November 2014, Vol. 69, No. 11
New Products
Michigan Contractor Tackles Deep Excavation Inside Building
JD Construction, headquartered in Lambertville, MI, was recently charged with installing the pour-in-place looping pit for a new 150 by 70 foot Alcos Slitting Line at Heidtman Steel Product’s new East Chicago facility located only a mile away from Lake Michigan.
It was a relatively simple $300,000 excavation project; other than the fact that the 10 by 16 foot looping pit needed to be formed up 40 feet below grade.
Oh, and just one other thing about the excavation project. It was inside a building.
With an excavation project as out of the ordinary as this, digging inside a building, shoring options are very limited. This was not the first time JD has worked for Heidtman installing the underground foundations for equipment. But in those past instances, JD was able to use four-sided trench shields to shore the pits, but that was not an option this time.
“This was the deepest hole we’ve ever needed to dig, plus it was in some tough soil conditions with a very high water table,” said JD Project Manager Dave Garno.
The deeper depth was necessary to accommodate the new slitting equipment’s capability to process newer, more advanced high-strength steel grades. “We knew we needed to find another shoring option for the deep pit; something that would work for this project specifically,” he added.
In researching a shoring solution to include in his bid for the job, Garno contacted trench shoring equipment manufacturer Efficiency Production whose trench boxes Garno had used in the past. Shoring Specialist Mike Ross in Efficiency Production’s Special Operations Shoring Division took Garno’s call.
“Because this excavation project was inside a building, overhead clearance was a big factor in designing a custom shoring system,” said Ross. “There wasn’t overhead clearance to drive sheets, plus vertical welding would have been required.”
Solution
Instead, the shoring solution Ross proposed was their industry leading Slide Rail System.
“We knew we would have no problem with overhead clearance using Slide Rail, because the largest one piece – our triple-rail linear post – is only 32-feet tall,” said Ross. “Plus, the building had a 60-ton crane which could be used to install the Slide Rail pieces that would be too high to install with an excavator.”
In addition to utilizing the overhead crane, JD had on site a Komatsu PC490 excavator and Yanmar VIO 80 mini track excavator.
Efficiency Production’s Slide Rail is a component shoring system comprised of steel panels (similar to trench shield sidewalls) and vertical steel posts. The shoring system is installed simultaneously as the trench or pit is excavated by sliding the panels into integrated rails on the posts – an outside slotted rail first, then an open-face rail on the inside – 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” system.
“We looked at other shoring methods, but determined that Slide Rail would be the most effective for our time frame, the site conditions, and for the least amount of cost,” confirmed Garno. With the shoring system decided, it was up to Efficiency’s team of engineers and Slide Rail experts to design a system that would work for the very challenging site conditions.
What Efficiency’s Special Ops staff drew up for JD was a ClearSpan Slide Rail System; 26-feet long, 30-feet wide and 32-feet deep. The system required JD to remove a large section of the concrete flooring and bench down 10 feet in order to reach the final 40-foot deep grade. This worked out perfectly as the top 10 feet of soil under the concrete was not reusable fill.
Efficiency’s system was ideal for the excavation project because ClearSpan’s design is unique to the industry in that it shores a large working pit without any need for cross-braces. The system stays entirely open by utilizing innovative waler i-beams on the outside of the system at the top, and inside the system to prevent deflection. The walers integrate into the Slide Rail system with the use of custom brackets with rollers that slide along the posts.
The Slide Rail equipment was rented from Efficiency Shoring & Supply’s Chicago Branch Office, who’s Branch Manager Mark Mitchell, and Shoring Specialist Sean Kerrins were regularly on-site to provide equipment support.
Given the complexity of the excavation and shoring dynamics, Efficiency also sent out Senior Slide Rail Installers Rod Austin, Tim Hurst and Al Baron; all Shoring Specialists in Efficiency Production’s Special Operations Shoring Division.
“It was a challenging pit to put in,” admitted Baron. “It was the first time JD had installed Slide Rail but their crew was patient and willing to try different techniques to keep the system moving down, which served them well in the end. Just preparing the excavation site, the amount of work JD put in – cutting through six to eight feet of concrete just to get to the point where we could put the system in – it was very impressive.”
Added Garno: “Efficiency really over-performed with the quality of support they provided us, especially with all three installers who were here several days helping to install the system. There are always challenges on any excavation project, but in this case there were no unexpected surprises. The Slide Rail System worked exactly the way it was supposed to, as we knew it.”
Given the complexity of the excavation and shoring dynamics, Efficiency sent out three Senior Slide Rail Installers including Al Baron (pictured); all Shoring Specialists in Efficiency Production’s Special Operations Shoring Division.
FOR MORE INFORMATION
Efficiency Production: (800) 552-8800, efficiencyproduction.com
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