![]() Hamburger told residents he expects that just taking some weight off the building along Mission “would slow substantially, if not stop” more settlement, adding that preliminary data shows the early phase “has been successful and exceeded the engineering team’s projections.” Millennium Tower Fix Shifts to Hasten Completion ![]() Ultimately, the building will be tied to 18 piles already sunk to bedrock, six on Mission and the balance on Fremont Street. The goal for now, he said, is to stabilize the tower’s north side so crews can dig much more to extend the foundation along the west side of the structure along Fremont Street. ![]() That is about half the load the Mission Street piles will ultimately carry, he said. In an email update Saturday to residents of the building, lead fix engineer Ron Hamburger said three million pounds of the building’s weight along the Mission Street side is supported by six piles that extend down to bedrock on the north side. The high-rise is currently tilting more than 29 inches at the northwest corner, about a third of that lean occurring after construction began back in 2021 on work aimed at stabilizing the building. Still, the task force urged that all new buildings be monitored for at least a decade after construction.San Francisco’s troubled Millennium Tower high-rise is now supported partially on one side to piles sunk to bedrock – bolstering that should assure the $100 million project will be completed without more sinking and tilting of the building, the fix’s lead engineer is telling residents. A tall building task force separately concluded that high-rise buildings - with properly designed foundations - should not sink more than four inches. San Francisco building officials say the city has long-term plans to shore up the seawall that protects the Embarcadero. “If you have all of this going on when you're right near the waterline, in some cases in San Francisco, then you have to worry about big storms that sea level comes up and inundation more frequently.” ![]() Parsons points out that ground level and sea level heading in opposite directions is a dangerous scenario for coastal cities. Parsons says he’s now studying Manhattan, because it is also sinking and faces the same threat as San Francisco from climate change. Not on this sort of scale that you're talking about,” Poulos said. “I've been doing foundation design for, I guess, nearly 30 years now, and it's not something that we've actually ever even thought about. “If you have a series of buildings, fairly heavy buildings all clustered together, they're going to influence each other,” said Harry Poulos, an internationally recognized expert on tall building foundations. He says while there may be no seismic concern for San Francisco, there’s been little research about the collective impact of entire corridors of high rises on the earth below. Oakland-based dance company celebrates 50 years Groundwater loss from adjacent construction has been blamed for the problem by the tower’s developers, while geotechnical experts say the key is that its foundation is not rooted in bedrock. The top nine all weigh more than 300-million pounds, but the only one that’s leaning significantly is the Millennium. Turns out that at an estimated 686 million pounds, the Millennium Tower is the third heaviest building in the city. “Clearly, the most density and the tallest buildings are centered in that downtown San Francisco area, and that's where we see the most calculated cumulative settlement from all of those buildings together," he said. “I looked at every building in the Bay Area, so just under a million buildings,” said U.S Geological Survey research geophysicist Tom Parsons, who estimates that over the last century, 3.5 trillion pounds of development and human activity – including the subsidence tied to loss of groundwater - have led to an estimated settlement of three inches across the entire Bay Area. The Millennium Tower may be the most recognizable sinking building in the city, but one researcher says earth-based and space-based observations confirm the entire downtown area around it is sinking as well.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |