Earthquakes are a fact of life in Southern California, but no one can predict with certainty when the next massive quake, known as "the Big One" will hit. Experts define the big one as a quake of at least a 7.8 magnitude along the southern part of the San Andreas fault. That fault line runs deep under the Coachella Valley.
The science began with seismologists, who looked at likely seismic accelerations-- meaning changes in velocity-- which could affect the arena during an earthquake. Engineers then took those accelerations, and designed the building to withstand powerful seismic forces.
"It's designed for 25% higher seismic forces than the new typical structure," structural engineer Ryan Anderson said. Anderson is part of the team hired by the developer, Oak View Group, focused on design and safety.
Daut asked him: "What are some of the safety features that people should know?" Anderson replied: "We're employing two high-performing and well-established seismic structural systems. The above grade structure utilizes buckling-restrained brace frames, and the below-grade structure utilizes special reinforced concrete shear walls. The steel brace frames that are encased are excellent at energy dissipation, are excellent shock absorbers, very predictable seismic behavior, and thus are very commonly used here in California."
Steel-frame buildings are designed to bend with the enormous forces of an earthquake without breaking. That's what happened at Dodger Stadium in July 2019, when the 7.1 magnitude Ridgecrest Quake shook Southern California. That same quake rattled an NBA game in Las Vegas, but did not cause any damage.
Compared to all the other numerous arenas that Oakview Group has built across the globe, the Coachella Valley Arena is designed for the highest seismic forces, and has the most structural precautions. The reason: the San Andreas Fault, and you can actually see the fault line just a short distance from the arena.
"Not surprisingly we found seismic forces are higher than all the other arenas we've designed in the US, and even within California. So this was a very key aspect of our structural design. It also required more braces, and larger braces than if the arena had been located in a different part of the country," Anderson said.
The arena must also meet California's rigorous building standards code, which has extensive requirements that were last updated a year ago. Riverside County's Building and Safety Department is the enforcing agency that reviewed all the plans, long before construction began. The county even has a full-time structural engineer on site to make sure everything is in compliance.
"We have some of the most advanced building codes in the nation," the spokesman for the California Office of Emergency Services Brian Ferguson said. "The higher a building goes, the greater the risk. There's load-bearing capabilities you have to meet to ensure you use the right type of construction material and it's constructed in such a way it will stand up if there were to be pressures faced upon it, either by capacity or by an earthquake or something else."
Daut asked Anderson: "How confident are you that the arena will be safe in the event of an earthquake?" He replied: "Confident. We have designed the arena for all the known seismic conditions that we can possibly know with the building code in mind, and believe we've designed it for all those conditions."
Something else to keep in mind: The arena is not tall compared to its horizontal dimensions. County officials said its shear walls and limited openings make it highly resistant to earthquakes. So if "the Big One" does hit, they say the arena may in fact turn out to be one of the safest places in the entire Valley