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September 25, 2016

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Las Vegas: ‘The implosions capital of the world’

Here’s how we blow up the buildings

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L.E. Baskow

The Gramercy real estate project implodes its 9-story residential tower Sunday, Feb. 15, 2015, in Las Vegas.

D-day

The Riviera, the oldest operating casino on the Strip, is expected to be imploded sometime this summer. The building could be razed as early as the end of June.

First the Clarion, then the Gramercy, soon the Riviera.

Las Vegas is back in the implosion business, picking up where it left off after a string of iconic resorts were brought down with explosives from 1993 to 2007. A quiet post-recessionary period followed in which implosions were limited to such structures as the O’Shea’s parking garage, but the spectacles began again in February when the Clarion and Gramercy were reduced to rubble. The Riviera is scheduled to be imploded as early as June. The historic hotel closes May 4.

“I think Vegas is probably the implosion capital of the world, and it’s not going to stop,” said Controlled Demolitions Inc. president Mark Loizeaux, whose company has flattened more than a dozen structures in Las Vegas.

Whether the revival of destruction is a good thing is a matter of taste, as implosions prompt a mix of emotions. For some people, it’s a thrill that demolition expert Herb Duane calls “the greatest free show on earth.” For others, it’s a pang of sorrow in seeing places that spawned warm memories collapse in a plume of dust.

But strip away the emotions, and what’s left is a complex feat of engineering that combines delicate timing measured in milliseconds, a balance of using just enough explosives to bring down a building without causing debris to fly everywhere, and security measures to protect the public.

When done correctly, a building disintegrates as it falls, leaving behind chunks small enough to be trucked away efficiently.

“It’s almost like structural origami. We take structures and we fold them in a fashion to make them collapse on themselves,” Loizeaux said.

When done wrong, the result can be deadly.

How does an implosion work? The first step to understanding the process is to know that it’s not about blowing the building to pieces. The explosions only trigger the process by destroying or weakening the support beams that hold up the building. Gravity and the titanic weight of the structure take over from there.

    • Setting the explosives

      Click to enlarge photo

      Fireworks before the implosion of Frontier.

      Placing the explosives

      Engineers examine the building to determine where to place the explosives. Buildings differ widely in materials and design, and engineers employ different methods, so there’s no one-size-fits-all formula for where to place the explosives or how to time them. Typically, the charges are set on several bottom and top floors, in places where they will crack or eliminate key support beams and pillars.

      Lower-floor charges

      Lower-floor charges allow the building to start falling, which allows the weight of the upper floors to crush the bottom ones.

      Upper-floor charges

      The explosives higher in the building are needed because those floors have less weight above them and need to be weakened to ensure they’ll fragment sufficiently as they fall.

    • How many explosives are needed?

      One of the arts of implosion is finding just the right amount of explosives. Contractors sometimes do a test blast on a steel beam or concrete pillar, using one that supports relatively little weight and won’t cause the building to collapse.

      Too few explosives

      The building could fall but not break into pieces small enough to be trucked away with the type of debris-removal equipment the contractor has available. If that happens, demolition work has to be done on the ground, adding time and considerable expense to the project.

      Too many explosives

      The blast could send debris flying, putting people nearby at risk. It also would be excessively noisy and would needlessly push up the cost of the project.

    • Timing the explosives

      Blasting caps

      Explosives are fitted with blasting caps — smaller, more sensitive explosives. The caps fire an initial detonation that sets off the larger, more damaging explosives. This is necessary because powerful explosives have been modified through the years to be safer, with fewer accidents during handling. But as a result, the larger explosives require more energy to be set off. Blasting caps also allow demolition experts to control timing of the explosions.

      How blasting caps work

      Each cap contains a delayed fuse, and the caps are color coded by the length of the delay. Caps with short delays are placed on the side of the building that should fall first. Caps with the longest delays are placed on the side of the building intended to fall last. It’s common for caps to be connected to a detonator either with an electric wire or a “shock tube,” a straw-like line coated with explosive powder.

    • Detonating the explosives

      To implode the building, all of the caps are ignited at the same time with the detonator, which sends a spark through the wire or shock tube. The charges then explode based on the length of their delays. The method is more foolproof than tying each cap to a long fuse, which could be cut by falling debris before it burned to all of the charges.

    • What kind of explosives are used?

      There are two general types of explosives used in implosions. One is dynamite, the other is a shaped charge — an explosive wrapped in a jacket of metal and formed into a shape that channels the force of the explosion in one direction. “You can stand behind a shaped charge and not feel a concussion,” demolition expert Herb Duane said. Shaped charges usually are used on steel-beam structures, because steel is denser than concrete, and a shaped charge directs the force of the blast in a way that can shear beams. The charges are placed directly on steel beams. Dynamite is used on concrete, placed in holes drilled deeply into the beams and pillars. It’s cheaper than shaped charges and just as effective on concrete.

    • Dynamite | There are many types of dynamite, but it commonly consists of sawdust or some other absorbent material soaked in nitroglycerin, formed into a cylindrical shape and wrapped in a protective paper skin. Dynamite can be lit by a fuse, like in old Western movies, but it also can be detonated with a concussion. In fact, nitroglycerin can detonate in strong concentrations just by being dropped. That being the case, modern dynamite for demolitions contains about a 60 percent mix of nitroglycerin to prevent it from exploding if it is mishandled. As a result, it has to be detonated using a smaller explosion provided by a blasting cap, essentially a bigger version of a firecracker, but one that can be set off electrically as well as with a fuse.

      To prepare a stick of dynamite to be exploded, a fuse or blasting cap is inserted in one end. The explosive goes off in all directions, creating a ball of destructive force.

    • Shaped charge | A shaped charge consists of an explosive known as RDX, a shortened form of a long chemical name, jacketed with copper. The charge is formed so there’s an inverted V or convex cone shape in part of it. When the charge goes off, that cone or inverted V is pushed out, creating a focused jet of copper that exerts about 3 million pounds of pressure and moves at a velocity of 5 miles per second. That jet moves through steel literally like a knife through butter, pushing it aside. Like dynamite, a shaped charge is ignited by a concussion from a blasting cap.

    Which way does it fall?

    ■ To the side: A building can be felled in any direction, like a tree, particularly if there are vacant areas adjacent to it. This allows debris to be trucked away more easily.

    ■ Straight down: It also can be collapsed into its own footprint if it’s too close to other structures. It all depends on what’s more safe, convenient and efficient.

    $2,000 to $3,000 typical cost of explosives for implosion projects

    However, cost varies depending on the type and quantity of explosives used. There are additional costs — transporting explosives safely, storing them in reinforced containers on-site and providing security while they’re stored.

    What about everything inside?

    Furnishings, fittings and combustible items — wood, carpet, etc. — are removed to reduce the risk of fire and to limit rubble. Interior walls that do not bear weight also are removed, so they don’t hold up the building during the implosion. Workers may cut slits in the structural steel beams and weaken concrete pillars and support beams with sledgehammers, which can help the building come down.

    Sixty years after welcoming the Riviera as a flashy trend-setter, Las Vegas is saying goodbye to the historic casino-resort.

    May 4 is the Riviera’s last day in business before it closes in advance of its eventual demolition. The Las Vegas Convention and Visitors Authority agreed in February to pay $182.5 million to buy the property and plans to replace it with convention space.

    The Riviera experienced plenty of glory on the Strip after it opened in April 1955 as Las Vegas Boulevard’s first high-rise.

    The hotel hosted scores of celebrity performers over the years: Frank Sinatra, Dean Martin, Louis Armstrong, Liza Minnelli, Barbra Streisand and many more. Liberace was paid an unheard of $50,000 a week — $438,000 and change in today’s dollars — to play at the hotel.

    The Riviera also made numerous appearances in film, including in “Casino,” “The Hangover” and the original “Ocean’s 11.”

    But the resort’s heyday is far behind it now. Overshadowed by the resort corridor’s swankier megaresorts, it no longer enjoys the prominence it once had. Its north Strip neighborhood is home to empty lots, aging buildings and unfinished projects abandoned during the recession.

    The Riviera’s closure is telling, not only for the chapter of history it concludes but also for the future it foretells. The convention space that is expected to replace it represents one of many ways in which Las Vegas’ tourism industry has evolved beyond gambling. The day after the Riviera shuts its doors, the next big resort project on the Strip — Resorts World Las Vegas — breaks ground.

    And as such projects get underway, the Riviera will join the many Las Vegas resorts before it that have been imploded to make way for the next big thing.

    – J.D. Morris

    What about trespassers?

    On the days leading to an implosion, contractors and emergency services personnel secure the perimeter and regularly sweep the building to ensure it’s empty. It’s common to cover stairwells, hallways and other surfaces with a thin layer of dust to monitor footprints.

    Engineering an implosion

    Much of an implosion plan comes down to experience and feel. Blueprints often aren’t available, and contractors can’t rely on them even when they can be located. Why? Blueprints don’t show deterioration and decay, and there’s no guarantee builders actually followed the plans when putting up the building. Demolition workers routinely come across examples of shortcuts and fraud, like mixing concrete too thin or not lacing it with enough reinforcement iron. “All it takes is one person getting paid off,” said Brent Blanchard of Protec Documentation Services. Computer modeling also is only so effective, because many variables can’t be determined, like whether the density of building materials is consistent throughout the building.

    The dunes

    The trend of Strip implosions began with the Dunes, which was razed with great fanfare Oct. 27, 1993, just shy of its 40th birthday. Steve Wynn cleared the historic hotel to make room for the Bellagio. The demolition doubled as an opening event for Treasure Island, also owned then by Wynn. Cannons on a TI pirate ship fired a simulated shot that “exploded” the Dunes marquee, then the resort’s North Tower was set on fire and imploded as fireworks erupted above crowd gathered to watch. The Dunes’ South Tower was imploded in July 1994 with no fanfare.

    Sometimes, implosions don’t go as planned

    During the Clarion implosion, an elevator shaft partially collapsed on itself but remained upright after becoming buttressed by debris that built up at its base. Some onlookers concluded that the project had gone wrong, but demolition engineer Mark Loizeaux said he had told local officials the day before the implosion that the shaft might not topple. He said he made contingency plans to attach a cable to the shaft and pull it over with a crane, which is what ended up happening.

    In 1997, the implosion of a hospital in Canberra, Australia, turned fatal when debris hurtled to an area where spectators had gathered, killing a 9-year-old girl and injuring nine other people. The girl died when she was struck by a two-pound piece of steel traveling 93 miles per second.

    Brent Blanchard, an implosion expert with demolition consulting firm Protec Documentation Services, said the fatality stemmed from an incompetent contractor using untested methods — attaching explosives to exterior surfaces and using heavy metal plates to direct the blasts inward.

    “That blaster was just brutally in over his head,” Blanchard said.

    In 2013, the implosion of two boiler structures at a power plant in Bakersfield, Calif., injured five people, including one man who had to have his leg amputated.

    Most implosions that don’t go as planned cause inconveniences, not bodily harm.

    Implosion may not be an option if a building is too close to structures around it that might be damaged, like a glass-walled office tower. Still, buildings set as closely as 8 feet away from neighboring structures can be felled.

    In the case of the Harmon Hotel, which is nestled between other structures at CityCenter, contractors opted to pick it apart instead of trying to bring it down with explosives.

    The Harmon was the subject of a years-long construction defects lawsuit that was resolved in December when MGM Resorts International, which built CityCenter, paid $173 million to settle it. Now the Harmon is being dismantled floor by floor and hauled away.

    Inadequate space between other buildings isn’t the only reason contractors may choose demolition over implosion. It may be financially advantageous to scrap or recycle the building materials, for instance, meaning demolition is a better option.

    And in the case of the old Candlestick Park in San Francisco, implosion plans were scrapped after neighbors raised concerns over the dust cloud that would emanate from the project. They believed the cloud would contain harmful particulates from building materials, including asbestos, PCBs and lead-based paint. The stadium is being demolished instead.

    But there are advantages of imploding over demolishing, which creates months of construction noise and dust and can draw trespassers.

    “Who wants to have an attractive nuisance in their neighborhood for six months?” demolition expert Herb Duane said.

    Did you know...

    ■ The 1,000-room Stardust, which when it opened in 1958 was the largest casino in Nevada and the largest hotel in the world, took 428 pounds of dynamite to demolish. Boyd Gaming imploded it to build Echelon, which never materialized. Genting Group now is building Resorts World Las Vegas on the lot.

    ■ Aladdin was the rare casino to be rebuilt and reopen with the same name after being imploded, although it since has become Planet Hollywood.

    ■ El Rancho, originally the Thunderbird, then the Silverbird, was imploded in front of a crowd of 2,000 spectators.

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