Painting bridges while waterway remains open

In the Lemmer - Delfzijl waterway, Bridge Farmsum received a major maintenance job. First, the rust present was blasted away. Then the drawbridge and bascule bridge were completely repainted. Sealteq carried out the total paint job in exactly three weeks.

When the Department of Public Works put out the application for the work, it was clear that execution time was an important item. The bidder with the shortest execution time and the least inconvenience to the surrounding area scored notional points and thus increased the chance of winning the work. This was reason for Sealteq Noord and contracting combination Van de Herik - SPIE to focus on this. They presented a Plan of Action with a lead time of three weeks. "Actually, it was a mission impossible," says Marcel Vrijs, project manager of Sealteq Noord. "We had to work extremely smart to make good on this promise."

Working at night

With the bascule bridge, Sealteq could get to work right away; the small lock was closed. The challenge was in the drawbridge. "About 50 to 100 ships pass through here per day," Vrijs says. "And the waterway had to remain open. That made it virtually impossible to work from our ship. In fact, if we had to move our ship 50 times a day to clear the fairway, we would hardly get around to working." On this, Sealteq decided to carry out the work on the drawbridge at night; the number of passing ships then drops to two to three.

At high altitude

The high water level and favorable weather conditions in late summer worked in Sealteq's favor. To secure the high work rate, the work vessel was equipped with heaters and air dryers, but these proved unnecessary in the high temperatures. "We first sprayed the underside of the bridge. Then we opened up the bridge so that we could tackle the balance plus the hameitorens from 20 m high aerial platforms. That took quite a bit of courage. With the continuous deployment of six craftsmen, the pace of work remained high."

High quality

The requirements for the paintwork were high. The paintwork had to protect against deterioration of the substrate from all non-mechanical influences. After maintenance, the bridge was not allowed to show corrosion, detachment from the substrate, blistering, cracking or chalking. And that for a period of seven years. Vrijs: "For this, we chose PPG's three-layer coating system. We have already applied this coating system several times; it only has good references. The seven-year warranty was provided by the paint supplier."

Thanks to the painting work, the lifespan of the bridges has been significantly extended. And Vrijs looks back on the work with a good feeling: "We completed the work exactly within the promised deadline and during this period the waterway remained accessible."    

Text | Liliane Verwoolde   Image | Sealteq North