Belltown, Seattle: Vacate and Dismantle

Look at this eyesore:

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Irreparable: The McGuire Apartments are coming down.
(Photo: Nick Denny)​

The McGuire Apartments, as this twenty-five story building is named, are no longer safe to occupy. The building's owners, Carpenter's Tower, LLC, announced that the structure, home to 272 residential apartments and four retail spaces, will be demolished sometime next year:

"While there are no imminent tenant safety issues, the experts involved in the investigation and repair of the building have indicated that there will be structural issues that could present safety issues by 2011 and beyond," said Brian Urback, with Kennedy Associates, the real estate advisor for Carpenter's Tower. "The McGuire is not in imminent danger of a structural failure and the experts have advised that the building be vacated by the end of 2010. Under the circumstances, we are taking steps to vacate the building over the next several months and to help our tenants relocate. Since the necessary repairs are impractical, the decision of the owner is to dismantle the building."

The building owner has informed officials at the Seattle Department of Planning and Development (DPD) of the extensive construction defects, which principally involve corrosion of post-tensioned cables and concrete material and reinforcement placement deficiencies. The post-tensioned cables are corroding because the ends of the cables were not properly protected with corrosion preventative paint, and the grout used to seal the cable ends and anchors was not the specified non-shrink grout and was defectively installed. As a result, water leaked into these areas and caused the cable ends to rust, and then corrode. In addition, reinforcement placement in the building's exterior frame is defective, resulting in cracking and spalling of concrete, as well as structural impairment.

DPD has written a letter indicating it will issue an order later this year finding the building no longer safe to occupy and requiring the owner to "correct the unsafe conditions or vacate the building by December 31, 2010, or earlier." The letter also indicates that the city is "requiring that the owner monitor the building condition and periodically submit inspection reports to DPD."

(Kennedy Associates)​

There is a bit of irony about this. Carpenter's Tower is owned jointly by the Multi-Employer Property Trust and Carpenter's Union, Local #131. And while many Seattlites have long complained that high-density residential construction around the city has been rushed and haphazard, the sad fate of the McGuire building is perhaps the most blatant evidence—short of catastrophic tragedy—one could ask for to demonstrate the problem. Construction of the building was finished in 2001.

Nine years old, and slated for demolition.

Carpenter's Tower has filed a lawsuit against the architects who designed the building, and the general contractor in charge of its construction.

As Dominic Holden put it, "Well, shit."
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Notes:

Kennedy Associates Real Estate Counsel. "Belltown Apartment Building to Be Vacated and Dismantled". April 10, 2010. PRNewswire.com. April 11, 2010. http://www.prnewswire.com/news-rele...ng-to-be-vacated-and-dismantled-90537069.html

Holden, Dominic. "New 25-Story Building in Belltown to Be Demolished". Slog. April 10, 2010. Slog.TheStranger.com. April 11, 2010. http://slog.thestranger.com/slog/ar...5-story-building-in-belltown-to-be-demolished

 

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wow, 9 years should be criminal, they need more stringent controls for buildings that tall. unfortunately the way companies and corporations are now they want to squeeze every dollar they can and so will shortcut whatever they can to do it and no one is stopping them.

 

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I wonder how much compensation those who bought apartments there will get, enough to pay off the bank and pay there deposit back for there next house i hope

 

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Deconstruction: Slow Drama

It will be a slow, artful process to watch. No dramatic bang. No tumbling to pieces in a cloud of dust. I wondered a bit about the word "dismantle" when I first read it, and need wonder no more:

If the McGuire Apartments high-rise in Belltown is indeed demolished next year, it couldn't be imploded like the Kingdome in 2000.

Instead, each floor would need to be cut apart, their concrete slabs gingerly lowered by crane, from the top down. By then, appliances would have been removed, windows dislodged, wiring yanked out, support steel carefully extracted. This wouldn't quite look like a reverse video of the 25-story building's erection in 2001, but a memorable scene nonetheless ....

.... This would be the first high-rise in Seattle, and among the first in the nation, to be deconstructed under 21st-century conditions that add to the challenge.

Three modern challenges:

• The concrete floors are laced with about 5,000 steel reinforcing tendons, under high pressure. Cut them the wrong way, and pieces of the structure could become lethal projectiles.

• Belltown is a dense urban area with pedestrians, buildings and traffic only a few feet from the shell of the high-rise.

• Most of the material probably would be recycled.

(Lindblom)​

While the owners of the McGuire still say the building must be demolished, the original builders are apparently saying they can fix the problem. No word on what is involved in that, or how much it would cost.

According to Dave Whitley of Nuprecon, a firm hoping to be considered for the razing project:

A spectacular implosion isn't possible because or problems with vibration, dust and debris, experts say. Instead, a variety of methods would be used.

Whitley said only very few buildings are ever imploded. He can't foresee using explosives at all in the McGuire. Once the shell was down to a five- to seven-story height, tall machines could knock down walls and floors, he said.

The most delicate task would be with high-pressure steel that was used to "post-tension" the concrete floors.

In post-tensioning, steel tendons are laced through a concrete beam or floor, then tightened like a rubber band. This compresses the concrete, adding strength and making cracks less likely. The steel bands also help the concrete floor support more weight, so less concrete is needed.

A spectacular example is the 2007 Tacoma Narrows Bridge, whose concrete struts were post-tensioned — to 56 million pounds across two of the three horizontal struts, adding seismic strength.

Typical high-rises require a mere 200,000 to 300,000 pounds per square inch, still enough to hang a semi-truck off the side of a building, said Ken Carper, a Washington State University professor and forensic engineer.

How serious a threat is this stored energy? In 1980, the roof of Congress Hall in Berlin suddenly broke apart and buried a man when steel tendons failed.

Before cutting apart the floors at the McGuire, engineers would need to devise an orderly sequence to loosen the steel tendons.

A healthy level of respect is called for to avoid a whiplash, Whitley said.

(ibid)​

Nuprecon does have experience with this sort of deconstruction; the firm is currently working a project in Portland, Oregon.

Apparently "about 80 percent" of the building can be recycled, but there is a question about how much of that is feasible economically. While concrete costs less to recycle than bury in a landfill, the thousand or so windows in the McGuire building will likely cost more to preserve for resale than could be recovered by selling them to another builder.

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Notes:

Lindblom, Mike. "Belltown high-rise won't be imploded". The Seattle Times. April 18, 2010. SeattleTimes.NWSource.com. April 19, 2010. http://seattletimes.nwsource.com/html/localnews/2011642329_salvage19m.html