- #Millennium tower tilts quarter four days install
- #Millennium tower tilts quarter four days full
- #Millennium tower tilts quarter four days series
In fact, a second test pile was installed in early December without the Dan Brown firm performing on-site monitoring.
#Millennium tower tilts quarter four days full
“For a situation like this, the reviewer needs to be on site and have full access to what’s going on.” “This is not a proper review,” said Bob Pyke, a geotechnical engineer and critic of the fix effort. 23 memo had been made public at the time the city okayed keeping the drilling firm off-site and limited its role to analyzing daily drilling data provided to them. Neither the latest tilting data nor the Dan Brown Nov. That was the month when fix work was halted as a precaution because of accelerated sinking and tilting. The report cites data showing that additional grout was twice pumped in during installation in August. The report estimates it took at least 5 cubic yards worth of additional grout to fill the void, which is the equivalent to about five tons of lost ground. The report noted that crews had to pump in truckloads of additional concrete grout to fill in the void created during pile installation. That loose layer of sand was then vacuumed up and removed in the drilling process.
While drilling more than 250 feet down, near bedrock, crews inadvertently “mined” or sucked out more than five tons of material. 23 report from the Dan Brown firm suggests an explanation. Soon after that letter, however, the city released data showing that over the four day period that the first 24-inch support pile was installed, the building had in fact tilted an additional quarter of an inch.Īlthough it does not mention any monitoring data, the Nov. Although acknowledging that amounted to an exception to the agreed-to provisions of the testing program, Hamburger said the city’s own appointed design review panel “does not believe this is necessary.” 30 letter – that “settlement monitoring indicates that no additional settlement or tilting occurred as a result of this 24-inch pilot installation.” He notified the city that the Dan Brown firm would no longer be present during upcoming testing. Seven days after that memo, fix designer Ron Hamburger notified city officials – in a Nov. The hope was to prevent losing ground under and around the foundation, because experts say it is a key factor in triggering building settlement. 23, obtained by NBC Bay Area, the firm revealed that more than five tons of soil had been inadvertently removed during the test pile installation. In a technical memo to a city building official on Nov.
#Millennium tower tilts quarter four days series
When the first of a series of 24-inch wide test piles was sunk to bedrock over four days in mid-November, the firm generated another report. Sign up for NBC Bay Area’s Housing Deconstructed newsletter. Veteran geotechnical engineer Bob Pyke said the sudden fluctuation is a telltale sign.Get a weekly recap of the latest San Francisco Bay Area housing news. The water pressure level was recorded at various depths more than 100 feet below the structure, where a layer of clay resides.
At the same time, there was marked fluctuation of water pressure below the foundation on the Mission Street side of the structure. 19 – shows a quarter inch of new tilt, as well as a tenth of an inch of settlement at the time the test installation occurred. The latest data – including the four days that the test pile was installed from Nov. Since work began to shore the sinking structure up on the north and west sides, the building has settled nearly 2 inches at the northwest corner and is now tilting more than two feet at that edge. The monitoring data tracks settlement, tilting and water pressure levels underneath the sinking and leaning structure since work began on a fix for the troubled tower in May.
#Millennium tower tilts quarter four days install
NBC Bay Area TV Newly released monitoring data shows that San Francisco’s Millennium Tower tilted a quarter inch during the four days it took to install the first test pile to bedrock last month. The only engineering expert I know who has experience of this magnitude is Mayor Teedy. San Fran needs to consult with an expert on these types of things before this gets out of hand.
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