Ep 8. World's Toughest Skyscraper
- February 22, 2018
The world's tallest and toughest skyscrapers are considered a marvel of modern engineering. In this episode of Building Giants, we get an inside look at the design and construction of one of the most challenging buildings in the world, the Wilshire Grand Center in Los Angeles.
The Wilshire Grand Center stands at an impressive 1,100 feet tall and 73 stories, making it the tallest building on the West Coast of the United States. Not only does it have a unique design that stands out from the surrounding skyline, but it also had to be built in a highly seismic region. The sheer scale and complexity of building a structure of this size demanded engineers and constructors to think and execute beyond their limits.
The design of the Wilshire Grand Center was inspired by the shape of a sail. However, this shape meant that constructing it left little room for error, as it created extra challenges in terms of structural integrity and earthquake resistance. The building needed to withstand seismic activity and wind speeds of up to 115 mph in addition to a significant vertical and horizontal load bearing challenge.
One of the most challenging aspects of the Wilshire Grand Center's construction was the creation of the building's massive foundation. To make the building seismically safe, engineers designed a slip joint system, which would allow the building to remain stable if there was an earthquake. In total, it involved excavating over 100,000 cubic yards of soil and pouring concrete that would weigh more than two fully loaded Boeing 747s. The team used sensors and data analysis to monitor the foundation construction, making sure it met every specification necessary for the slip joint system to function perfectly and keep the building secure in any situation.
Another challenge of the Wilshire Grand Center's construction was from the floor structure, where steel beams and concrete poures together to form the overall structure. It was a race between constructing floors and the engineers designing the building's next structural challenge, with the floors acting as a foundation to support those designs. When discussing the difficulties they faced during construction, the engineers reveal the architectural and construction meaning behind the term "cresting the wave," which highlights the moment when the structural height of the building meets the floors, and the building becomes self-supporting.
The team, for this project, also developed a unique and creative solution for earthquake resistance by designing and implementing a huge external steel frame. They refer to the structure as a "hat-truss" design rather aptly because it sits atop the building like a hat to provide extra vertical and lateral strength. The design made it possible to have an open, column-free space upon entrance to the building while simultaneously building in enough strength to ensure that the skyscraper would remain standing during any seismic activity.
However, even with the innovative technology, precision, and craftsmanship that went into the construction of the Wilshire Grand Center, the biggest test of the build was moving crews extra high up in the structure to complete the final stages of the project. The tower crane they used on the site could only reach up to the 73rd floor, leaving the 73rd to 77th floors to be completed using 470ft high suspended scaffold called the "sky walk" which would have to be climbed with harnesses manually. As the engineers introduce the challenges of constructing such a unique skyscraper, we hear from the workers who explain their experience of climbing up and down the structure. It is a fitting end to this episode, and an excellent reminder of the human effort that goes into creating these engineering marvels.
Building Giants season 1 episode 8, The World's Toughest Skyscraper, takes engineering and construction to new heights. It shows the dedication, ingenuity, and logistical challenges faced in making a great engineering feat like the Wilshire Grand Center in the heart of LA, which continues to inspire awe and amazement to this day.
