Overpass A12-Utrechtsebaan: green gateway to The Hague

By creating nine city entrances, the Municipality of The Hague formulates the ambition to make residents and visitors feel welcome in the outdoor space of the residence.

One of those city entrances concerns the A12-Utrechtsebaan, an access road that, as a "Green Entrance," focuses not only on the motorist but also on the cyclist and walker. In that context, an overpass was recently completed near the Malieveld that better connects the green areas the Koekamp and the Haagse Bos. Construction company Gebr. Schouls from Leiden realized the sleek and slender designed structure on which, surrounded by substantial vegetation, a bicycle path and footpath were constructed.

Gebr. Schouls was awarded the D&C contract on the basis of the Most Economically Advantageous Tender on the basis of best value for money, with the maximum score being achieved on the construction phasing/minimizing disruption component. Despite harsh weather conditions and corona problems, the company managed to successfully complete the construction of the overpass within a time frame of only five months. Given the diverse nature and scope of the work, this can safely be called a daring feat, project manager Leen van Belen agrees. "The project presented the necessary challenges especially in terms of planning. The overpass was constructed in the months of February and March. The layout, paving and finishing of the artwork took place in April through June. While the design and production phase was already tight, with the new flora and fauna season approaching, it was also important to complete all night work before April. On top of that, all work on or above the Utrechtsebaan had to be carried out at weekends due to traffic. In the end, we managed to construct the overpass during the eight weekends when the Utrechtsebaan was closed."

Eye for green

The artwork fits seamlessly into the surrounding ground level next to the tunnel trench. The crossing at the Malietoren over Utrechtsebaan has been made about 25 meters wider than the existing viaduct.

At the same time, the structure, composed of precast concrete elements, is generously planted with trees and shrubs, so that cyclists and pedestrians experience the overpass as one natural whole. "The structure, situated at a busy sight location, is built and founded on the existing construction of the Utrechtsebaan," Van Belen continues. At the same time, full account has been taken of existing green spaces and future developments. "Prior to the work, we transplanted the larger trees present and the deck of the overpass was dimensioned for the future traffic load. This made connecting the deck elements to each other and to the center support complex, as they had to be poured together on the job." 

Another masterpiece delivered by Gebr. Schouls concerned the installation of the last part of the capping. Because of the dimensions and shape it was not possible to transport this 'capstone' as a whole to the project site. Hence, the final section was split into two separate prefabricated parts that were poured together on a steel frame at the construction site. Then the colossal whole was transported with a
700-ton crane lifted into place from Utrechtsebaan.

All-round specialist

Since 1930, Gebr. Schouls of Leiden has grown into a medium-sized contractor within concrete, road and hydraulic engineering. With the help of skilled employees and modern equipment, the company realizes projects in various disciplines. Gebr. Schouls carries out the projects on the basis of the classic RAW specifications, on the basis of Design & Construct (with or without the Systems Engineering system) and in construction team. This enables this all-round construction specialist to realize assignments from the design phase to the commissioning of the object.

Special precast elements

The precast concrete elements for the overpass were supplied by Waco of Bergen op Zoom. Waco stands for constructive and architecturally sound products that are developed, designed and manufactured using advanced techniques. An approach that keeps work on the construction site to a minimum. 

"The precast elements supplied for the Overkluizing A12-Utrechtsebaan project can be called special in several ways," says Van Belen. "First of all, they are characterized by minimal tolerances on the large amount of reinforcement that comes out of the elements and has to fit together in the work. In addition, they are distinguished by a double-curved shape at the edge of the overpass. In the horizontal plane they have a curve, in the vertical plane an arch."