The project was challenging in that manholes needed to be installed right in the middle of two different intersections; one street being a major thoroughfare that needed to remain open to traffic.
DiPaolo Construction, of Calumet City, Ill., recently completed a $14 million underground utility project to install personnel access manhole structures over an existing combined storm/sanitary sewer line in the south Chicago community of Hegewisch.
The project was challenging in that the manholes needed to be installed right in the middle of two different intersections; one street being a major thoroughfare with bus routes, requiring DiPaolo to keep one lane of traffic moving in each direction.
The second big challenge was finding a solution as to how to safely shore the 18 by 24 ft. wide (5.5 by 7 m), 24 ft. (7 m)?deep excavation while disrupting the intersections as little as possible. Traditional means of shoring such as trench boxes were immediately ruled out. It was not possible to over-excavate enough to install trench shields and still keep traffic moving. Sheeting is usually the first alternative to trench shields, but vibrating sheeting into place also was unfeasible because of the potential to disturb or undermine the adjacent road and buildings.
DiPaolo needed an active shoring system which maintains pressure against the soil at all times, does not require extra equipment or over-excavation; and most importantly, keeps workers safe throughout the entire excavation and underground utility installation process.
After some research, DiPaolo found an alternate shoring option that met all safety and excavation requirements: a slide rail shoring system from Efficiency Production Inc. But, the slide rail solution also came with a new set of challenges, that of the bureaucratic variety.
“The city of Chicago’s department of water management was not at all familiar with slide rail, and they wanted to see every type of documentation on every part of the system before their engineers would approve it,” explained Sal DiPaolo, vice president of DiPaolo Construction. “Engineering notes, calculations, 3D CAD drawings, installation instructions; fortunately all of which Efficiency was able to provide.”
Efficiency’s universal slide rail is a component shoring system comprised of steel panels (similar to trench shield sidewalls) and vertical steel posts. The system can be used in a variety of configurations. Efficiency’s slide rail system can be configured into small four-sided pits; an obstruction-free ClearSpan configuration; or in a Multi-Bay configuration to install large tanks and structures, or lengths of pipe more than 40 ft. Slide rail is considered “active shoring,” installed by sliding the panels into integrated rails on the posts, and then pushing the panels and posts incrementally down to grade as the pit is dug; a process commonly referred to as a “dig and push” shoring system.
DiPaolo rented from Efficiency a modified four-sided pit system that utilized two Shore-Trak panel guides. The panel guides replace regular slide rail panels, which allowed DiPaolo to install stab sheeting tightly around the existing sewer line on both ends, 12 ft. (3.6 m) into the excavation. Shore-Trak panel guides are an exclusive feature of Efficiency Production’s slide rail system.
Once the existing and active 72 in. (183 cm) combination sewer was uncovered and excavated below the pipe’s invert, DiPaolo cut open a large section of the pipe and inserted two 16 in. (40 cm) HDPE lines, creating a flume that kept the water flowing and the pipe active. DiPaolo installed a precast 9.5 by 17 ft. (2.9 by 5 m) manhole base structure in the open section, with a second structure on top of the base that transitioned to an 8 ft. (2.4 m) diameter round manhole with access from the road.
This entire process was repeated again in the middle of another intersection, utilizing all the same slide rail components.
“Everyone on the crew really liked it,” said DiPaolo Foreman, Juan Carranza. “We had a lot of water in the hole but that didn’t cause any problems installing the slide rail system.”
DiPaolo ran well points connected to 8 in. (20 cm) vacuum pumps provided by Griffin Dewatering Midwest.
Because this was DiPaolo’s first time using its slide rail system, Efficiency sent out Senior Slide Rail Specialist Rod Austin to assist with the initial installation.
“Rod was very helpful pointing us in the right direction from the beginning,” Carranza further explained. “It’s very important to square up the system at every stage of installation, and Rod really emphasized that. I think it really helped to get the guys familiar with the system and how to install it properly.”
Regarding slide rail, Sal DiPaolo concluded: “I thought it was a great approach for the unusual challenges of this particular project. I’d certainly use it again in the future, if it seemed like the right application for the project.”
Founded by Angelo DiPaolo in 1960, DiPaolo Construction is a 50 year, family-owned company. Angelo DiPaolo is a past president of the National Utility Contractors Association, and DiPaolo Construction remains a strong and active member of the Underground Contractors Association of Illinois.
For more information, visit www.efficiencyproduction.com.
James McRay is the Director of Marketing & Media for Efficiency Production Inc. He can be reached at 800/552-8800 or via email at email@example.com.