Can you dig it?

Unearthing the evolution of power shovel technology

Every summer, gearheads gather to strut their classic cars. Show-goers marvel at rumble seats, whitewall tires, and gratuitous fins. Wouldn’t it be cool if there was a club for enthusiasts of vintage construction vehicles, too?

There is: the Historical Construction Equipment Association (HCEA). Mechanics, retired operators, and history buffs restore and maintain old machinery once used to scoop and move the earth for foundations, tunnels, roads, and farms. Check out the video below. The New England chapter holds their annual show this weekend. If you go, you’ll see vintage bulldozers, dump trucks, tractors, and clam shell excavators in action.

100_ton_steam_shovel,_circa_1919For some reason—maybe all those childhood readings of Mike Mulligan and His Steam Shovel—we’re particularly taken with the antique cable excavators. First patented by William Otis (cousin of elevator safety brake inventor Elisha Otis), the steam shovel was crucial to some of America’s great builds, from iconic Manhattan skyscrapers like the Chrysler and Empire State buildings to enormous engineering projects like the Panama Canal.

2006131175834_Erie_B2To dig dirt at the turn of the century, a steam shovel operator pulled levers to yank on steel cables that would work a bucket at the end of a dipper stick attached by winch to a boom. When the bucket was full, the shovel would swivel around on a turntable and the bucket’s “tongue” would loosen, dumping the dirt into a waiting truck.

Diesel power made the steam model obsolete, and diesel shovels in turn were supplanted by the widespread adoption of hydraulics in the 1960s. Fortunately for posterity, folks from the HCEA have made an avocation out of salvaging, fixing, and exhibiting these and other fun-but-outmoded construction vehicles. The group also has chapters in New Jersey, Florida, and Southern California. Here’s some footage of restored steam shovels and other vintage vehicles at work:

The new wave

While we have a soft spot for that old-school equipment, our minds are blown by the latest advances in digger technology. At this year’s CONEXPO-CON/AGG & IFPE show—a conclave of researchers, engineers and construction industry game-changers—all eyes were on the large-scale 3D-printed steel excavator.

An innovative team made up of industry, academic and government partners collaborated to create the first fully functional excavator using 3D-printed components. This impressive development, called Project AME (for “additive manufactured excavator”), represents a potential leap forward for the industry.

Project AME diagramThe machine’s cab, boom, and heat exchanger were 3D-printed. Using low-cost steel, the seven-foot-long, 400-pound boom was printed in a mere five days, while the carbon fiber cab was created in just five hours, with no loss to aesthetics or function.

The crowd at this year’s CONEXPO-CON/AGG and IFPE had the opportunity to watch this excavator do its thing. Additive manufacturing—the process of manufacturing layer by layer from 3D model data—allows engineers to print products on demand, virtually eliminating the need for mass storage and lowering transportation costs. The futuristic excavator has the potential to reduce material expenses and maintenance duties, while simultaneously cutting fuel emissions. ForConstructionPros reported on the process:

Project AME was in good company at the convention. Cat COMMAND made a strong showing with hands-on demonstrations of a remote-control digger. Cat developed this technology in 2016 with the introduction of RemoteTask, a remote control system exclusive to Cat Skid Steers and limited to a 1,000 foot wireless radius. Since then, substantial progress has been made.

With Cat COMMAND, technicians can remotely operate machinery from significantly farther distances, bolstering both safety and productivity while maintaining high standards of efficiency and accuracy. A well-designed Cat COMMAND station seats the operator comfortably and provides integrative, wireless control of the machinery’s systems, further reducing on-site dangers such as prolonged exposure to noise, dust and vibrations. The system exhibited at CONEXPO allowed an operator to work from—dig this—1,400 miles away:

The convention is only held every three years. Who knows what we’ll see at CONEXPO-CON/AGG 2020? A giant 3D-printed, remotely operated, drone digger that flies in to scoop from above, and also delivers your coffee without spilling a drop? We’ll just have to wait and see.

This post was a collaboration between Suffolk’s Insurance Coordinator Lindsay Davis and Content Writer Patrick Kennedy. If you have questions, Lindsay can be reached at ldavis@suffolk.com and Patrick can be reached at pkennedy@suffolk.com. You can also connect with Patrick on LinkedIn here or follow him on Twitter at @PK_Build_Smart. Video editing by Suffolk Intern Simone McLaren. Audio track: Bennie Moten’s Kansas City Orchestra, “Kater Street Rag.” 

Demo, hold the dust

Safer, smarter practices in demolition

Sometimes, before a new building can go up, an old one must tumble down. Whether it’s fallen into disrepair and been deemed unsafe, or a new development can’t feasibly incorporate the old, some structures end up on the wrong end of a wrecking ball.

But modern demolition entails more than just smashing things or blowing them up. Complicated layouts such as aging power plants and bridges present unique challenges. Asbestos or other hazards might well lurk. And to be green, reusing and recycling are de rigueur. Let’s explore a new wave of innovation in the art and science of deliberate destruction. 

Hats off for the hat method

Three rival Japanese firms manage to demolish high-rises without smashing or blowing up anything at all. Across the nation, hundreds of towers more than 100 meters (328 feet) tall were erected four or five decades ago. Most aren’t up to the nation’s current, more stringent earthquake codes. That means a big demand is nigh for efficient, environmentally responsible demolition that doesn’t disturb the neighbors. (In densely-built Tokyo, as in many cities, there’s hardly even room to swing a wrecking ball today.) To meet that demand, the Taisei, Takenaka, and Kajima corporations are in a race to perfect a technique whereby a building is dismantled floor by floor.

In the Taisei and Takenaka systems, a protective “hat” or “capping” hangs from a high-rise’s roof. Covering the top three floors, this suspended scaffolding is covered with dust and noise barriers. Inside, crews cut holes in the floors and install temporary columns and giant hydraulic jacks. Then with jackhammers and excavators, they break apart the floors and walls. A ceiling traveling crane brings the refuse to an opening where a telpher crane lowers it to the ground floor. There, workers load the broken-up concrete and steel onto trucks that ferry it to a recycling center.

An illustration of the Taisei Ecological Reproduction System. To truly geek out on this, see the sequential diagrams in this slide show. (Source: Taisei Corp.)

Once a floor is demolished, the jacks lower the capping, and the cycle repeats. In this way, Taisei shrunk the 139-meter (456 feet) Old Grand Prince Hotel Akasaka by two floors every 10 days.

That project was covered by Wired and other American outlets. However, the Italian engineering firm Despe has been taking down buildings in a similar manner for years. They call their method Topdownway:

Taisei takes the method further by using a telpher crane that actually generates electricity. Though the crane itself uses electrical power, the motion of the crane dropping and rising creates energy that is captured and stored in a battery. The new energy powers lights and fans inside the capping.

Kajima’s demolition method is similar, using giant hydraulic jacks to shrink a building, but they dismantle from the bottom. The Kajima Cut and Take Down Method takes inspiration from a Jenga-like traditional Japanese game, Daruma Otoshi. See the time-lapse video of a Kajima project:

Cons and pros of these seemingly painstaking methods? It takes months to deconstruct a building, and it isn’t cheap. But Taisei estimates it reduces carbon emissions by 85 percent, noise levels by 20 decibels, and dust by 90 percent. Despe says its system contains 100 percent of the dust. Plus, the Italian company provides clients with advertising space on its highly visible protective tent.

Work in the enclosed space is not subject to the whims of weather. And best of all is the safety benefit. Whether inside the “hat” or operating from the ground floor, there’s no danger of debris or equipment falling on workers or passing pedestrians.

When failure begets success

Even the more dramatic form of demolition—using explosives to effect a controlled implosion—can be done in a smarter, more efficient way. A new entity in the UK offers a streamlined, tech-enhanced process, using robotics as well as explosives honed in the military.

The Atom Project comprises three firms that came together in the wake of tragedy. In February 2016, the conventionally planned demolition of the UK’s Didcot Power Station went awry when the building partially collapsed, killing four workers. For months, it wasn’t even safe to enter the teetering ruin to retrieve the workers’ bodies.

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An AR demolition robot at work.

The power plant owners fired the previous demolition contractor and brought in Arcadis, AR Demolition and Alford Technologies to collaborate on a solution. Pooling their experience, they used point cloud laser surveys to assemble a 3D model of the site to plan the number, placement, and strength of explosives. Top-of-the-line Kiesel demolition robots—capable of switching attachments in minutes—rolled in to cut and remove anything that could be salvaged.

The robots then placed linear cutting charges in the planned locations. These are explosives engineered to blast a knife-like cut into steel or concrete. They’re common in the military, but not yet in commercial demolition. “There’s a reticence about adopting the technology,” Alford Technologies Managing Director Roland Alford told the Construction News, “but it is totally reliable.”

The effort succeeded in bringing down the rest of the power plant—entirely remotely. The three companies decided to continue their partnership. Alford declared, “This is the iPhone moment for demolition,” a potential sea change in the way demo is done.

Rise of the “robots’” relevance

Of course, demolition robots themselves are not new. Swedish-based Brokk sold its first such vehicle in 1976. But their use is growing, for safety and cost reasons. Although they’re not, strictly speaking, robots.

“‘Demolition robots’ is the generally accepted term,” said Peter Bigwood, VP of sales and marketing for Brokk’s North American division. “It sounds cooler and trips off the tongue better than the more accurate nomenclature, which would be ‘remote-controlled demolition machines.’”

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Precision cutting with a Brokk machine.

Human technicians operate electric-powered Brokk and similar machines from a safe distance—as much as 100 yards away if need be. At trade shows, Bigwood will ask potential customers, “And would you like Brokk binoculars with that?”

Bigwood says several factors explain why his company is selling more Brokks than ever before—even with new competition from Husqvarna, suggesting “the pie is bigger,” he said.

“It’s really hard to get labor in construction,” Bigwood said. “There are parts of the country where you won’t find a guy who’ll operate a jackhammer.” Those who will are aging. “The spirit is willing, but the flesh is weak. They hurt their back or shoulders,” and that leads to expensive workman’s compensation claims. “If a robot costs 150 grand, that might be cheaper than a couple shoulder operations.”

Added to that, Bigwood said, is “a greater emphasis in the industry on safety, which as a human being I welcome wholeheartedly.” Hammering from afar using a remote control box means “keeping your workforce safe so they can go home at night.”

Demolish smart

Oftentimes, smart demolition is simply a matter of smarter planning. Derrick Chery, project manager on a Suffolk job in East Boston, worked with JDC Demolition to demolish a smokestack. Before imploding it, the team calculated the radius of the area that would be filled with smoke and dust; they then flooded the area to drastically reduce the dust.

“It’s not common to do a takedown that way, but it saved us a lot of time,” Chery said. “A few mini-excavators picked up all the brick and it took us only a couple hours to get it cleaned up,” versus the delays in a dust cloud scenario.

ENR recently reported on an innovative approach to a complex project, the dismantling of an abandoned sugar factory in Colorado. The team there used careful planning and asbestos-proofed trucks in order to defer the asbestos abatement to an outside facility.

And for complexity, you can’t beat the San Francisco–Oakland Bay Bridge. In three sections—two suspension bridges and a cantilever bridge—this 1930s structure stretched four and a half miles across the bay. With the opening of a new and more quake-resistant Bay Bridge, the old bridge has been under deconstruction since March 2015. The gargantuan effort includes cutting, imploding, and shipping away trusses on barges. Essentially, crews are taking the bridge apart in the reverse order of how it was built.

What happens to the materials?

Many in the Bay Area have wondered, what’s to become of the 167,100 tons of steel that made up the Bay Bridge? Most of it will be sheared to size and reused in construction projects across the country.

But much of the steel has been set aside for public art. For example, AECOM—an architectural firm that has been a frequent collaborator with Suffolk—will turn some of the salvaged steel into stylized benches and planters along a new river walk called Clipper Cove Promenade. Pedestrians will be able to stop and relax on pieces of the old bridge as they take in views of the new.

AECOM river walk

A rendering of AECOM’s Clipper Cove Promenade. (Rendering courtesy of Oakland Museum of California)

Recycling can happen on a smaller scale, too. A Suffolk project team in southern Florida found 16 pallets of unused paint in a site slated for demolition. “It’s amazing that much paint was sitting around,” said Suffolk Senior Virtual Design & Construction Manager Kyle Goebel.

Rather than pay for disposal (or worse, cart it off to a landfill), Goebel arranged to donate the paint—all $25,000 worth—to the local Habitat for Humanity. Soon Habitat’s volunteers will be painting the walls of affordable homes in the region. “The cost of living is always an issue here,” said Goebel. “The fact that we were able to salvage this material efficiently and for a good cause was a great use of resources.”

Crash, boom, bang

Of course, recycling, robots, giant jacks and noise barriers, and all these innovative demo methods do lack one thing: the satisfying punch of a wrecking ball or dynamite implosion. So in case you need to scratch that itch, we’ve put together this little montage. Enjoy!

This post was written by Suffolk Content Writer Patrick L. Kennedy. Video edited by Suffolk Content Marketing Manager Zachary Leighton. If you have questions, Patrick can be reached at PKennedy@suffolk.com. You can connect with him on LinkedIn here or follow him on Twitter at @PK_Build_SmartYou can reach Zach at ZLeighton@suffolk.com or connect with him on LinkedIn here.

Throwback Thursday: Rebuilding Old Ironsides

Imagine a ship is docked at your local port, and it towers over nearly every building in the neighborhood. That was the awesome sight of the USS Constitution in the 1790s, as it was under construction off Boston’s North End. Even without its masts, the frigate was the height of a four-story building. Only the steeple of the Old North Church could compete with that on the local skyline then.

We bring this up not only because the Tall Ships just visited Boston, but also because if you think about it, shipbuilding is a sister industry to our own land-based form of construction. Like a city high-rise, a ship is a unique, standalone structure (with its own name) that can take years to design and build. This feat was all the more impressive in the age of sail, when the endeavor relied largely on human brain and brawn.

And yet, in the case of Constitution—the last ship standing of the U.S. Navy’s original six, and the world’s oldest commissioned warship afloat—what might be more impressive is the dedication to re-building. Since she first put to sea in 1797 to protect Yankee merchant voyages, every American generation has produced engineers, architects, carpenters, and other builders who pitched in to patch up a national treasure. That holds true today, as the current crop of restorers apply high-tech tools to the preservation of “Old Ironsides.”

To see for ourselves, we descended into the dry dock.

The eagle of the sea

Undefeated in the War of 1812, Constitution was already a legend when she entered the brand-new, Quincy-granite dry dock in Charlestown, Massachusetts, on June 24, 1833. (That’s 184 years from this Saturday.)

That’s where and when the story of Constitution’s repeated extensive overhauls begins in earnest. At minimum, the frigate needed new planking, masts, rigging, decking, stem, head, and quarter galleries. After an erroneous report got out that the Navy planned to scuttle her, a young Oliver Wendell Holmes published an ode to “the eagle of the sea,” which rallied Americans to her defense and assured her survival. The Navy decided Old Ironsides would be the first ship to get a new treatment.

dry dock design

USS Constitution Section in Dry Dock No 1 (Rendering courtesy of the Naval History & Heritage Command Detachment Boston)

After six years of construction, the Charlestown Navy Yard’s Dry Dock One opened a week after its twin in Norfolk, Virginia. Both designed by Bay Stater Loammi Baldwin, Jr., they were the first large-scale dry docks in the States. Now the Navy could repair its fleet without resorting to the arduous process of “careening” a ship—that meant using weights to tip it over, first on one side then the other.

dry dock expansion

Dry Dock One’s 1940s expansion. (Photo courtesy of Charlestown Navy Yard Boston National Historical Park)

The dry dock was considered a marvel of engineering even decades later, and it was still used to service vessels during WWII. Although the dock had to be lengthened twice—from 341 feet to, eventually, 415—its width has remained the same, 86 feet at its widest point. “The interior of this dry dock was so well designed in the late 1820s,” said Margherita Desy, the official historian of the Navy’s Boston detachment, “that with the right shoring, you can put a flat-sided vessel in here, you can put a submarine in here—you can put vessels in this dock that could not have been conceived of by Loammi Baldwin 184 years ago.”

The coolest thing about the dry dock is how it works. Start by thinking of it as an artificial inlet. After a ship is towed in, another vessel called a caisson is towed to the entrance. (It’s not unlike other kinds of caissons you may have read about, here and here.) The caisson is filled with water and sunk into place.

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Your fearless blogger drops in to the dry dock. (Photo by Patrick Kennedy)

Then the dock is drained—slowly, so as to ease the ship onto its keel blocks. While the ballast water at the bottom of the caisson weighs it down, the pressure of the harbor beyond holds it at the dock’s seaward end, creating a watertight door.

When repairs are finished, the dock is flooded again, the caisson is emptied and floated out of the way, and the ship is towed back out into the harbor.

The operation requires a complex system of reservoir, tunnels, culverts, valves, and gates. In the 1830s, a steam engine powered eight pumps that could empty the basin in four to five hours. The caisson itself took 24 men working hand pumps 90 minutes to drain.

That old wood caisson is long gone, and even its 1901 steel replacement was replaced in 2015. And today’s pumps are diesel-powered. But though the dock’s technology has changed over 184 years, its basic principles remain the same. “It’s like with any tools,” Desy said. “We still use planes and saws; it’s just that we plug them in.”

Check out the time-lapse video of Constitution entering the dry dock in 2015:

Plugging in

Just as the pumps have been updated, the means and methods of restoring the ship itself have kept pace with the times. For Constitution’s current round of renovation, a naval architect used computer-assisted drawing (CAD) software to redraw plans for the work, make precise measurements, and document the project.

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This CAD drawing shows the spar and rigging plan for Constitution as she will be rigged at the end of the 2015-2017 restoration. (Photo courtesy of the Naval History & Heritage Command Detachment Boston)

The 3D virtual model is a far cry from the quill pen that Joshua Humphreys used to design the Navy’s first six frigates in the 1790s. (A frigate, by the way, is a war vessel with at least three masts and one covered gun deck. It’s also a fun thing to say aloud, especially when you’ve given up on something.)

And whereas 18th-century loggers seemed to have their pick of trees from an infinite supply—the thick wild woods that covered most of the East Coast—modern timber concerns know to practice sustainable forestry. Indeed, there’s a grove in Indiana devoted solely to timber for the Constitution. To procure the white oak timber for the ship’s hull planking, the Navy set aside 150 white oak trees in the forest around a naval facility in Crane, Indiana. “Constitution Grove” was dedicated in 1976.

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White oak delivery in Charlestown. (Photo courtesy of the Naval History & Heritage Command Detachment Boston/Margherita M. Desy)

“It’s a managed forest,” said Desy. “As the trees grow, their lower branches are trimmed and each tree is allowed a lot of sunlight. Because, to qualify as trees for Constitution, they have to be at least 45 feet in length from base to crown, and at least 40 inches in diameter at the base.” In 2015, thirty-five of the trees were felled, and eventually 350,000 pounds of white oak were delivered to Charlestown.

Here we should point out that “Old Ironsides” is just a nickname, earned when cannon balls bounced off her hardwood hull. It was sturdy New England white oak and dense, rot-resistant live oak from Georgia—not iron—that repelled the attacks. However, below the water line, the frigate’s hull has always been sheathed in copper, to keep out wood-eating shipworm. In fact, master metalworker Paul Revere imported an innovation from England (by way of a little industrial espionage) when he opened our nation’s first copper rolling mill to provide the Constitution’s second copper coating, in 1803.

Another innovative tool used in today’s restoration work is the Gemini Universal Carving Duplicator in the Charlestown Navy Yard’s restoration workshop. The decorative carvings along the ship’s bow—like much of the ship—have been replaced time and again. The most recent set (based on earlier drawings and models) dated to 1930. To produce a new set, carpenter Josh Ratty used the Gemini duplicator to trace the 1930 carvings with a blunt stylus hooked up to a router that mimics its motion, making the real cuts in fresh planks.

“It’s like a manual 3D printer,” said USS Constitution Museum spokesman David Wedemeyer. Check out Ratty and the duplicator in action:

The Constitution wraps up its current phase of restoration next month. Still seaworthy, still officially in service, she’s the oldest vessel in the world still capable of sailing under her own power. But rather than sail off into the Atlantic after leaving dry dock, she’ll stay at the Charlestown Navy Yard, where generations of Americans can continue to enjoy visiting her and hearing her stories.

Special thanks to the U.S.S. Constitution Museum and the Naval History & Heritage Command Detachment Boston. There’s plenty more info about the restoration work on the detachment’s blog. And consider a visit to the Charlestown Navy Yard this summer. (Note to our readers in California: you get your own dose of tall ships in September! See http://www.ocean-institute.org/tall-ships-festival.)

P.S. Safety being a prime focus here at Suffolk, we especially appreciated the following PSAs posted at the Charlestown Navy Yard…

2017-05-17 12.10.03 Ouch crop

This post was written by Suffolk Construction’s Content Writer Patrick L. Kennedy. If you have questions, Patrick can be reached at PKennedy@suffolk.com. You can connect with him on LinkedIn here or follow him on Twitter at @PK_Build_Smart. 

We have the technology … why not wear it?

As the wearable technology market continues to grow, we round up a few of the newest and most innovative articles of attire intended to boost safety and productivity in construction.

Lending a bionic hand

Ekso Bionics’ Zero-Gravity Arm aims to make operating heavy hand-held machinery easier and safer. The company gained its rep producing exoskeletons—wearable robotic aids for soldiers and the partially paralyzed—and is now branching out into bionics for the construction trades.

Ekso’s new Zero G arm renders power tools (up to 36 pounds) virtually weightless. Though exoskeleton technology takes some getting used to, noted a Wired reviewer, the effect is to enhance the user’s strength, mobility, and endurance. The system works on the same principle as the Steadicams used in Hollywood, swiveling about on springs and counterweights. The bionic arm also absorbs the powerful feedback produced by power tools, reducing strain on the worker.

When put to the test (see video below), a worker using the zeroG arm completed a jobsite task not only faster, but with more accuracy and much less fatigue. Meanwhile, a worker using the traditional method tired sooner, and took far longer to complete the task:

(For a less polished but more comprehensive video exploration of the Zero G Arm, check out Marko Kaar’s review.)

Tactical textiles

In Britain, more than 10,000 insurance claims have been made for vibration white finger and carpal tunnel syndrome over the past decade, according to the British Health and Safety Executive. That’s a cost of £20 million to £250 million (or roughly $25 million to $322 million). And these conditions result from continuous operation of vibrating hand-held machinery.

Seeking to combat these permanent industrial diseases, a new wearable technology being developed at Nottingham Trent University in the UK warns construction workers when a hand injury is imminent. The e-gloves, not much bulkier than average heavy-duty work gloves, are embedded with tiny sensors that warn workers when they’re exposed to dangerous levels of vibration.

Only 2 millimeters long, the sensors are imbedded into a yarn textile and knitted into the gloves. The seemingly simple technology performs an impressive safety duty. When triggered by dangerous levels of vibration, these tiny sensors warn wearers to stop work.

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A prototype of the e-glove. (Photo courtesy of Nottingham Trent University)

Vested interest

Redpoint Positioning has developed an innovative safety vest that protects workers and has the potential to improve incident reporting, drive efficiency, and cut costs.

Embedded with Redpoint’s indoor GPS tracking system, this high-tech personal protective equipment (PPE) gives full visibility to jobsite operations. When a worker enters a designated “danger zone” on the jobsite, it triggers the vest’s flashing red lights and audio feedback, while managers receive customized digital data on the worker’s location. The data is tracked and logged to help manage on-site safety practices.

Redpoint calls the technology a “wireless safety net,” lending an integrated approach to PPE. Of course, some workers might chafe at the thought of being tracked, and it is important not to abuse the technology, said Gary Cunningham, recently retired as Suffolk’s national safety director. “It has to be a partnership,” Cunningham said, with the shared goal of reducing injuries.

But “if you’re afraid of a tracking device,” said Suffolk Senior Safety Manager Joe Villela, “throw away your cell phone!” At 1700 Webster in Oakland, Villela gave workers radio frequency identification (RFID) tags to wear. “The whole point is safety,” he said. “In case of a catastrophic event, such as an earthquake—which on the West Coast we know is not a matter of if but when—we can make sure everyone is out of the building.”

The RFID tags, from Trimble, were effective, though they weren’t as flashy (literally) as the Redpoint vests:

A step forward for construction footwear

SolePower founder Hahna Alexander was recognized by Toyota’s “Mothers of Invention” female entrepreneurs’ series. Her innovation: generating electricity through footsteps. Alexander found a way to harvest kinetic energy from the human motion of a heel hitting the ground. The energy then transfers into a mechanical system, which, in turn, uses it to spin a micro-generator. In simple terms, human energy fuels kinetic chargers, providing a better, lighter power source.

This power source, when placed inside the back of a work boot, wirelessly gathers data and measures worker safety, efficiency, and productivity. The SmartBoot technology promises to keep workers safe, fit, and productive, and could be valuable on a worksite in lowering accident rates, tracking hours and monitoring workers’ locations in the event of an emergency. In turn, these incredible Smartboots could save money, lives and time, and improve incident reporting accuracy on the jobsite.

This post was written by Suffolk’s Insurance Coordinator Lindsay Davis. Content Writer Patrick Kennedy contributed additional reporting. If you have questions, Lindsay can be reached at ldavis@suffolk.com and Patrick can be reached at pkennedy@suffolk.com, or you can connect with him on LinkedIn here or Twitter at @PK_Build_Smart.

Throwback Thursday: Water Under the Bridge, Danger Under the Water

This blog post was written by Dan Antonellis in honor of Brooklyn Bridge Opening Day, which was Wednesday! After 14 years of construction, the Brooklyn Bridge opened to traffic on May 24, 1883, connecting Manhattan and Brooklyn for the first time in history. Dubbed the “eighth wonder of the world,” the bridge changed New York City forever.

Fill a bathtub with water and find a drinking glass. Flip the glass upside down and push it to the bottom of the tub. The water from the tub won’t get inside the glass because of the air trapped inside. It’s about air pressure, physics and other science-related topics I won’t even attempt to explain in this post.

Now stay with me. Picture tiny people standing inside that glass on the bottom of the tub, chipping away at the porcelain with miniature picks and shovels. The air in that glass will eventually run out, so you’ll need a tube poking out of the top of the glass and up and out of the water so that good air can come in and bad air can get out. After all, these tiny people need to breathe as they continue picking away and digging at the bottom of your tub.

Holding a glass upside down at the bottom of the bathtub is the basic premise behind one of the most intriguing and dangerous feats in U.S. engineering and construction history — the building of the underwater foundations that would lie at the bottom of New York’s East River and support the massive towers of the historic Brooklyn Bridge.

The Great Bridge

The vision for “The Great Bridge” (later named the Brooklyn Bridge) was simple enough — to connect Manhattan and Brooklyn and open travel and trade between the two independent cities. (Brooklyn was its own city until it was annexed by New York City in 1898.) The bridge would eventually span 1,600 feet across the river, connecting two masses of land that had been separated by water for millions of years.

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An early plan for the Brooklyn Bridge. (Courtesy of the National Archives and Records Administration)

The Brooklyn Bridge was designed like most suspension bridges. While they differ aesthetically and hold distinct places in history, they all share certain visual and engineering characteristics in common. Cables that stretch from bridge towers to the highways like giant spider webs. Roads seemingly suspended in air — many of which can span from 2,000 to 7,000 feet long. And of course, the massive towers that stand tall and strong, anchoring the bridge components to the earth and literally holding it all together. Those towers need to be firmly grounded and dug into bedrock, like any other tall structure.

Back in 1869, long before the days of pounding piles into the ground using sophisticated equipment and heavy machinery, there were men, picks and shovels. And plenty of danger to go around. Continue Reading ›

Stop the sway, a simpler way

Streamlining the counterweight systems that limit a building’s wobbles

Take note, high-rise builders and daring designers. You know those giant counterweights, called tuned mass dampers, that keep spindly skyscrapers and bridges from swaying in the wind? Well, now there’s a pint-sized portable tuned mass damper.

Wait a second. How does a regular tuned mass damper even work? A little background: especially at great heights, a structure can be strong without being stiff, and when it lacks stiffness relative to the forces acting on it—wind, footfalls—it can swing perceptibly. The building won’t topple, but the movement can cause occupants alarm, discomfort, even nausea. A notorious example, Boston’s John Hancock Tower, swayed as much as three feet off its base before dampers were added.

Increasingly common in Manhattan, the typical tuned mass damper (TMD) is essentially an enormous counterweight on springs or a pendulum, built into the top portion of a tower. When high winds push on the building, the weight swings in the opposite direction, staying the tower’s shift. But in order to make it work, engineers have to “tune” the damper to match the building’s natural frequency, ensuring that the weight swings just enough to counteract the wind. (Frequency being the speed of a vibration.) Practical Engineering explains it all with a fun video here.

The drawbacks are size and cost. For example, the 728-ton steel ball that stabilizes the 1,667-foot-tall Tapei 101 tower in Taiwan cost $4 million—and it takes up six stories of prime real estate.

A lighter package

By contrast, a portable tuned mass damper, under development at Virginia Tech, weighs about 275 pounds. And a building owner with no technical training can adjust the damper’s settings with a five-dollar iPhone app.

Of course, the damper itself will cost more than $5, but it will be affordable, says its inventor, Mehdi Setareh, an architecture professor and the head of the Vibration Testing Lab at Virginia Tech. “What I’m trying to do is reduce the cost so it can become more common,” Setareh told us. “It’s like what Henry Ford did with cars.”article-image.img.490.high

Setareh’s invention is best suited to those modern buildings constructed of lightweight materials and given swooping, eye-catching shapes with computer-aided design. Setareh is himself an award-winning structural engineer who helped design the dramatically cantilevered headquarters of MFP Automation Engineering (right).

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Such bold designs have become more common—and along with them, so have complaints about noticeable vibrations, according to Setareh. His lab has studied and helped modify structures such as a theater balcony in Detroit and the monumental stair in the Zaha Hadid–designed Broad Art Museum in East Lansing, Michigan (left). “The floors are designed for strength,” Setareh hastened to point out. “When people walk on the floor, it holds the load, no problem.” But a slight bounce gives users the unwelcome impression of shakiness. “It can be scary, or at best annoying.”

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A prototype portable tuned mass damper. (Photo Courtesy of Virginia Tech)

Rather than sacrifice aesthetics or boost costs by building with heavier beams, said Setareh, architects (or, after the fact, building managers) can apply a simple fix. Acting like a shock absorber, the portable tuned mass damper (PTMD) consists of a weight on springs, tuned to have a natural frequency close to that of the floor. When the floor is rattled by foot traffic, the springs are activated and the movement of the weight pushes back against the movement of the floor, neutralizing it. “When the floor goes down, the damper mass goes up,” Setareh said, “and when the floor goes up, the mass goes down.”

The device sits two feet high and weighs a fraction of the floor, but it compensates by moving ten to twenty times faster than the floor vibrates. “So even though the mass of the [PTMD] is, say, 200 pounds, it’s like 4,000 pounds of force moving against the floor,” Setareh said. “That’s how it reduces the vibration substantially,” up to 60 percent in the Virginia Tech lab’s testing facility (see below).

A result of rocketry

That’s a fine solution for a variety of unique buildings—hospitals, theaters, corporate headquarters. But what about a straightforward residential high-rise? It’s hard to imagine a small, convenient version of the titanic TMD at Tapei 101.

And yet, a team at NASA has developed a damper the size of a coffee can (though it sits in a long pipe filled with water) that can stop a tall building’s shakes in a heartbeat. Spun off from rocket technology, a variation of this “disruptive tuned mass” has been installed on the new 32-story 461 Dean in Brooklyn, the world’s tallest modular building. It turns liquid into a secondary mass that absorbs and dissipates the energy of a building’s vibrations.

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461 Dean, the world’s tallest modular building.

Engineering firm Thornton Tomasetti licensed the technology and adapted it to 461 Dean (right), which is built of lightweight steel modules. Thornton Tomasetti’s rooftop system, which they call a fluid harmonic absorber, consists of four U-shaped PVC pipes, each 50 feet long and three feet in diameter. Air springs are fitted to the outside of the pipes and tuned to a certain “sloshing frequency,” explained Michael Wesolowsky, a Thornton Tomasetti engineer. The tubes are pressurized so that during a wind or seismic event, air pushes on the water, and then vice versa.

“The liquid is tuned to slosh back and forth at exactly the same frequency as the building’s movement, but out of phase,” said Wesolowky, “pulling the building back in the opposite direction,” thereby keeping it steady.

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Installation of fluid harmonic absorbers on 461 Dean’s rooftop. (Photo courtesy of NASA)

“It’s like the air spring in your car,” added Elisabeth Malsch, another Thornton Tomasetti engineer, “if you have a newer, fancier car.”

Already, the system has performed well on high-wind days, Malsch said. And it has advantages over the gargantuan conventional TMDs. The absorber at 461 Dean (the first of its kind in a commercial application) is “cheaper, lighter,” said Malsch. “It required very little reinforcement” to the building below. It’s also easier to tune, not to mention maintain. After all, “we know how to patch leaks in pipes,” Malsch said.

Like the PTMD out of Virginia Tech, the fluid harmonic absorber can be installed after initial construction is complete, if a structure turns out to behave differently than predicted in high winds. The Smithsonian speculated that historic landmarks built before earthquake codes might be retrofitted with the NASA-bred system, another benefit of which is its fast-acting nature. (Skyscrapers can still sustain damage during the few seconds it takes for a quake to activate a conventional, pendulum-style damper.)

Malsch can attest that older buildings are good candidates for the addition of such a cutting-edge streamlined damping system. Her office is in Manhattan’s 40 Wall Street, at 71 stories the world’s tallest tower when it was completed in 1930 (before being surpassed by the Chrysler Building a few months later). On windy days, the structure’s age is apparent—or audible.

“Every six seconds,” said Malsch, “you can hear it creak.”

This post was written by Suffolk Construction’s Content Writer Patrick L. Kennedy. If you have questions, Patrick can be reached at PKennedy@suffolk.com. You can connect with him on LinkedIn here or follow him on Twitter at @PK_Build_Smart.

A park or farm in the last place you’d look

Inventive designs cram bounties of vegetation into unexpected spaces

In dense and growing cities, plant life is at a premium. Urban planners know the benefits of a bit of botany. As San Francisco-based advocacy group Canopy explains, trees suck up carbon dioxide while they pump out oxygen, making our air cleaner. Trees’ leafy cover provide shade, while their roots mitigate flooding. Grassy parks visually break up our concrete streetscape with green space, and they promote community interaction and physical activity. All of this makes city living healthier than it would be otherwise.

But designers have to be pretty creative to pursue these goals in the midst of a development boom. That’s why around the world, architects are finding innovative ways to carve out some elbow room for greenery in the built environment.

green2Pictured above and at right, the Botanic Center in Brussels represents one such solution. The architect, Vincent Callebaut, has proposed dramatically sprucing up a 1977 concrete apartment block with the addition of 274 planter beds to the façade and a striking “Chrysalis” on the roof—a steel-and-glass observation pod filled with a variety of plants and topped with wind turbines and a solar panel array.

From Tapei to New York City, from structures that reach the sky to tunnels that run beneath our feet, here are a few other designs that feature flora in unlikely quarters.


Agora Garden

Another Callebaut creation, this twisting tower in Tapei topped out last November and is slated for completion next September. (Inhabitat has a very cool slideshow of Agora Garden under construction.) As you can see from the above rendering, every one of its 22 stories will be packed with tree- and shrub-laden balconies. And these aren’t simply aesthetic amenities. Callebaut intends for residents to have sufficient outdoor space to grow their own produce. He estimates the plants will absorb 130 tons of carbon dioxide a year. On top of that, the building will incorporate solar energy, rainwater recycling, composting and other measures to further limit its impact on the environment.

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The Lowline

You may have heard of New York’s High Line, a park running along a disused section of elevated rail tracks. The Lowline takes that idea underground. An abandoned trolley subway tunnel beneath the streets of the Lower East Side will serve as the site for the world’s first underground park. How will the park’s plants flourish? Solar irrigation. A network of mirrors brings sunlight through pipes down into the tunnel, where the sun, normally, wouldn’t shine. The development team built a proof-of-concept Lowline Lab that proved a popular attraction over the past year or so. That bodes well for the full Lowline, projected for completion in 2021.

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Pier 55

British starchitect Thomas Heatherwick designed this 2.4-acre park to be sited atop an artificial island in New York’s Hudson River. Alternately called Diller Island after its developer, Barry Diller, Pier 55 is slated for completion in 2019. A distinctive element of the island is its support system. Heatherwick designed it to lie upon hundreds of concrete columns rising out of the water to varying heights, for a rolling landscape effect, up to 62 feet. While traditional steel piles have already been driven into the bedrock in the center of the site, the mushroom-shaped columns about the perimeter will be hollow precast concrete piers, to be filled with concrete on site.

Although the Army Corps of Engineers signed off on the design, the project recently stalled in federal court. However, it has weathered several court challenges so far, and it has the support of the mayor, the governor, and neighborhood groups. In any case, the design suggests the possibilities opened up by building on water—a long tradition in coastal cities. (Stay tuned to this blog for more on artificial island construction.)

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Mashambas

Skyscrapers are typically found in cities. But the winners of the eVolo Magazine 2017 Skyscraper Competition, Polish architects Pawel Lipiński and Mateusz Frankowski, instead direct our attention to rural, sub-Saharan Africa, where more than 40 percent of people live in absolute poverty. (The United Nations defines absolute poverty as a condition in which people suffer from not only low income but also a lack of access to food, safe drinking water, shelter, and other resources.) To attack this problem, Lipiński and Frankowski imagine a farming and educational center in a temporary, modular high-rise that can be assembled, disassembled, and transported from one site in need to another.

The Polish team’s prize-winning concept, Mashambas (from a Swahili word meaning farmland) would feature a permanent farmer’s market on the ground floor, with elevated “fields” for farming on the floors above. The structure would also contain warehouses—for fertilizer, seeds, drones, and equipment—and classrooms. In the architects’ vision, staff would use those classrooms, as well as the farming modules, to train local subsistence farmers in modern agricultural practices. The farmers would then move on to growing crops in their own fields nearby. Eventually, the community would become self-sufficient, and the Mashambas tower could be dismantled and shipped to the next village, leaving behind the anchoring farmer’s market and one-story warehouses.

To be sure, a vertical farm might work at least as well in a cramped urban environment, but by siting their winning eVolo design in a developing rural region, Lipiński and Frankowski are raising awareness of the struggle farmers there face.

Mashambas interior

This post was written by Suffolk Construction’s Content Writer Patrick L. Kennedy, with additional research by Suffolk Intern Simone McLaren. If you have questions, Patrick can be reached at PKennedy@suffolk.com. You can connect with him on LinkedIn here or follow him on Twitter at @PK_Build_Smart.