For transportation agencies, properly identifying and responding to potential geotechnical issues in the design stage is essential for ensuring cost-efficient, timely and highly functioning projects. California Department of Transportation (Caltrans) developed a seismic cone penetrometer (SCPT) to anticipate the effects of earthquakes on Interstate 405.
In the wake of the COVID-19 pandemic, Caltrans had to find alternative ways to communicate project information with internal and external partners. As an innovative solution, the agency devised the 360 Tours program, a unique approach to public involvement.
Caltrans’ success with seismic cone penetrometer testing (SCPT)
Advanced Geotechnical Methods in Exploration (A-GaME) are proven tools and technologies that provide benefits ranging from speed, cost-effectiveness, safety and more. The seismic cone penetrometer testing (SCPT) is one of those tools. Through inspecting the stratigraphy of a site and calculating the material’s strength properties, SCPT can be used to build earthquake resilient structures. According to FHWA, the SCPT played an important role in subsurface characterization and the direct seismic design of the bridge foundation on a Southern California project.
The California Department of Transportation (Caltrans), in partnership with the Orange County Transportation Authority (OCTA), required the use of SCPT as a part of the site characterization program for Interstate 405. Located in Orange County, the I-405 project is a 2-billion-dollar investment consisting of 16 miles of road widening, the widening or replacement of 30 bridge structures and designing more than 100 earth retaining structures. The design build contractor performed SCPT exploration and analyzed the soil seismic parameters to develop bridges that meet earthquake loading requirements. The SCPT calculations were then used to identify ground motion for the foundation design and the geo-structural design.
To learn more about Caltrans’ I-405 Improvement Project, click here.
A 360° experience: Caltrans’ answer to public involvement during the pandemic
During the pandemic, Caltrans had to reconsider their methods of engaging with internal and external partners. With face-to-face meetings limited, the department found it difficult to communicate their decisions on a variety of issues. Caltrans took a unique approach to public involvement in its projects with the development of 360 Tours. This online tool centralizes project information into an interactive 3D model that allows visitors to explore existing conditions and view potential solutions.
The agency utilized 360 Tours for its State Route 37 planning and environmental linkages project. Users could “zoom in” on interesting areas and observe the effects of sea-level rise on future roads through project illustrations, videos and interactive questions. With interactive visuals such as this, Caltrans created a more inclusive and accessible engagement process for all users.
To learn more about Caltrans’ Resilient SR-37, click here.