C-13 Broadway Corridor, Package B

Completed in 2019 by Southland Contracting, the C-13 Broadway Corridor, Package B Project consisted of the construction of 510 linear feet of 120-inch liner plate siphon tunnel lined with one 48-inch and two 36-inch fiberglass reinforced (FRP) pipes. Two diversions structures and two siphon structures. The project also includes replacing 81 linear feet of 60-inch and 41 linear feet of 66-inch FRP gravity sewer mains. 778 linear feet of 36-inch recycled water line was also relocated by open cut methods. Other key aspects of this project include bypass pumping of sewer mains for required connections, Asphalt paving, sidewalk and curb repair and utility relocations. Subsurface conditions consist of both man-made and natural alluvial deposits overlying marine clays. The marine clays consist of tan clays overlying gray to dark gray clay-shale which are generally hard to moderately weathered. The project is currently delivering 54 MGD of the planned 270 MGD of combined sewer overflow (CSO) storage for treatment, as well as accommodating future connections to other tunnels in the overall system. The project consisted of a subterranean pump station, 60 feet wide by 98 feet long by 66 feet tall, constructed 275 feet below ground. Access to the pump station occurs through a 275-foot deep by 44-foot inside diameter (ID) main access shaft. An additional equipment shaft, 279 feet deep by 23 feet in diameter, was constructed and lined with cast-in-place concrete. A 6-foot ID tunnel connects the existing screen and grit shaft to the new pump room 180 feet.