Mactaquac Generating Station Dam
Hood Canal Bridge
Wastewater Circular Cut
Mega Demo Circular Cut
IT'S A DIRTY JOB, BUT SOMEONE HAS TO DO IT
Wastewater Plant Sewer Removal
Very few people enjoy really dirty work. But a recent job in Louisville, Kentucky required special people who did not mind doing something a little dirty and unique to get the project finished. Also, special equipment with a number of capabilities was necessary as well.
The Morris Forman Wastewater Plant required reconstruction on a sewer line. The project consisted of updating "live" sewer lines, striving to make more efficient pump systems at an upgraded head works facility.
A total of three separate junction boxes were constructed early on. The boxes were responsible for diverting a large portion of the 105 million-gallon daily average flow. These sections would eventually tie into the new pump systems, for this was the main goal of the entire project.
The first step of this tremendous project was to make three separate cuts on each of two 72-inch diameter reinforced concrete pipes using modular Cutting Edge wire saws. On each of these pipes, a two-inch gap was made at the bottom between the junction box floor and the pipe's underside, making enough room for the diamond wire. Mid-cuts were also made to reduce weight and ease removal. The saw and configuration of the pulleys allowed the cut to be made in "one stroke."
For the very large 132-inch line, special preparations for cables and rigging were made. The contractor placed PVC pipes under excavated pipe and then poured a new floor. The Cutting Edge team used several PVC pipes to feed wires and back-up bare cables around the line. Construction set-ups on site reaches as high as 25 feet above the top of the pipe. After set-up, the crew made a radial cut in the 11-foot-tall pie-shaped sewer pipe. A cut of this size is perhaps the largest live sewer pipe cut ever made. Six cuts were made to allow removal of 5 huge sections.
During the work, the operators were not exposed to any sort of raw sewage flow. Approximately 50 percent of the cutting was completed underwater. The diamond wire system allowed cuts to be made at a safe distance from the work crew.
Compared to alternative methods, wire sawing was best. Debris quantity was low and did not flow into active pipelines; therefore, stray pieces did not damage or block any pumps. It was not necessary to shut down the line being worked on; the team worked while the line was still being used to transport sewage.
The primary concern for the job was to make sure the wires held up. We only encountered 3 wire breaks, taking care not to over pressure the wire connections. Hard wood shims were used to prevent direct closure of pipe onto wire.
A total of only 3 technicians were responsible for wire cutting. Additionally, a part-time crane operator and rigging man were on the job. Although the numbers were low, each man had a specialty to provide a unique solution to this project. The skill of the wire saw operators was the key to the cutting phase. They had to make good connections, run wire saw at safe speed and direction, stop to check condition of wire, place shims in cut line, and taper the cut to facilitate removal. The project at the Wastewater Plant was precisely on time, while providing considerable savings over conventional methods.
Along with the operators' hands-on work, junction box construction contributed to the completion of a successful job. It provided a base to begin other work on the sewer line. This type of preparation was necessary to make sure no surprises occurred. Proper planning before and during this job was especially important around the sewer because the cutting and removal was performed under live flow conditions. This particular project required some up front engineering and planning meetings with the general contractor.This was a dirty job, but with strong project planning, knowledgeable and experienced operators, and fast work with a wire saw, it certainly wasn't as dirty as it could have been!
Miami Valley Hospital In Dayton, Ohio Gets Entire New Wing
In September of 1998, Cutting Edge Services, Corp. was called upon to remove a reinforced concrete stair tower, 70-feet high, 12 feet across and extending 15 feet off of the face of a building, to make way for a large, new wing to Miami Valley Hospital in Dayton, Ohio. This job was made more challenging because it had to be done quietly. The tower was adjacent to critical care patient rooms and sensitive operating rooms.
Cutting Edge Services was one of the first contractors to pioneer diamond wire construction sawing for North America in 1983. The company was glad to be called to perform these services. The company's strengths were perfectly matched with the job that needed to be done.
Any time there are large facilities or very thick structures that require precision removal, projects that require limited access, heights or very unusual thicknesses, Cutting Edge Services can be of help.
The portion of the work that needed to be done at the hospital was to make room for a 221,000 square foot addition.
The expansion provided more space to encompass a new emergency department, surgery, recovery and outpatient surgery as well as a new central service distribution.
The hospital chose Cutting Edge Services because they wanted a firm that had the capability of removing the existing materials without making any great noise to interrupt the patient care in the building. This work was accomplished in an area adjacent to patient care rooms as well as the operating and emergency departments.
Cutting Edge Services came up with a scheme to cut the tower from the top down and cut through the walls, stair sections and other concrete attachments with one single wire cut. Our company's pricing was most likely in line with other techniques that might have required more labor. Wire sawing required less use of labor and more use of the equipment.
It is precisely this increase in productivity that has helped the number of wire saw jobs mushroom. Jobs are completed in less time with less manpower than required by conventional demolition. Such conventional methods as jackhammers, hoe-rams, and explosives create a considerable amount of noise, dust and vibration. The diamond wire saw, on the other hand, creates very little noise, no dust and does not weaken surrounding structures because of vibration. Additionally, the length of the wire is virtually unlimited -- any size cut can be made.
In operation, the diamond-embedded wire is driven and guided by a pulley system. The guide wheels or pulleys are mounted near the structure to be removed and generally are no larger than 16 inches in diameter. The power unit can be placed several yards from the work area. The pulley system allows for the removal of heavy reinforced concrete where the work space is limited or in areas that pose a safety hazard for the operator.
In a typical cut, a small hole is drilled at each end of the cut to be made. The wire is passed through the two holes and then coupled together. It is placed on the drive wheel and around idler wheels that guide the wire. Water is used to cool the wire and to wash away the slurry created by the cutting operation. Wire tension is maintained via a hydraulic "stroke" motor that pulls the main drive wheel along its sliding carriage assembly. The main drive assembly is a simple fly-wheel that is hydraulically driven.
This job presented several challenges. Cutting Edge was blocked from access inside the hospital, so the only access was from the outside. Also, as the structure was being cut free, it had a tendency to become unstable. Since the cutting for this job started at the top, the biggest challenge was that there wasn't room to really run a wire saw at the various elevations, so they had to run the wires from the ground up. In addition, with diamond wires, the longer they get, the more complicated projects become. For this job, it took a 250-foot length of wire to make the initial cuts by running the wire up along the side of the building and transitioning to a horizontal cut at each elevation.
Also, there were approximately 40 two-inch diameter wire access holes that were drilled for the wire access points. For rigging, there were approximately 60, four-inch diameter holes drilled through the composite section, consisting of four inches of brick and then an air space and 12 inches of reinforced concrete.
Diamond wires used were the center type cable, 11 millimeters in diameter. A separate contractor was responsible for the crane lifting and the removal of the concrete. The company utilized an 80-ton capacity truck-mounted hydraulic crane. All-terrain mobile lifts were used for the drilling crews and technicians to access the elevated points.
The structure came off as a three-sided shape that had to be handled carefully. A spreader bar was used to apply even vertical loads to the pieces on the wall so the structure didn't collapse when it was picked up as any type of significant movement or loss of a large section of the piece could have caused damage to facilities and equipment below.
There was a limitation on the size of the pieces that could be picked up with the crane, so Cutting Edge Services helped size the sections that were coming down. They also planned the layout, starting from top down, to determine where all the horizontal cuts would be made. The whole cut was done in eleven pieces, each weighing up to 35,000 pounds each.
Once most of the holes were drilled, Cutting Edge Services proceeded with the horizontal wire cut and worked its way down. After removing the first two pieces, the structure was stable enough with this method of cutting so the crane could be moved off site while the remainder of the horizontal cuts were completed.
This left the structure attached to the hospital only on the vertical face. From there the company finished the project with the second of two wire saws that made flush cut against the hospital face and freed those stair tower sections. Then each section of the tower was cut through, lifted off and lowered to the ground for removal.
The hospital was quite satisfied with the results. What they really enjoyed was the fact that the wire cutting was extremely quiet. Cutting Edge Services didn't even need OSHA ear protection to be able to work adjacent to the wire cutting operation. Also there was no vibration or dust.
Another advantage for the wire saw was that it didn't take up much space. The contractor was able to keep the equipment in a small pad adjacent to the hospital. Excavation around the stair tower to the west and to the south of the staging area was very close to where the wire sawing was performed.
In appreciation for its good work, Cutting Edge Services was invited back to complete the second phase, which involved the cutting of a second, similar tower.
Battelle Saves $270,000 Using Wire Saw for Radiological Decontamination & Decommissioning
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Wire saws are ideal for removing large sections of heavily reinforced concrete in pulp and paper mills, steel mills, bridges, dams, power plants and for cutting concrete in any area where space is restricted. Battelle and the U.S. Department of Energy used the wire saw for decontamination and decommissioning of radioactive concrete due to its capability to perform cutting with low noise levels, no vibration and no dust.
The first privately-owned research reactor built for radioactive material and reactor core studies at Battelle is now part of a Department of Energy (DOE) program involving radiological decontamination, decommissioning and restoration. The United States Department of Energy contracted with Battelle Memorial Institute to perform environmental restoration on Battelle's JN-3 facility at a Battelle Research Park near West Jefferson, Ohio. Battelle performed atomic energy research including the fabrication of uranium and fuel elements, reactor development, submarine propulsion, fuel reprocessing and safety studies of reactor vessels for DOE and its predecessor agencies from 1943 through the mid-1980's.
The JN-3 reactor was built in 1955 and operations were shut down in 1974. In 1975 the reactor was decommissioned to a restricted level using the regulatory limits required at the time. The original decommissioning project included the removal of the fuel and water used in the reactor operation. This decommissioning brought the building to near-free release levels. Twenty-five years later, the instrumentation to detect residual radiation has improved dramatically, allowing lower regulations than the release levels required. At the present time, DOE and Battelle are working under a shared cost program to return this facility to a condition suitable for use and/or release without any radiological restrictions.
This phase of the Battelle Columbus Laboratories Decommissioning Project was intended to reduce the minimal contamination in the building to the present release levels for use without radiological restrictions. Most of the remaining low radiation levels monitored in the building are from the irradiation of metals in the reactor walls, bioshield and other structures. They do not present a health hazard for Battelle, the workers or the public. However, the As Low As Reasonably Achievable (ALARA) principles Battelle is working under for this DOE project demand the building reach free-releasable radiation levels. In order to reach this level, Battelle removed the massive concrete structures, such as the reactor's bioshield, and miscellaneous contamination from this radioactively "cold" building before it was demolished.
The JN-3 building on Battelle's West Jefferson North site was remediated through removal and disposal of the radioactively irradiated bio-shield. The bio-shield was built of high-density six-foot-thick concrete with carbon steel reinforcement to protect personnel from high levels of radiation produced during the reactor's operation. The manual removal of such a large structure would have required expending considerable time, effort and possible worker exposure. Battelle needed a better alternative. "We constantly search for more advanced technologies to aid in the remediation process and then back that up with continuous improvement," stated Carl Brenner, Battelle's JN-3 Project Manager. "DOE recommended a concept called Accelerated Schedule Technology Deployment (ASTD) to help advance the technology," he added. As a result, Battelle proposed the use of diamond wire sawing to reduce the cost of the bio-shield removal while also facilitating the necessary radiological control during removal and disposal.
Battelle accepted bids from contractors with expertise in wire sawing and selected Cutting Edge Services Corp. "This is a critical job that requires cutting expertise, innovation and problem-solving capability," said Battelle's Support Engineer Cidney Voth. "I have worked with Cutting Edge President, Tim Beckman, for a number of years at other sites and found him qualified for this task in the selection process."
Cutting Edge employees completed 40 hours of training in order to work in this radioactive environment. Training included radiation worker training, security and orientation training, bioassay and dosimetry operations, and procedure/work instruction orientation. The contract assumed that each worker would spend 2 hours per day involved in dress-in/dress-out activities as well as daily operational meetings. All the work was performed in compliance with OSHA (Occupational Safety and Health Act) and Battelle Safety and Health requirements.
The scope of work also included the removal of a non-radioactive 29 x 24 x 2 foot-thick wall and 4 x 9 x 4 foot-high pedestal inside the bio-shield. A Brokk hydraulic hammer or "rubble maker" was used for this demolition because the wall was non-radioactive and the operation could be carried out in less time. However, it became apparent that quicker was not better! The hammering created large amounts of dust that had to be controlled with mist spray to reduce the air-borne dust exposure. The water then had to be collected and disposed in a radioactively controlled area causing additional challenges to the Battelle/Cutting Edge team.
The next challenge was to remove the remaining 12,000 cubic feet of concrete that made up the bio-shield structure. Holes were core drilled at strategic locations of the concrete structure so that the diamond wire could be fed through in order to complete the loop of diamond wire before cutting could begin. The diamond wire is a multi-strand cable with diamond segments threaded on it that is looped through a series of pulleys and is continuously pulled through the concrete. Since virtually no concrete structure or cross-section is too large to cut, wire saws are used whenever other cutting methods are impractical.
The Cutting Edge team had to wire saw the concrete wall into 5-10-ton blocks that could be lifted out by the overhead 10-ton crane. The target weight for each block was 17,000 pounds and 64 blocks were removed before the project was completed. The bio-shield consisted of two types of concrete. The standard concrete was 170 pounds per cubic foot and those blocks averaged 8 tons. The Barytes concrete had a higher density of 220 pounds per cubic foot and those blocks averaged 9 tons. Four diamond wire technicians used two wire saws and two hundred feet of 11-mm and 15-mm diamond wire to cut a total of 12,000 cubic feet before the project was completed. The operators began with the removal of the top T-shaped concrete and then began cutting sections free starting from the top.
The diamond wire has many advantages in addition to the productivity and time efficiency in dismantling large concrete structures. An operating wire saw has low noise levels and because water is used to cool the diamond segments, little, if any, dust is generated during the cutting operation. In addition, wire sawing does not weaken the surrounding structure because there is no vibration and thus the stability of the remaining concrete is not affected. Hammering of the concrete introduces the possibility of making the radioactive material in the concrete unstable, which can be a major risk. Finally, only a small area of the one-inch diameter wire saw comes in contact with the radioactive material minimizing clean-up operations. From a radiological control standpoint, this technology provides a more efficient material disposal, more effective contamination control and better personnel exposure control.
Another key advantage that was the direct result of wire sawing was much lower water usage. Because the water from the cutting operation had to be handled as radioactive material, the disposal of large quantities posed a difficult challenge for Battelle and Cutting Edge. In the first few days of sawing, 1,000 gallons of water per day were required. Though this is not unusual, the disposal of nearly 55-gallon drums of contaminated water per day was unacceptable. Shipping costs for 55-gallon drums were $8 per cubic foot plus $20 per drum.
Cutting Edge devised a water recycle system that removed material from the radioactive water. The recycle system allowed the sediment to settle out of the water so that the water could be recycled. Only the resulting sediment needed disposed of as radioactive waste, and the usage of fresh water dropped to 50 gallons per week!
Once the eight-foot-thick concrete sections are lifted out by crane they were lowered and then wrapped in a special protective yellow wrapping by Battelle workers for transport to a DOE-approved disposal site in Utah. Each concrete block was numbered sequentially and the weight was displayed to facilitate transportation and later loading.
This type of work has paved the way for future projects of this caliber. A critical mission of the DOE is the restoration of public and private facilities and sites contaminated during the course of work for the federal government. The successful use of the wire saw on this project could result in other radiological decontamination, decommissioning and restoration projects under the DOE.
Precision Underwater Cutting
Required in Great Egg Harbor
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In September 1999, Kiewit/Tidewater, AJV began constructing a new 3,450-foot-long bridge over Great Egg Harbor in Ocean City, NJ adjacent to an existing bascule bridge. The new structure had battered (angled) piles that required precision cutting underwater to complete the new bents. Kiewit contracted CSDA contractor member Cutting Edge Services Corporation of Cincinnati, OH to complete this unusual job.
The job required precision cutting of 82 pre-stressed concrete cylinder piles, which would support the new bridge structure. The hollow piles were 54 inches in diameter and driven deep into the tidal floor at an angle. In order to cut the piles correctly, Cutting Edge Services needed to find a way to make a precision cut below the surface of the water, severing pre-stressed reinforcing strands and spiral-wrapped rebar, while also preserving the structural integrity of the piles. The elevation of the cut also needed to be closely controlled. Because the piles were located in the harbor, this limited-access job also required a saw that would work consistently in salty underwater conditions. Additional factors that complicated this project were the tidal changes, cold weather and "snapping" of the pre-stressed strands as they were cut. Kiewit and Cutting Edge Services put their heads together and came up with a unique solution to this complicated cutting task.
"This project demonstrated a successful mix of creative client; a talented manufacturer and a professional concrete cutter," said Tim Beckman, President and CEO of Cutting Edge Services. "It took persistence from all three parties to complete this unique wall saw application in a timely manner."
Cutting Edge Services conceptualized a modified wall saw on a circular track that would perform in underwater conditions. They contracted with CSDA manufacturer member Diamond Products, Elyria, OH, to create a modified wall saw and track. To facilitate shop fabrication and testing, a 54-inch-diameter, hollow, pre-stressed concrete pile was shipped to Diamond Products' shop in Ohio. Diamond Products modified a DZ Wall Saw and created an I-beam guide rail circular track customized to fit around the concrete pile. Special guide rollers were needed to hold the saw onto the circular track. They also added additional remote operation capabilities, blade indicators and hydraulic-actuated stabilizers at the request of Kiewit and Cutting Edge Services. Diamond Products tested the modified saw using various blade diameters and segment configurations to ensure uniform depth of cut without penetrating the inside of the hollow pile. This was an extremely important factor because if the piles were overcut, they could fall and cause unsafe conditions; if they were undercut, they could not be removed without damaging the remaining pile.
While the saw was undergoing final assembly and testing, Kiewit designed and fabricated a custom support work platform to hold the operators while they were running the circular wall saw. This platform included a tapered steel pole that centered the cutting apparatus into the concrete piles and maintained stability during cutting operations. The DZ saw and support mechanism were powered by a large hydraulic unit located on a nearby barge. A control panel could monitor and perform all setting and saw operations by remote control. The blade depth could also be monitored by indicator lights. The modified circular I-beam track was attached to the support platform by chains to keep saw movement independent of the platform. Once operators had lowered the saw to the desired level, a hydraulic piston locked the saw track in place around the pile and held it firm during cutting. When the saw was not in use, it was kept submerged in a special solution on the deck of the barge.
To begin the cut at each pile, a crane operator lifted the entire support platform and modified wall saw, lined it up with the pile to be cut and carefully lowered it into the hollow core of the pile. This was somewhat difficult, as the piles were set at an angle in the water. After lining up the saw and setting the actuator pistons for the track, operators began the cut by making a 1-inch-deep, 360-degree pass around the pile. Operators then made a second 360-degree pass, cutting an additional depth of 2 inches. They completed the cut with a third pass, making the total cut 6 inches deep. A total of 82 piles, in groups of four, six or eight per bent, were cut with this timesaving machine. Typical cuts were made in one hour versus several hours with hand tools and a dive team. Kiewit confirmed that significant time and money were saved with this unique diamond-cutting saw.
Cutting Edge Services Corporation has been a CSDA member since 1998. They are a specialty diamond cutting contractor, offering engineered field services and equipment for the nuclear, forest products, hydro, industrial, decommissioning and bridge markets. The business began in 1997 and is based in Cincinnati, Ohio. CEO and President, Tim Beckman, has over 30 years experience and helped commercialize construction wire sawing in 1983.