The perils of prefab, as Atlantic Yards modular tower is stopped and lawsuits start flying
Poor Popular Mechanics. One of the problems of print versus the web for news is that everything can change between the time you put a story to bed and it comes out in print. They just did a major article looking at the construction of the Atlantic Yards 32 storey modular tower, showing people busily working in the factory.
The key, [Forest Ratner VP Roger] Krulak explains, is the welding of detailed design to standardized production. On a conventional site, workers build from a fairly crude set of construction drawings. Getting everything to fit involves a surprising amount of improvisation. By contrast, 461 Dean is built from blueprints of the sort used in the aerospace industry. The placement of every component is predetermined and referenced to a single, fixed point—no on-the-fly measuring required. "Two guys working off a plan like this can build 20 walls a day," Krulak says. "In a period of three days you're building all the walls for a whole floor." And in two years you've got yourself a high-rise.
Except you don't.
Construction was far slower than originally projected, and was halted in August . Then in September, the lawsuits started flying. Skanska, the construction giant, had given Forest Ratner a fixed price contract to build the whole thing, and then found that in fact they couldn't actually do it. According to Norman Oder of The Atlantic Yards (and Pacific Park) Report,
Skanska claims that the design was flawed.
There is risk in this Project substantially in excess of a conventional high-rise commercial building, and that risk arises directly from a defective design," wrote Kennedy, who also blamed Forest City for unwisely cutting corners in preparing the project.
Developer Forest Ratner blames Skanska.
Forest City, which in available legal filings has not yet directly responded to Skanska's warnings about leaks, has blamed the Skanska for numerous implementation errors and said the builder “belatedly—and falsely—claimed the modular design is defective.” .... Clearly contradicting Skanska’s stance, Forest City in legal papers said that Skanska "confirmed in writing that there were no flaws in the design or constructability of the modular units” that would have caused a material increase in the cost of unit fabrication.
Norman Oder has done an extraordinary job of covering this story, and dug up serious documentation, where each party blames the other for hundreds of pages, that makes fascinating reading. But fundamentally, the problem appears to come down to the basic concept of sticking factory-built boxes into a structural frame, like drawers into a cabinet. The tolerances have to be extremely tight, or errors can accumulate as the building goes up. Steel actually compresses under load and columns get shorter, and beams bend under load; this all has to be taken into account in the design. That's why in many cases, the cladding is added after instead of coming from the factory; getting everything to line up is really hard. That's why Skanska writes:
It is impossible to predict that the building when completed will perform as designed; and in particular, it is impossible to predict that the curtain wall joints will be and, over time, will remain effective barriers to the passage of air and water... [I]n simple terms, no one knows if the building is going to leak.
Forest City is standing behind the concept of modular. According to Norman Oder:
“We believe the system is compelling, and works," Forest City CEO MaryAnne Gilmartin said at a conference September 16, adding that the stall was not a "referendum" on modular, which would be validated by a finished building.
As the spokespeople for the modular construction industry what we can say is: When executed properly, this process is more resource-efficient and reduces the overall construction schedule compared to a comparable site-built project, period! What we do know about this project is that it was “unconventional” even for the modular industry.
So what went wrong here? One source told me that you could see this coming from the day the project started, that both parties were warned that tolerance accumulation was going to be a problem, that there were dozens of red flags. I was told that both Forest Ratner and Skanska were willfully blind.
It's all a really big shame, given how much attention has been paid to this project, how it was going to be a new model for building more quickly at lower cost. Other people are doing it in Britain and China, why not in North America? But as I said in my first post on the building in 2011,
The whole thing boggles the mind. Having worked in prefab for a number of years, I can tell you that it's complicated, more than just piling up boxes like Lego. To have changes in builders and architects, intellectual property battles, and fights with unions in a City like New York while trying to build the world's tallest prefab, and save time and money? Fuggedaboutit.
Read the Skanska document here, it gets scary around page 106. And again, thanks to Norman Oder and his Atlantic Yards (& Pacific Park) Report