Combined Sewer Overflow Investigation

Voss Labs inspected a combined sewer overflow (CSO) structure in the San Francisco Bay Area. VL engineers performed a visual inspection and non-destructive testing, extracted concrete cores, quantified areas for repair, and provided recommendations to stabilize the structure prior to repair efforts.

The soffit was severely scaled due to acid attack from hydrogen sulfide gases. In addition to the acid attack, chlorides were present in significant enough concentrations to depassivate the reinforcing steel and induce corrosion. These two deterioration mechanisms worked in concert to cause 100% loss of reinforcement in multiple areas on the soffit of the structure.

Voss Labs provided repair recommendations, total areas for repair, and oversight regarding the depth of material to remove to reach a sound substrate.