A moving platform, which shook a seven-foot-high rack of electronic equipment and seismic sensors during a demonstration Friday, is a key tool to help create safer buildings and schools in B.C.
The platform, a new multi-directional shake table at the University of British Columbia’s Earthquake Engineering Research Facility—part of the civil engineering department—was demonstrated May 11 at a provincial government announcement of new schools to receive seismic upgrades.
Shake tables test structures under simulated earthquake conditions. During a two-part demonstration, the table’s operators simulated the 1999 magnitude 7.6 earthquake in Taiwan. First, they made the table shift from side to side in one direction—the traditional way of testing structures. Then they created more realistic, multi-directional movements that actually occur when an earthquake hits.
The only one of its kind in Canada, the multi-directional shake table illustrates the increasingly sophisticated tools engineers have at their disposal to test seismically unsafe structures and figure out how to upgrade them to appropriate standards.
Seismic testing facilities have been in place at UBC since at least the 1970s, while the Earthquake Engineering Research Facility opened in late 2003.
The multi-directional shake table was completed this year and it’s one of two large shake tables in the facility, which also has smaller shake tables, along with an array of other testing equipment.
Carlos Ventura, the facility’s director, said scale models of buildings can be placed on a shake table to see how they react under various conditions. Building components, such as walls, can also be put on the table to see how they react to shaking. A retrofitted wall can be tested to see if the retrofit works as expected.
“[The shake table is] being used to develop retrofit strategies,” Ventura said. “We develop some ideas of what we think will be a low-cost retrofit and then, before that way of strengthening the building [is accepted], we construct a model and we put it on the shake table, shake it, and do different experiments. That allows us to confirm the theory.”
He added the demonstration was arranged to make the public “aware of the tools we have available and the facility we have here in Canada to accomplish [seismic research].”
The demonstration followed a May 11 press conference in which Education Minister George Abbott announced seismic upgrades for 14 B.C. schools. The upgrades were allocated based on updated seismic assessments that identified 152 high-priority schools with at least one high-risk building section that needs structural upgrades.
An Association of Professional Engineers and Geoscientists of British Columbia-UBC team has worked with the Ministry of Education since 2005 to refine seismic risk assessment and mitigation strategies for schools.
Through its research, the APEGBC-UBC team has developed new assessment tools and procedures for engineers to determine how different sections of school buildings in different parts of B.C.’s seismic zones will withstand different types of earthquakes, technical guidelines for engineers to follow when planning retrofits and access to ongoing support from APEGBC’s technical review committee, and a seismic analyzer that gives engineers access to a large amount of seismic retrofit analysis to help in the assessment and retrofit design of school structures.
“We will continue improving the capabilities of the software. We’ll be doing more testing to check different retrofit systems and we’ll be assisting the technical review board,” Ventura said.