Loading and unloading platform of temporary RHB bridge elements

Much of the soil for dike reinforcement Tiel-Waardenburg is delivered by ship. A temporary loading and unloading platform consisting of four coupled Retro Bridge bridge elements of the heaviest category (RHB) has been created near Opijnen in the Waal River.

Retro Bridge has been engaged by construction consortium Mekante Diek to supply four Retro Heavy Bridge elements. "Usually we rent these bridge elements for highway applications," said Han Kastermans, Retro Bridge's director. "The elements meet the current European standards, EURO code I-III Load Model 1,2 and 3. This enables us to achieve a maximum free span of 40.5 meters." Such a large span was not an issue at dike reinforcement Tiel-Waardenburg. There are other "forces" at play here.

Extreme loads

Four coupled RHB elements of 13.5 by 2.5 meters form a platform of 13.5 by 10 meters. "The elements were transported from our yard in Beringe to Tiel and lifted onto a pontoon. Then they were placed in the water with a crane ship on the specifically provided supports," Han explains. "We then bolted the elements together to form one rigid platform. It forms the 'home base' for large cranes bringing sheet piles and clay ashore. So the platform must be able to withstand extreme loads. But our RHB concept is well entrusted with that. The cover plate alone is 22 mm thick. The element therefore has a weight of 18.5 tons. Specifically for this application, we have equipped the elements with an anti-collision construction at the head, consisting of special guardrail posts and sleeves, which are designed to withstand a horizontal impact. On both sides is our standard BN catch rail."

Mekante Diek constructed an earth wall that acts as an entrance and exit ramp to and from the platform. "This could also have possibly been done with a temporary bridge construction, but was not chosen here," says Han. The RHB platform will remain in place for at least three years. "After that it will be dismantled and we can reuse the bridge elements elsewhere. All in all, a great project for us that underscores the versatility of our temporary bridge elements."