When one of the largest refineries on the West Coast needs repairs, it is no surprise that time is of the essence. Capable of producing 270,000 barrels of crude oil per day, the refinery primarily produces transportation fuels from refined crude oil. Officials at the facility noticed that the reinforced concrete supporting its coke drums was badly delaminated, with large cracks and falling concrete. Four years prior, the facility had been repaired using shotcrete, but the repair failed. As such, it was crucial to the owner that this repair was a long-lasting, durable solution.

Completed during three separate turnarounds, the project was broken into manageable phases to ensure the repairs were completed in a timely fashion. The project began with the removal of a circular arc of 13 linear feet of the steel skirts that support the 80-foot-tall drums. Structural Preservation Systems (SPS) crews performed demolition of the vertical surface of the octagonal concrete faces using pneumatic chipping hammers. Approximately 13 linear feet of concrete face was also repaired at a time as the skirt was removed and replaced. The team water-blasted and prepared the exposed reinforcing steel and augmented steel bars in regions of reduced cross-section after the corrosion was removed. A mechanical anchor system was installed along the prepared concrete surface to assist in engaging the repair materials with the existing concrete substrate, forming a composite when subjected to load. The polymer composite formwork anchor system was then installed, and the repair areas were prepared using high-pressure water-blasting. Crews installed a passive cathodic protection system to help mitigate future corrosion damage of embedded steel reinforcing, and welded wire fabric was also installed within repair cavities to control cementitious repair material shrinkage. Vertical formwork was designed, fabricated and installed. SPS crews then site-mixed, placed, consolidated and finished a high-strength, shrinkage-compensated, pre-bagged repair material within the formwork. Once cured, the formwork was removed, and a water-based curing compound was applied to repair areas. Grout blockouts were prepared prior to the skirt replacement with high-strength, machinery-grade grout placed under each new skirt section. Crews then saw-cut the slab soffit (i.e., underside) at the base of the penetration to function as a drip edge to prevent moisture travel and further damage by embedded metal corrosion. Throughout the project, quality assurance and control (QA/QC) inspection programs were in place.

Because this project occurred during a planned plant shutdown, there were several other contractors working at the site. In fact, a welding contractor was working in the immediate proximity and just above the SPS crew, so special precautions were taken to ensure the safety of crews from airborne sparks and dripping hot weld metal. The team faced many stops and starts due to coordination with the other trades within the same construction "envelope," which made adherence to the schedule critical. Project construction personnel were split between day and night shift crews. These crews worked seven days a week on 12-hour shifts. Additionally, several contractors were working in an extremely tight space - a three-foot walkway - which made communication essential to project success. While the crews were working on two of the coke drums, the other remaining drums were on-line. Several times a day, the coke had to be removed from each of the "live" drums, requiring the crew to stop work and wait until the "coke cutting" process was complete. 

Completed in three phases during planned shutdowns, the project began in June 2007 and was completed in July 2008. The owner was extremely pleased with the result of the project, and the repair should last more than 15 years. The project was finished ahead of schedule, and all three phases were completed safely.