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article.by Bernard P. Krzys
It is an unusual company that thinks it is good business to a],ways be going in the hole. But in the manhole rehabilitation business that is exactly what AP/M Permaform strives to do. “We have successfully rebuilt more than 3000 manholes in the U.S., Canada and the Caribbean either directly or through our licensees since 1987," boasted president William Shook. Shook's background is in the water and sewer business as a distributor and Supplier. He worked with underground utility contractors supplying pipe and other materials when he began to see the need for manhole rehabilitation.
In 1987, Shook joined forces with Carroll Trimble, a contractor in Arkansas who had developed a system for pouring new manholes and was working on adapting the technology to repair existing manholes. The two began rehabilitating manholes with Trimble's system, and were incorporated in 1988.
Last year, New England Electric Company (NEEC) had some severely leaking manholes and catch basins located within a tidal area on its property in Lynn, Mass. At high tide, ground water washed contaminated soil into the storm and sanitary lines through these structures. The seal had to be bottle tight and strong enough to withstand the groundwater pressure of the North Atlantic tides.
"Our licensee in New England, Utility Pipeline Services, offered a three inch seamless interior of Permaform with admixtures to densify and waterproof the concrete at our recommendation," advised Shook. "All the structures were rebuilt and sealed in place in less than two weeks. Recently inspected by NEEC, they were reported to still be 'bone' dry."
This is not an uncommon problem for us to solve," Shook stated. In, 1989, the company's licensee in Virginia, D&S Contractors of Richmond, had a similar problem with two manholes on either side of a yacht basin in Newport News. The water level in the manholes raised and lowered with the tide. Besides weakening the brick structure by washing in the supporting soil, the salt water was severely impacting their bacterial treatment process.
While the tide was out, forms were set interiorly without any excavation or interruption of sewer flows. A concrete wall was poured behind the forms and then removed after the concrete had set. The old manhole was structurally restored and totally encapsulated from the tidal water. Public works administrator William Cutts stated, "We didn't think these manholes could be saved but the cost of dewatering for excavating was prohibitive. We are more than pleased with this process."
What sets the Permaform system apart from other manhole rehab systems is that it is a fully structural repair that can be done completely without any excavation whatsoever, claims Shook. Other no-excavation repair systems are not fully structural, according to Shook, and other structural repairs frequently require some kind of external, digging.
"When we exhibited at the first U.S. No-Dig conference in Washington, D.C. in 1988, we noticed that many products and services were offered for inspection and for pipe relining but, aside from us, manholes were being ignored," said Shook.
The international exposure at No Dig made Shook realize that the problem with decaying manholes was indeed a world-wide problem. In hopes of participating in the international market, Shook and Trimble sold a portion of the company to Insituform Group Ltd. of the United Kingdom. Unfortunately, the international projects never materialized as promised.
"This union just didn't work out the way we had hoped," Shook stated. "Our concentration has been on manholes only and we found that we could ill, afford to limit ourselves to just one relining process. In 1991, we bought back their share of the business."
The company's newest solution, Permacast, is a centrifugally applied cementitious liner. The synthetic mortar is cast from a patented robotic applicator positioned in the center of the manhole. A dense, uniform layer is compacted in-place at any thickness from one-quarter to two inches depending upon the degree of deterioration and the depth of the manhole.
"It was designed to augment our Permaform system since it served to enhance and seal those manholes which are still structurally sound," said Shook. "Last fall when the City of Naperville, IL., watched us doing some, they insisted on trying it themselves."
"Since we have an aggressive in-house program for manhole rehabilitation, we tested a number of processes," commented John Vose, Naperville’s sewer superintendent. "Permacast provides high quality and eliminates confined space entry. It works particularly well in our narrow chimneys."
The two systems were designed to be complementary, that is, Permacast for manholes that are structurally sound but need enhancement or sealing-and Permaform for those needing complete structural repair. To their surprise, Performance Pipelining Inc., the licensee in northern Illinois, recently completed one manhole that required both systems.
A pulp plant in Wisconsin had a brick manhole with a void outside its wall, according to Michelle Kiest, president of Performance Pipelining. “They would not let us get into the manhole because it was ready to collapse and it was impossible to dig up because of its location. They were delighted that we could stabilize it first with a one-inch wall of Permacast.
"The next day it was safe to enter without fear of collapse. We then set our forms and filled the huge void outside the old wall with high-strength concrete. We were completed in two days at a savings to the plant of more than $20,000."
Shook views his company as a problem-solver, as they have helped clients overcome "some of the nastiest manholes you can imagine," he said. Permaform’s philosophy of using innovative technologies to solve the customers' manhole problems helps keep the company successful despite always being "in the hole."
The author is publisher of Trenchless Technology.
TRENCHLESS TECHNOLOGY August 1994
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