Lisnave Docks 20 and 21, Setúbal

The LISNAVE dry docks, built on the Sado River estuary in the 1970s, provide an important infrastructure for naval construction and repair work.

Over the years, they have been maintained, preserved and repaired on various occasions. Impressive structural rehabilitation works were undertaken in the 1990s, during which 38,000 m2 of concrete walls were repaired. A further rehabilitation phase is currently underway, involving the repair of approximately 18,000 m2 of concrete base slabs, two kilometres of technical galleries and a repeat repair of 5,000 m2 of walls. The concrete is repaired with recourse to hydrodemolition for the removal of the degraded concrete, which is then replaced by applying dry sprayed shocrete using dual-chamber machines. This method has proven to offer great durability over the past 20 years since the walls were last repaired. In an extremely aggressive environment, such repairs have a recurrence rate of 10% over 20 years.