Structural Preservation Systems (SPS) was contracted to restore the gear box foundation at a refinery located in the south. From this one project, SPS was hired to complete two additional projects at the refinery when a turnaround management company contracted them to perform cementitious grouting and anchor bolt replacement on five heater pedestals, and the owner also contracted SPS to repair the hydrocracker makeup compressor foundation.
On the gear box foundation, several areas of the epoxy grout cap were cracked. Because of these cracks, oil was then able to penetrate the foundation. The oil penetration, coupled with increased vibration levels from the equipment, caused additional cracking and a reduction of the foundation's overall structural capacity. The project began with the removal of equipment to access the soleplate. Pneumatic equipment was used to remove the existing grout and loosen the soleplates, which were also removed. Next, the existing concrete was abrasive-grit-blasted to remove any contaminates and prepare the surface for the new repair material. Mechanical anchors were installed to the existing concrete substrate to help bond the new grout. Mortar-tight formwork was placed around the perimeter of the base substrate. After the soleplate was aligned in all axes, epoxy grout was poured into the forms and forced under the soleplate using a header box.
The weather presented a challenge for this project. Completed in January, the air temperature averaged 40 degrees Fahrenheit. For proper epoxy placement and flowability, the foundation had to be 70 degrees Fahrenheit, and the material had to be a minimum of 65 degrees Fahrenheit. To ensure these requirements were met, the area surrounding the foundation was enclosed in a tent, and heaters were installed to ensure the foundation was the proper temperature. Additional safety precautions were taken during the heating process. Since the heaters had to run through the night, a crew member remained at the site and ensured that nothing caught on fire as a result of the heaters.
In addition to the gear box foundation project, SPS also repaired the five heater pedestals and the hydrocracker makeup compressor foundation. As part of the heater pedestal repairs, the existing grout and delaminated concrete was removed. Anchor bolts were removed and new bolts aligned using a template. Mortar-tight formwork was placed around the perimeter of the pedestals. After proper alignment of the soleplates and formwork, the cementitious grout was mixed, placed and consolidated. The hydrocracker makeup compressor foundation was repaired in a similar manner to the gear box foundation using epoxy grout as the repair material.
Throughout the project, the owner was involved in several quality control hold points. Further, a representative from the grout manufacturer was onsite for technical questions and to ensure proper mixing and placement techniques of the epoxy grout. The owner was extremely pleased that the project was completed so quickly during the plant's planned shutdown. Most important, the work was performed safely. Reciprocating equipment foundations are technical projects that require an experienced team and proper material selection, both of which made the project a success.