August 28th, 2012
SEISMIC SAFETYPreserve Infrastructure, by Catherine Higgins.
The Utah Seismic Safety Commission brings a diverse group of experts together to reduce earthquake risk.
The fifteen member board was created to assess Utah’s earthquake risks, to promote awareness and to support state and local government efforts to protect public safety during and after a quake.
“The commission provides an integrated picture of seismic concerns for the whole community,” says Josh Sletten, UDOT Structures Design Manager and USSC Commissioner. Sletten represents the transportation point of view as the commission plans and implements ways to improve earthquake readiness in Utah. While the commissions efforts are not transportation centered, Utah’s transportation system is an important part of the overall picture since the transportation system is a vital part of response and recovery after a quake.
Keeping roads open
Two of UDOT’s key roles are to have an emergency response plan in place and to identify key routes that will remain operational after a major earth quake. The emergency response plan uses workers that are nearest the scene of the emergency to quickly inspect and identify the risk to the traveling public on structures and roadways. Next, engineers will strategically visit locations, starting with the most vulnerable areas first, to properly address affected structures.
Identifying key routes that provide access to hospitals, shelters and emergency services is an ongoing process as the community changes. Once key routes are identified, UDOT engineers take all aspects of the roadway into account. Structures especially are of great concern and UDOT builds structures like bridges and overpasses to withstand major quakes.
UDOT bridges are designed and constructed to AASHTO design standards which account for hazard events such as earthquakes. Many of the bridges on I-15 through the Wasatch Front have been rebuilt in the last 15 years. While UDOT does not anticipate extensive damage to the transportation system, some damage will occur. And, uncertainty exists when it comes to events, such as power outages and how those events will affect the transportation system.
The USSC works closely with the United States Geological Survey on ways to identify potential risk during a quake. The USGS has developed a software program called ShakeCast to generate estimated damage data for structures like buildings and bridges. In an actual seismic event, ShakeCast can also be used to send notification to infrastructure owners indicating the level of shaking and estimated damage from the quake. For UDOT, using ShakeCast means that we know the level of damage that is likely to occur, according to Sletten.
When it comes to seismic safety, planning is critical. The USSC issued a strategic plan in 1995. Since that time, 27 of the 35 critical objectives have been met. By participating in the USSC, UDOT and other critical infrastructure owners and emergency service providers can work together to ensure that Utah citizens are as safe as possible during and after a major earthquake.