Whidbey Island, WA
Located on Whidbey Island in Washington State, Fort Casey was one of 29 locations chosen for updated reinforcement. As a part of what was known as the “Triangle of Fire”, Fort Case, Fort Worden and Fort Flagler had to defend the entrance of the Puget Sound. Construction began in 1897 and ended in 1901 but the fort was equipped and used for training until the mid-1940’s.
In 1955, Washington State Parks acquired Fort Casey and opened it up for public use. With the help of some government funds, the fort grounds had regular maintenance but other parts of the Battery Moore section were in major need of some repairs. Most of the original concrete showed major signs of damage due to substantial corrosion of the reinforcing steel.
Finally in 2006, the Washington State Parks department made a budget of $600,000 to begin a full structural overhaul on the Battery Moore. The restoration was going to return the structure to its original glory while adding some modern elements along the way and with the use of batteries, lights and speakers it would turn the Battery into a live action example of how Fort Casey operated in the early 1900’s.
Phase 1 of the Repair
The engineering and architect team inspected and developed a scope of work for the impending repairs. After a full survey was performed, the focus was not only on repairing the existing structures but also about protecting against the brutal salt air from the Puget Sound. With all of this in mind, the design team put together a scope of work for Phase 1 that included repairs on gun emplacements 3 and 4 with gun emplacements 1 and 2 to be done in Phase 2.
During Phase 1 after the concrete preparation was completed, the repair work began with the cathodic protection on the existing square bar steel reinforcement. This was crucial to the project as the original concrete was mixed using local sand and aggregates directly from the sound. The existing concrete showed high levels of chloride so any materials used had to prevent future corrosion. All repair mortars were highly polymer modified and included integral corrosion inhibitors to protect the surrounding steel. There was also a significant amount of epoxy injections performed on many of the vertical surfaces while FRP materials were used to strengthen the deteriorated columns.
Phase 2 of the Repair
Over the next 10 years, additional funding had to be secured to begin Phase 2, which came out to approximately $200,000 (a third of the Phase 1 budget). To repair 1 and 2 of the gun emplacements, the scope of work had to be paired down significantly. With another 10 years of deterioration to take into consideration the focus of Phase 2 was mainly to restore the structural integrity of the Battery Moore.
When Phase 2 began, the team noted that there were areas with extreme cracking and some critical areas on the verge of collapse. While preparing the concrete, the source of existing concrete aggregate needed to be addressed. There was large rounded river rocks some 4” in diameter that were used throughout the gun emplacements and in conjunction with this system the existing concrete became extremely soft. As the crew removed the deteriorated concrete, some areas became so fragile that they would disintegrate on impact with an electric chipping hammer. No heavy equipment was used in the prep work due to the fragile structural capacity of the existing concrete. With most of the square steel reinforcement intact after sand blasting, the existing reinforcement was coated with epoxy rebar stirrups to support the repairs.
Sika Product Solution
In conclusion, Sika was honored to contribute products to help aid in the restoration of this historical landmark. Overall, the impact of both repair phases were very extensive but the contractor was able to restore the Battery Moore into a safe and education public area. People are now able to wander the grounds and begin to feel the sense of what it was like to work and live in Fort Casey during both World Wars.