Contractor’s Aim is True with Trenchless Technology

Project Profile:

• Hoffman and Hoffman was started in 1976. Began using the Grundomat pneumatic boring tool in 1993. Aplington, IA – Electrical job – 12 bores under sidewalks, and streets up to 65 feet and 10 bores up to 85 feet in downtown.
• Waterloo, IA – hospital – 130 foot bore under parking lot completed in 78 minutes.

“Do the job right the first time so you don’t have to do it again.” That’s just one of Deuy Hoffman’s favorite sayings. Deuy credits his dad for that. His brother Dave agrees. The Hoffman brothers are contractors in Waterloo, IA. They both agree that this saying has been a big part of their success.Hoffman and Hoffman was born in February of 1976, with just 5 employees, a combo plow and a couple of trucks. In the beginning, the Hoffman brothers mainly installed telephone lines. In 1979 when the cable television industry started taking off, a large part of their work became cable installation.

After several years, the Hoffmans focused on Geo-thermal heating unit installs. When the fiber optic boom began in the early 90’s, the Hoffmans decided to move back to cable installs. That kept them and their 25 man crew closer to home

Spotting A New Trend

Since then, there has been an insurgence of work from the electrical construction market. Dave says, “While 80% of our work remains in the telephone and cable industries, some of the small towns now supply their own electric. We are involved in putting a lot of their lines underground. That has increased more in the last 3 years than ever before.”

Trenchless Technology

The Hoffmans have been using trenchless equipment, specifically pneumatic boring tools, since 1976. Despite the application’s potential, during those early years, accuracy and reliability were not as they are today. Dave recalls, “We didn’t like to send them [boring tools] over 50 feet because we could never depend on the depth of the tool. It would end up being too deep or too shallow and we’d end up hunting for it.”In the summer of 1993 in Kalona, IA, the Hoffman brothers were introduced to a pneumatic piercing tool with a reciprocating head. Dave says, “A representative of TT Technologies stopped down to show us a tool [Grundomat]. We had about a 100 foot bore. We launched the tool at 7 feet deep and when it showed up between 7 and 7 1/2 feet deep on the other side, I was sold.”TT Technologies Product Specialist Jay Clark explains, “The Grundomat piercing tool has a reciprocating head. The chisel head assembly moves independently of the main casing, creating a pilot bore for the rest of the tool body to follow. This ultimately leads to greater bore accuracy.”

With long bores and accuracy no longer a problem, the Hoffmans were confident enough in their tool to expand their trenchless applications. They then purchased another Grundomat to do shorter distance bores under sidewalks and driveways for service lines.

Accuracy Is The Key

As more and more lines go underground, accuracy becomes vital. In 1996, the Hoffman brothers were contracted to replace failing 30-year-old underground street light lines for the city of Aplington, Iowa. Dave explains, “The city strung temporary lines, above ground, between the street light poles along US Highway 20 which runs directly through downtown Aplington. It was very unsightly.”The Hoffmans needed to install new conduit underground for those lines. In residential areas, the crews bored under driveways and sidewalks in sandy loam. Twelve bores, as long as 65 feet, were successfully completed, but the hardest part of the job was yet to come.Downtown, the Hoffmans needed to bore from light pole to light pole underneath sidewalks and next to buildings. Dave and Deuy each headed a crew, took opposite sides of the street with 3-inch diameter piercing tools and got ready to bore. They were working in very tight quarters. The city cut launch and exit pits at the base of each light pole. The pits were 24 inches deep, 5 feet long, but only 15 inches wide. The Hoffman crews also had to contend with abandon underground coal cellars. To ensure accuracy, each crew used a telescopic aiming frame and surveyor stakes. With the exception of one bore that hit a coal cellar, each of the 75 to 85 foot bores was successfully completed on the first try. Deuy’s crew finished first. That portion of the job was wrapped up in one day, with each crew boring 390 feet. The entire Aplington electrical job was completed in 2 1/2 days.

Trenchless Lighting

Accuracy was also needed in the fall of 1997 when the Hoffmans were contracted by a Waterloo hospital to replace electrical conduit between two light poles in their parking lot. The hospital’s security department had been trying to get the problem fixed for sometime, but no one wanted to trench the parking lot.

Even so, Dave and Deuy were hesitant to send a piercing tool because of the length of job, 130 feet. They never sent a piercing tool over 100 feet before. After much debate, they decided to try it. The bore needed to be made within a depth of 18 to 26 inches in order to avoid two storm sewers and an unwanted “speed bump” in the asphalt of the parking lot. After digging launch and exit pits, the Hoffmans again used a telescopic aiming frame and surveyor stakes from TT Technologies. They determined that there was a 4 1/2 inch grade difference between the poles and launched the tool from the lower pit. One hour and eighteen minutes later, it emerged on the other side just 2 inches right of center and 20 inches below the surface. A small crowd that gathered watched in amazement.The 1 1/4 inch conduit was installed. The launch and exit pits were backfilled and the asphalt replaced. The entire job took just 4 1/2 hours.Through industry and technology changes, the Hoffman Brothers have survived and prospered for 22 years. Why? According to Deuy it goes back to lessons learned from their dad, “Do the job right the first time so you don’t have to do it again.” For the Hoffmans, that means using trenchless technology.

 

by Jim Schill

CEE News, June 1998, Page 10