by Mike Fernandez

Denver, CO. - 3/2000 - A true team effort has taken place to transform the underground infrastructure that once supported the Fitzsimons Army Hospital in Aurora, Colorado into one that will support the University of Colorado’s state-of-the-art Health Science Center. The U.S. Army recently turned over ownership of the site to the City of Aurora which promptly initiated the $15 million project that was awarded to Colorado Jaynes Natkin Co. of Thornton, Colorado. In a joint venture, the prime contractors accepted the responsibility for the installation of the water, sewer, electrical, telephone, fiber optic, and steam line systems outside of the new research facility. They have organized 20 contractors and their subcontractors to completely replace the aging infrastructure and incorporate it into the city’s system. Bill McComas, project manager for Colorado Jaynes Natkin, stated, "The project required extensive planning and front-end coordination to minimize the impact on the ‘in-operation’ facility. The ‘corridor’ designated for utilities was critical and could not be deviated from. The utilities virtually had to be layered. None of this could have been realized without all party’s commitment to a team effort."

This team includes Mayer, Lemke, and Landsiedel General Contractors (MLL) of Wheat Ridge, Colorado, who are responsible for completing 8 poured-in-place concrete steam vaults that measure 12 feet in heigth x 24 feet in length x 24 feet in width.

When planning for the project MLL determined that their forming crews required minimum clear excavations of 29 feet in length x 29 feet in width x 20 feet in depth to install the vaults in the type "C" soil. Surrounding buildings and roads complicated the installation process and the existing utility’s adjacent to or, in some cases, within the excavations posed significant risks. All of these factors demanded research into trench shielding & shoring options that would minimize the risks, improve production, and meet O.S.H.A. requirements.

After considering sloping, beam & lag, sheet piling, and shot crete systems, MLL’s Phil Mayer contacted Trench Safety Equipment of Denver, a United Rentals Company, for an alternative trench shoring solution. Trench Safety Equipment, a distributor of Efficiency Production, Inc.’s trench shielding & shoring equipment, contacted the manufacturer to inquire about a Slide Rail System (specially engineered steel panels that slide down guide rail posts). Upon evaluation of the soil reports and blueprints, Efficiency Production recommended using a combination of their Universal Slide Rail System^TM, with ClearSpan^TM walers, and a Shore-Trak^TM cross trench utility system. The system consisted of sixteen 8 foot high x 16 foot long x 5 inch thick steel panels, and internal and external waler beams that connect to corner and linear posts. The Slide Rail posts and panels could be easily positioned in confined areas near buildings and utilities with minimal vibration during the installation. Narrow Shore-Trak panels could also be precisely positioned around obstructions. This combined system was capable of shielding an unobstructed four-sided pit measuring 33 feet in length x 33 feet in width x 16 feet in depth while accommodating the existing buildings and utilities!

The elimination of cross trench braces in the unobstructed pit made the installation of the vaults much easier since the crew could pour the walls without having to work around or under any shielding components. They also did not have to sacrifice or abandon cross members that are typically used in other trench shielding systems. This effective solution enabled the crew to quickly install the shielding system and successfully form, pour, and strip a 12’ x 12’ x 24’ vault all in 10 working days!

One of the 4 pits that have been installed within a 5 week period required the combination of Efficiency’s Slide Rail & Shore-Trak shoring systems since an 8^1/2 foot x 8^1/2 foot live steam tunnel ran diagonally through one corner of the excavation. Additionally, utility’s ranging from 18 to 24 inches in diameter paralleled 3 sides of the excavation extending from 6 to 18 inches outside of the system and 7 to 16 feet in depth. A 48 inch manhole structure lying within inches of a corner added to the challenge. The system consisted of two 16 foot Shore-Trak^TM (cross-trench utility shielding system) guide frames that connect to corner and linear Slide Rail posts and eight 2 foot wide x 20 foot tall Shore-Trak panels that were inserted through the guide frame and pinned in place at the necessary heigth above the tunnel. This innovative system successfully maintained clearance and soil stability around the existing steam tunnel! (refer to photo).

MLL subcontracted with Belair Excavating of Denver, Colorado to excavate the pits, install the trench shielding system, and complete the final grading at the bottom of excavations. Belair used a CAT 330 excavator, a Hitachi 450 excavator, a Volvo BM 120 front end loader with forks, and a Bobcat skid steer to achieve the job. Cole Cattoor, project manager for Belair Excavating, commented on the advantages of installing Efficiency’s trench shielding systems. "We are very pleased with the shielding system… (It) is an efficient way to provide shoring in areas where sloping could not be done. It was fast and easy to install and very user-friendly…We have already researched using the same system for our next project."

Efficiency Production’s System Installation Specialist Doug Austin and Trench Safety Equipment’s Kris Graham have been on the site with expert technical and product support to insure a smooth installation. "The service and support we received from Doug Austin and Kris Graham was ‘above excellent’...TSE is known for solving problems that contractors face," stated Cattoor.

Providing solutions to underground construction problems is a key element that is necessary to succeed in the highly competitive construction industry. As stated by Trench Safety’s Kris Graham, "Efficiency’s Slide Rail System and their support team of engineers and installers are letting us look at projects that cannot be done with other types of shoring in our rental fleet. This gives Trench Safety Equipment and our customers a competitive edge at the bidding table and at the job site." This competitive edge, the ability to coordinate the team of top quality crews, and the unique capabilities of each of the contractors, equipment distributors, and manufacturers have helped Colorado Jaynes Natkin achieve success on this extremely challenging project.

One of eight poured-in-place steam vaults nears completion at Univ. of Colorado's Health Science Center.		An 8-1/4 ft. square concrete steam tunnel passed diagonally through one corner of this vault excavation requiring the use of Shore-Trak panels and guide frames to shield around the crossing utility.