High-Level Productivity

Structural Steel Erector Uses New Wire Feeders to Deposit More Weld Metal
August 11, 2010

When completed, Lincoln Square in downtown Bellevue, Wash., will house luxury residences and office space with breathtaking views of Lake Washington and Mount Rainier. Below the residences, amenities include a 16-screen luxury cinema, renowned restaurants, home-related shopping at fine stores, the corporate headquarters of Eddie Bauer, and offices for Microsoft Corporation's North American Sales operations.

Designed by Sclater Partners Architects and built by general contractor SKANSKA (phase I) and GYL Construction (phase II), the facility fulfills the architect's vision of "creating places people gather." Similarly, erecting the structural steel of floors 5 through 29 of Lincoln Square (phase II) brought together the team of Apex Steel Inc., Pacific Welding Supplies LLC/Tec Welding Sales and Miller Electric Mfg. Co.

Apex Steel is a Puget Sound-based commercial steel contractor that employs approximately 100 ironworkers and a small office staff. Its successful approach to construction is based on strict schedule adherence, accurate cost control and a safe, motivated workforce largely comprised of Ironworkers from Local 86.

President and founder Kevin Koester, a union member since 1986 who still "carries his book," built Apex Steel on the principles of integrity, quality and innovation.

"We pride ourselves on safety, being on schedule and adapting to the circumstances," Koester said. "We've done a lot of rare, different projects, and we always figure out a way to do it, and stay safe and fast."

According to GLY's website, the Lincoln Square Office Tower features a concrete core, structural steel frame, and full glass and aluminum curtain wall system exterior. Building services include an HVAC system accommodating 24-hour cooling requirements, with a full integrated and expandable state-of-the-art security system. The building will be connected to Bellevue Place, a mixed-use project across NE 8th Street, by a sky bridge as well as an underground tunnel to facilitate shared parking availability within Kemper Development's adjacent mixed-use properties, referred to as The Bellevue Collection.

Building On Top

One of the biggest challenges in taking on the project was figuring out how to build 25 floors right on top of an occupied five-floor shopping center. Fire protection demands alone required "dedicating three employees to a fire watch, using hoses to wet down all the surfaces to make sure a welding spark doesn't progress further," Koester said.

With an active sidewalk and street on the ground below, Koester's team field-engineered cantilevered nets extending up to 30 feet from the building's walls. One of the hallmarks of ingenuity is improvisation, which is exactly what was required when Koester realized they wouldn't be able to truck in enough steel each day to keep his employees busy for a full 10-hour day. Unlike most construction job sites, here there was nowhere on-site for Apex to park supply trucks, which meant the company had to park on city streets to deliver its material.

"The city didn't want to interrupt commerce, so they gave us from 6 a.m. to 8 a.m. to unload. If we wanted, we could get an extra hour by moving over to another street," Koester said. "The problem is, we couldn't get enough iron to support us for the day, so we decided to work eight-hour shifts instead of 10, which we would have liked to have done."

Perhaps the biggest logistical challenge faced by Apex, however, was erecting the 400-foot tower crane on top of the existing five-story building.

"There's a fine line between the structural engineer's means and methods and reality," recalled Ironworker superintendent Joey Miller. "While a computer can make design easier, there's no computer that can substitute for the actual process of hanging steel. It's up to us to figure out how to actually put a structure together."

The tower crane support is largely built from 12-inch-diameter steel pipe and thick stiffeners. Each corner of the crane base, which is actually on the 6th floor, has three support pipes that transfer the load to the core of the building, which is tied in to the core with more pipe on the 5th floor.

"We couldn't just drop in a pre-fabricated crane and support system," Miller said. "We had to finagle it in piece by piece, weld the pieces together, tie the crane back with a ton of come-alongs, and the erect the whole structure so that it was level within a sixteenth of an inch up and down its 400-foot height."

It took Apex Steel six months building the tower crane system and pedestrian protection before the rest of construction could even begin.

Productivity Challenges

Despite the initial challenges, Apex Steel maintained its competitiveness throughout the entire erection process, which lasted from January through October 2006. One way Apex Steel stayed on schedule was by flux cored welding with Miller's new SuitCase X-TREME 12VS wire feeder. Designed to meet the demands of the construction welding market, this 35-pound feeder features a rated output of 425 amps at 60-percent duty cycle.

"The SuitCase X-TREME 12VS is a tool that helps us be more productive," said Koester. "It also gives us the versatility to make full penetration welds on columns that are 300 pound-feet to 400 pound-feet, as well as make partial penetration welds on columns that are 150 pound-feet to 200 pound-feet. For example, we used this feeder on the Lincoln Square project, which has smaller welds, as well as for our recent work at SeaTac airport and Overlake Hospital in Bellevue, where the columns were larger."

Because the SuitCase X-TREME 12VS can weld at much higher outputs, contractors such as Apex Steel can increase deposition rates by 10 percent to 20 percent or more when welding position and procedures permits higher amperages.

At the heart of the SuitCase X-TREME 12VS is a contactor rated for an output of 425 amps at 60-percent duty cycle. Other design improvements include digital meters as standard, overall enhanced arc quality and a Soft Start function that improves arc starts with larger wires. From service perspective, maintenance personnel especially appreciate the ability to remove the chassis in 15 minutes with one tool.

The SuitCase X-TREME features a polypropylene case, which the military uses to protect computers and other electronic equipment. Not only can the case withstand normal construction use, it can even withstand being run over by a 1-ton pickup truck. "Slide rails" along one side of the case allow the feeder to be dragged by the gun or power cable without damaging the case or cause dirt to pile up on control.

"Time is a huge factor. That's where a steel erector can make it or break it as a company," Koester said. "If welding equipment breaks down, that can cause another remobilization of tools, manpower and work preparation at a new location. On a job like this, the labor costs alone are about $85 to $90 per man, per hour.

"That's why we need to use reliable equipment like the SuitCase X-TREME feeders. They've been used and abused, but are holding up well."

Author Information
Mike Vandenberg is a product manager for Miller Electric Mfg. Co.

         
 

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