Walton Debuts New Slide Rail System for Mobile Project

Wed September 10, 2008 - Southeast Edition
Kerry Lynn Kirby




A half-million-dollar piece of equipment commonly used in Northeast cities has cut the cost of a drainage project in the Deep South and eased the job’s impact on the surrounding area, said Alabama contractor John G. Walton.

Before his company bid on a job to alleviate serious flooding problems on South Florida Street in Mobile, Ala., by installing a culvert in the narrow two-lane roadway, Walton said he flew up to New Jersey to check out the Griswold Machine & Engineering Inc. (GME) E+S slide rail system.

“They took us to some sites,” said Walton, president of John G. Walton Construction Company in Mobile, recalling one roughly half-mile stretch near Yankee Stadium in the Bronx, N.Y., where the slide rail system made it possible to work in a very confined area without causing a big disruption.

“It’s used an awful lot in the Northeast,” he said. “Everything up there is so confined, you can’t open things up.”

Walton said he thought the slide rail system would be perfect for the South Florida Street job, which was being rebid after initial bidding on the project proved so high that it was set aside.

“When we researched the project before it was bid, we discovered that it was more economical to purchase and use over the life of the job than driving sheet piling, which everyone considered to be the conventional way of shoring,” he said. “We calculated that it was approximately half the cost of sheet piling, and it can be used over and over again.”

In addition to its cost effectiveness, Walton said the equipment allows his crew to contain excavation to a smaller area while minimizing the impact of the actual construction work on surrounding buildings.

So his company made the substantial investment and was rewarded with the contract for the first phase, completed in April, which involved building an 8- by 10-ft. (2.4 by 3 m) culvert in the roadway of South Florida Street from Airport Boulevard to Emogene Street.

Using the slide rail system saved approximately $500,000 in sheet piling, said Walton, noting it was the first time a GME E+S slide rail system was used in Mobile or the surrounding area. It also paid off in helping the firm win the $3.4 million contract for the second phase, which got under way June 1, he said.

“It really gave us a competitive edge on this next phase,” he said.

The job covers 1,000 ft. (305 m) of roadway and about 2 acres (0.8 ha) overall, continuing the drainage system from Emogene Street north on South Florida Street, Walton said.

It entails building an 8-by-6-ft. (2.4 by 1.8 m) culvert at depths ranging from 12 to 20 ft. (3.6 to 6 m).

While the job is on schedule for completion by Jan. 1, 2009, there have been some delays caused by “unexpected utility conflicts” in the intersection of South Florida Street and Emogene Street, Walton said.

“A BellSouth line in this intersection has caused us to use a precast section of culvert to expedite the utility conflicts and allow us to proceed with the culvert installation without relocating any utilities which would have caused further delays,” he said.

They’ve also had to deal with water from recent excessive rainfall.

They are averaging 10 workers on the job, including subcontractors, said Josh McElhenney, the project manager.

C. Thornton Inc. of Mobile is pouring all the concrete on the job to include the cast-in-place culvert. Nordan Contracting Company Inc., of Whistler, Ala., is doing all the water and sewer work on the project. H.O. Weaver and Sons Inc. of Mobile is doing all the asphalt paving on the project. Ozark Striping Company of Ozark, Ala., is doing the striping on the job.

Walton commended both C. Thornton and Nordan Contracting for doing an excellent job of maintaining the workflow to keep the project on schedule.

The slide rail system is being used for shoring the whole length of the job, Walton said.

A Caterpillar 345 excavator is being used to excavate the trench and to install the slide rail system and move it as the culvert is being poured and backfilled, he said.

Some smaller excavators, dozers and compactors also are being used on the job.

Mini-excavators, including a Bobcat 325, are being used in the bottom of the trench because they can fit where larger equipment can’t, McElhenney said.

A vibratory hammer was used to drive sheet pile, he said.

Approximately 10,000 cu. yd. (7,645 cu m) of material have to be excavated to place the culvert in the street.

The job will require approximately 1,000 cu. yd. (765 cu m) of concrete and approximately 1,000 tons (910 t) of asphalt, according to McElhenney.

As Labor Day approached, workers were completing work on the intersection of South Florida and Emogene streets and a single southbound lane of roadway on South Florida Street that was being left open to alleviate traffic problems and allow access to businesses, McElhenney said.

An Ingersoll Rand SD-105DX soil compactor was at work the last week of August readying the intersection for paving.

A contractual requirement to keep a lane open added to the cost of the project because it will require C. Thornton to pour concrete from the other side of the roadway, Walton said.

They’ve been using the slide rail system to keep open a roughly 80-ft. (24 m) trench. “That gives us enough room to dig and pour backfill,” McElhenny said.

As they progress along the route of the culvert, they’ll keep moving the last section of slide rail system shoring up to the front of the job, explained Gary Horton, general superintendent on the job.

According to the Griswold Machine & Engineering Inc. Web site, its slide rail system works differently from other slide rail systems.

“The GME E+S slide rail system offers an open track system that allows for panels to be pivoted into place, more like a door, then clamped into the linear rails before sliding into place. This is different from systems that thread panels into closed rails from overhead. The GME E+S system self-adjusting rollers in a box frame strut ensures that the struts remain level as the excavation from within the trench is made and the slide rail is pushed to grade,” says the firm’s Web site.

The system allows for slide pivot clamping, the use of smaller excavators, and faster installation and removal, with fewer workers needed for slide rail installs, according to the GME site.

Walton said he thinks the GME E+S slide rail system is going to be used more widely in Southern cities like Mobile in the future.

“As you have more urban construction and reconstruction, you’re going to see this more and more,” he said. CEG