Starting at 5 p.m. Saturday, more than 2,000 truckloads of concrete will be driven through downtown L.A. as workers begin building what promises to be the tallest structure west of the Mississippi.
The concrete pouring project at the New Wilshire Grand site is expected to last nearly 20 hours.
Wilshire Boulevard and 7th and Figueroa streets in the vicinity of the construction site will be closed from noon Saturday to 10 p.m. Sunday.
Visitors can take in the bright lights and the armada of trucks from the sidewalks of Figueroa Street and Wilshire Boulevard.
The New Wilshire Grand foundation is expected to be poured without interruption, something that will be verified by an official from Guinness World Records.
An hour before the concrete begins to flow, the USC marching band will lead a parade beside the construction site.
There will be speeches from Yang Ho Cho, chairman of Korean Air, which is developing the project; Chris Martin, chief executive of AC Martin Partners, the project's architect; Assembly Speaker John A. Pérez; state Sen. Kevin de León; Mayor Eric Garcetti; and City Councilman Jose Huizar.
Aside from being an engineering first, the work this weekend is one of the most critical junctures of the project, which is estimated to cost more than $1 billion.
The New Wilshire Grand will feature five levels of subterranean parking, convention space, office suites and a 900-room hotel in the signature tower, which will rise 1,100 feet from the street to the top of its architectural spire.
The logistics for the pour are daunting. Crews have been preparing the site for five months, excavating a pit 18 feet deep and nearly two-thirds the size of a football field.
Ironworkers have lined the pit with nearly 7 million pounds of reinforcing steel, to which nearly 84 million pounds of concrete will be added.
Other foundations are commonly poured in sequences and connected with reinforcing steel and ancillary slabs of concrete, but the engineers for the New Wilshire Grand insisted this foundation be created in one piece to provide the tower with greater structural support.
The major challenge is to make sure the concrete arrives on time. Because it must be poured within 90 minutes of being mixed, CalPortland Co. will have 208 concrete trucks on the freeways as they make as many as 10 deliveries each to the site over the weekend.