Broad Creek Improvements and Force Main

EBA provided geotechnical instrumentation and monitoring, construction inspection and testing, and condition surveys for expansion of an existing pump station, along with construction of a 3,500-foot-long, 66-inch-diameter tunnel with 3 shafts to accommodate a new 48-inch sewer force main.

EBA conducted pre- and post-condition surveys along the tunnel alignment to document structural defects before and after construction. The geotechnical instrumentation program included nine inclinometers, three standpipe piezometers, three automated seismographs, borros-type subsurface monitoring points, and structure and surface monitoring points. During shaft excavation and advancement of the tunnel boring machine, EBA’s survey crew captured daily optical monitoring point readings that were then reviewed by our geotechnical instrumentation engineer.

During construction, EBA inspected pile load tests and production piles; conducted compaction testing of newly placed fill; and performed concrete, mortar, and grout testing. The pile load testing program included compression, tension, and lateral load tests for the 12-inch auguered cast-in-place piles created to support two large storage vaults.