Cooling Tower Demolished in SRS Footprint Reduction

-Original article in the Aiken Standard-

In a matter of seconds, a $90 million structure that took three years to complete was reduced to millions of pounds of rubble as the cooling tower at Savannah River Site’s K-Reactor was imploded Tuesday.

The 450-foot-tall, 345-foot-wide tower was safely demolished Tuesday as part of the sitewide Footprint Reduction Initiative funded by the American Recovery and Reinvestment Act (ARRA). The second-largest cooling tower to be demolished worldwide, K Cooling Tower was completed in 1992. It was conceptualized to cool the water in a reactor in support of national defense initiatives, which were ceased soon after.

The demolition was managed by American Demolition and Nuclear Decommissioning Inc. with specialists Controlled Demolition Inc. handling the placement of explosives and implosion.

The total cost of the project is $3,982,430, which includes bringing down the tower, breaking up the larger pieces and then transporting the rubble to SRS’ on-site landfill.

“The cooling tower demolition project is unlike any other closure initiative taking place at the site,” said Dewitt Beeler, Savannah River Nuclear Solutions (SRNS) director of Area D&D Projects. “It isn’t every day that we deal with the demolition of a structure the size of the K Cooling Tower, and it was clear early in the process that we needed expert help.”

In all, more than 3,860 holes were drilled at strategically selected spots on the tower and loaded with explosives. The charges were detonated in a controlled fashion involving precise sequencing and timing to ensure the tower fell in a selected impact-zone.
“The demolition of the K Cooling Tower marks the achievement of a significant milestone in the Recovery Act mission at SRS,” said Rita Stubblefield, deputy federal project director for the Department of Energy. “It has allowed us to create new jobs while reducing the site’s cleanup footprint.”

Alaskan Tower Demolition Starts LORAN System Decommissioning

Original article with photos can be found by clicking here.

CDI’s video angles can be found on our YouTube Channel.

With cracks as sharp as the frozen Arctic air, a 1,357-ft steel communications tower in Port Clarence, Alaska, tumbled to the ground on April 28, the first step in the U.S. Coast Guard’s decommissioning of its network of LORAN radio navigation facilities across the country.

The 400-ton, 45-segment triangular steel tower is the largest man-made structure to be felled by explosives, according to Controlled Demolition Inc. (CDl), Phoenix, Md., which performed the operation as a subcontractor to Jacobs Field Services North America.

For nearly 50 years, the remote installation located 75 miles north of Nome was one of 24 land-based LORAN stations throughout the U.S. that broadcast low-frequency signals to help ships and aircraft determine speed and position. The increasing precision and reliability of GPS technology rendered LORAN obsolete. Its powerful transmitters were silenced in February.

The Coast Guard now has until Sept. 30 to determine the future of its LORAN installations, which include operational and support buildings, transmitters, towers, and, in some cases, full water and sewer systems.

While more remote facilities such as Port Clarence will be demolished, others may be repurposed within the Coast Guard and the U.S. Dept. of Homeland Security, or be transferred to other federal and state agencies.

“We’ve received approval to sell about one-third of the sites,” says Commander David Savatgy, commanding officer of the Coast Guard’s civil engineering unit In Juneau, Alaska. He adds that Coast Guard-owned properties such as the oceanfront LORAN station on Nantucket Island, Mass., may prove attractive to both public- and private-sector bidders.

“Any funds from property sales will be put back into the decommissioning program,” Savatgy adds.  “In the case of facilities on leased land, we’re talking with landowners to see what they want to do.”  But because it could be several years before some properties are transferred or demolished, the facilities will be hardened to BRAC Level III status, with no future reuse expected. “We’ll also assess the Coast Guard’s environmental liability at the sites,” he says.

Because of the Port Clarence tower’s deteriorated condition-three of the 21 oil-filled cylinders in its ceramic base insulator were cracked and empty-a controlled demolition was more cost-effective than manual dismantlement, which would have taken several weeks. And with the ground still frozen, Savatgy says it made sense to take down the tower before thawing turned the ground into a quagmire. “Otherwise, some of the fallen pieces might bury themselves up to 15 ft in the muck, complicating the clean-up work,” he adds.

CDl’s staged sequential detonation used 32 linear-shaped charge explosives, each weighing less than 10 Ib, to differentially release the 1/2- and 314-inch-thick structural guy and top loading element  (TLE) radial link plates, located just above the anchorages at grade. Forged bridge sockets were also charged at the radial locations.

The tower was felled in a folded method with 75% of its height released in a southerly direction, and the top restrained by the upper radial guys on the north side.

“Folding the top portion of the tower back on itself reduced the debris field without causing damage to a transmitter building containing friable asbestos located just 14 ft away,” says CDl President Mark Loizeaux.

Although the tower demolition was spectacular to witness, Savatgy admits that he and others feel a sense of loss at its demise. The Port Clarence station, with eight reinforced concrete buildings on foundations set in permafrost, was built in 11 months for $2.7 million. “It means the end of a mission that the Coast Guard has been doing for a long time:’ he says. 

Mark Loizeaux named as Top 25 Newsmaker of 2009 by Engineering News Record

Original article with photos can be found by clicking here
Follow-on article detailing ENR’s selection of Mark Loizeaux can be found by clicking here

The Top 25 Newsmakers of 2009

Many people serve to improve the construction industry every day. And each year, for 45 years, the editors of ENR have reviewed the stories they have written during the year and selected people featured in them for special recognition. They are chosen for delivering innovations, achievements and services that advance the construction industry. Additionally, each year one of them is honored with or our top award, the Award of Excellence. The identity of the Award of Excellence recipient will be revealed and the award presented on April 8, at the Award of Excellence gala in New York City. But first, in the pages that follow, ENR salutes all the Top 25 Newsmakers of 2009.

J. Mark Loizeaux

Loizeaux Triumphs Over His Most Daunting Implosion in More Than Four Decades

Loizeaux’s experience, expertise and dedication to safety led to the successful controlled demolition of a faulty Texas tower.

Mark Loizeaux has imploded some 2,000 structures in his four-plus decades with Controlled Demolition Inc., which was started by his late father, John. Mark has taken down cooling towers, arenas, stadiums, bridges, tall and short buildings, steel frames and concrete frames—all over the planet.

But none of his previous jobs match the implosion of the structurally ailing, 379-ft-9-in-tall Ocean Tower project in South Padre Island, Texas. After more than six months of intense preparation, CDI dropped that building successfully on Dec. 13, without injuries or incidents.

The topped-out, half-clad and partly furnished condominium tower was as close to a stumper as they come because it was a distressed, unstable hybrid structure. There was ongoing differential settlement between the unbonded post-tensioned concrete section at the base and the reinforced-concrete tower.

Observers say the failed structural elements looked as if they had been through an earthquake. Responsibility for the problem is the subject of litigation between the owner and the project’s geotechnical and structural engineers.

The distress meant Loizeaux could not rely on the structure’s behavior during the shoot. Beyond that, the site, surrounded by protected dunes, the Gulf of Mexico and roads, was hemmed in. Also, it was only 12 ft to the property line of a residential development.

Imagine Rodin’s “The Thinker.” That was Loizeaux on several occasions during the second half of last year, as he pondered his approach to the implosion. “A good deal of my time was spent sitting on a sand dune, a half mile away, looking at the building,” says Loizeaux. The job “was very provocative mentally,” he adds.

Loizeaux, who made eight trips to the site, says he also spoke “endlessly” with his brother and partner, Doug, about the strategy for imploding the building. Loizeaux knew he had to use delayed charges to straighten the slightly listing building, tilt it toward the Gulf and drop it into a pile of well-fractured rubble. But he says he was not sure of the specific timing of the implosion sequence until a week before the event.

“The implosion of Ocean Towers went so smoothly that it was as if we had rehearsed this several times,” says Javiar Vargas, South Padre Island’s assistant chief of police. “This was mainly due to the calm, collected manner of Mark and his experience and expertise.”

Loizeaux is not a stranger to these pages. For his expertise and other accomplishments, ENR has named Loizeaux a Newsmaker four times since 1972.

Faulty Tower’s Implosion Will Set New Height Record

By Nadine M. Post, for Engineering News Record November 25, 2009

Original article with photos can be found by clicking here

The specific date in December for the implosion of the faulty, 376-ft-tall condominium tower on South Padre Island in Texas has not been set. But the demolition contractor says it has solved almost all the quandaries of one of its most challenging razings using explosives. If all goes according to plan, when the dust settles, Controlled Demolition Inc. (CDI) will have broken the height record, which it set in 1975, for imploding a reinforced-concrete tower.

The Ocean Tower job is one for the record books, and not just because it is 15 ft taller than the São Paulo, Brazil, tower that CDI previously took down. The preexisting structural damage means loads are not being transferred through the remaining structure in a “fully predictable, much less programmable fashion,” says J. Mark Loizeaux, president of Phoenix, Md.-based CDI. That means more caution during prep work.

CDI has never encountered such a heavily reinforced building. “We have never had to preblast openings in walls of a building we were going to implode,” says Loizeaux.

In broad strokes, the plan is to first straighten the tower, which has a slight tilt to the north, then tilt the tower to the east toward the Gulf of Mexico about 15 degrees and drop the tower vertically—all in about 12.5 seconds. But the devil is in the details, and CDI ranks the job as its second most difficult implosion, after Seattle’s Kingdome.

The tall, slender construction of the tower and its structural design and layout offer very few column lines and rotational reaction points to work with before all control over the structure is lost when it begins to fail vertically, says CDI. “The success of the implosion is, literally, going to turn on about 3.5 seconds of CDI’s delay sequence,” says Loizeaux. “After that, it’s in the hands of gravity.”

There also are complications related to the two-way, post-tensioned beam system at the base of the tower and in the parking garage. The many variables make Loizeaux “professionally concerned.”

The beachfront site isn’t helping. CDI has to design the collapse to avoid any impact on houses just 150 ft away, as well as nearby dunes, a road, other infrastructure and a park. The task would be easier if the tower were not founded on sand, which conducts vibrations.

“Everything looks like the vibration levels are well within safe limits for the adjacent buildings,” says David K. Miller, principal of Seismic Surveys Inc., Frederick, Md. The geotechnical consultant based its review on historic data from imploded tall buildings on beaches.

Debris remains a concern. To protect surroundings, workers are installing fencing, followed by geotextile screens, around columns, core walls and the periphery of the tower to floor 27. In front of the two nearest houses, CDI plans to build two- and three-story screens, covered with geotextile, each at least 100 ft long.

The development’s structural problems are attributed to differential settlement between its 33-story structural concrete tower and the three-level parking garage—200 ft x 238 ft in plan—on which the tower sits. Responsibility for the differential settlement, which reached 14 in. in places, is the subject of ongoing litigation.

The post-tensioning of up to 2,000 kips would have been challenging enough to accommodate in the implosion had the beam grid been complete. But there was a void left in garage slabs for the job’s tower crane, outside of the high-rise footprint (see slide 7). There, the lack of post-tensioning would create an uneven condition during an implosion. “If I get asymmetrical failure in garage columns surrounding the tower, it will cause the tower to skew out of the design path as it falls,” says Loizeaux.

To prevent this, CDI plans to equalize the condition by using explosives at the outset of the implosion to eliminate the post-tensioning on the opposite side of the garage before bringing the rest of the high-rise down.

Another headache, still unresolved, is how to handle the shores, highly engineered aluminum-alloy posts, installed to replace failed columns and beams. One idea is to put charges against the shores backed up with sandbags. Then, CDI would kick the shores out in concert with the tower implosion sequence. There are also 14-in.-deep H columns, in structural steel, under two failed tower columns. For this, CDI is considering using linear-shaped charges that would cut the steel during the implosion.

CDI decided to install cabling in the tower to provide structural integrity to “confidently” move the structure toward the east before starting the vertical failure. In all, crews are stringing and tensioning more than 3,000 ft of cable.

Crews have finished conventional pre-demolition of a 200-ft x 106-ft section of the garage, where the tower is designed to land. The clean concrete debris will act in concert with the exposed pile caps and piling to help direct debris impact energy at grade through the piling. That will reduce the energy available for a damaging surface wave, says Loizeaux.

CDI, which does not need permits for the implosion, has been in contact with the area’s various regulatory agencies. “CDI is worried about anybody entering the implosion zone,” says Javier Ch. Garza, South Padre Island’s interim chief of police who is coordinating security for the event. The biggest concern is pleasure boats filled with spectators, he says.

CDI Launches YouTube Channel

“The Art of Implosion” – A graphically beautiful and technically challenging industry. It’s no surprise to us that we receive numerous requests for video footage each day from students of all ages and ‘fans of the industry’ from all over the world.

For this reason, we’ve decided to launch our own channel on YouTube. Each and every project CDI performs (and as is documented via video by our sister company, The Loizeaux Group, LLC) will be catalogued here in video segments containing one or more angles of each demolition project. In the information block for each video segment, we will also include general details about the project such as name, location, brief structural information, date and time performed as well as who CDI was contracted by for the work.

Be sure to click on the ‘Subscribe’ button to be notified when new video projects are added.

Our sincere thanks to all for your continued interest in our work. We hope you enjoy watching!

Click here for CDI’s YouTube Channel

The Science of Sinking the Vandenberg

Link to original article with photos can be found by clicking here.

On the surface, it sounds like a simple plan.

Each of 42 charges totaling 179 pounds of explosive material will create 3 million pounds of pressure per square inch, tearing 42 holes in the hull of the Gen. Hoyt S. Vandenberg below the water line.

That’s the science, but bringing the old ship down will require as much art as engineering savvy. Getting the ship and the 6 million pounds of iron and concrete ballast inside it to settle properly on the sandy floor — seven miles southeast of Key West and half a mile from the nearest reef — required years of model-making, planning and input from explosive experts, engineers and scientists, said project founder Joe Weatherby.

Permits from 18 different agencies define the location, surveyed during more than 130 dives, according to Sheri Lohr of Artificial Reefs of the Keys.

“There have been hundreds of dives by just about everyone we could round up,” Weatherby said. “Local dive operators, folks from the [Florida Keys National Marine] Sanctuary, Mel Fisher divers, Special Forces divers, we took comments from the public at one time — everyone. We made sure there are no Spanish galleons down there.”

The Florida Fish and Wildlife Conservation Commission also approved the site.

The goal is to have the ship stay upright as it sinks straight down, then settle on the ocean floor 140 feet below, said Mark Loizeaux, of Controlled Demolition Inc. of Maryland, which has brought down oil rigs, offshore towers and such buildings as the Seattle Kingdome, Titan missile launch facilities and Alfred P. Murrah Federal Building in Oklahoma City.

Essentially the Vandenberg under water should look the same as it does today moored at the Truman Waterfront.

Series of thuds

Reef Makers CEO Jeff Dey is helping Loizeaux and his team and naval architects determine where on each side of the hull to place the 21 cutting charges.

Each charge will contain four small charges positioned like a square picture frame, each of which will detonate in a tenth of second from the other, Loizeaux said. They will not all detonate at the same time in an effort to minimize the environmental impact, Dey said.

“From a technical aspect, we want the buoyancy to stay in the center of the vessel, above the center of gravity; that way the ship stays upright,” Loizeaux said.

The holes created by the explosives were positioned by marine architects, Dey said.

“We’re making the holes where we’re told to make them,” Loizeaux added.

The charges are essentially military charges that will explode at 27,000 feet per second, cutting a narrow line through the hull.

“The cutting charges are designed to leave a sharp line, like a knife,” Dey said. “A very clean cut.”

The team assembling those charges will use a non-electrical system to detonate the charges, similar to those used in military and civilian operations, which most commonly are started using a fuse.

“We’re not using an electric system because we’re on a steel vessel in water in Florida, with the possibility of thunderstorms,” Loizeaux said.

Those explosives and the blasting material used to ignite them will be “nowhere near each other until we’re at sea,” he said.

“It’s going to be anti-climatic,” Dey said. “There will be explosives, but this ain’t Hollywood. You’ll hear a series of thuds, a little vibration in the water and the vessel will start to move below the waterline.”

Like an elevator

Crews have been scuttling the Vandenberg over the last few weeks. How those holes are cut into the ship is just as important as where the explosives are placed, Dey said.

Scientists and engineers with the Stevens Institute of Technology in Hoboken, N.J., built scale models to determine how the ship should be scuttled.

“Same weight and everything was to scale,” Dey said. “They made the calculations and cut holes in the exterior of the model and did several sink tests using black powder.”

In those tests, the model Vandenberg sank as engineers had hoped, though slightly from stern to bow, and settled nicely on its hull in 2 feet of water, Dey said.

The real Vandenberg should sink in about two to five minutes.

“Optimally, we’d like to see it go down like an elevator, straight down,” Dey said.

Once the ship is sunk, a dive team comprising 20 members of the Monroe County Sheriff’s Office and Key West police and fire departments will examine the ship to make sure all the explosive charges detonated. If there are still live charges, a second team of divers will hit the water and remove them, said Bob Smith, former head of the Florida Keys Community College dive program who is overseeing the dive teams.

The divers, who will be taken to the Vandenberg and working from two Mel Fisher treasure salvaging vessels, will make sure the ship sank properly and the super structure has not shifted or parts fell off as it went down.

“If something has shifted we want to know,” Smith said.

The failed sinking of the Spiegel Grove off Key Largo in 2002 used an entirely different method that involved flooding the interior chambers with water. The 510-foot ship landed upside down after it sank two hours early, forcing workers and local dignitaries who were on the deck to scramble to disembark.

With her bow anchored by a heavy chain, workers began filling the stern chambers, but pumped in too much water, which filled one side more than the other, causing it to roll as it descended.

After contractors hoisted her on her side, Hurricane Dennis finished the job, its strong waves pushing her upright.

With the Vandenberg, the key from an explosive contingency standpoint is redundancy, Loizeaux said.

“If you need one, put two,” he said. “The number of openings will be far more than is required for the sinking. Adding explosives is not expensive; getting everything in place and there is the expensive part.”

Engineers also are concerned about air pockets forming in portions of the ship that could cause the Vandenberg to list as she sinks. Much of the scuttling above the waterline is designed to provide the displaced air an avenue to escape, Dey said.

For all the science behind the sinking, one of the biggest concerns is the one beyond anyone’s control. The sinking is scheduled sometime between May 26 and June 1.

“The largest contingency will be the weather,” Loizeaux said. “At the end of the day, we need Mother Nature to work with us.”

Facing the challenge – CDI brings down RCA Dome with a bang

Original article with photos and video can be found by clicking here.

Controlled Demolition Inc used 272 kg (600 lb) of explosives, placed as 875 individual sequenced charges, to bring down the former home of the Indianapolis Colts, the 60,272 seat RCA Dome, in less than 20 seconds.

The RCA Dome had been a feature of the Indianapolis skyline for the last 25 years, but with its tenants moving to a new stadium, the Lucas Oil Stadium, the structure was slated for demolition. Sabre Demolition Corporation, based in Warners, New York, was brought in by the Indiana Stadium and Convention Building Authority to carry out the job, and in turn subcontracted the explosive side to Controlled Demolition Inc, of Phoenix, Maryland.

Pre-blast preparation work lasted for a year, with the stadium stripped out – ‘momentos’ were sold off by public sale and other stadium elements were salvaged for use in the new stadium – and a degree of environmental remediation was carried out. Sabre deflated the stadium dome in September and also demolished low-rise interior sections of the stadium.

While this work went on, CDI drilled and prepared high-rise sections for the placement of the explosive charges that were to bring the Dome down.

Facing the challenge

The nature of the site created a number of distinct challenges for CDI.

Vibration and over pressure resulting from the blowdown were a concern because of the proximity of adjacent structures and the presence of underground utilities and critical services. CDI therefore made use of its extensive experience to estimate the likely vibration displacement (peak particle velocity) and frequency of vibration on the existing soil strata beneath the stadium to project the amount and type of vibration that the implosion would generate.

This, along with estimates of likely air overpressure from the detonation of explosives, was used to predict the impact of the implosion on the community and facilities adjacent to and beneath the RCA Dome site.

Numerous turn of the century brick arch sewers ran under the stadium footprint 3 m (10 ft) below the playing surface. These combination storm and sanitary sewers drain 25% of Indianapolis and interruption of flow would have been catastrophic, with the potential for high insurance claims.

CDI therefore designed a protective grid that Sabre placed above the sewers where they passed under and within the fall area of the high-rise sections that CDI was to bring down. Monitoring of flow both before and following the implosion indicated no damage to the sewers or interruption of flow.

Rail concerns

The effect of the implosion on nearby rail transportation links was also a concern. CSX Rail’s main line carried more than 40 trains per day and passed within 19 m (62 ft) of the 42.5 m (140 ft) high press box addition to the RCA Dome. CDI arranged for pre and post-implosion surveys of the CSX line and the three bridges carrying it adjacent to the site.

A carefully planned delay sequence and the installation of over 305 m (1,000 ft) of steel core cable between the press box and stadium allowed CDI to bring down the press box without damage to CSX property. Trains were running within two hours of the implosion, well ahead of CSX’s schedule for restoration of service.

As if this was not enough, the Crowne Plaza Hotel and Resort, part of Indianapolis’ historic Union Rail Station, was as close as (22 m (70 ft) to part of the structure. A Community Outreach Programme was therefore put in place with the Crowne Plaza and more than a dozen other major hotels and other third party properties.

This began months before the actual implosion to ensure clear and unambiguous communication with the adjacent owners as well as creating minimal impact of the implosion on day-to-day operations of these facilities.

The Indianapolis Convention Center (ICC) looked forward to the removal of the Dome to allow it to expand its complex to attract even more national convention events for the benefit of the Indianapolis economy. The ICC facilities that had to remain stood on the west and north sides of the Dome site, with the closest being 5 m (16 ft) away at ground level on the west side.

The concourse levels between the Dome and ICC were demolished conventionally before the implosion to physically separate the Dome from the ICC structures. The upper cantilevered section of the RCA Dome actually overhung the ICC on this side, which was one of the reasons this adjacent property owner strongly supported the implosion of the RCA Dome.

For reasons of third party risk management, it was preferable to the ICC Management to have a single implosion event when the ICC was empty rather than have ongoing conventional demolition operations during Convention Center events for a period of months. The decision paid off and the International Automobile Show opened in the full Convention Center just 24 hours after the RCA Dome implosion took place.

Originally scheduled for July 2008, the fall of the Dome did not in fact take place until 20 December. This delay was caused by other construction delays at the Colts new home, the Lucas Oil Stadium, which for several months prevented the Colts from releasing the RCA Dome for demolition. The implosion approach allowed CDI’s client Sabre to make up more than half of the time lost from this delay in starting construction of the new ICC complex – something standard demolition techniques would not have allowed.