Seismic Shift

Seismic Shift

Atougher seismic ordinance could rattle a few Medford business owners seeking to remodel buildings but could save a lot of lives in an earthquake.

The city recently adopted an ordinance that would trigger automatic seismic studies on buildings slated for more than $100,000 in remodeling, or for remodeling that costs $15 or more per square foot.

"There may be some prospective business owners who shy away from this type of expense," said Chris Reising, Medford's building safety director.

Under the old ordinance, many business owners have already upgraded downtown buildings, including those at Rogue Community College, the Sparta Building, the former Bohemian Club on Main Street, Four Daughters Irish Pub, Lawrence's Jewelers and Organicos.

Reising said the kind of seismic retrofits that would be required are designed to stabilize the building in an earthquake to provide time for occupants to escape. The retrofits would not guarantee a building would be salvageable after an earthquake.

As an example, Medford City Hall underwent extensive seismic upgrades, but only to ensure the building stays standing long enough for occupants to leave, Reising said.

"The idea is that people are safe and can get out of the buildings," he said.

The city has expanded the types of buildings that may be required to undergo seismic improvements. The ordinance previously applied mostly to unreinforced masonry, such as brick buildings. The new ordinance includes older, tilt-up concrete buildings, structures with parapets, and buildings that have a lot of openings on the bottom floor.

The new ordinance would require a "rapid" Federal Emergency Management Agency seismic study if a business owner proposes a higher level of occupancy in a building, such as converting a warehouse into a church.

An engineer would use a FEMA form, which has a checklist of possible problems. If the building receives a low score, or if the building is going to have a new use with more occupants, it would have to undergo a seismic retrofit as part of the remodeling.

Under the new ordinance, a building owner could be eligible to make the improvements in stages over many years rather than all at once.

Seismic standards are tougher in some areas of the country. In Los Angeles, after an earthquake in 1971, the city identified buildings that were required to be upgraded even without a change of use.

State and local emergency planners are preparing for a major earthquake in Oregon.

The last substantial earthquake in Southern Oregon occurred in 1993, when a 6.0 quake in Klamath Falls killed two people and caused extensive property damage.

The Oregon Legislature approved a plan recently to make the state less vulnerable to the devastating affects of an earthquake that could leave the Medford area isolated for an extended period.

Oregon is located in the Cascadia Subduction Zone, a 600-mile fault line stretching from California to British Columbia. Scientists have predicted a 9.0 or higher earthquake similar to the one that struck Japan in 2011 could strike Oregon at any time.

Old, brick buildings are particularly vulnerable to collapse, and are often the most likely candidates for a retrofit.

Nabil Tahe, owner of Precision Structural Engineering Inc. in Klamath Falls and Medford, said an average seismic study could cost $2,500, but the amount depends on the size of the building and other factors. Tahe uses a slightly different form to assess the structure of a building than the FEMA form approved by the city.

If the structural study determines that seismic work is necessary, additional engineering to design the reinforcement and upgrades could cost 3 to 5 percent of the value of the building. The actual retrofit work could cost 20 to 30 percent of the value of the building, Tahe said.

He said he has designed retrofits for schools, banks and other buildings throughout Southern Oregon.

In general, buildings made of light material, such as wood houses, tend to do better during earthquakes, Tahe said. Older buildings with heavier materials tend to sustain more damage, he said.

Tahe said the earthquake retrofits are designed to help older, less earthquake-resistant buildings survive.

"It's made to save lives," he said. "Some of the buildings are very dangerous."

Reach reporter Damian Mann at 541-776-4476 or

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