Seattle-based Charter Construction was contacted by Chubb Insurance to inspect and assess repairs for a client’s existing cistern structure on a private island located in the Puget Sound San Juan Islands, just north of Seattle. The cistern serves as a reservoir for the island, holding 110,000 gallons of water, and is the sole source of water for drinking, irrigation, pool, and bathing. This was a vital project for its residents.
The owners had noted that the cistern was starting to show signs of collapse. Charter worked with the structural engineering team that was brought in by the insurance company, and the assessment by the engineer and Charter had determined the structure had failed from the ground up.
Charter Construction went through the structural design and construction process to bring the cistern up to code.
The existing structure housed the failing cistern. The building also doubled as a game room and storage.
and supply longevity that comes from having a low-maintenance, simple structure. It also had to withstand the hostile weather environment found in the outer regions of Puget Sound.
Charter worked closely with the structural engineering team through the design process to address the signs of collapse, including:
• Soilerosioncausingthefoundationperimetertocrack • Water draining out of the structure holding tank
• The structured interior rotting and falling apart
Before construction, the Charter had to protect the exist- ing island environment to maintain its fragile ecosystem. Charter built a structure on the island’s tennis court to house all the contents removed from the failing structure during demolition. Local marine transport was used for materials, concrete pumps, trucks, equipment, and soil disposal. There were 120 trips made by barge, and 160 yards of concrete were transported. There were 2,400 cubic yards of soil removed from the project site and transported to Lopez Island (a nearby larger island) for disposal. The soil that went back to the project site had to be inspected and treated to ensure it was not contaminated by any non-indigenous seeds. There were 250 yards of new soil imported to the island.
There was a team of 55-60 people directly performing throughout this project. Labor was transported by the Washington state ferry system to Lopez Island. Trips took three hours one way, and a private boat was needed to get from Lopez Island to the project site. Charter often used its company plane to facilitate consultant review, labor delivery, and cost-efficiency.
Demolition of the pre-existing building. Remnants of the original cistern liner and other plumbing can be seen.
“The location of this project was by far the most unique [of any project we’ve worked on],” says Vavi Brinkley, project manager, and Wes Snowden, director of CDR development and insurance team leader at Charter. “We were at the mercy of the tides when it came to material delivery and export. A large portion of the project was directly tied to preserving the natural setting and pro- testing the shoreline.”
Cost control was also essential. Due to the remote location, using local resources was essential to the financial well-being of the project. Charter’s team worked with local resources to build relationships and obtain subcontractor bids to carry out the project scope. Charter used the knowledge of both the architects and engineers to ensure all scope was carried out and that nothing was missed, even when performing value engineering. This also lowered the need for RFIs.
The buildings on the island had to be built for longevity and to withstand severe natural elements including wind storms, heavy rain, and saltwater. Unlike the original failing cistern/shop that resided on the property, the new structure was built with an easily replaceable liner and is now a long-lasting, easily serviceable structure. Numerous pro- professionals including engineers and product specialists were called upon to ensure the design was sound and met the needs of the client.
This project presented many challenges — the biggest being the coordination of access to a remote island location.
Brinkley says, “[Some of our biggest concerns were] how would the weather impact the project? Was the water deep enough surrounding the island to bring in barges and heavy equipment? Was it even a possibility to import concrete to the island in a timely manner without it setting up? Would we be able to find subcontractors willing to work within the logistics of a project?”
The need to schedule the use of local marine transport for concrete pumps and other job site necessities was critical since there were no direct road routes to the project site. Using local transport created steady project timeline revisions and required the team to be flexible when working with different trades involved with the project.
The Charter team also learned that construction costs are much higher when completing work in remote locations. “Keeping this in mind is essential when monitoring and maintaining costs for a project like this,” Brinkley says. “Simple items such as materials delivery or scheduling labor suddenly become complex tasks when factoring in ferry/shuttle timelines or tide schedules. These factors can impact the overall project schedule and budget quickly.”
Foundation and cistern prep work prior to concrete.
Concrete deliveries arrived via barge; there were no accessible routes via road to the island. All deliveries had to arrive via water transport.
Completed cistern building. The new building features a new game room, the addition of a shop and storage, and was restored to its original condition.
This was Charter Construction’s first opportunity to complete private island work. Charter delivered the cistern as specified, returned the island to its original condition, and completed the project in the two-year anticipated duration without any accidents.
“Watching the team come together and find solutions to the logistical and construction challenges that came about daily [was the most rewarding aspect of this project- ect],” says Brinkley. “The final product blended so well with the natural environment. It is difficult to believe how such an intrusive project left such a minimal impact on its surroundings.”RIA