The project is the first of three phases to add one High Occupancy Vehicle (HOV) lane in each direction of Interstate 5 in Orange County from Avenida Pico to San Juan Creek Road. The project purpose is to provide continuity of the I-5 mainline HOV network within the project limits; maximize overall performance by minimizing weaving conflicts at the termini of the HOV lanes and maintaining travel speeds for HOV lane users; provide intermittent auxiliary lanes, where needed, to relieve congestion at diverge and merge locations; minimize right-of-way acquisition; relieve congestion within interchange areas, on- and off-ramps, and at local intersections (including Avenida Pico); and reduce congestion on I-5 within the project limits.
The project encountered several challenging differing site conditions that Shimmick worked with the Owner and its Subcontractors to mitigate and complete the project successfully. The project involved the installation of CIDH foundations at the bridges. During the course of drilling the CIDHs a differing site condition was encountered as groundwater was encountered at a much higher elevation than shown in the geotechnical report. Shimmick worked with its drilling subcontractor and the Owner to implement an alternative drilling method that mitigated the groundwater issue and allowed for successful installation of the CIDHs. While installing the project’s soil nail wall, Shimmick encountered a differing site condition of beach sand at the wall location. To mitigate the impacts of this differing site condition, Shimmick worked with the Owner to develop an alternative wall design that could be successfully installed in the difficult ground conditions.