Contribution of Steel Casing to Single Shaft Foundation Structural Resistance
TRB’s National Cooperative Highway Research Program (NCHRP) Research Report 872: Contribution of Steel Casing to Single Shaft Foundation Structural Resistance proposes revisions to bridge design specifications based on comprehensive analytical and testing programs for investigating the effects of steel casing. Bridges are often constructed with a single enlarged shaft foundation supporting a column. In many cases, the shaft foundation is constructed with a permanent steel casing. The combination of the steel casing and the interior reinforced concrete is typically called Concrete-Filled Steel Tube (CFST) or Reinforced Concrete-Filled Steel Tube (RCFST). Determining the properties of the composite RCFST section and at what point along the shaft the section can be considered a composite section may lead to design improvements a reduction in construction cost.