The Treasure Island Bridge will be closed to vehicle traffic on Thursday night from 11pm to 6am Friday morning.
Boat traffic will not be affected as the west spans will be fully operational and the east spans can be used if needed.
The two nose locks on the north span will be rehabilitated. The two hydraulic cylinders and the related fittings that connect the cylinders to the two large steel pins that lock the two spans together in the closed position will be replaced.
The two lock assemblies will also be cleaned and painted. The filters and vegetable-based hydraulic oil in each hydraulic power unit will be changed.
The bridge also will be closed on May 5.
The two hydraulic cylinders removed from the north span will be rebuilt with new seals and installed in the south span along with new oil, filters, cleaning and painting of the nose lock assemblies.
The north span opened in June of 2006 and has had over 27,000 openings.
The south span opened in August of 2007 and has had about 24,600 openings. This preventive maintenance should keep the four nose locks in good operating condition for another 10 years.
The four traffic gates will also have maintenance performed during this closure which can only be done when they are in the lowered position.