Wednesday, June 15, 2016

Why did debris fly off B3 tower? Contractor says site up to code, blames high winds (but now will exceed code)

So, why were pieces of wood and cement flying off the under-construction 38 Sixth Avenue (aka B3) tower the past two Sundays, alarming residents and triggering partial stop-work orders from the New York City Department of Buildings (DOB)?

Blame the very high winds, said executives for Tishman Construction, which is the general contractor for the site, currently a 16-story superstructure on its way to be a 23-story building.

That explanation--as well as an offhand analogy to tornadoes on CNN--left a conundrum for listeners at last night's bi-monthly Atlantic Yards/Pacific Park Community Update meeting, held at 55 Hanson Place.

As the executives put it, the site safety plan was up to code, but violations ensued when the wood started flying off.

That suggests that, for buildings of a certain height in the notorious wind vortex area around the Williamsburg Savings Bank tower (see 2003 article), the construction safety code is not enough. Indeed, the executives said they are taking several measures beyond the code to heighten safety.

Atlantic Yards as a special case

In other words, Atlantic Yards/Pacific Park, a huge project tightly wedged into a residential district on two flanks, is a special case. (The one wind study conducted regarding the project, released in November 2006, concerned the significantly windy impact of the finished towers, not the impact of wind on construction.)

As Regina Cahill, president of the North Flatbush Business Improvement District and a longtime neighborhood resident, put it last night, “It seems this is another case of specific site logistics, because of the area that it’s in and the high vortex winds we’ve all experienced…. have a clear effect on this building."

She urged those overseeing construction "really attend to the high wind conditions around the site. Because it’s only going to get worse."

Somewhat similarly, Empire State Development (ESD), the state agency that oversees/shepherds the project, required 16-foot construction fencing--twice the height that's typical--to protect Prospect Heights residents from noise and dust around the southeast block of the project. 

However well-intended, the fencing has narrowed streets, caused traffic jams (and honking), and, residents believe, contributed to several vehicular crashes.

"We know that everyone recognizes this is an atypical project due to its location and size," the Barclays Center Impact Zone Alliance, a coalition of nearby stakeholders, said in a letter read at the meeting last night expressing hope and appreciation that recent coordination with ESD will lead to more community responsiveness. 

That was read before the Tishman discussion, but seemed relevant.

"Freaked out and frustrated"

"As you can imagine, we're feeling as freaked out and frustrated as you are about the incidents of debris coming off construction during the high winds," said Forest City Ratner Chief of Staff (and Greenland Forest City Partners spokeswoman) Ashley Cotton, leading off the discussion.

"I have invited my colleagues from Tishman to explain what's going on, and why this will never happen again," she said.

(However, it did happen again, within the week, which suggests that the extra precautionary measures were not implemented by last Sunday. It was not explained last night exactly when the extra measures were decided on, or fully implemented. Presumably, full implementation before this past Sunday would have precluded the second incident.)

Eric Reid, Stephen LaSala, Miguel Padin

Tishman's explanation

Tishman Senior VP Eric Reid began by explaining how "safety is a cornerstone of our company," and how they required safety plans from contractors, and follow a post-Superstorm Sandy storm preparedness bulletin from the DOB.

After the incidents, he said, "we've had multiple reviews from the [DOB's] BEST [Buildings Enforcement Safety Team] squad and other DOB inspectors in our building... They have no observation to make. If it was anything minor, we would have addressed it right away."

Tishman, he said, hired an outside engineering firm to inspect the guardrail system systems and decking operations, the source of the debris that fell off the building. The last of those outside reports were submitted last night to DOB. "I’ve just had a confirmation that what they’ve seen on site," Reid said, "does meet the storm preparedness code."

Tishman has increased oversight, he said, making "the five or six key personnel who handle these materials every day... personally accountable to the DOB, by name, so it’s not just a faceless field staff." They also have required "daily correspondence from those accountable individuals, in the field" to the DOB, "ensuring that the guardrails are secure."

Also, Reid said, Tishman has increased design standards in two cases beyond the bode. The "vertial nets" at the perimeter of the building are required to be only five feet high, but they've now installed "full-height vertical nets," which are the height of a building's floor, presumably at least nine feet.

Tishman has also heightened the attachment of guardrails--the perimeter fencing that keeps workers from falling off--to the deck. "We've increased the number of stanchions," he said, and have "banded the guardrails back to the deck. So if there is a wind event, the guardrails now have more support, and they’re also lashed back to the plywood deck."

"The BEST squad has asked for a number of reports," he said. "We expect a re-inspection tomorrow, and the stop-work order to be lifted shortly thereafter."

Asking questions

If they were code-compliant, I asked, how then did this happen?

It was due to the incident, Reid said, and Cotton followed up. "If you’re code compliant, and an incident happened, then you’re technically not code compliant."

Tishman's Miguel Padin added, in response to my question, that the DOB had levied violations which should result in monetary fines, which will be administratively adjudicated.

What caused the wood and other materials to blow off, asked resident Steve Ettlinger.

"High winds," replied Reid.

"It was insufficiently secured," Ettlinger followed up.

"After the incident, we reviewed the plywood, the guardrail, it still had the nails sticking out," Padin responded. "It just so happens that the wind picked up the plywood... It wasn't that it wasn't secured as required… You have on TV, on CNN, you have these tornados passing through areas, it rips everything apart... There's only so much you can do."

(I'm not sure that the Williamsburgh bank wind vortex is sufficiently analogous to Tornado Alley.)

Padin then mentioned some of the additional safety measures, and added that the deck has openings to allow wind to escape, which also should heighten safety. "We don’t want incidents to happen, we don't want people to get hurt," he said. "It's in our best interest to make sure our site is safe."

Another hazard?

Prospect Heights resident Robert Puca said those walking by the building often see wood planks sticking out from the perimeter of a floor.

"That's not a code violation," Reid responded. "That's banded and stacked, ready to be lifted by the crane to the next floor. It's braced in the back."

Puca said the wood is visible overnight.

"The code allows you to stack material," Padin responded, noting that one-third of the length is permitted to stick out from the building's perimeter.

I wonder if they're rethinking that one too.

No comments:

Post a Comment