The Traversing Bar Rake System (TBRS) is a trash rack raking system for the intake structure of a power plant. It consists of a monorail supported by several columns and a mechanized rake. The purpose of HEA’s work was to establish the static seismic loads on the TBRS by de-coupling the live loads from the dead loads and applying pertinent seismic design factors. This was made difficult due to the fact that the TBRS is an inverted pendulum type structure, base-isolated from the main building. The static seismic loads were then provided to the client for use in their structural model.
Initially, our engineering team analyzed the Traversing Bar Rake System’s seismic response to determine effective seismic weights in each direction. Appropriate seismic design forces were calculated from the effective weight values based on CBC 2007 (ASCE 7-05) standards. The TBRS acted as a base isolated structure (ASCE 7-05 Chapter 17) and ultimately maximum forces acting from the TBRS to the main structure were presented to the client for use in their static analysis.