10-story wooden building withstands 100 earthquakes in test

The wooden building was built to full size, stood on a 93-square-meter test platform, and withstood multiple earthquake-simulated shakings.

TallWood timber building undergoes shake table testing in San Diego in May. Photo: Sandy Huffaker/Bloomberg — TallWood's timber building underwent "shake table" testing in San Diego in May. Photo: *Sandy Huffaker/Bloomberg*

The 34-meter-tall wooden building is the tallest structure ever to be subjected to simulated earthquakes on the world's largest high-performance "shake table," which uses hydraulic actuators to push a steel platform to simulate seismic forces. The shake table tests took place at the University of California San Diego campus and are part of the TallWood Project, Bloomberg reported on June 6.

The TallWood project is testing the seismic performance of tall buildings made from mass timber – a material made from layers of wood glued together – which is becoming increasingly popular as a more sustainable alternative to carbon-intensive concrete and steel.

The 10-story wooden building has already survived more than 100 earthquakes, and that number will continue to rise before the testing ends in August. "The building is experiencing earthquakes that it will never experience unless it has a lifespan of 5,000 years," said Thomas Robinson, founder of Lever Architecture, the US firm that designed TallWood.

The first three floors of the 34-meter-high building are clad in orange and silver panels around the glass windows. The rest of the building is open, with four horizontal rocking walls on each floor designed to minimize structural damage during an earthquake. The team also designed the interior walls and staircases to withstand strong shaking and installed sensors throughout the building. Two five-story metal guard towers stand on one side, and cables anchor the building to the ground on the opposite side to prevent it from toppling over if it collapses during testing.

Two protective towers of a wooden building in testing. Photo: Sandy Huffaker/Bloomberg — Two protective towers of a wooden building in testing. Photo: *Sandy Huffaker/Bloomberg*

On a May morning, engineers programmed their shaking tables to recreate two earthquake disasters. The first was the 6.7 magnitude quake in Los Angeles in 1994. In just 20 seconds, the disaster caused more than $40 billion in damage as buildings and highways collapsed, killing 60 people. The second was the 7.7 magnitude quake in Taiwan in 1999, which destroyed many concrete and steel skyscrapers and killed more than 2,400 people.

After half an hour, experts deemed the building safe to enter. Shiling Pei, principal investigator of the TallWood Project and associate professor of civil and environmental engineering at the Colorado School of Mines, inspected the third-floor walls and floors. “This is exactly the result we expected, no structural damage. That means the building can be used again quickly,” Pei said.

Avoiding costly structural repairs and getting buildings back up and running quickly helped reduce the economic and social costs of the earthquake, Robinson said. He also said the TallWood building's outer walls remained straight despite the violent shaking.

Once the earthquake testing is complete, the building will be dismantled and its components recycled to build other test structures. The team hopes the results will spur the construction of more tall mass timber buildings, demonstrating their strength.

Thu Thao (According to Bloomberg )

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