The open-concept hall has floor-to-ceiling windows to enjoy the best views of the coastline and Possession Sound. Photograph by Benjamin Benschneider, courtesy of IMCO General Construction

The Washington State Ferry operated by the Washington State Department of Transportation is the largest ferry system in the United States. This is the first new terminal in 40 years. Its complex site conditions and cultural significance have affected the design and construction of a $187 million project. The project is divided into multiple contracts to ensure on-time delivery. 

To alleviate congestion and earthquake problems in the 63-year-old terminal surrounded by other developments, the new Mukilteo Ferry Terminal is part of Interstate 525, the state’s second busiest ferry route with 4 million passengers per year and is expected to be walkable By 2040, the number of passengers will increase by 124%-built one-third of a mile east of the existing structure, a gas station abandoned by the US Air Force during World War II-causing environmental pollution.

At the same time, as the signing site of the Cape Eliot Treaty of 1855 and dozens of Native American tribes and countries, the site has profound cultural significance. 

Dan Alire, KPFF project engineer, said that the combination of culturally sensitive land and potentially contaminated areas meant that the dock site was elevated 7 feet. "We need to be very sensitive to this cultural meaning, which really drives many decision-making consulting engineers on the project. 

Nearly 50 subcontractors and as many as 80 personnel were on site at one time, and the leaders of the site held weekly cooperation meetings to let the entire team understand the overall situation and upcoming work. Photograph by Benjamin Benschneider, courtesy of IMCO General Construction

The design of the new terminal building is a 30-foot x 100-foot coastal Salish longhouse with a large meeting hall, and enjoys water views and sustainable development features with the coastal Salish tribe-with LEED gold as the goal. Including photovoltaics, rainwater harvesting and natural building ventilation. Brett Himes, IMCO's senior project manager, stated that the team is working within the sustainability goals, sourcing specific types of wood locally and obtaining appropriate certifications. "We spent a long time finding suitable materials for cross-laminated wood panels," he said. 

Himes said that the glulam frame and cross-laminated wood roofing system were self-finished projects by IMCO. "This is a very challenging range because the solar system is integrated into the lid," he said. "There are a bunch of routing channels for wiring." Because of the schedule in the fall, they faced the risk of weather affecting their work, so they acted quickly. "It is an amazing feat to be able to build a roof as quickly as we do," Himes added. "It looks great, wood and glulam. All the cedar siding on the structure really completes the building." 

IMCO took over after the previous contractor built the foundation, and found that the foundation was not inclined and needed to change the steel order, wall thickness and elevator shaft. IMCO's laser scanning ensures accuracy. 

The staff of IMCO laid the concrete foundation for the maintenance building. Photo courtesy of Will Austin Photography, courtesy of IMCO General Construction

Respecting the heritage and culture of the tribe requires innovative thinking, because the team is almost impossible to conduct on-site excavations. The team, including IMCO General Construction, leading the onshore portion of the construction project for $51 million, must find a pleasant medium to raise the site as much as possible to bury all utilities without excavation, and at the same time Prevent coastal flooding and over-expansion to fill the budget with expensive. The tidal range of up to 18 feet makes the design more tricky, because the elevated passenger bridge must operate at both low tide and high tide, and both have an appropriate ADA slope. This is totally a balancing act.

Dealing with multiple contractors on site, as well as doing onshore and offshore work at the same time. "No one really knows what will happen," Himes said. “We all play in the same sandbox and coordinate well. We have established a good partnership [with contractors and owners] to facilitate each other’s work and complete the work safely." 

The history of the site provides ample direction for construction. In addition to the legacy of the treaty providing a strong background for the design of the building and limiting areas where contractors may interfere, the history of pollution from the site's former fuel tank yard and ammunition facility set the tone. IMCO has established a process in cooperation with the country to classify all soils and deal with pollution off-site in a timely manner. "We are fully prepared for this, we deal with employees, and when we encounter problems, we will deal with them quickly," Himes said. "We may have delays, but we solved the problem very well." 

The tribal cultural works of local Native American craftsmen are displayed at the toll booth of the Mukilteo Ferry Terminal. Photograph by Benjamin Benschneider, courtesy of IMCO General Construction

Bryant Bullamore, WSF construction manager, said that the test boreholes set the boundaries of culturally sensitive and environmentally sensitive areas, and the archaeologists on site ensured they abide by all tribal agreements.

But even after careful planning, the site’s history continues to throw old pipes, old fuel lines, and debris into unexpected places. Himes said that coordination and planning kept the project on track. 

The plan also enabled IMCO to resolve any concerns that might delay the project in advance. After hearing about the delay in utilities for another Washington state ferry project in Seattle, IMCO formed a working group to convene stakeholders within 18 months of completion to ensure that the commissioning would not be delayed. 

"Because this is a brand new terminal, there are no protocols in place for fiber optics, Internet, telephone, and electricity, and there are no multiple items that must be handled during construction," Himes said. "We worked closely with DOT-although this is not our real responsibility-to come up with a planning tool because we fear that we will not have the utilities we need." 

This process helps to complete the project on time, and IMCO takes the lead in efforts to coordinate with the owner to make decisions that move the schedule forward. "I think if we don't have that planning tool, things will get stuck," he said. "The transparency between the teams is very good, and we look forward to the future, and finally did not deal with all the problems." 

The project started in 2017 and opened to traffic in the spring of 2021. It includes a terminal building, a maintenance building, overhead passenger loading, a toll plaza with four toll stations and seven parking lanes, a water docking and loading structure, and a bus connected to the transit center. Cars and trains, as well as improvements to intersections and promenades. 

Due to concerns about shutdowns related to the sensitivity of the site, the project was divided into four different contracts to ensure that it moved forward. Although this adds to the complexity of coordination, the contractors cooperate well and keep the project started on time. It also opened the project to contractors with unique expertise.

The team stated that the sustainable design of the project is beneficial to the surrounding communities because safety, access and waterfront areas have been improved. Photograph by Benjamin Benschneider, courtesy of IMCO General Construction

Orion Marine Group built the high-risk part of the basic trestle, while IMCO used trenchless technology to treat the deep rainwater system to avoid disturbing the site. Manson Construction performed the remaining maritime works, while IMCO built buildings, road works, and utilities in separate contracts. "The different contracts and phases are an important part of how we proceed and how we mitigate some of the major risks that we know exist," Alire said. 

Coordination with the contractor did not stop, as multiple state agencies, the city of Mukilteo, and 11 federally recognized tribes were all part of the project. "There are so many people, so many unique parts," Alire said. 

The site required an innovative rainwater system, including bioretention facilities, modular wetlands, and a large permeable pavement sand filtration system, all of which work together to treat water. IMCO said the project is similar to a huge filter to drain, clean and discharge runoff. The parking area for 250 cars is equipped with filter cloth, sand and gravel. IMCO proposed a plan to crush the existing concrete and reuse it as a filler instead of completely dismantling and removing it from the site. This helps with the timeline and budget, and reduces the risk of discovering or affecting potentially sensitive archaeological areas below. risk. 

Himes said that a permeable concrete area about the size of a football field is used to collect all rainwater "like a bathtub." There are no manholes, sumps or pipes, just an infiltration system that filters and cleans the water before releasing it back to Puget Sound. , "The system results are very good."

Coordination with the tribe goes beyond the historical nature of the site. Architect LMN is committed to tribal heritage throughout the design of the terminal, and IMCO is involved in helping to add tribal art to the two large glass elevator shafts by the water, which are the first things passengers see when approaching the building one. 

Himes said that IMCO needs to figure out how to put the Tulalip Tribe artist's work on the glass and digitally print it between two glass plates. "It's cool and big," he said. "It is very important to listen to the artist and adapt as much as possible, not just to interrupt and say that this is what is happening, but to bring him into the team. This is much more than our glass contractor expected, but we I have to say,'We will work as a team and make sure we do this.'" 

It is not always unusual to have strong support and teamwork on a project, but Himes said that it is valuable to be willing to solve problems in the difficult bidding work and deal with a large number of problems and challenges in a timely manner. "We are public Low-priced bidders for work, from a relationship point of view, this can be difficult because there are a lot of financial burdens," Sims said. "I think the team involved couldn't be better. We don't want the work to end." 

Tim Newcomb is a newspaper and magazine reporter in western Washington, covering the design and construction of buildings and transportation in the Northwest.

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