成功安装了在旧金山定居千禧塔的陷入困境的基金会升级的24英寸长期飞行员堆之后，建筑物检查部（DBI）已允许安装第二个飞行员堆，从12月1日开始。
“我们的立场是基于三个36英寸产生的最小整体和解和倾斜。飞行员套管和一个24英寸。旧金山DBI临时董事帕特里克·奥里丹（Patrick O’Riordan）在11月30日给千禧塔协会的信中说。他补充说，如果第二个桩的安装成功，DBI将“支持沿弗里蒙特街的另外24英寸飞行员堆的安装”。
Shimmick completed the installation of a 24-in.-dia pile at the 645-ft-tall residential condominium using a revised method designed to stem accelerated settlement that had been caused by the perimeter pile upgrade. The手术在11月19日完成了三个使用修订技术的三个飞行员桩套管之后，这是11月19日完成的。
The foundation team developed the new procedures after the remedial foundation work, intended to correct some 17 in. of tower settlement, had instead accelerated settling and tilting by 1 in.
No Further Measurable Settlement or Tilt
No further measurable settlement or tilt occurred during the installation of the pile and there has been no movement detected since, beyond the movement that was occurring naturally, says Ronald O. Hamburger, a senior principal with Simpson Gumpertz & Heger and the engineer-of-record for the $100-million fix, which has been likened to putting a bumper jack next to a flat tire.
汉堡，谁haltedthe pile work on Aug. 20 after reports of accelerated tower settlement, hopes to get a nod for the third pile “to confirm that the pile installation results are repeatable,” he says.
The combined results of the three pile installations and the three 36-in.-dia casings installed in October will enable the foundation team to predict building settlement and tilt through the completion of the project and will demonstrate that the foundation upgrade can be finished without endangering the tower's functionality or safety, says Hamburger.
对于从11月15日开始的第一批飞行员堆工作，钻探花了两天多了。船员于11月18日放置加固，并于11月19日进行混凝土。
The remedial pilot program, begun in October, involves testing two construction activities: 1) installation of a 36-in.-dia steel outer casing to a depth of about 106 ft below grade; and 2) installation of a 24-in.-dia steel-encased, cast-in-place concrete pile down about 270 ft.
The pile upgrade calls for 52 concrete-filled steel-pipe piles within the steel casings, along two sides of the occupied building. Currently, Shimmick has installed thirty-six 36-in.-dia casings and seven 24-in.-dia piles.
