requires about 6,500 cubic meters of concrete and about 1,100 tons of reinforcement. On an abutment near the junction with the existing A16, the individual segments are pre-built. Roebroeks: "This will be done in 3 successive phases, which will be carried out one after the other like a 'train'. At the rear part of this location, the reinforcement is manufactured. By means of 2 interlocking UNP profiles with transport rollers in between, the reinforcement is pushed to the 'casting yard' with a crossbeam and a shovel. Here the concrete tray and road surface are then poured using Doka's total formwork system."

Top 50 wall formwork system

The formwork structure developed by Doka for pouring the base of the road surface is made up of elements of the Top50 wall formwork system, placed in a U-shape. Because the road surface is wider than the lower casing, horizontal formwork elements are placed on the outside of this formwork structure, on which the road surface is poured. The base is poured first. When it is sufficiently cured, a support structure is made in it for the road surface, which is then poured on site. After the concrete cures, the box is unloaded using hydraulic jacks and the road deck segment is pulled through with a winch over plain bearings to the front part of the pre-construction site, where it is finished and cleaned. Then the segments are "launched" across the A16. 

Roebroeks: "The entire formwork structure was pre-assembled at Doka Nederland in Oss and assembled into formwork on site. In Austria, we have a large database with an enormous amount of knowledge. We have specialized engineering departments there for each specific market segment. We are in constant contact with Austria for solutions for buildings or bridges that we build in the Netherlands, such as the Green Arch. They have a lot of data coming from different settings in different countries. From there, they can contribute to an effective solution for a complex situation in the Netherlands, whether it is high-rise construction, bridge construction or civil engineering. That's where our strength lies."

Because, Roebroeks points out, in the Dutch market the required knowledge among contractors about the most suitable formwork techniques could be improved. "Contractors want a certain speed in the construction process. That is only possible with formwork systems that can guarantee a cycle. But then you need the knowledge for that. Depending on the complexity of a project, a formwork system should be chosen that can add value."

Forward integration

Roebroeks would therefore argue for forward integration in the construction column. "That means that we already hook up with the main contractor or preferably even earlier, with the architect, because at that stage you already have to answer the question of how you want to build. Do you choose precast because on a small inner-city construction site you don't have room for storage? Do you choose slide formwork for high-rise buildings in inner cities, or do you end up with traditional formwork that meets the requirements in terms of speed and price? We can look for a formwork system that meets the conditions. That's why we like to be involved as early as possible. That gives the most added value."