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A heavy rainfall event washed away a significant portion of the hillside. Unfortunately, this was close to a retirement home in the town of Pinole, CA. The hillside fell away from the building and ended up taking along a large section of the parking lot. As an effort to rebuild the area, lightweight cellular concrete (LCC) was proposed as a lightweight fill material preventing any future rainfall events from threatening the structure.

LCC is a strong candidate for fill material when faced with slide repair. The low-density material does not add excess load to the hillside and can safely rebuild for active traffic or vehicle storage.

For the Bay Park project in Pinole, a gravity wall system was installed corresponding to each lift of LCC. A uniaxial geogrid was installed between lifts to add rigidity and strength to the wall and LCC structure. The final depth of the LCC fill was 20’ and achieved in 2’–3’ lifts over the course of 9 days.

A double track for the Burlington Northern and Santa Fe (BNSF) Railway is being constructed at the San Diego River Bridge. The Mid-Coast Transit Corridor project is being built in two stages to keep the track operating throughout construction.

Cellular concrete is being used to raise the track’s elevation and also being added in between full-height Mechanically Stabilized Earth (MSE) panels due to the access on either side of the wall.

Due to the increase in vertical pressure from the additional fill load for the embankment supporting the Metro’s track row, unreinforced concrete encasement for the Department of Water and Power (DWP) duct banks directly underneath were susceptible to settlement/cracking.

The chosen backfill material was a low-density fill material in between Mechanically Stabilized Earth (MSE) walls. Cellular concrete substantially reduced the fill loads on the duct banks and eliminated the potential for damage/settlement to the existing DWP lines underground.

The Port of Long Beach is the owner of this design-build project. Cellular concrete was elected due to the presence of compressible material. Approaches to the bridge address settlement and stability consideration on the in-situ soil and the magnitude of the earthquake design. A total of over 200,000 CY have been placed on the project in 6 different locations, using precast panels with LCC as the backfill material.

Class II and Class III material is being utilized on the east side approaches to the bridge. At the lower portions of the fill, Class II cellular concrete will be poured to maximize the load reduction. Class IV cellular concrete will be used at the uppermost layers (directly under the pavement). The design approach included treating the LCC material as embankment material and designing the structure as a typical length of MSE wall reinforcement. Steel ladder reinforcement and ribbed steel straps were used. No reported/observed performance issues or concerns have been encountered to date.