by Mike Fernandez

Odessa, FL. - 2002 - Tampa Bay Water (TBW) awarded a $13.7 million contract to Kenko Inc. of Tampa, Florida for the underground work at their Cosme Transmission Main project. On a horoscope hunch Kenko’s President, Jeff McGrand, lowered his bid by $10,000 and came in at $6200 under the second bidder. This big job consists of installing 43,800 lft. of 64 inch (i.d.) steel pipe with cement mortar lining in 50 foot joints for the purpose of diverting flow from TBW’s water system to St. Petersburg’s water treatment plant and Hillsborough County's utility system.

The 8-mile pipeline runs through areas where the water table is 3 to 4 feet and the soil changes from sand to rock and clay to muck. The high water table and changing soils would make it difficult to keep the 11-17 foot deep trench dry and clear for 50-foot pipe joints, but Kenko, United Rentals-Tampa, and Efficiency Production have devised a unique solution to meet the challenge.

Every Challenge Presents an Opportunity

Kenko’s McGrand and Phillip Wilburn of United Rentals-Tampa reviewed the project specs and developed a plan for a long in-line trench shielding system that met the soil and pipe requirements and could still be pulled quickly along the trench as the pipe installation progressed. McGrand, declaring his gratitude to Wilburn "for going the extra mile," said, "I found Phillip Wilburn to be as knowledgeable in underground shoring as anyone I have worked with before!" They pursued the idea with Efficiency Production’s Engineers Mike West, Nathan Bone, and Doug Austin who finalized a custom designed system that combines a 40-foot and a 28-foot trench box into one 68-foot modular unit! Recessed pulling lugs were crafted at the ends of the shields to attach shackles for joining the boxes so they could be pulled in tandem. "The two boxes were sturdier than one long box," stated Kenko General Superintendent Billy Newton. "A single box would bow at that length and it would have to be thicker and heavier to withstand the pressure."

Each shield is an Efficiency HT8 model with panels measuring 8 inches thick and 10 feet in height. Pin-in-place spreader arches were set at the adjoining ends of each box to allow greater clearance for the pipe joints. "With this setup we’re averaging 500 feet per day and we made 850 feet, 17 pipe sections, on our best day!" said Newton. When one door closes another opens, likewise, the situation that produced this solution has actually increased production on the job significantly!

The Right Tools for the Job

Undoubtedly, heavy machinery is necessary to manage the pipe installation and the shield combo so Kenko is using Komatsu PC750LC and PC400LC excavators, a Komatsu PC300LC excavator with a wheel compactor, Komatsu WA500 and WA450 Loaders, Komatsu D65 and D61 Dozers, a Bomag 213 compactor, and a Volvo A25 off-road truck. The PC750LC with an 8-foot bucket is used to pull the shields along the trench. "They just hooked onto the front spreaders with that big bucket and slid it down the trench in seconds…it was unbelievable!" observed Gary Stephens, Efficiency’s National Sales Manager, who was on hand to watch the system in action.

On Site Personnel

The Cosme project’s on site personnel included Kenko General Superintendent Billy Newton, Project Manager Frank Gizzo II, Superintendent Bill Koehler, Crew Foreman John Crawford, Engineers Ken Wilson and Tony Galvez from Post, Buckley, Schuh, & Jernigan, and Phillip Wilburn and Richard Hearn of United Rentals.

Completion

This part of the TBW project was started in December 2002 and, due to effective planning, is scheduled to finish on time in March 2003. Kenko’s Frank Gizzo also attributes the positive results to greater production with the shielding system. "Production is increased by moving less dirt [saving time and money] and it also makes for a safer project," stated Gizzo.

Kenko History

Kenko’s corporate office is located in Minneapolis, Minnesota and they have permanent regional offices in Calimesa, California; Phoenix, Arizona; Dallas, Texas; and Tampa, Florida. They have successfully completed public works pipeline contracts in 22 states. Typical contracts include directional boring, micro-tunneling, soft ground tunneling, major concrete pours, and roadway construction. Comprehensive site exploration permits Kenko to design the correct dewatering method and shoring systems for each particular situation. Kenko is also developing a new Safety Incentive Program based on the "Zero Injury" concept that will reward employees for projects with "Zero Lost Time Accidents".