With its privileged geographic location and favorable climate, the Lisnave shipyards – built in the 1970s in the Sado River estuary – are a key national infrastructure that serves clients from around the world. Continuous modernization and maintenance have justified the ongoing interventions on this infrastructure. The Lisnave hydrolift, an extraordinary engineering achievement, is used to dry dock ships for maintenance operations. This semi-buried structure is made up of reinforced concrete walls and slabs. The lock chamber, 320 meters in length, was constructed in sections with expansion joints equipped with water-stop profiles.

Intervention goal

This contract focused on the waterproofing of the hydrolift lock joints, which were showing signs of deterioration. Foundation settlement issues had caused ruptures in the water-stop joints. To restore watertightness in the affected expansion joints, the specified waterproofing systems were installed.

Applied Technique

The specified waterproofing systems were installed: the Jeene system was applied to the emerged joints with the lock chamber empty, and the Carpi system was applied to the joints in sections that are permanently submerged.

Additional information

The main constraint on the project was the requirement to carry out the installations with minimal interference to the normal operation of the hydrolift. The functionality of the lock is essential for enabling the entry and exit of ships to the three ship repair platforms. Another notable aspect of the project was the execution of works in submerged conditions.