The A44 in the RijnlandRoute project: complex phasing

In order to carry out the work to widen the A44 including the renewal of five structures near Leiden, a plan was devised by construction consortium COMOL5 to carry out this work while keeping the A44 open.

The various works and the large number of artworks within the project require very extensive phasing with complex issues. We sit down with Wim Guis, project manager at COMOL5, Robert Englebert, chief engineer of civil works and Joey Lalloesingh of the province of South Holland, project manager of civil works.

The five phases around the A44

"The work will be divided into five phases, which we are applying to ensure that traffic on the A44 will experience little or no disruption from the work," says Guis. "We are dealing here with the national highway and the underlying road network, we are working with many different disciplines, have to coordinate with various municipalities and water boards, and the area is home to large companies including Janssen Biologics of Leiden and Airbus. In the first phase, we rerouted the A44 to make room for the construction of the new Ommedijk interchange that will make the connection to the sunken location of the new N434," Guis mentions. "The second phase was the realization of a diverging diamond interchange (in English: Diverging Diamond Interchange - DDI) at Leiden-West, a type of intersection that takes up less space, creating room to build without restricting traffic flow. In the third phase, we shifted the A44 to the west and move to the fourth phase, where we build the east side of the overpasses. In the fifth phase, we make sure that everything around the A44 can be put into use and a final situation is created. Then it will be 'business as usual' again for road users."

The five structures of the A44

Englebert on the artworks in the A44: "The northernmost artwork is the viaduct over Robert Boyleweg. To the south we come to the viaduct over the N206, the Plesmanlaan, which integrates the bicycle tunnel parallel to the N206. Then we come to the bridge over the Oude Rijn River." Added Lalloesingh: "The Old Rhine Bridge will be a combination of the existing bridge and the new bridge. So unlike the other structures, where new is built next to old, after which old is demolished, the Old Rhine Bridge will be spared." Guis explains, "The existing bridge over the Old Rhine has been reinforced to extend its service life. The old bridge was a bascule bridge, which was fixed during the work. The new bridge is a fixed bridge."

Englebert continues his enumeration, "Finally, we have the viaduct over the Ommedijkseweg and the Ommedijk interchange, which is integrated into the sunken position. Throughout the phasing, the main road on the right will be done first, followed by the main road on the left. Traffic can continue on the A44 at all times." Guis mentions that each viaduct will be demolished in one weekend.

The current state of affairs

The four northernmost engineering structures are ready for the change of traffic. This summer, the A44 will be rerouted to the new location, after which the old structures can be demolished. Lalloesingh: "We are now entering an important new phase and expect to have reached the final situation on the A44 by the summer of 2021, on the understanding that work on the N434 will still be in progress and that the Ommedijk interchange will not yet be in use. In conclusion, Englebert says, "By then we will have completed a major project in complex phases. All the while allowing traffic to continue its journey unhindered. A fine interplay between design, preparation and execution of the work, which can only take place thanks to the integrality between the various disciplines."

RijnlandRoute

The RijnlandRoute is a project of the province of South Holland and consists of a new road connection between Katwijk, via the A44, and the A4 near Leiden. The road solves current bottlenecks and guarantees traffic flow in the Holland Rhineland region, particularly around Leiden and Katwijk.

Two of the three RijnlandRoute projects are now under construction. The N434/A44/A4 project, which includes the bored tunnel, is being carried out by contractor combination Comol5. Comol5 is an international contractor combination of the TBI companies Mobilis and Croonwolter&dros, VINCI Construction Grands Projets and DEME Infra Marine Contractors. The N206 ir.G. Tjalmaweg project is being realized by Boskalis. The third project of the RijnlandRoute, the N206 Europaweg, is still in preparation.

www.rijnlandroute.nl