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Thu August 23, 2012 - Southeast Edition
Just one way. According to the Florida Department of Transportation (FDOT), there was only one approved method for shoring a trench within the right-of-way of an Interstate; driven tight sheeting.
So that was the shoring system in the bid when primary contractor Better Roads Inc. was chosen as low bidder to widen a critical stretch of Interstate I-75 near Tampa, including installing new storm-sewer and other underground infrastructure.
But as most excavation contractors will tell you, tight sheeting a trench is time consuming, costly, requires specialized equipment, and often means extended periods of down time for work crews.
“Installing sheet piling would have been tedious and could incur thousands of dollars in damages trying to drive the sheeting into the cap rock of the Pasco [Florida] area,” said Anthony Bosco, project manager of Haleakala Construction, Better Roads’ subcontractor responsible for installing 7,600 linear ft. (2,316 m) of new storm sewer RCP just 25 ft. (7.6 m) away from one of the busiest sections of freeway in the state.
In other words, Better Roads and Haleakala needed a better shoring solution. It needed to find something that was a cost saving alternative to sheeting, and, met all of FDOT’s strict regulations for shoring.
And then it found one.
Approves Efficiency Slide Rail
Paul Strazzulla, shoring specialist of local equipment distributor Professional Shoring & Supply, had an opportunity to pitch to Better Roads and Haleakala the option of an Efficiency Production manufactured slide rail shoring system as a potential alternative to sheeting.
“Haleakala had used slide rail many times before, and so they knew it was a cost savings over sheeting,” said Strazzulla. “And Better Roads liked the idea that slide rail was a cheaper alternative to sheeting. It was really a matter of convincing the [Florida] DOT’s engineers that slide rail works like sheeting when it comes to meeting all the safety and environmental protection requirements,” Strazzulla said.
“The cost savings was about 15 to 20 percent over sheeting,” said Brent Harrison, Better Roads’ project manager. “And, I’d say we are gaining about 30 to 35 percent more pipe production using slide rail. Plus, you can train a good pipe crew to install Slide Rail, rather than needing to hire a specialized sheeting contractor.”
Efficiency’s universal slide rail is a component shoring system comprised of steel panels (similar to trench shield sidewalls) and vertical steel posts. The highly versatile 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 over 40 ft. (12 m).
“Just like tight sheeting, slide rail is considered ’positive shoring,’” said Mike West, Efficiency Production’s vice president of engineering. “Slide rail is 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. We refer to this as a ’dig and push’ shoring system.” The advantage of slide rail is that like sheeting, there is absolutely no over-excavation which means that pressure against the surrounding soil, nearby building foundations; or in this case, the ground below and adjacent to the freeway, is maintained throughout the entire installation and removal of the system.”
Sheeting Slide Rail Switch
The first step to getting the approved shoring method changed from sheeting to slide rail was to submit a Valued Engineering Change Proposal (VECP) to FDOT.
“Calculations, tab data, 3D CAD drawings, case studies; the State’s engineers wanted to see everything we had on slide rail,” added West. “And we were able and willing to provide it to them.”
In the end, after more than eight months of examination, consideration and multiple documentation from Efficiency and Better Roads, Keystone Engineering, FDOT’s contracted engineers on the project, did agree that slide rail was a cost savings over sheeting on this project and could be used as an alternative positive shoring system.
“Then it became a matter of paperwork,” said Bosco. “Because not only did the state need to say ’yes, this is a cost savings’ but because this is a federally funded project, all the correct federal agencies needed to agree that it was a cost savings as well.”
The significance of this determination goes well beyond Better Road’s I-75 project. In the future, any contractors will be able to bid slide rail instead of sheeting for FDOT let projects.
Slide Rail Versus Trench
Shields and Other Systems
Slide rail is installed simultaneously as the trench or pit is excavated.
“And we can install it with our own machines and equipment,” said Harrison. “It is a lot easier to just switch out a bucket on your excavator with quick-connect, than having to bring in a hammer or even a crane.”
In comparing slide rail to traditional trench shields, again slide rail offers the biggest advantages.
“Conventional shields are very stationary and once the spreader pipes or arches are in, you need to move the machine to dig out areas under the spreaders,” said George Carillo, Haleakala’s project foreman. “We can install pipe faster by using slide rail, due to the fact that unlike other slide rail systems we’ve used, Efficiency’s slide rail has parallel beams connecting regular trench box spreaders that move up and down in the linear posts so we could dig in and around the moving spreader pipe.”
Haleakala used two Komatsu PC400 excavators to install and remove the Slide Rail components, plus they had two Komatsu 380 loaders and a Cat D5 dozer in support.
Efficiency Slide Rail Offers
Haleakala rented from Professional Shoring & Supply more than 300 ft. (91 m) of slide rail equipment, enough to configure a long linear multi-bay system to safely shore the pipeline trench along I-75. The system included 8 ft. (2.4 m) tall, 16 ft. (4.8 m) wide steel panels that slide down integrated rails on 14 ft. (4.2 m) tall linear posts, creating more than 30 separate 16 ft. wide “bays.”
An 8 ft. tall panel is installed first in the outside slotted rail of the post, then another into the inside open-face rail of the post creating a trench depth of 16 ft. Efficiency Production is the only slide rail manufacturer to offer an open-face rail design on its slide rail posts, which greatly reduces the potential of the panels binding against the soil, according to the company.
The 7 ft. (2 m) tall, one foot (.3 m) wide parallel beams that roll up and down the slotted rail on the inside face of the linear posts have spreader collars — like trench shield sidewalls — which pin 10 ft. (3 m) long spreader pipe; creating a 12 ft. (3.6 m) wide interior trench space to install the 48, 54, and 60 in. (122, 137 and 152 cm) combination concrete pipe and 16 precast 6-ft. square manholes.
“With the linear design, Haleakala is able to install pipe in the front ’bays’ between the linear posts, while backfilling and removing the system in the back,” explained Brian Campbell, Professional Shoring’s senior slide rail installer who assisted the Haleakala crew with the initial installation of the system.
“Then, the panels and posts that are pulled from the back can be installed into the front of the system ahead of where the pipe is going in. We call this ’leap-frogging’ the system, and it allows the contractor to reutilize equipment which saves them money,” Campbell said.
Concluded Bosco, “The quality of engineering support I received from Efficiency and Pro Shoring has been unparalleled, and I’ve dealt with just about everybody in the Florida shoring industry.”
More Shoring Challenges, More Solutions
While putting in the new pipeline, Haleakala encountered a crossing water-main and force-main, plus they had a 96 in. (244 cm) bored-in utility that needed to be tied into the new pipe. Again, more shoring challenges. Fortunately, Professional Shoring & Supply offers an exclusive Quicksheet Guideframe that integrates seamlessly into the linear slide rail system. Installed instead of the slide rail panels, the sheeting guide frame allows 2 ft. (.6 m) wide overlapping KD-6 sheeting to be positioned tightly around the crossing utility while maintaining “positive” pressure against the outside soil all the way to grade.
Better Roads Inc. has been a southwest Florida asphalt contractor for more than 30 years.
It has more than 300 employees; and is a member of the Florida Transportation Builders Association, Asphalt Contractors Association of Florida, National Asphalt Pavement Association and the area Chambers of Commerce.
For more information, visit www.betterroads.net.
Haleakala Construction Inc. (HCI), headquartered in Naples, Fla., is a Florida certified underground utility construction firm that principally installs potable water systems, sanitary sewer systems, storm drainage systems, underground fire main systems and conduit. HCI was established on Oct. 1, 1984, as a sole proprietorship and incorporated on Jan. 2, 1987.
For more information, visit www.haleakalaconstruction.com.
With offices in Orlando, Tampa, and Jacksonville, Fla., Professional Shoring and Supply is an official Efficiency Production Inc. trench shielding and shoring equipment distributor. Efficiency Production, “America’s Trench Box Builder,” manufactures a wide selection of standard and custom trench shielding and shoring systems. Efficiency’s products are designed specifically for safe and cost effective installation of utility systems and infrastructure improvements. All products are P.E. certified to meet OSHA standards.
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; [email protected]
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