Temporary bridges in and over A9 ensure mobility

The road widening of the A9 between Badhoevedorp and Holendrecht by the Department of Public Works is an iconic project in itself, especially for Janson Bridging. With no fewer than eight temporary bridges, four of them in the highway, it is the largest rental project ever for the Dutch division. In addition, the project also has several firsts. For example, the brand new JSB4 bridge system is being used for the first time and the largest temporary highway bridge ever is being built right next to Amstelveen's city center.

A request from construction consortium VeenIX for eight temporary bridges also meant some switching gears for Janson Bridging Nederland, acknowledges Abdelhakim el Harchaoui, Project Manager at Janson Bridging Nederland. "It involves four bridges in the created highway bypass and another four bridges over the highway. The bridges over the highway are different in type and design. Two bridges are exclusively for pedestrians and cyclists and two for combined traffic. The eight temporary bridges are all different in shape, length and span. They are also composed of different bridge systems, ranging from beam bridge systems such as the JSK type and plate girder bridge systems JSB1, JSB2 and the brand new JSB4."

Monitoring on traffic loads

Janson Bridging has its own engineering department, its own project managers and its own mechanics. "We have everything in-house to handle such a complex project quickly and efficiently," says Marcel van Fessem, General Manager at Janson Bridging Netherlands. "The lines of communication between Janson and VeenIX are therefore very short. We also have a huge stock at our disposal, and that was definitely an advantage, given the short time frame in which everything had to be realized. Our new JSB4 bridge system was developed at an accelerated pace for this project, partly fed by requests from other European countries. The JSB-4 is a further development of the existing JSB systems, focusing on a development specifically for highway applications. As a result, the JSB-4 system is a lot stronger and more resistant to fatigue due to the heavy and high volume of traffic movements. The temporary bridge is continuously monitored for (heavy) traffic movements to understand the impact of traffic movements on the bridge elements. With this information, we can prove mathematically that the bridge is sufficiently strong for the remaining period or for deployment in follow-up projects." During the design of the system, Van Fessem says special attention was also paid to the noise produced by a bridge. "As a result, the updated JSB-4 design is significantly quieter than other systems."

With the new JSB4 bridge system, the largest temporary highway bridge in Europe has been built in Amstelveen. "With a length of 94.5 meters and a width of 32.5 meters, it is almost a soccer field," El Harchaoui outlines. "Incidentally, this bridge consists of three spans, each 31.5 meters long. The longest (and heaviest) elements were used in a temporary bridge measuring 81 by 12.5 meters that consists of only two free spans of 40.5 meters." Van Fessem adds: "Our modular concept allows us to use standard modules to provide customization. And that worked well here. Of course there are an awful lot of variables and interfaces that we have to manage, but we do that together with VeenIX."