The Bandon School District is working on a series of seismic retrofits to its facilities, and has issued a for the seismic retrofit of Bandon High School‘s gymnasium and cafeteria. The construction manager-general contractor method will be used for the $1.125 million project.

A pre-proposal meeting for the project has been scheduled for Sept. 24 at the high school, at 550 Ninth St. S.W., in Bandon. All interested contractors are advised to attend in order to familiarize themselves with job site conditions.

Bid proposals will be due by Oct. 8.

The full RFP documentation may be picked up in person on Sept. 18 at ZCS Engineering offices, at 524 Main St., Suite 2, in Oregon City.

The high school was built in 1975. in a sizable earthquake is greater than 10 percent, according to the Federal Emergency Management Agency and the Oregon Department of Geology and Mineral Industries.

Portions of the school other than the gym and cafeteria were retrofitted in 2016, according to the Coos Bay World, and the district’s Ocean Crest Elementary School last year.

Currently, another retrofit is under way at Harbor Lights Middle School in Bandon. Deficiencies in the gymnasium, fifth-grade classrooms, sixth-grade classrooms, choir room, art room and band room all are being addressed. Rafters are being shored, new double-pane windows are being installed and other work is being performed.

All of the prior seismic retrofit projects were built by Scott Partney Construction of North Bend.

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Portland’s Burnside Bridge, age 92, may not look so old.

But appearances don’t mean a lot when it comes to the ability to withstand an earthquake’s devastating forces that can flatten a bridge in a matter of seconds. That possibility is driving Multnomah County‘s plan to pursue either a seismically enhanced retrofit or full replacement of the Burnside Bridge, which connects West and East Burnside Street across the Willamette River.

Since 2016, county officials have studied more than 100 possible options for enhancing the bridge’s resiliency and safety. Last week, they revealed that options have been narrowed down to those final choices.

“It wouldn’t be a true retrofit, because there’s one (bridge) section over the (Interstate 5) freeway that would have to be new,” Multnomah County Communications Coordinator Mike Pullen said. “There’s no way to upgrade the old bridge over the freeway without closing the freeway, as well as the train tracks. In anything we do, we’d replace that with a new structure; otherwise we’d have the freeway closed for six months to a year and that’s just unacceptable.”

The other option, or group of options, Pullen said, is to replace the bridge entirely. The type of bridge would be determined in the future, should this route be chosen.

“Some of the (options) we’d expect to advance would be a higher fixed bridge, meaning it doesn’t open for ships,” he said. “And then there are movable bridges. They have different advantages. The higher bridge never has to open, so ships aren’t delayed.”

The county has ruled out three other options that had been under consideration: doing nothing; performing a full seismic retrofit; or retrofitting a different Willamette River bridge.

This spring and summer, county officials will take on the third and final step in determining the Burnside Bridge’s future. Public input will be received during that period, both online and through a series of open house meetings to be held in the summer.

Thursday’s announcement came the same day that the Oregon Department of Geology and Mineral Industries released a study stating a projected magnitude 9.0 earthquake along the Cascadia subduction zone off the Oregon coast could injure 27,000 Portland residents and displace more than 85,000 others.

The two preferred groups of options will be evaluated based on seismic resiliency, ease of use by nonmotorized transportation, connectivity to existing streets and transportation modes, equity, environmental impact and financial stewardship.

Cost estimates for a new or refurbished bridge remain nebulous, given very little is known about the final shape of the project. However, a preliminary timeline allocates up to $415 million for construction alone over the next decade, when the project will be designed and built. Also, $80 million more could be spent on design and engineering work.

Burnside Street is a designated regional lifeline route, giving it priority for projects of this type. And with a recent Oregon State University study finding the chance of a Cascadia subduction zone quake occurring within the next 50 years at up to 40 percent, county and state officials are not waiting to take action.

County officials are currently accepting public input on the two remaining options and expect a final decision to be made by fall 2018. Then the exact type of bridge or retrofit will be examined and chosen.

“We’re still in the early planning period on this one and we still have a ways to go,” Pullen said.

People can share their viewpoints and find out more about the plan by visiting .

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Minimizing the dangers posed by landslides to people, roads, utilities and rail lines will likely become easier and cheaper thanks to the work of professors at Portland State University and Oregon State University.

Adam Booth, assistant professor of geology at PSU, is working with Oregon State professors Ben Leshchinsky and Michael Olsen to perfect a landslide prediction method that relies on a LIDAR (Light Detection and Ranging) system.

“LIDAR has been around for 15 years now,” Booth said. “It lets us see what the bare earth looks like.”

The system has been used largely by aircraft to help geologists map the surface below a tree canopy. That visual record shows where landslides have struck. However, this new method is able to help scientists identify when the slide struck, not just where.

“Once you date the landslides, you know how likely it is in a given year,” Booth said.

In the past the only way to date landslides in a given area was through the time-consuming and expensive process of radiocarbon dating rocks from a debris field.

The process that Booth and his colleagues use is a combination of radiocarbon dating and LIDAR scanning. When an area is found with multiple landslides, samples are taken from a small number of slide areas; their ages are determined using traditional radiocarbon dating.

For nearby slides, LIDAR then conveys ages that correspond to radiocarbon dating. LIDAR measures the relative variability in the topography that tells geologists how weathered rocks and debris are within the slide. A debris field with a smoother surface is older because erosion and weather dull rough edges over time. A rougher debris field has undergone less wear and therefore is younger.

Combining that data with the information from the radiocarbon dating gives scientists a complete picture of slide ages within a given area. Knowing the age of a range of landslides can tell scientists how often slides happen historically in an area. That information can be combined with a historical database of landslides kept by the Oregon Department of Geology and Mineral Industries (DOGAMI) to get an even clearer picture of the frequency and causes of slides.

“We can narrow (the age of a slide) to between a few hundred to a few thousand years,” Booth said. “We can compare it to climate info and figure out (whether) we get a higher landslide frequency during a cooler and wetter climate.”

The method does have limitations. The process can estimate slide frequencies only over a large area, usually at least around 15 miles. It can’t determine where a specific landslide will occur or if a specific acre or square mile of land is any more susceptible to landslides than the one next to it.

“It has to be a large enough area where you have a number of landslides to study,” Booth said.

It also has to be an area that has been historically active. The process can’t determine the level of increased risk for a scorched area, such as the Columbia River George. That still requires expensive drilling to see what is happening under the surface.

“We have to find out where is the water,” Leshchinsky said. “That has to be done by drilling to characterize the subsurface. Until we develop X-rays that will get us under the surface, we have to use these expensive methods.”

The new process can still be helpful for parties that plan, build and maintain transportation, utility and rail lines. Currently, the process is being used on the southern Oregon coast to help Oregon Department of Transportation officials determine where they should direct equipment and personnel to clear potential slides this winter.

“They have an interest because they have a lot of linear infrastructure,” Leshchinsky said. “We are in a very mountainous state with quake hazards. This can help ODOT to prioritize the roads.”

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