Investigation and Failure Analysis of Deep Underground Sewage Pump Station

摘要

An underground concrete sewage treatment pump station facility located in Bessemer, Alabama had a structural failure in April 2005 soon after it was commissioned. This pump station built into a 100 feet deep excavation in dolomite bedrock is approximately 360 ft long and 230 feet wide. This substructure has three major functional areas; the wet well, the dry well, and the flume. The failure was manifested by the rupture of the mat slab and distress in a significant number of structural elements in the form of wide cracks and spalls. By performing simplistic as well as a detailed analysis using finite element analytical techniques, it was determined that the primary cause of failure was due to the as-designed mat foundation of the structure not having adequate capacity for the hydrostatic forces at the time of failure.