A new interceptor sewer for the southeast quarter of Mason, Mich., was recently completed by Jule Swartz and Sons Contractors of Jackson, Mich.
Swartz installed 1,500 linear ft. (457 m) of new SDR-26, 24 in. (60 cm) pipe in 14 ft. (4.2 m) lengths, plus seven new manhole structures. The new sanitary sewer replaces an existing 10 in. (25.4 cm) sewer that had been running at near full capacity and was in need of an upgrade. Wolverine Engineers and Surveyors Inc. was the engineering firm hired by the city of Mason to oversee the project.
Welcome to the Obstacle Course
The new sewer line starts at the Mason skate park, and then runs across a softball field to Rayner Creek. It progresses along the south bank of the creek and then turns south between homes to Columbia Street. After turning at a manhole, the line continues east underneath Columbia Street where it ties into another 1,500 linear ft. of new 24 in. SDR pipe (not part of the city contract).
The circuitous route of the pipeline wasn’t even the most challenging aspect of the project. On several occasions, the pipe-laying crew encountered various obstacles both foreseen and unexpected. In each instance, Swartz and Wolverine’s ingenuity were critical in keeping the install on-track.
Obstacle #1 – Tricky Cross-Utility
On the turn south from the creek to Columbia Street, Swartz encountered a cluster of seven duct banks that were 5 ft. (1.5 m) deep, rather than the blueprint’s indicated 3 ft. (.9 m). This prevented the crew from continuing to shore the trench with a set of trench boxes that they had been using. In the trench were two stacked 8 by 24 ft. (2.4 by 7.3 m) and 4 by 24 ft. (1.2 by 7.3 m) HT6 (6 in. thick sidewalls) trench shields manufactured by Efficiency Production. Even with just one trench box, they could not position the trench shield under the conduits.
Rather than risk endangering anyone in an un-shored trench, Al Swartz, president and co-owner of the company, contacted Efficiency Production Inc. — a manufacturer of trench shielding and shoring — to brainstorm possible shoring solutions. Conveniently headquartered in Mason, Efficiency supplied Swartz a modular aluminum Build-A-Box trench shielding unit, which could be assembled by hand and easily positioned under the cross-utilities and directly against the trench boxes.
“The Build-A-Box comes in very handy a lot of times when we encounter a variety of obstacles, because it’s designed to be assembled into a variety of configurations,” said Swartz.
Obstacle #2 —Rerouting
It was planned that the new sewer line was going to punch through a 60 by 92 in. (152.4 by 233 cm) storm culvert located under the intersection of Columbia and Matthews streets. “But when we started excavating, we found a watermain running exactly where we needed to put in the shoring,” said Clint Martinez, project supervisor of Wolverine. “The watermain completely surprised us due to the fact that it went underneath the culvert but turned a little bit going under the culvert. If it wasn’t for that slight turn, we wouldn’t have had a problem with it.”
The storm culvert also had deteriorated, and was filled almost two-thirds full with silt. Again, ingenuity prevailed and Swartz and Wolverine decided to cut the culvert and pour-in-place a 14 by 16 by 9 ft. (4.2 by 4.8 by 2.7 m) bypass vault which they could run the new sewer line through. However, there was still the problem of the watermain that was in the way of the shoring. “We decided to reroute 150 ft. of the watermain around where we were working with 8 in. iron ductile pipe. That put us back a week,” said Martinez. Additionally, the new potable line needed a 6 in. tie-in running north and a 4 in. tie-in running south.
Obstacle #3 — Congested Intersection
A second smaller storm culvert (42 by 65 in.) also was identified a few yards east of Matthews Street, and it was decided to pour-in-place a second 10 by 22 by 9 ft. (3 by 6.7 by 2.7 m) bypass box culvert. Both new box culvert vaults were set 18 ft. (5.5 m) deep in the ground and contained access chimneys up to street level.
However, there was still the issue of shoring both excavations for the pour-in-place vaults. “We needed a different size shoring system than what was planned, and we were lucky that Efficiency was right in town, and could swap out the components with a different size,” added Martinez.
Sheeting Guide Frame’s Perfect Fit
Swartz rented from Efficiency their innovative Slide Rail — Shore-Trak Sheeting Guide Frame System. Efficiency’s Shore-Trak is the industry’s only pre-fabricated, custom-engineered, cross-utility shoring system that integrates seamlessly with Efficiency Production’s Universal Slide Rail System. The system allowed the crew to safely shore the pit around where the bypass vaults were poured-in-place, but also to shore closely around the existing corrugated metal storm culverts which ran through the pit on two sides.
“Without the Slide Rail System, we would have had to drive regular sheeting, which would require renting a crane at $150 an hour to vibrate-in the sheeting,” said Swartz. “It probably would have taken twice as long, and the slide rail is just so much easier; it is just so much more flexible and consistent.”
Efficiency’s Universal Slide Rail is a component shoring system comprised of steel panels (similar to trench shield sidewalls) and vertical steel posts. The versatile system can be used in a variety of configurations, such as small four-sided pits; large unobstructed working pits as big as 50 by 50 ft. (15.2 by 15.2 m) with Efficiency’s ClearSpan System; or in a linear Multi-Bay configuration to install lengths of pipe over 40 ft. (12 m).
The configuration of the Slide Rail was a 16 by 32 by 12 ft. (4.8 by 9.7 by 3.6 m) pit (benched down 8 ft.) in “2-bays” with one pair of linear posts and parallel beams pinning-in-place a set of two 14 ft. (4.2 m) standard trench box spreaders as cross members. Shore-Trak Sheeting Guide Frames replaced panels on the opposite sides of each of the bays to accommodate the sharp angle of storm culverts.
Martinez commented that, “This was the first time I’ve seen an Efficiency Slide Rail go in the ground, and I was very impressed with the system. I really liked the Shore-Trak™ Sheeting Guide Frame, because we could put in the stab-sheeting around the culverts, and still be integrated with the rest of the system.”
A 30 in. (76 m) 3/8 steel casing ran inline through both bypass vaults, then 80 ft. (24 m) of 24 in. (60 cm) HDPE bore pipe was snaked through the casing in both bypass vaults and tied into manholes on both ends. “We really did the things that no one wanted to do,” said Swartz of his crew and of the project.
“Everyone worked very well together, and we had very good coordination and communication,” said Martinez. “When it got frustrating and we wanted to throw our hands up and walk away, it was really a collaborate effort to come up with the solution for whatever new challenge we were dealing with.” About the Swartz team, Martinez added, “I can’t say enough about them. Everything is done right, and everyone is very safe on the job. And, they really try to minimize the impact on the community and the neighborhood.”
The job started in June 2007, and was completed by the end of July. Swartz had on site a Komatsu PC 200 and a Komatsu PC 300. They also used a CAT 314 with rubber tracks and a JCB 214 S Front Loader.
Jule Swartz and Sons Inc. is celebrating it’s 41st year as a family-owned business in Jackson, Mich. Today, the company specializes in site development and road building. Founder Jule Swartz retired in 1990, but his sons and grandchildren continue to manage and operate the company.