The Double H Pipeline consists of 488 miles of 12-inch steel pipe designed to carry petroleum from Dore, ND to Guernsey, WY. Completion of a 20-mile segment near the southern end of this pipeline project was falling behind due to the rugged terrain the pipe was passing through, frequent steep slopes, elevation changes, and the requirements of the trench breakers that had been specced into the job. The contractor installing the line had previously been building trench breakers, or water stops, out of sand bags and then applying concrete slurry to bond the bags together. Areas where breakers were to be built also had to be keyed in, causing additional time delays. Some of those keyed in areas ended up being much larger than needed. Due to these delays, the backfilling process was being pushed back in some areas, often by weeks. Portions of the line were being backfilled while other portions, where the breakers were needed, were left with exposed pipe.
In addition to the time delays, this sand bagging was also very costly. The contractor was paying a price for each bag installed, and the average breaker was around 80 bags. Bags had to be filled off-site, then delivered to the site, and two men had to go down into the trench with two other men above the trench passing bags in. Cost overruns became an issue.
Finally, the contractor was always focused on job site safety and understood that having two men in the trench was less than ideal. The potential for an accidental collapse of part of the trench was a real concern as such an accident would be devastating to anyone down in the trench.
Spray foam trench breakers offer a tremendous time savings over construction of sand bag breakers, and were also offered a cost savings to the contractor. Two man crews for Innovative Foundation Supportworks were able to construct as many as 50 breakers in a single day when sand bagging crews struggled to construct 10. Furthermore, since the foam bonds so well to the sides of the trench, the excavation crews were able to stop keying in each location where a breaker would be installed, streamlining another aspect of the job and allowing that machinery to be utilized elsewhere.
In addition to the time and cost savings, the crew members who had previously been responsible for going into the trench were now freed up to focus on other tasks. The project had fallen behind, so this added manpower to the workforce helped the contractor get back on schedule.
Also, the workers for Innovative Foundation Supportworks were able to construct the spray foam trench breakers without going down into the trench, which insured a safe work environment and offered the contractor great peace of mind. The low exothermic temperature of the reaction of the foam insures that it will not harm the pipe, and the foam actually cradles and supports the overall structure.
Innovative did encounter key-in’s that were very large, and would have required vast numbers of sand bags. Despite the large size of the excavations in these areas, our crews were still able to construct trench breakers to elevate sub surface erosion concerns.
General Contractor: Hiland Partners
Sub Contractor: Sunland Construction INc.
Certified Trench Breaker Installer: Innovative Foundation Supportworks®