We are ready to start casting the talk out live to remote participants. Zoom is blocked for some users so we will use Teams. If you are planning to join us on the stream, please let Jill know at [email protected] and a Teams invite will be sent to you.

Speaker and Topic: Our speakers will be Rachel Hunt, P.G., Associate Engineering Geologist, Landslide Technology, Boise, Idaho, and
Benjamin George, P.E., C.E.G., P.G., Senior Associate Engineer, Landslide Technology, Portland, Oregon.
They will present "Rockfall Risk Reduction: Investigation, Design, and Construction across Oregon, Washington, Montana, and Alaska"

Roadway cut slopes have long presented risks for rockfall and other slope instabilities. While reactionary risk reduction is still common, many Transportation Agencies have been more proactive implementing programmatic approaches to reducing risk from rockfall and slope failure events. In our experience programmatic rockfall projects have five stages. Project initiation is first undertaken to identify geohazards and prioritize rockfall risk reduction needs based on rockfall history, safety concerns and/or incidents, and infrastructure protection. This could be conducted on a programmatic or emergency basis. This stage is initiated by the Transportation Agency. The next stage, site reconnaissance includes a detailed geological assessment to characterize rock slope conditions and geohazards. This stage is either completed by the Transportation Agency or a consultant team contracted to provide either a supporting or leading role. Data analysis and modeling is the third stage of project development, where site characterization data (i.e., geologic mapping, geohazard characterization, discontinuity measurements, photogrammetry/lidar, slope monitoring) are collected, compiled, and analyzed. During this stage, conceptual rockfall risk reduction options are developed based on field observations and analysis results. Mitigation design, the fourth stage, includes development of final designs so that construction documents (i.e., plans, specifications, and an engineer’s estimate) can be prepared for preferred risk reduction measures. Construction of rockfall risk reduction measures is the last stage in addressing rockfall concerns. Successful construction often relies on support from the design engineer that includes technical guidance, as-built documentation, and engineering support to construct the measures in accordance with the design intent.

This presentation describes our approach to rockfall risk reduction along roadways highlighting our methods for site reconnaissance, data analysis and modeling, and construction support. Several mitigation case histories from Oregon, Washington, Montana, and Alaska will be discussed featuring our approach to rockfall risk reduction.