Renovation of movable section Haringvliet Bridge

2500 hours of welding per week

In a large production hall at our shipyard in Krimpen aan den IJssel, the new bridge valve is being built. It consists of a steel bridge deck over which traffic will eventually drive and the ballast box, the counterweight needed to move the bridge.

Loose steel plates are delivered to the hall. These are hundreds of puzzle pieces cut into shape that are assembled and welded together. This is a mega job, with 50 men welding every week. That’s 2,500 hours of welding per week.

When the welding is finished, the bridge will receive a double preservation system for extra longevity. The completely assembled bridge weighs a total of 2,000 tons. A large and heavy object, but the dimensions on the structure are accurate to 1 mm, a precision job.

Short lead time

In most projects, the design process consists of several phases: from pre-design, to final design and finally to execution design. The lead time for this project is short; during the period between June 9, 2023 and July 28, 2023, the individual components are already being installed. The new steel bascule bridge and the new rack road should be ready before then.

As a result, designs for some of the components have already been made in the pre-phase. For example, the drawings of the bascule bridge were already completed and the design of the gear track for the drive were also ready.

Additional bridge
To make the first steps of the renovation possible, an temporary bridge was installed next to the Haringvliet Bridge in January. This bridge consists of a large pontoon with retrobridges (segments) installed from the pontoon on the mainland. The bridge will be used for various works, including the removal of the rack railway, replacement of the controller and renovation of the basement. Thanks to the bridge, workers will have access to the site through the basement’s side, which will not interfere with traffic on the A29.

Tilting operation
An important milestone in the Haringvliet Bridge renovation project was reached on February 14th. The new bridge valve, which has an impressive weight of 725 tons and is no less than 57 meters long, was tilted with the help of the floating sheerleg ‘Matador 3’ and accurately placed on the frame of SPMT trucks. This colossal operation, made possible by the entire team, from engineers to skilled employees of Bonn & Mees, was successfully completed and deserves great credit.

Building a bridge valve is always a complex task. Most of the welding takes place on the underside of the bridge, so the structure is built upside down. After installing girders and troughs at the bottom, the entire structure must be tilted to perform work at the top. Due to the enormous size and weight of the bridge trap, complex calculations and special auxiliary structures are required in advance to safely carry out the tipping operation. The successful tilting operation of the Haringvliet Bridge was therefore an extraordinary milestone in the project.

Bascule basement
While traffic continued to race across the bridge, the Mobilis and Struijk teams worked hard in April in the bascule basement of the Haringvliet Bridge. They worked seven days a week and 24 hours a day to complete the extensive job.

By working intensively now, the summer months can be used optimally for work that can only be carried out when there is no traffic crossing the bridge. In addition to demolishing old concrete and steel structures, construction of the new bridge is already underway in some areas.

Lifting out old bridge valve
On Friday, June 16, the old valve of the Haringvliet Bridge was removed after nearly sixty years of service. Using three floating trestles, the valve, also known as the bridge trap, with an impressive weight of 1,860,000 kg was lifted out. The process of lifting out the old bridge valve was in collaboration with Bonn & Mees Floating Derricks BV and HEBO.

Lifting new bridge valve
After the flawless load out and the successful transport to the Haringvliet Bridge, a crucial moment in the entire project followed on Monday, July 3rd: the lifting of the new bridge valve. Because of the stormy weather, it remained uncertain until the last moment whether the lifting operation could proceed and the decision was postponed several times. Monday morning the wind was still quite strong but fortunately it came from a favorable direction. A final GO followed at 10 a.m. after which the valve was picked up and from then on there was no turning back. A few very exciting hours followed in which all the steps were calmly and controlled.

Lowering a 2,050-ton 57×26-meter bridge, while swaying in the wind, with only 1.5 cm of clearance all around in the basement, was an immense challenge. Wooden wedge-shaped guide beams were strategically placed to force the bridge roughly into place. Tapered pins were used to position the bridge’s pivot points down to the last millimeter.

The largest lifting gantry, Matador 3, carried the entire weight of the bridge’s ballast box, 1,300 tons in total and therefore had a draft of 6 meters. Especially for this, the lifting area had to be dredged beforehand.

Project manager Patrick Bos explains, “The lifting was done with three floating cranes that were deployed almost at their maximum capacity. And although the colleagues of Bonn & Mees Drijvende Bokken BV and HEBO are ‘lords and masters’ when it comes to lifting operations, this was a very special lifting under heavy conditions for them too.”

Almost plug and play
In Hollandia Infra’s factory hall, the bridge valve is already fully pre-assembled. Including the movement work by Machinefabriek Rusthoven and the cabling by Croonwolter&dros. This ensures that installation time on the construction site can be reduced to a minimum.

What next?
The next phase in the project is the adjustment of the tooth track with which the bridge will soon be opened. The teeth on this 20-meter-long 100-ton curved gear track, must be adjusted to 1 mm accuracy with the gears of the moving bridge. An intensive job, during which the bridge valve is moved back and forth with electric winches. Meanwhile, Mobilis colleagues will reseal and asphalt the roof of the bridge basement.