New Pump and Placing Boom Combination Debut on Seattle Bank Tower
Under the supervision of Seattle-based general contractor Sellen Construction Co., Inc., Brundage Bone’s new BP 8800 trailer mounted line pump and KVM 39 X detachable placing boom are flexing their muscles on the 42-story Washington Mutual Bank in downtown Seattle.
Before this combination went to work on the tower’s elevator core, columns, and decks of the steel-frame structure, Brundage Bone Concrete Pumping, operating from their Seattle location, utilized six boom pumps from their massive fleet to pour the 8-foot deep foundation for the tower in mid-September, 2004.
Rolling onto the site at around 11:00 pm on a Friday night, Brundage began their weekend setting up one S 58 SX, one S 61 SX, and four S 47 SX boom pumps around the 230’ x 240’ x 95’ deep excavation. The city of Seattle accommodated the pumps and 80 trucks from ready mix supplier Cadman, Inc., Seattle, by closing down all traffic adjacent to the site with the exception of one metro bus lane.
“In between pump set up, pouring and tear down, the whole ordeal took around 17 hours,” says Sellen Construction Project Superintendent Rich Olender. “At our peak we were pumping about 900 yards an hour.” Crews installed a total 10,202 cubic yards of low heat, 5,000 psi concrete with a 6-inch slump over a 15-hour period.
The completion of the mat pour marked the beginnings of the new headquarters for Washington Mutual bank, designed by NBBJ of Seattle. The tower is only a portion of the Washington Mutual/Seattle Art Museum Expansion Project located between First and Second Avenues and Union Street. In addition to the bank, construction is proceeding on 335,000 square feet of above grade space for the Seattle Art Museum (SAM), which will connect to the existing 4-story museum. The three buildings will have distinct identities on the exterior but will be linked in the interior at several floors.
The new bank building will allow Washington Mutual to consolidate their facilities from nearly 1.3 million square feet of space in a dozen different locations in downtown Seattle to the approximately 890,000 square feet afforded by the new building. The underground garage will accommodate approximately 710 vehicles, providing parking for most of the bank’s employees as well as weekend visitors to the museum and neighboring Benaroya Hall and Place Market. Washington Mutual has also purchased the existing garage adjacent to the site for further development.
Besides providing one convenient location for bank employees, project owner 1301 Second Avenue, LLC says the project will allow for future expansion and continued growth of both Washington Mutual and SAM.
To complete the pumping and placement of the structure’s concrete, Brundage purchased a BP 8800 trailer mounted line pump and a KVM 39 X detachable placing boom from Schwing America. The pumping/placing team is right on track at the downtown site, and crews are enthralled with the performance of the new products.
“We purchased both the pump and the boom specifically for this project,” says Bill Henshaw, General Manager of Brundage Bone’s Seattle location.
The design of the KVM 39 X eliminates the hydraulic reservoir and motor from the body of the boom.
To utilize the full 114 feet of horizontal reach, Brundage mounted the boom on top of a 52-foot mast erected in the interior of the building’s elevator core wall. Several wedges installed in the form system, designed by Peri Formwork Systems, Inc., Bolton, Ontario, keep the mast stabilized. Further support is provided by a pin driven through the body of the mast that rests on saddles also installed as part of the forming. As decks are completed, the entire form system is raised by an electric and hydraulic jacking system.
Henshaw appreciates the simplicity behind the mounting system. “Because it is actually a part of the forming system, it rides right with us. The general contractor isn’t forced to tie up the crane removing and relocating the boom. We’re using the placing boom on a daily basis and it hasn’t hindered the carpentry, finishing or other labor schedules.”
The uniform concrete placement accomplished with the 39-meter boom and BP 8800 results in less raking and finishing time, meaning contractors remain on schedule while providing a higher quality product. The self-climbing system also provides time saving benefits; the boom remains in the same position throughout the project, with no need for removal and remounting to other locations. With 40,830 square feet of coverage, the KVM 39 X covers a wide area from one location, while on-site cranes remain free to complete other work.
Making its debut as the industry’s premier highrise pump is the contractor’s new BP 8800. Equipped with a Generation III concrete pump, the trailer pump provides high pressure and output to 123 cubic yards per hour, easily meeting the demands of the bank site’s daily requirements. The high-pressure, double shift Rock Valve and 562 horsepower engine provide the performance and reliability needed on a project of this caliber.
“This pump handles everything with so much ease,” says Henshaw. “With all we’ve required of it thus far, the 8800 hasn’t had to work harder than 725 psi.”
Henshaw considers the BP 8800 an investment in Brundage Bone’s future, if not the future of highrise construction. As the most consistent user of separate placing booms in the country, Brundage crews on the Washington Mutual site immediately recognized the endless applications for the line pump. “It’s got so much power, I’d say it’s almost over-qualified for this project,” says Henshaw.
Washington Mutual is expected to begin taking occupancy of its portion of the project in early 2006. The Seattle Art Museum is expected to open the first phase of its new expansion space in 2007.