Clean and green in the Evergreen State

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Bernadette Smith
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04.2014 HOFFMAN BUILDS: Clean and green in the Evergreen State You know the project is a big one when a small portion of the overall scope of work is an eight-year, $320 million job.

1 HOFFMAN BUILDS: Clean and green in the Evergreen State You know the project is a big one when a small portion of the overall scope of work is an eight-year, $320 million job. Hoffman Construction recently put the finishing touches on its part of King County s $1.8 billion Brightwater Treatment System in unincorporated Snohomish County, just north of Woodinville, Wash. The third of the county s three regional wastewater treatment plants, Brightwater is built on 114 acres and designed to treat 36 million gallons of waste water per day. It serves the north end of King County and south Snohomish County. The overall project includes a liquids and solids treatment plant and conveyance system that consists of more than 20 different structures, 14 miles of tunnels for influent and effluent piping, a LEED Platinum environmental education center, and an extensive public trail system. Liquid waste from north end businesses and residences is conveyed to the treatment plant, where it receives treatment by primary clarifiers, aeration basins, membrane bioreactors and disinfection areas and other treatment steps before discharge through a large diameter tunnel system into Puget Sound. During Hoffman s eight years on the job, the team faced a number of unique challenges and offered many cost saving options, resulting in a project that stands as an example of a modern treatment facility that delivers on its promise of being a public amenity. Owners: King County Design Team: CH2M Hill, Brown and Caldwell, Mithun Construction Cost: $320,000,000 Size: 114 acres Location: Woodinville, Washington LEED: Platinum (Education Center)

STORMWATER SOLUTIONS The treatment plant sits on just over half of the property s 114 acres, with the rest of the space dedicated to public use with trails, ponds and sculpted earthwork

Hoffman s early efforts focused on the site s northern 40 acres, where crews performed considerable mitigation work to ensure construction would not affect Little Bear Creek, a

The project was required to obtain an individual stormwater permit; a strict permit typically reserved for projects the size of Sea-Tac Airport.

expensive filtration or chemical treatment systems.

it makes its way into the nearby wetlands and waterways.

2 STORMWATER SOLUTIONS The treatment plant sits on just over half of the property s 114 acres, with the rest of the space dedicated to public use with trails, ponds and sculpted earthwork to limit the visual impacts of the structures and enhance the natural setting. Hoffman s early efforts focused on the site s northern 40 acres, where crews performed considerable mitigation work to ensure construction would not affect Little Bear Creek, a salmon-bearing stream adjacent to the site. Because of the site s size and sensitive surroundings, Hoffman s work was held to extremely high environmental protection standards. The project was required to obtain an individual stormwater permit; a strict permit typically reserved for projects the size of Sea-Tac Airport. To help protect the nearby habitat, Hoffman built four stormwater detention ponds and a land application system that distributed rainwater and construction runoff without the use of expensive filtration or chemical treatment systems. Stormwater is pumped from detention ponds and sprayed onto the rest of the property using oversized sprinklers, dissipating the water and allowing it to cleanse itself naturally before it makes its way into the nearby wetlands and waterways. We appreciated that Hoffman recognized the importance of meeting the permit requirements and took the stormwater management program seriously, said Stan Hummel of King County s Wastewater Treatment Division, who served as Brightwater s project manager during the design phase. We had a design that worked, and resulted in an excellent record of performance over a multi-year construction project. Aerial view of the north mitigation area Mitigation area provided 40 acres of fish habitat Two of the tower cranes were mounted on rails to access the long Aeration Basins and the Headworks/ Grit Removal/Primary Clarifier areas

A detailed 3D laser scan of the site provided precise topography We appreciated that Hoffman recognized the importance of meeting the permit requirements and took the stormwater management

the project required Hoffman crews to flatten the site and bring it to near-subgrade before structural excavation could start.

eventually molded into landscaped berms between the plant and the highway.

Hoffman frequently laser-scanned the stockpile to determine cut-and-fill requirements and balance the material for optimal placement.

3 A detailed 3D laser scan of the site provided precise topography We appreciated that Hoffman recognized the importance of meeting the permit requirements and took the stormwater management program seriously Stan Hummel King County Wastewater Treatment Division Building Information Modeling was applied to coordinate the complex concrete structures EARTHWORK EFFORTS The phasing of the project required Hoffman crews to flatten the site and bring it to near-subgrade before structural excavation could start. Crews moved more than one million cubic yards of dirt, transferring much of it to the west side of the site where it was stockpiled, used as backfill once facility construction was underway, and eventually molded into landscaped berms between the plant and the highway. Crews used Building Information Modeling (BIM) software on many aspects of the project, including the earth movement process. Hoffman frequently laser-scanned the stockpile to determine cut-and-fill requirements and balance the material for optimal placement. The 3-D laser scans were used by a number of the team members throughout the course of the project, from earthwork contractors to landscape designers. Hoffman s phasing of the earthmoving work and close coordination of material placement eliminated hundreds if not thousands of potential truck trips to and from the site. This effort to reduce traffic in the area was extremely important to the community and reduced project costs. Structural excavation and shoring for the headworks/grit removal/primary clarifiers

Mixed Liquor recycle pumps which supplied product to the Membrane basins from the Aeration Basins SHIFTING GEARS TO SAVE MONEY Hoffman offered a number of value engineering suggestions throughout the

4 Mixed Liquor recycle pumps which supplied product to the Membrane basins from the Aeration Basins SHIFTING GEARS TO SAVE MONEY Hoffman offered a number of value engineering suggestions throughout the course of the project. Most significant was its role, in collaboration with engineer CH2M HILL, in adjusting the siting of the structures to reduce the amount of excavation required. When the construction commodity pricing market became increasingly volatile about 60 percent of the way through design, the owner directed the team to work together to find ways to reduce the cost of the project. The project s initial design placed all the physical structures on the east side of the site, which would have required more extensive excavation and shoring to place buildings as designed; two-thirds below grade. Hoffman did extensive analysis of the shoring and earthwork impacts of several alternative site designs and the potential cost savings they would provide, said Patrick Burke, principal project manager with the Bellevue, Wash., office of CH2M HILL. Following a series of workshops with Hoffman and CH2M HILL, where the team balanced functional and aesthetic requirements, the county selected an option that would shift the structures 50 ft to the west, where site topography was lower. This meant more of each structure would be above ground, saving considerable excavation and backfill costs. Careful design of the foreground landforms and landscape provided a site design that still offers visual screening but with substantially reduced earthwork from the original concept, said Burke. It s a great example of providing value: optimizing visuals and construction costs without compromising function. By also realigning some of the building s footprints, Hoffman crews were also able to reduce the distance between each structure so the interconnecting galleries and associated piping could be downsized. The combination of these efforts saved the project more than $1 million.

Neuros Turbo blowers providing air to the fine bubble diffusers Aeration basins fine bubble diffusers being inspected Membrane cassette being uncrated and prepared for installation 48

informed decisions on alternatives, said Hummel. They were able to give us real and meaningful feedback on the cost and constructability of value engineering proposals.

In some cases, Hoffman suggested design modifications that tailored the design to their construction means and methods, Hummel said, resulting in cost savings.

Hoffman also revisited an early design that called for the demolition of one of the light industrial buildings originally on the property.

5 Neuros Turbo blowers providing air to the fine bubble diffusers Aeration basins fine bubble diffusers being inspected Membrane cassette being uncrated and prepared for installation 48 Mixed Liquor header that supplies the Membrane Bioreactor system Aeration Basin under hydrostatic testing Having Hoffman as part of the team during the design phase helped us to make informed decisions on alternatives, said Hummel. They were able to give us real and meaningful feedback on the cost and constructability of value engineering proposals. Hoffman had excellent suggestions, which improved project quality and reduced cost. In some cases, Hoffman suggested design modifications that tailored the design to their construction means and methods, Hummel said, resulting in cost savings. For example, some minor changes to the main gallery footing design allowed Hoffman to use sheet piling and formwork rather than building new formwork at additional cost. Hoffman also revisited an early design that called for the demolition of one of the light industrial buildings originally on the property. Instead of the wrecking ball, Hoffman suggested the former soup company s decommissioned manufacturing plant be used as the temporary construction offices. Hoffman eventually remodeled the building for use as the county s permanent operations and maintenance facility instead of building a brand new structure. This saved approximately $5 million. These money-saving changes, along with other value engineering efforts that included process improvements and alternate material selections resulted in more than $60 million in savings for the project. Hoffman did extensive analysis of the shoring and earthwork impacts of several alternative site designs and the potential cost savings they would provide Patrick Burke Principal Project Manager Office of CH2M HILL, Bellevue, WA

6 Public art is integrated throughout the site and structures

BRIGHTWATER CENTER: EDUCATIONAL CENTER IS KEEPING IT GREEN Brightwater s education and community center serves as a centerpiece for the public on a site that might otherwise be viewed as an

7 BRIGHTWATER CENTER: EDUCATIONAL CENTER IS KEEPING IT GREEN Brightwater s education and community center serves as a centerpiece for the public on a site that might otherwise be viewed as an industrial facility. Designed as the front door of the treatment plant, the Brightwater Center is a 16,000 SF building that serves as a community gathering space, conference center, and educational facility that interactively details the path of wastewater from its origination to its discharge into Puget Sound. Brightwater has partnered with the local non-profit IslandWood to offer programs for local schools. Meeting space is designed to accommodate up to 250 people and can be broken down into smaller configurations. Amenities include an exhibit hall, laboratory classrooms, kitchen facilities and a resource library. It is surrounded by 70 acres of public open space with three miles of walking trails and 40 acres of natural habitat. The center achieved LEED Platinum certification from the U.S. Green Building Council. Sustainable elements include the reuse of existing and recycled materials, natural ventilation and daylighting, energy efficient lighting, radiant floor heating, solar panels made in Washington and reclaimed water for irrigation and toilets.

8 HOFFMAN BUILDS Creative Solutions Value Relationships

2011 Local Outstanding Civil Engineering Achievement Awards Outstanding Civil Engineering Achievement Structures

2011 Local Outstanding Civil Engineering Achievement Awards The Seattle Section ASCE Local Outstanding Civil Engineering Achievement (LOCEA) Awards recognize projects that have improved the quality of