UPDATE: City Hall Hearing Held on Millennium Tower's Sinking Problem
SAN FRANCISCO (CBS SF) -- San Francisco's leaning Millennium Tower was the focal point of an hours-long City Hall hearing today. It comes after it was found construction on the retrofit to help stop the tower from sinking and tilting was actually contributing to it.
Experts and the city leaders made it clear that as it stands right now, the Millennium Tower is not in any imminent danger of structural failure. The chief engineer says it can actually tilt far more than it already is. But a city supervisor is skeptical.
ALSO READ: More KPIX 5 coverage of Millennium Tower
Supervisor Aaron Peskin called for the hearing a few months ago when it was discovered construction work on the voluntary retrofit, referred to as the Perimeter Pile Upgrade, designed to fix the tower's sinking and tilting, was actually making the problem worse.
Supervisor Peskin asked the fix's lead engineer Ron Hamburger if the building might have been better off without the fix.
"If we had not done the fix, the building would have settled and tilted as it apparently has today in about four years," Hamburger replied. "The building would have been better off today, but it would not have been better off four years from now."
Hamburger clarified what we have been reporting, that the fix was voluntary.
"In our opinion, the fix has never been necessary from a structural perspective, from a safety perspective," he said.
He also gave supervisors a timeline of the tilting: In 2009 when the building was first completed, it was tilting four inches to the north and zero inches to the west. By 2018, the building was tilting six inches to the north and 14 inches to the west. By 2020 when the perimeter pile upgrade started, the building was tilting seven inches to the north and 17 inches to the west.
By the end of August, when construction on the fix was put on, hold the building was tilting nine inches to the north and 23 inches to the west. As of Thursday, the Millennium Tower is tilting 9.5 inches north and 23.5 inches west.
But Hamburger says the numbers are not as dramatic as they sound. He says they have new data that suggests the building can tolerate a lot more.
"We just recently completed an update of that evaluation, where we looked at the building tilting as much as almost 3 feet to the north and almost 80 inches to the west," said Hamburger.
"The question is, how does the building perform in a high magnitude, seismic event, the big earthquake," said Peskin.
Limited work on the tower's retrofit got the green light to continue last week after a test on a less disruptive construction method proved to work. During the hearing Hamburger said engineers have increased their frequency of monitoring settlement and tilt.
But after the hearing, Peskin told KPIX he has more questions he wants answers to.
"I don't think that the building is in imminent danger, but I do think the city has the obligation to plan for the long term," said Peskin.