Photos: The grand plan: building the Wilshire Grand tower

Construction workers guide a jumping wall form system into place as it is lowered into position by a crane into the core of the Wilshire Grand tower. (Mel Melcon / Los Angeles Times)

April 25, 2014 8:58 PM PT

Beneath its design is the engineering of what is arguably the most complicated high-rise to be built in the U.S. Calculated to sway during powerful Santa Anas and absorb ground movement during severe earthquakes, it is wedded aesthetically and technically to the unique footprint of the region.

Carpenters do warmup exercises to loosen their muscles before starting their shift on the Wilshire Grand tower. (Mel Melcon / Los Angeles Times)

Chris Martin, chairman and CEO of Martin Project Management, at the Wilshire Grand tower site in downtown Los Angeles. Martin’s firm is overseeing the construction. (Mel Melcon / Los Angeles Times)

Ironworker Joseph Voll tightens rebar during construction of the 1,100-foot-tall Wilshire Grand tower. It will be the tallest structure west of Chicago, its developers say. (Mel Melcon / Los Angeles Times)

Ironworker Joel Ruvalcaba tightens up rebar during construction of the 73-story, 1,100-foot tall Wilshire Grand tower in downtown Los Angeles. (Mel Melcon / Los Angeles Times)

Yang Ho Cho, chairman of Korean Air, and his daughter Heather Cho, executive vice president, inside a hangar at Korean Air’s headquarters in Seoul. (Mel Melcon / Los Angeles Times)

A secretary bows her head as Yang Ho Cho, Chairman of Korean Air, makes his way into his office at Korean Air’s headquarters in Seoul, Korea. (Mel Melcon / Los Angeles Times)

Yang Ho Cho, chairman of Wilshire Grand property owner Korean Air, and his daughter Heather Cho, executive vice president, at company headquarters in Seoul. (Mel Melcon / Los Angeles Times)

David Martin of A.C. Martin Partners, the firm responsible for the design of the Wilshire Grand tower, shows a model of the 73-story skyscraper. (Mel Melcon / Los Angeles Times)

Geologist Rosalind Munro of AMEC, a geotechnical consulting firm, at the Wilshire Grand tower construction site in downtown L.A. Before construction started, Munro went down a borehole eight stories deep to verify the stability of the building site. (Mel Melcon / Los Angeles Times)

An overview of the New Wilshire Grand project construction site. (Mel Melcon / Los Angeles Times)

The USC marching band leads a parade on Figueroa Street in downtown Los Angeles to kick off what became the world’s largest continuous concrete pour. (Mel Melcon / Los Angeles Times)

Turner Construction Co. general superintendent Michael Marchesano, left, and Bill Depasquale, field operations superintendent, stand on the 18-foot-thick foundation of the New Wilshire Grand tower. (Mel Melcon / Los Angeles Times)

Remote-controlled booms are used to place concrete with accuracy as workers pour the foundation for the New Wilshire Grand tower. (Mel Melcon / Los Angeles Times)

David De Loera wipes concrete from his face while helping to pour the foundation for the New Wlishire Grand tower. (Mel Melcon / Los Angeles Times)

Pipes are moved into position for the concrete pour at the New Wilshire Grand project. (Mel Melcon / Los Angeles Times)

A temporary pipe is put into place to keep concrete from splattering as workers pour the foundation for the New Wilshire Grand tower in downtown Los Angeles. (Mel Melcon / Los Angeles Times)

Another concrete truck arrives at the New Wilshire Grand construction site. The record-setting pour required 2,100 truckloads delivering 21,200 cubic yards of concrete weighing 82 million pounds. (Mel Melcon / Los Angeles Times)

A concrete truck dumps its load into a pump at the New Wilshire Grand tower construction site. (Mel Melcon / Los Angeles Times)

Trucks dump their loads into pumps that send concrete through booms to the foundation. (Mel Melcon / Los Angeles Times)

Workers gather on Figueroa Street before the record-setting concrete pour for the foundation of the 73-story, 1,100-foot-tall New Wilshire Grand tower, which will be the tallest structure west of the Mississippi River upon its completion. (Mel Melcon / Los Angeles Times)

A temporary pipe is put into place to keep concrete from splattering as workers pour the foundation for the New Wilshire Grand tower. (Mel Melcon / Los Angeles Times)

Workers direct concrete from a boom into the foundation of the New Wilshire Grand tower. (Mel Melcon / Los Angeles Times)

Los Angeles Mayor Eric Garcetti, left, and Yang Ho Cho, Chairman of Korean Air and the developer of the New Wilshire Grand project, push the switch on a remote control held by construction worker Mike Casad to activate the first pump during the start of the concrete pour. To the right of Cho is his daughter Heather, and at far right is State Senator Kevin De Leon. (Mel Melcon / Los Angeles Times)

WHEN FINISHED, the New Wilshire Grand will rise 1,100 feet and be the tallest building west of the Mississippi. The logistics for the concrete pour are daunting; crews have been preparing the site for five months. (Mel Melcon / Los Angeles Times)