Bridge girders

The challenge

A new crossing over the Albert Canal called for 36 welded plate girders, the longest 32 metres. Road salt, spray from passing barges and an underside that is hard to reach for maintenance led the client to ask for a duplex system: metallizing for the long term, paint for colour and an extra barrier.

Our approach

The girders arrived by barge at our Temse quay and went straight into the blast hall. Metallizing needs a sharper profile than paint, so we blasted to Sa 3 with steel grit and checked the roughness before every spray session. Zinc went on within four hours of blasting and was sealed to close its pores before the epoxy and polyurethane layers. Each girder had its own inspection sheet with film thickness, adhesion and climate readings.

The result

All girders left Temse by water again, which saved 36 exceptional road transports. The contractor received a complete ISO 12944 documentation package, and the system is specified for more than 25 years before its first major maintenance.