During a maintenance shut down, the Client discovered multiple problems with the deteriorating conditions of their silos at the Brunner Island Generating Station. The walls of a silo are typically subjected to both the normal pressures of stored materials and the vertical frictional shear produced by the coal material inside – as well as the effects of corrosion. Recognizing that the failure of a silo structure could lead to a catastrophic collapse, they asked TAI for emergency response. TAI’s structural engineering division responded the next day and worked with TAI’s Inspection and Test division to start performing and documenting the visual inspections, hammer test and ultrasonic thickness survey of seven steel and concrete reinforced coal silos. Our structural engineers remained on site during the repairs to expedite any design changes if unexpected conditions were encountered during demolition and remediation.
TAI also provided project management to complete inspection and testing services on four concrete silos measuring 41 ft diameter x 80 ft high and three steel silos measuring the same. TAI field inspectors and engineers provided all safety equipment and fall protection during the project. This project included complete visual inspections with pictures of all silos including the beam/silo seat area. UT surveys used both single point and magnetic UT crawler systems to gather an average of four thickness readings per square foot from the silo deck to the tripper floor. Hammer tests were used as well as on accessible areas to aid in determining the integrity of concrete surfaces.
Summarized deliverables:
- TAI’s Inspection team are certified to API inspection standards and certified in accordance with ASNT SNT-TC-1A-Level II for UT Thickness Testing.
- Provided PPL with an executive summary of the inspection findings with pictures and recommendations along with a visual inspection report.
- Reports included AutoCAD drawings of the silo detailing the locations of all testing.
