The final piece of the tallest building west of the Mississippi was put in place last week. Construction workers installed a 10-ton steel spire atop the 73-story tower, giving the building its final height of 1,100 ft.
The spire is the final piece of the tower’s distinctive sail-shaped roofline, which will feature an infinity pool and an observation deck with city views that extend to Santa Monica. The building is the first in downtown L.A. to be constructed without a flat roof. It will also include a luxury hotel on the upper floors, offices on the lower floors, five levels of subterranean parking as well as a five-story podium with retail and dining options.
The tower is also built to withstand severe earthquakes. Its gravity system consists of a concrete core wall with steel box columns (called buckling-restrained braces, or BRBs) and structural steel framing outside the footprint of the core. The BRBs serve as overturning resistance and are supported by the core. Forty of them are being used for the lower configuration of the building and span across three stories of office space. Each one weighs more than 23 tons and is rated for 2200 kips. An “electroslag” welding technique was used to weld the BRB gusset plates to the steel plates embedded in the concrete core wall. (See our previous post about the project for more on the BRBs.)
Thornton Tomasetti provided the structural engineering and performance-based design services to engineer-of-record Brandow & Johnston. Schuff Steel (an AISC member and Certified fabricator) fabricated and erected the structural steel for the project. AC Martin is the project’s architect and Turner Construction is the general contractor.
For more about the project, visit www.wilshiregrandcenter.com.