By Garry Robins
US Engineers will severely stress 10-storey tower on the University of California’s quake table in San Diego to test the mettle of tall wood building.
A 10-story wooden tower will be shaken with the force of the 6.7 Northridge earthquake and could answer serious questions about the durability of ‘tall timbers’ and how well they can handle quakes and other natural disasters.
This is the tallest building ever placed on the shake table, which just underwent a $16.3 million upgrade that will enable researchers from around the world to more realistically simulate temblors.
The new project is being led by the Colorado School of Mines, which will subject the tower to shaking that will be equivalent to the magnitude 6.7 Northridge earthquake, which struck the San Fernando Valley in 1994, killing 60 people. The testing will begin in February.
The tower is mostly composed of cross-laminated timber along with steel, making it different from traditional tall buildings, which are mostly steel and concrete.
“We’re trying to see if we can construct mass timber buildings that would be resilient in high seismic zones,” said Shiling Pei, a mining school engineer and the project’s co-director.
In this case, resiliency refers to a building’s ability to survive strong shaking without suffering structural damage.
As engineers note, wood has been used in building construction for thousands of years. But they say advances in design are making it possible to efficiently build strong, safe structures eight stories or higher that are primarily composed of wood. The concept is being hotly pursued, in part, because wood is a sustainable material.
Earlier this year, construction was completed on Ascent, a 25-storey mixed-use residential tower in Milwaukee that is primarily made of wood. It is the tallest structure of its kind in the world.
Unlike southern California, Ascent is not located in a highly active seismic zone. Engineers won’t know how resilient tall timber buildings truly are until they complete the sort of shaking experiment now under way.
Shiling Pei is hoping things go well.
“A lot of (tall timber) construction is pre-fabricated in the factory,” he said. “Everything is precisely cut. Everything fits. You can assemble it like Ikea furniture.”