The concrete will then be sculpted around the columns to restore them to their original look. The contract also calls for constructing rock columns in the ground surrounding footings that are near the San Diego River. The columns will increase the stability of the ground around the footings, where the potential for liquefaction may exist.
Liquefaction often occurs during earthquakes causing the soil to react like a liquid.
A tragic example of the damage liquefaction can cause is the collapse of the Cypress double-deck structure in the Loma Prieta quake in 1989. When the shaking started, the ground became very unstable, and the structure collapsed. With the placement of stone columns, the footings of the bridge will have more support during a quake. Since it was constructed in 1973, this interchange has received several awards for its beauty. Part of this project will encase the columns with concrete and steel.