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เรื่องเกี่ยวกับ innovation in process
Wednesday, July 23, 2008
A Concrete Fix to Global Warming
A new process stores carbon dioxide in precast concrete.
By Tyler Hamilton
Credit: Carbon Sense Solutions
A Canadian company says that it has developed a way for makers of precast concrete products to take all the carbon-dioxide emissions from their factories, as well as neighboring industrial facilities, and store them in the products that they produce by exposing those products to carbon-dioxide-rich flue gases during the curing process. Industry experts say that the technology is unproven but holds great potential if it works.
Concrete accounts for more than 5 percent of human-caused carbon-dioxide emissions annually, mostly because cement, the active ingredient in concrete, is made by baking limestone and clay powders under intense heat that is generally produced by the burning of fossil fuels. Making finished concrete products--by mixing cement with water, sand, and gravel--creates additional emissions because heat and steam are often used to accelerate the curing process.
But Robert Niven, founder of Halifax-based Carbon Sense Solutions, says that his company's process would actually allow precast concrete to store carbon dioxide. The company takes advantage of a natural process; carbon dioxide is already reabsorbed in concrete products over hundreds of years from natural chemical reactions. Freshly mixed concrete is exposed to a stream of carbon-dioxide-rich flue gas, rapidly speeding up the reactions between the gas and the calcium-containing minerals in cement (which represents about 10 to 15 percent of the concrete's volume). The technology also virtually eliminates the need for heat or steam, saving energy and emissions.
Work is expected to begin on a pilot plant in the province of Nova Scotia this summer, with preliminary results expected by the end of the year. If it works and is widely adopted, it has the potential to sequester or avoid 20 percent of all cement-industry carbon-dioxide emissions, says Niven. "If the technology is commercialized as planned, it will revolutionize concrete manufacturing and mitigate hundreds of megatons of carbon dioxide each year, while providing manufacturers with a cheaper, greener, and superior product." He adds that 60 tons of carbon dioxide could be stored as solid limestone--or calcium carbonate--within every 1,000 tons of concrete produced. Further, he claims that the end product is more durable, more resistant to shrinking and cracking, and less permeable to water.
"It almost sounds too good to be true," says civil engineer Rick Bohan, director of construction and manufacturing technologies at the Portland Cement Association, in Skokie, Illinois. He points out that the idea of concrete carbonation has been around for decades but has never been economical as a way to strengthen or improve the finished product. In the late 1990s, researchers showed how carbon dioxide could be turned into a supercritical fluid and injected into concrete to make it stronger, but the required high pressures made the process too energy intensive. Carbon Sense Solutions claims to achieve the same goal but under atmospheric pressure and without the need for special curing chambers. "I'd be really skeptical," adds Bohan. "But if someone has a revolutionary process, we'd love to see it."
Precast concrete products represent between 10 and 15 percent of the North American cement and concrete market. While the figure in some European markets is 40 percent, most concrete is mixed and poured at construction sites outside the control of a factory setting (and Carbon Sense Solutions' process). "Considering concrete is the most abundant man-made material on earth, and that the precast market is growing, the estimated carbon dioxide storage potential of this is 500 megatons a year," Niven says. "That is on par with other global carbon dioxide mitigation solutions, such as carbon capture and geological storage."
Research professor Tarun Naik, director of the University of Wisconsin-Milwaukee's Center for By-Products Utilization, says that all concrete absorbs carbon dioxide over time if left to cure naturally--but only up to a point. The gas usually penetrates the first one or two millimeters of the concrete's surface before forming a hard crust that blocks any further absorption. Naik says that something as simple as using less sand in a concrete mix can increase the porosity of the finished product and allow more ambient carbon dioxide to be absorbed into the concrete. It's simpler than Carbon Sense Solutions' accelerated curing process and can be applied to a much larger market, he says.
Other groups are taking aim at emissions from the cement-making process itself. Researchers at MIT are seeking new ingredients in cement that are less energy intensive, while companies such as Montreal's CO2 Solution have an enzymatic approach that captures carbon-dioxide emissions from cement-factory flue stacks, converts the greenhouse gas into limestone, and feeds it back into the cement-making process. Calera, backed by venture capitalist Vinod Khosla, even claims that it can remove a ton of carbon dioxide from the environment for every ton of cement it produces.
ตึกสร้างเลียนแบบรังผึ้งในธรรมชาติ ประเทศจีน
MAD Architects Honeycomb Skyscraper
by Mike ChinoBe it their biomimetic form, their integral strength, or the their beautiful visual texture, lately we can’t get enough of hexagonal honeycomb structures. The latest to catch our eye is the stunning Sinosteel International Plaza by Beijing-based MAD architects. More than just a striking façade, the building’s hexagonal curtain is based upon climate modeling and serves to regulate the structure’s temperature and daylight by varying the size of each cell’s window.
Seeking to set it apart from your average slate-grey skyscraper, MAD designed the SinoSteel Plaza to be “natural, organic and futuristic.” Situated in Tianjing near BoHai Bay, the complex comprises two structures: a 1,174 foot tower and an adjacent hotel.
Each building’s elegant white façade plays an integral role in its energy efficiency: “By mapping the different air flows and solar direction across the site, we were able to position different sized windows accordingly, minimizing heat loss in the winter and heat gain in the summer.” The façade also acts as the building’s main structural support, which allows the interior spaces great flexibility for the types of use they can accommodate.
Construction is currently underway and the complex will be completed in 2011.
+ MAD
Via dezeen.com
ใช้ eco system เป็นระบบจัดการน้ำเสีย
Inhabitat
LIVING MACHINES: Clean, Green Waste-Water Recycling
by Olivia ChenResembling a tropical forest more than a concrete refinery, John Todd’s Living Machines offer an attractive solution to waste-water management. Consisting of a series of ecosystems that work together to break down water contaminants, Living Machines present a natural and eco-friendly way to filter and clean waste-water. The concept was recently awarded a Buckminster Fuller Award for its elegant application in cleaning up Appalachia’s water supply, and the innovative approach to waste-water management is currently being adopted and adapted by many eco-minded individuals around the country.
Converting sewer sludge to fresh water is no easy job; traditional treatment plants consume massive amounts of money, energy, and resources. John Todd’s Living Machines re-envision waste-water management as an eco-conscious endeavor, conserving water and reducing overall treatment costs with minimal sludge disposal, water purchases, sewer surcharges, and chemical use.
Part natural and part man-made, “Living machines” offer a manner of re-organizing natural resources to transform water from dirty to clean. In their most basic design, waste-water pulses through a minimum of three different ecological systems that process and filter it in different ways. Each ecological system is isolated from the others so that it can treat waste-water based on its own unique needs, after which the water cycles on to the next community.
Since the technology uses “helpful bacteria, fungi, plants, snails, clams and fish that thrive by breaking down and digesting pollutants”, selecting and then cultivating diverse communities is key in order for all compounds to be treated. The magic lies in understanding how the organisms interact and combining them just right so that they can soak up the nutrients they love, helping them grow while providing us with clean - if not drinkable - water.
Since their inception Living Machines have seen a variety of applications. Their rather remarkable use of living organisms makes them a shoe-in for use as an educational tool, as they are at Oberlin College, and the have also popped up at resorts, lake restoration sites, and even at chocolate maker Ethel M’s factory in Nevada.
+ Living Machines
+ John Todd
Green concrete eyed for Mesa del Sol
New Mexico Business Weekly - by Kevin Robinson-Avila NMBW Staff
Albuquerque's budding Mesa del Sol development could become the launching pad for a chain of factories to supply western markets with a popular green construction material known as autoclaved aerated concrete block.
The material has been around for 80 years and is widely used in Europe and Asian countries, but it's fairly new to the U.S. market. Now, Thomas Tulk and Michael Baron -- partners in newly formed Aercrete LLC in Santa Fe -- plan to invest $21 million to build the first factory in the U.S. interior.
To be located a short distance from Albuquerque Studios, the 65,000-square-foot facility will supply green concrete for Mesa del Sol residences and buildings, and then expand outward to surrounding states, Tulk said.
"We'll start with Mesa del Sol and then push out by rail to the western region," Tulk said. "Mesa del Sol provides an immediate market for us, but we see huge opportunities in places like California, Arizona and Colorado. The Albuquerque plant will leverage our entrance into the other markets, but in the next five years we plan to build four more factories in California, Oregon and Missouri."
Tulk said autoclaved aerated concrete's wide acceptance outside the U.S., plus growing domestic demand for green construction, will allow Aercrete to rapidly build a local market.
The special concrete is made from a simple mix of sand, cement, lime, gypsum and water formed into solid blocks with high-pressure, steam-curing autoclaves.
The end material weighs about one-fifth as much as normal concrete, making it easier to transport and manipulate. It's fire resistant and has excellent thermal characteristics that help keep buildings cooler in summer and warmer in winter. Its insulating properties also make it an extremely effective noise reducer, and it's resistant to mold and pests because it contains no organic elements, Tulk said.
"With AAC, houses and buildings often use 30 to 40 percent less energy to keep cool or heated," he said. "It's fully recyclable, and it can be disposed of in landfills with no risk of chemical contamination because it's basically just sand and air."
It's also less expensive than other construction materials, such as wood, brick or steel, said Kent Beierle, principal of Albuquerque-based architectural firm Environmental Dynamics Inc.
"There is no holy grail building material, but this one comes close," said Beierle, who has designed homes with the imported concrete. "If they build this plant, I think it will change the way construction is done in the Southwest."
Some 500 factories currently make this particular concrete worldwide, but only two operate in the U.S., in Georgia and Florida.
Baron and Tulk hope to break ground on the Mesa del Sol factory this fall and begin operating in 2010.
"We'll create the first center for AAC production in this area," Baron said. "All the ground work is done at Mesa del Sol. We have an option on a multi-acre site and we're ready to go."
Mark Lautman, director of economic development at Mesa del Sol, said Aercrete's plans are quite advanced.
"The completion of economic development deals are hard to gauge, but we think this is a fait accompli," Lautman said. "We see the production facility happening. It's mostly a question of what time frame."
It's also a question of funding. Aercrete is raising capital to build its plant, including $8 million in private equity and the rest through debt financing and equipment leasing, said Anant Vashi of ClearCreek Partners, a boutique investment firm helping Aercrete raise funds. The company made its first major presentation to local investors on July 24.
"We're looking for a core group of New Mexico institutional investors to show that the state is really behind this, then we'll approach some out-of-state investors," Vashi said. "We're in various levels of discussion with a number of financiers."
Still, Les Matthews -- managing partner at Mesa Capital Partners -- said the current slump in U.S. construction could complicate things.
"I'm certainly impressed with the product and the management team, but the big challenge they face is getting debt financing," Matthews said. "Equity providers will likely condition investment on raising credit for equipment and construction. That can be a big hurdle given the credit markets today."
Assuming the plant is built, Tulk and Baron project rapid growth, reaching profitability by the second year of operation. With all five of Aercrete's plants up and running, the partners project more than $200 million in revenue by 2015. At that point, they would seek an exit through acquisition.
If the plant is built at Mesa del Sol, Albuquerque Economic Development will assist in obtaining a $3 million incentive package, including job training and tax breaks, from the respective government agencies.
The plant will be highly mechanized, with about 60 full-time workers once it reaches full capacity, Baron said.
[email protected] | 348-8302
August 7, 2008
Cement from CO2: A Concrete Cure for Global Warming?
A new technique could turn cement from a source of climate changing greenhouse gases into a way to remove them from the air
By David Biello
CLIMATE CHANGE CURE?: By running the flue gas from Moss Landing's mammoth smokestacks through ocean water, a new company can make cement from carbon dioxide pollution.
COURTESY OF DYNEGY
power plant on the California coast burn through natural gas to pump out more than 1,000 megawatts of electric power. The 700-degree Fahrenheit (370-degree Celsius) fumes left over contain at least 30,000 parts per million of carbon dioxide (CO2)—the primary greenhouse gas responsible for global warming—along with other pollutants.
Today, this flue gas wafts up and out of the power plant's enormous smokestacks, but by simply bubbling it through the nearby seawater, a new California-based company called Calera says it can use more than 90 percent of that CO2 to make something useful: cement.
It's a twist that could make a polluting substance into a way to reduce greenhouse gases. Cement, which is mostly commonly composed of calcium silicates, requires heating limestone and other ingredients to 2,640 degrees F (1,450 degrees C) by burning fossil fuels and is the third largest source of greenhouse gas pollution in the U.S., according to the U.S. Environmental Protection Agency. Making one ton of cement results in the emission of roughly one ton of CO2—and in some cases much more.
While Calera's process of making calcium carbonate cement wouldn't eliminate all CO2 emissions, it would reverse that equation. "For every ton of cement we make, we are sequestering half a ton of CO2," says crystallographer Brent Constantz, founder of Calera. "We probably have the best carbon capture and storage technique there is by a long shot."
Carbon capture and storage has been identified by experts ranging from the U.N.'s Intergovernmental Panel on Climate Change to the leaders of the world's eight richest nations (G8) as crucial to the fight against climate change. The idea is to capture the CO2 and other greenhouse gases produced when burning fossil fuels, such as coal or natural gas, and then permanently store it, such as in deep-sea basalt formations.
Calera's process takes the idea a step forward by storing the CO2 in a useful product. The U.S. used more than 122 million metric tons of Portland cement in 2006, according to the Portland Cement Association (PCA), an industry group, and China used at least 800 million metric tons.
The Calera process essentially mimics marine cement, which is produced by coral when making their shells and reefs, taking the calcium and magnesium in seawater and using it to form carbonates at normal temperatures and pressures. "We are turning CO2 into carbonic acid and then making carbonate," Constantz says. "All we need is water and pollution."
The company employs spray dryers that utilize the heat in the flue gas to dry the slurry that results from mixing the water and pollution. "A gas-fired power plant is basically like attaching a jet engine to the ground," Constantz notes. "We use the waste heat of the flue gas. They're just shooting it up into the atmosphere anyway."
In essence, the company is making chalk, and that's the color of the resulting cement: snow white. Once dried, the Calera cement can be used as a replacement for the Portland cement that is typically blended with rock and other material to make the concrete in everything from roads to buildings. "We think since we're making the cement out of CO2, the more you use, the better," says Constantz, who formerly made medical cements. "Make that wall five feet thick, sequester CO2, and be cooler in summer, warmer in winter and more seismically stable. Or make a road twice as thick."
Of course, Calera isn't the only company pursuing this idea—just the most advanced. Carbon Sciences in Santa Barbara, Calif., plans to use flue gas and the water leftover after mining operations, so-called mine slime, which is often rich in magnesium and calcium, to create similar cements. Halifax, Nova Scotia–based Carbon Sense Solutions plans to accelerate the natural process of cement absorbing CO2 by exposing a fresh batch to flue gas. And a number of companies are working on reducing the energy needs of Portland cement making. The key will be ensuring that such specialty cements have the same properties and the same or lower cost than Portland cement, says Carbon Sciences president and CEO Derek McLeish.
But the companies may also find it challenging to get their cements approved by regulators and, more importantly, accepted by the building trade, says civil engineer Steven Kosmatka of the Portland Cement Association. "The construction industry is very conservative," he adds. "It took PCA about 25 years to get the standards changed to allow 5 percent limestone [in the Portland cement mix]. So things move kind of slowly."
Calera hopes to get over that hurdle quickly by first offering a blend of its carbon-storing cement and Portland cement, which would not initially store any extra greenhouse gases but would at least balance out the emissions from making the traditional mortar. "It's just a little better than carbon neutral," notes Constantz, who will make his case to the industry at large at the World of Concrete trade fair in February. "That alone is a huge step forward."
"Could you take this calcium carbonate and add it to Portland cement? You sure can," Kosmatka says. "Could you add it to the ready mix to replace some of the Portland cement? You probably can do that, too." That would help to rein in the greenhouse gas emissions from buildings—both from building them and powering them once they are built—that makes up 48 percent of U.S. global warming pollution.
Nor are there any limitations on the raw materials of the Calera cement: Seawater containing billions of tons of calcium and magnesium covers 70 percent of the planet and the 2,775 power plants in the U.S. alone pumped out 2.5 billion metric tons of CO2 in 2006. The process results in seawater that is stripped of calcium and magnesium—ideal for desalinization technologies—but safe to be dumped back into the ocean. And attaching the Calera process to the nation's more than 600 coal-fired power plants or even steel mills and other industrial sources is even more attractive as burning coal results in flue gas with as much as 150,000 parts per million of CO2.
But Calera is starting with the cleanest fossil fuel—natural gas. The company has set up a pilot plant at Moss Landing because California is soon to adopt regulations limiting the amount of CO2 power plants and other sources can emit, and natural gas is the primary fuel of power plants in that state. According to Constantz, some flue gas is already running through the company's process. "We are using emissions from gas-fired generation as our CO2 source at the pilot plant where we are making up to 10 tons a day," he says. "That material will be used for evaluations."
The California Department of Transportation (Caltrans) has expressed interest in testing the cement, and Dynegy, owner of the Moss Landing power plant, is also intrigued. Although no formal agreement has been struck, "their proposed technology for capturing CO2 from flue gases and turning it into a beneficial, marketable product sounds very interesting to us," Dynegy spokesman David Byford says. "There are very good technologies for capturing the emissions of other pollutants. The carbon issue is something we are just turning our attention to now, and so far it's been quite elusive."
City Weighs Extent of Concrete Retesting
New York City is working to determine how extensively it needs to test the strength of concrete in buildings around the city after learning that prosecutors have found evidence that the area’s largest testing company often falsified results, officials and people briefed on the matter said on Wednesday.
The company, Testwell Laboratories, has been hired in recent years to analyze the strength of concrete on a raft of public projects, including work for the city, as well as legions of commercial and residential buildings that were constructed in the area. But investigators have discovered evidence indicating that for at least five years, the company has falsified some concrete test results, according to several people who have been briefed on the investigation, being conducted by the Manhattan district attorney, Robert M. Morgenthau.
The company has denied the allegations. Because the investigation is not complete, a spokesman at the city’s Department of Buildings said that while some retesting will surely be done, officials were unsure how many buildings they might have to retest. They also have to determine whether to test existing buildings or just those currently under construction.
But as prosecutors analyze evidence seized from Testwell’s offices in June, including detailed computerized records of concrete compression tests, the potential scope of the undertaking facing the city, private builders and developers looms large.
With the city alone, Testwell holds roughly $12 million in contracts and has done millions of dollars in work for the government agencies that build schools, and has done work on bridges and subway tunnels. Among the projects where investigators have uncovered irregularities in the testing are the new Yankee Stadium and the Freedom Tower in Lower Manhattan.
Although a retesting program may be expansive, structural engineers and construction industry experts downplayed any safety concerns. They said that most concrete produced in the city is generally of such high quality that they do not believe there are likely to be many problems with building stability. But the tests are required by the city’s building code, and if their integrity is in question, it is unclear whether buildings that have not had viable tests would be in compliance with the code.
“We have put together a plan to retest,” said Tony Sclafani, the Buildings Department spokesman. “It’s going to be a sampling of sites under construction. This will involve both reviewing paperwork as well as actual retesting.”
Mr. Sclafani, who would not speak about the criminal investigation, said that the department, as part of a broader citywide review of construction practices, is also examining procedures associated with concrete construction “to better insure the integrity of these operations.” It will include a review of the design and placement of concrete, as well as concrete testing and the companies that perform such work.
Mr. Sclafani would not provide any details of the plan or any estimate of its cost, or say how the department, which has been plagued by a shortage of inspectors, would carry it out.
Construction and inspection practices in the city are already under scrutiny as a result of a series of fatal accidents and arrests on corruption charges.
The prosecutors — along with inspectors general at a half-dozen other agencies and public authorities, including the Metropolitan Transportation Authority — are examining the results of the company’s tests on steel and for the presence of asbestos, according to the people who have been briefed on the investigation, who spoke on the condition of anonymity because the inquiry is continuing.
Testwell’s lawyers declined to comment on Wednesday.
It is unclear how many of the roughly one million buildings in the city were built with concrete analyzed by Testwell. The people briefed on the inquiry could not say how many times the tests appeared to have been falsified, but they said evidence indicated that improper results were far from isolated.
The Buildings Department’s computer system does not have the capacity to track which continuing or completed projects were built with concrete analyzed by Testwell.
“Everyone that did business with them, public and private, is going to have to go through the same process,” said one person who has been briefed on the investigation. “How many contractors, how many owners, how many owner’s reps, structural engineers and city agencies are going to have to go through this, I don’t know.”
Last month, when the investigation was first disclosed, lawyers for the company defended its work and said its officials had done nothing wrong.
They noted that the company had cooperated when investigators searched Testwell’s offices in Ossining, N.Y., taking roughly 200 boxes of documents and computers. One of the lawyers, Martin B. Adelman, said at the time: “They are quite confident that at the end of whatever this investigation is, it will show that they have done their job correctly and honestly.”
No one has been charged in connection with the inquiry.
The office of the Metropolitan Transportation Authority inspector general, Barry L. Kluger, which is involved in the Testwell investigation, has also begun a review to determine what type of work the company performed for the authority.
While the review has not been completed, investigators there have found that Testwell worked as a subcontractor on six projects and also had a continuing contract with New York City Transit to do testing as needed, one official said. The work included concrete tests on the South Ferry Terminal and the Second Avenue subway line and tests on steel welds on the approach to the Throgs Neck Bridge.
The official said the office plans to ensure, as part of its review, that retesting is done where needed for the authority, which is involved in some of the larger public works projects in the city.
A spokesman for the New York State Dormitory Authority, which is also working on the investigation with Manhattan prosecutors, said the agency stopped using Testwell in February after discovering some unspecified irregularities. The authority paid the company $3.9 million for testing services on more than two dozen projects in the last five years. They include several that the authority built for city hospitals, the City University of New York and the State University of New York.
“When we discover irregularities with the services provided by a testing firm, we take it upon ourselves to engage another testing company to re-inspect, and we do what is necessary to ensure the quality of the work and the integrity of the project,” said the Dormitory Authority spokesman, Marc Violette.
The testing of concrete by companies like Testwell is one of the most basic safety measures used for all kinds of construction projects in the city, from office towers and apartment houses to bridges and subways. Testing companies, both at job sites and in their laboratories, are supposed to conduct a variety of exams to make sure that the concrete was properly mixed and that it meets industry standards for strength and durability.
Testwell, according to people briefed on the case, falsified compression tests. Such tests are the key to determining the strength of the material used in reinforced concrete buildings, according to Vincent J. DeSimone, the chairman of DeSimone Consulting Engineers.
The tests are typically performed on concrete that has been poured into cylinders 12 inches long and 6 inches in diameter. The samples are sent to a lab, where they are crushed to the breaking point in a machine that measures its strength to ensure it meets the building engineer’s specifications.
The tests are conducted 14, 28 and 56 days after the concrete is poured.
“It’s the only way we know at the onset of the project that the material meets our specs,” said Mr. DeSimone, who has been working in the industry since 1959.
While he called the testing a linchpin of the process, he said that there have been few recent instances of failures or distress, like cracking or sagging.
Opportunity road: Flexi-Pave created with water conservation in mind
Tampa Bay Business Journal - by Janet Leiser Staff Writer
CLEARWATER — Kevin Bagnall has spent eight years developing a product he says enables rainwater to replenish Florida’s aquifers in urban areas while also diverting millions of tires from ending up as hazardous material in landfills.
Like any entrepreneur who has exerted untold energy and personal financial resources bringing an invention to market, the native Englander and founder of KB Industries Inc. hopes his product will bring financial rewards.
Flexi-Pave is a permeable material made from shredded old tires that’s used for sidewalks, parking lots and bike trails. It allows rainwater to flow downward, through it and into aquifers.
Liberty Property Trust uses Flexi-Pave to ensure the survival of oak trees in the parking lot of its newest office building at Woodland Corporate Center. The building is Tampa’s first multi-level office building gold certified by the U.S. Green Building Council for the use of environmentally sustainable building practices.
Flexi-Pave surrounds the property’s oak trees, allowing rainwater to reach the roots, saving the foliage from an untimely death, said Jody Johnston, city manager and VP for Liberty in Tampa.
The product isn’t expected to replace asphalt or concrete in the construction industry, Bagnall said. Instead it should be used where there’s a problem with stormwater runoff or erosion control or to save trees.
Tests show that Flexi-Pave allows water to pass through it at a rate of 2,000 gallons an hour, Bagnall said. That means the roots of trees located near the material will grow downward instead of upward, eliminating costly repairs from broken pavement.
Growing acceptance
One of Bagnall’s challenges is convincing engineers and developers that the product is worth its additional cost and that it will hold up over time. Flexi-Pave is about $1 more a square foot than concrete and twice the cost of asphalt.
The University of Central Florida’s Stormwater Management Academy has been studying Flexi-Pave’s porosity and strength for about six months, said Marty Wanielista, director of the academy.
“It’s an excellent product,” Wanielista said. “It’s extremely promising.”
Wanielista expects Flexi-Pave to gain Florida’s official seal of approval for use in sustainable building within the next couple months.
In addition to its role in saving rainwater, Flexi-pave serves another important environmental purpose. It diverts tires from landfills.
Floridians alone dispose of 19 million tires annually, Wanielista said.
Going global
Bagnall isn’t limiting his marketing to the Bay area. He has also started a company in the United Kingdom, and he says the product is being considered for the Olympics in London.
Several months ago, KB Industries installed about 8,000 feet of sidewalks in Lansbrook, one of Pinellas County’s upscale neighborhoods. In July, the company installed a trail and parking lot at the University of Florida in Gainesville.
KB Industries’ revenue is projected to hit $5.2 million this year, Bagnall said. Densely populated urban areas are the company’s prime target.
“Wherever there’s a dense population and waste, that’s where we can be at,” he said. “The only thing that changes is language and currency.”
In a Downturn, Discounts Can Be Dangerous
Posted by Jeff Stibel on August 21, 2008 1:09 PM
Often the first thing companies do during a downturn in the economy is reduce prices on their products and services. Call it an economy-inspired sales promotion.
But is this a sound strategy? Do consumers always want the cheapest price? Can a price reduction actually hurt rather than help?
While it may be necessary in some cases to reduce prices, discounting has its risks. The biggest risk is that it can create a negative long-term perception of a product and a down-channel effect, ultimately leading to market-share erosion. Discounting can turn a Rolex into a Timex; a Barneys into a Macys; a Mercedes into a Chrysler. Just look at what happened to AOL when they discounted their services: they dropped their prices in some cases to zero, yet saw significant brand and market share erosion.
And discounting can also be dangerous to low-cost providers not focused on brand. Value-minded consumers have long-term memories and it is hard to retain market-share when the economy recovers and you try to raise your prices or eliminate promotions.
In some cases, it may make sense to buck the trend entirely and increase prices.
In fact, many companies--including Abercrombie and Fitch, Web.com, Hershey, Blue Nile, and Vodafone--are taking this counterintuitive approach. To be sure, many are blaming the cost of commodities and these increases will put a strain on short-term growth. But over the long-run this could build brand value. Abercrombie and Fitch recently announced they were raising prices, in part to help realign their clothes with high-quality-and their sales rose 5% as a result.
Don't get me wrong; there's no doubt that discounting and sales promotions are a vital sales technique when done correctly. It inspires excitement and creates a call to action. However, when offered at the wrong times--for no other reason than to boost sales--it can cut the other way and create brand deterioration.
Here's why:
Consumers give you their hard-earned money in return for something that meets or exceeds their perceived value. It doesn't matter if they're buying a hot dog, a handbag, or staying at a five-star hotel; consumers want to see value and quality in return for their money.
And studies have shown that in many cases, the more people pay, the more value they ascribe to their purchase. Money plays a funny role in the purchase process: it anchors perceived value. If you discount prices during adverse times, consumers may begin to question the original value.
Starbucks, which just posted its first-ever earnings loss, has begun to offer lower-priced options on its menu, such as the recently announced $1 cup of coffee with free refills. This strategy may boost sales in the short-term but I suspect it will hurt the Starbucks image in the long-term (and so does CEO Howard Schultz, who once said, "Our marketing will emphasize quality and service, not price.")
When you discount, you undo the "placebo effect" of higher prices. And this leads to a decaying belief in the value of the product offered. So it may be short-term thinking to devalue a consumer's perceived value of a product simply to move more merchandise during shifts in the economy.
There are ways around this, of course. Consider the auto industry, typically the first to discount their way out of economic woes. Chrysler recently did something to preserve their price while offering a discount for something that does not affect their brand: gas. Chrysler cleverly took discounting to the next level by offering up a $2.99 gas guarantee for three years on all new car purchases within its fleet. The idea was to subsidize the fuel that goes into the new car, not the MSRP of the car itself. They followed a hugely successful promotion from GM in 2001, which discounted the financing instead of the price of the car itself. To be sure, the auto industry has far more problems than brand deterioration, but this approach is nonetheless smart marketing during tough times.
So if you're considering discounting prices during this recession, consider the long-term consequences and the potential for inadvertently re-positioning your brand. And if you must, it may be better to focus on something ancillary--such as gas or financing in the auto industry--rather than what your brand truly represents. Because once that veil is pierced, it may be incredibly difficult to go back and reestablish the value proposition to your consumers.
TRAVELODGE HOTEL MADE FROM SHIPPING CONTAINERS
by
Adrianne Jeffries
Travelodge recently opened a hotel in Uxbridge, England that is constructed entirely from prefabricated shipping containers. The completed design uses eighty-six containers of various sizes that were retrofitted into bedrooms and bolted together onsite. The exterior has been clad and fitted with windows, thus converting the assemblage into a seamless 120-bedroom hotel. Verbus Systems estimates that the structure’s prefab composition saved the hotel chain more than half a million pounds and at least 10 weeks of construction.
Verbus Systems claims that the hotel’s modular construction makes its construction 40-60% quicker than traditional building methods, plus it doesn’t require complicated construction processes or specialized labor, which helps to reduce cost. They also quote a 70% reduction in on-site waste. The interiors are indistinguishable from other Travelodge hotels, and after construction, the exterior betrays nothing.
Travelodge plans to follow up with a 307-room version at Heathrow. They expect to save up to 10 million pounds (18.6 million dollars) a year on hotel development by using this new method.
+ Verbus Systems
+ Travelodge
Via worldarchitecturenews.com
Article published Monday, October 6, 2008
Plastic bridge in Huron County may be path to the future
By DAVID PATCH
BLADE STAFF WRITER
NORTH FAIRFIELD, Ohio - Bridges don't get much smaller than one carrying Ridge Road over a Huron River tributary in Huron County's Fairfield Township. "It's only 17 feet long. Even at 20 miles an hour, it's like half a second to cross it," said Douglas Nims, an associate professor of civil engineering at the University of Toledo. But Mr. Nims and several of his students were there to observe when the Huron County Engineer's Office installed a replacement last month, and they will be back in the future to take readings from an array of sensors built into the structure. That's because the new Ridge Road bridge is not made of steel or concrete or even wood. It's plastic, reinforced with fiber glass. The only metal on it is the guardrails. Inside are 16 gauges to measure the strain placed on the bridge by the loads that cross it, and eight that measure deflection - the degree to which it bounces or is pushed around by traffic.
“Per square foot, it’s probably the most instrumented bridge in the world,” said Mr. Nims, whose ongoing bridge research includes studying the massive Veterans’ Glass City Skyway on I-280 in Toledo, a structure more than 4,500 times as long as the Huron County structure - not to mention hundreds of feet higher and four lanes wider. The professor’s interest in the Ridge bridge shows that small bridges matter too. Historically, small spans on rural roads tend to crumble, not under heavy traffic pounding, but rather from the effects of heat, cold, rain, and winter weather, plus the corrosive effect of salt used to combat the latter. “Salt eats the deck. What could [it] eat on a plastic bridge? What could rust?” said Joseph Kovach, the Huron County engineer, who secured a $155,000 Federal Highway Administration grant to install and study the plastic structure, hand-built at a Kansas factory and trucked to Ridge Road.
Nonetheless, the effects of cyclical heating and cooling, and even sunlight exposure, on plastic need to be studied before the material can be used on a broader basis for structures like bridges, Mr. Kovach said. By testing it on a lightly used rural road, he said, any problems that arise won’t disrupt much traffic.
With a materials price of $73,000, the bridge cost somewhat more than a traditional concrete or steel-beam structure of the same size, Mr. Kovach said. But it is expected to last considerably longer than traditional bridges, and the modular design and light weight allowed it to be installed in just a few days, including time needed to ramp the roadway to it, he said. Speed of installation and portability, Mr. Kovach and Mr. Nims said, could make modular plastic bridges ideal for military engineers building bridges in combat zones. The panels also have tested successfully as barrier material to protect soldiers’ foxholes from explosive ordnance, the professor said. And once such bridges’ components are made in regular production, rather than custom-built by hand, their price should decrease, both men said. Before building the bridge panels, Kansas Structural Composites of Russell, Kan., made a small sample panel that was stressed until destruction at a University of Cincinnati laboratory, Mr. Nims said. The maximum load it could withstand proved to be 10 times stronger than expected, he said. Once the bridge was built, county officials maneuvered two dump trucks weighing a combined 240,000 pounds onto it, and the sensors inside the panels measured “very small” shifting from the load - much smaller than normal bridge-design maximums. Under normal traffic, vehicle weights won’t come anywhere close to that test, Mr. Nims said. Yet for all its strength, the plastic used to build the bridge panels isn’t solid. Instead, it’s two slabs with a honeycomblike structure in between. The inside is only about 15 percent solid, Mr. Nims said, but that’s all that is needed to give the bridge its strength. Anything more would just be additional weight that the structure would have to support, he said. Mr. Kovach said the bridge doesn’t even sound like a conventional structure. “When you step on it, it sounds like hollow Styrofoam,” the county engineer said. The bridge design is similar to one Kansas Structural Composites built in the 1990s near its plant and studies. Mr. Nims said he knows of one other plastic bridge in Ohio, in Hamilton County, but isn’t familiar with its construction or research. Considering the Ridge bridge’s small size, the professor doubts it will attract too many visitors, though he was surprised when a man showed up during the pre-opening testing Sept. 26 hoping to be the first person to drive across it. “He was very disappointed to find out we’d been driving trucks back and forth across it all day,” Mr. Nims said. Contact David Patch at:
[email protected]
or 419-724-6094.
Permanent Link
Precast Bridge Abutments Cut Construction Time
Wisconsin's first test of construction method going well
Story and Photos by Mike Larson, Editor -- Western Builder, 10/20/2008
The abutments, each consisting of seven pre-cast panels mounted on pilings, are the first pre-cast, segmentalabutments ever used in a Wisconsin Department of Transportation (WisDOT) highway project.
If the concept works as planned, it could eventually be approved for general use in WisDOT projects.
This first co-operative application of the technique is being spearheaded by the University of Wisconsin-Madison's engineering department and WisDOT.
Alfred Benesch & Company, Kenosha, WI, designed the bridge, including the pre-cast abutments, as a subcontractor to the university. Edward Kraemer & Sons, Inc., Plain, WI, is the prime contractor for the bridge project, which also includes a box culvert about a mile further up the road.
Technique Could Put Up Concrete ForAbutments In Two To Three DaysMichael Oliva, professor of engineering at the UW-Madison, says the major benefit of using segmental, pre-cast bridge abutments is quicker assembly and controlled quality.
Demolition And Construction Done In Stages
David Koepp, WisDOT's manager on the project, says the construction plan calls for Kraemer to demolish and rebuild one lane at a time, so there will always be one lane available to carry traffic throughout the project. Traffic from each direction is controlled by stop lights at the ends of the construction zone.
“If we'd demolished the whole bridge at once,” he says, “all traffic, including emergency vehicles, would have to detour eight miles to get around the construction site. So we always need to keep one lane open.”
Work Moving AlongKraemer is completing major construction for the project with a crew of four and one 100-ton lattice-boom crawler crane that handles a wrecking ball, clamshell bucket, pile driver, 1-1/2-cubic-yard concrete bucket, and all the lifting.
Kraemer began demolition of the western half of the existing bridge in September, and the entire project is scheduled for completion by early November.
After demolishing the western half of the existing bridge, Kramer drove 12 40-foot-long steel H piles into the creek bed until each reached 72-ton bearing capacity. Each pile was spotted and double-checked using a GPS system.
To be certain the pilings would align with the pockets in the pre-cast panels, each pile had to stand within 1-1/2 inches of vertical over its full height.
Driving all of the pilings for the western half of the bridge took just one day.
After the pile driving had been completed, Kraemer excavated and filled around the piles with washed stone to provide a bearing surface for the wall sections.
First Panels Set In About 30 Minutes EachThe first three abutment panels were set on the morning of September 26. The two wall panels weighed 29,500 pounds and 30,900 pounds, while the wing wall came in at 40,400 pounds. All three pieces had been cast and cured for 30 days at Spancrete's facility in Green Bay before being trucked 235 miles to the site.
As each piece arrived, Kraemer's crew picked it off the truck, placed it over the pilings, and aligned it in about 30 minutes.
Said Proffitt, “The pockets in the panels slid over the pilings easily, and final alignment of the panels went quite quickly. We checked them with a laser transit, and all ended up right on the money.”
Deck To Be Cast In PlaceThe abutments and deck for the western half of the new bridge are scheduled to be finished by early October. The process will then be repeated for the eastern half of the structure.
Unlike the abutments, however, the deck will be constructed using the conventional cast-in-place method, which entails forming, placing rebar, and pouring and curing concrete.
Overall, using the pre-cast abutments is expected to reduce the overall construction time by about 30 percent, compared to forming, casting and curing them in place.
Potential Strong For Even Larger Time SavingsSays Professor Oliva, “Pre-cast bridge abutments could well provide Wisconsin's bridge designers and builders with another effective method for meeting the state's highway needs.”
“We need to monitor how this bridge performs over time to know for certain, but the abutment construction seems to be going as well as expected.”
Oliva says that using pre-cast bridge abutments would offer an especially large advantage for contractors when building abutments that sit in water. That's because the bottoms of the pile voids could be plugged and the piles grouted without having to build and later dismantle a cofferdam.
Further gains in speed could come, he says, by combining a pre-cast deck with the pre-cast abutments. “Eventually, we would like to also make the bridge deck of pre-cast panels. Using pre-cast abutments and pre-cast decking together would enable a contractor to assemble an entire bridge in just a few days,” said Oliva.
NTSB Expected to Adopt Final Report on I-35W Bridge Collapse;
Agency Probe Cites Gusset Plate Design Flaw
The National Transportation Safety Board is expected to issue a ruling late Friday on the probable causes and contributing factors of the Aug. 1, 2007, I-35W bridge collapse in Minneapolis that killed 13 people and injured 145. Their findings will be released formally at the conclusion of a two-day public board meeting that opened Thursday in Washington.
During Thursday's testimony, federal investigators said they had discovered a major design flaw that dated to the bridge's original design in the mid-'60s -- the steel gusset plates that held beams together were only half the required thickness. The bridge was in the midst of repairs at the time of the collapse. Equipment and supplies at one point of excessive weight in the center span caused weak plates to give out, which pulled down the adjacent sections in turn.
The NTSB has been investigating the catastrophic failure of the eight-lane, 1,907-foot-long highway bridge over the Mississippi River over the past 15 months since the collapse. The board made the two-day meeting available via a live webcast, which is being archived for later viewing online. The NTSB planned to release a summary of their final report shortly after the conclusion of the meeting. The entire report will be released in "several weeks," according to the NTSB.
>> Do a Google News search for coverage of the NTSB's meeting and findings here.
>> See the NTSB investigator's presentation slides explaining the bridge's collapse here. (PDF file)
>> Watch the archived webcast of the meeting at the NTSB Web site here.
>> View the NTSB's media advisory on the meeting here.
ASCE has maintained an interest in the investigation and in the follow-up work performed by the Minnesota Department of Transportation, and has compiled roundups on the federal and state efforts with links to official reports, contracts, photos and other materials.
>> View coverage of the NTSB's investigation here.
>> View coverage of Minnesota DOT's investigations and bridge reconstruction here.
>> View ASCE technical reports on bridge failures, inspection standards and more here.
>> View ASCE's condolence message to members following the collapse, outlining some follow-up efforts here.
AsiaOne
The Urban Redevelopment Authority (URA) is seeking feedback on the proposed names for the world's first curved double helix pedestrian bridge and an art park at MarinaBay, due to be completed by end 2009.
The new bridge and art park completes the 3.5 km waterfront loop connecting the necklace of attractions in MarinaBay. The bridge comprises two components - a vehicular bridge, which is parallel to Sheares Bridge, and a pedestrian bridge, which is uniquely designed to resemble the double helix structure of DNA.
The public can have a preview of the double helix structure, as the first helical segment of the pedestrian bridge has been installed this month.
At the northern end of the bridge will be Singapore's first art park featuring 27 art works by Singapore youths. These were selected from 136 entries submitted in a competition in March 2006, which express ideas based on the theme "Aspirations for Life in Singapore".
There will be a landscaped maze and also a rock wall featuring 18 drawings of Singapore icons, and an interactive "hop-scotch" lighted flooring. Construction works on the ArtPark will start in May next year.
URA proposes to name the pedestrian bridge "The Double Helix" or "The DNABridge", and the vehicular bridge the "BayfrontBridge".
The vehicular bridge is named after Bayfront Avenue, the future road which it will form part of. This name will serve as an instinctive, easy-to-remember locational reference for all road users.
The proposed name for the art park is "ImagiNation Park", to reflect the boundless creativity and possibilities for the future of Singapore.
The public can share their views on the proposed names on the newly revamped MarinaBay website at www.marina-bay.sg from now till 14 December 2008.
Operators Are Hooked On Crane Camera
By Tudor Van Hampton
A company in Hawaii has discovered a new way to give crane operators a set of “eyes” when working in the blind. The HookCam is a patent-pending device that snaps onto a crane’s hook and wirelessly transmits the scene on a full-color, flat-screen monitor in the cab.
The device is geared toward safety, but it also increases production, according to Chris Catanzaro, operations director for Kailua-based Pacific Systems Solutions. “It actually decreases the time you need the crane because it increases productivity by 40% in the blind and 26% in open spaces,” he says.
Operators who have tried out the HookCam “absolutely love it,” says Peter Juhren, national service manager for Salem, Ore.-based Morrow Equipment LLC, one of the camera’s test outfits. “We were very impressed with the system.”
The HookCam rents for $1,250 a month, which includes installation, maintenance and repairs. Pacific Systems is working on a lower-tech model that it can sell because the current camera costs about $40,000. “We are trying to come out with a product that is easier to maintain and more user-friendly, where it is just plug and play,” Catanzaro says.
Shanghai Skyscraper Named “Best Tall Building”
By Anya Kaplan-Seem
The Council on Tall Buildings and the Urban Habitat has named the Shanghai World Financial Center the “Best Tall Building Overall” for 2008. Designed by Kohn Pedersen Fox (KPF) and completed last year, the building was chosen from among four “Regional Tall Building” winners, including The New York Times Building by Renzo Piano Building Workshop with FXFOWLE, London’s 51 Lime Street by Foster and Partners, and the Bahrain World Trade Center by Atkins.
Based on what you have seen and read about this project, how would you grade it? Use the stars below to indicate your assessment, five stars being the highest rating.
The Shanghai World Financial Center, which boasts the highest occupied floor in the world, was chosen as the winner for “its revolutionary structural design and inspirational symbolism,” according to the council. Formed out of a square prism intersected by two “cosmic arcs,” the building includes a distinctive, multi-story trapezoidal aperture at its upper floors. The firm’s design was inspired by two Chinese burial symbols: “a square prism essentially representative of the earth, and a heaven symbol—a circular disc with a circular aperture cut through it,” says Bill Pedersen, FAIA, of KPF. “We wanted to do a building that was a genuine expression of the relationship between the earth and the sky,” he explains, “and also that could be connected to the culture within which it is placed.”
The tower’s tapering form is more than an aesthetic move—it also allows the building to maximize floor plate and material efficiency. Structural innovations by the engineering firm Leslie E. Robertson Associates succeeded in increasing the building’s volume by 20 percent while retaining its original weight, thereby minimizing its total embodied energy. And the range of floor plates that the design’s unique geometry creates allowed KPF to “negotiate the different program necessities” of the building’s office, hotel, and retail components, according to Pedersen.
Though the building is replete with unusual features, Pedersen singles out one as particularly important: the tower houses a seven-story observatory and two sky walks on the 97th and 100th floors, thereby opening its most spectacular spaces and best views to the public. “One of the things we’re most proud of in this building,” says Pedersen, “is that the top 80 meters are devoted to functions that everyone can go in and enjoy.”
Work recently got under way on the Shanghai Tower, which is rising next to the Shanghai World Financial Center. Read our story.
Bridges built from recycled plastic
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Axion International Holdings, of Basking Ridge, N.J., said the engineers constructed a pair of bridges made entirely from recycled plastic products at Fort Bragg, N.C., and had M1 Abrams tanks driven across the spans.
The M1 Abrams, manufactured by General Dynamics (NYSE:GD), weighs nearly 70 tons, making it too heavy for the vehicle to use most standard bridges and roads.
Axion, in a release, said its composite technology withstood several tank crossings during the tests June 11 at Fort Bragg.
An article on the U.S. Army Corps of Engineers Web site said its Construction Engineering Research Laboratory was involved in the design and building of the test structures. Other U.S. Department of Defense officials were on hand for the testing.
"The first crossing was greeted with a big sigh of relief from some of us and a hardy round of applause from about 30 people in attendance," Richard Lampo, a CERL materials engineer and leader of the project, said in the article.
The company said its new bridges are made entirely from recycled consumer and industrial plastics. The two test thermoplastic spans were made from more than 170,000 pounds -- said to be the equivalent of more than 1.1 million 1-gallon milk jugs -- of recycled plastic. The structures are less expensive to build than traditional wood timber bridges often used on U.S. military bases.
"This represents a truly historic event for both structural engineers and environmentally conscious individuals across the nation," Axion Chief Executive Officer James Kerstein said in a company release.
"Not only are these bridges able to support the weight of a M1 Abrams tank, they are less expensive to build than wooden, concrete or steel bridges and are designed using higher-quality 100 percent recycled structural solutions in a manner that is nearly maintenance-free and eco-friendly."
Axion said its bridges incorporated the company's patented structural materials made from recycled plastic and a patent-pending I-beam design. It also claimed speed of installation and reduced costs for construction and maintenance as benefits.
The tests indicated the structures held up well under both moving and static weight loads and withstood stresses caused when the M1 operator applied the vehicle brakes while on the bridge.
Darryl Butler, a civil engineer with Fort Bragg's Directorate of Public Works, said: "We expect the advantages of the plastic lumber bridge will be lower maintenance costs and the ability to meet long-term training needs. The potential for this innovative material is only limited by the commander's requirements and the mission."
Axion said it developed its patented process in conjunction with researchers at Rutgers University. It says the resulting products are "ideal replacements" for construction materials such as wood, steel or concrete.
© 2009 United Press International, Inc. All Rights Reserved.
As Unbreakable as ... Glass?
A CLEAR VIEW A project lets visitors see all angles from the 103rd floor of the Sears Tower in Chicago. Builders are experimenting with new materials and methods to expand the use of glass in construction. More Photos >
CHICAGO — To truly appreciate how glass can be used structurally, make your way to 233 South Wacker Drive in downtown Chicago. More precisely, make your way 1,353 feet aboveSouth Wacker, to the 103rd floor of the Sears Tower.
Multimedia
Building With Glass
Don’t Look Down
Tempered for Strength
Once there, take a few steps over to the west wall, where the facade has been cut away. Then take one more step, over the edge.
You’ll find yourself on a floor of glass, suspended over the sidewalk a quarter-mile below. If you can’t bear looking straight down past your feet, shift your gaze out or up — the walls are glass, too, as is the ceiling. You’ve stepped into a transparent box, one of four that jut four and a half feet from the tower, hanging from cantilevered steel beams above your head. The glass walls are connected to the beams, and to the glass floor, with stainless-steel bolts. But what’s really saving you from oblivion is the glass itself.
The boxes, which opened last week as part of an extensive renovation of the tower’s observation deck, are among the most recent, and more outlandish, projects that use glass as load-bearing elements. But all glass structures have at least a bit of daring about them, as if they are giving a defiant answer to the question: You can’t do that with glass, can you?
You can. Engineers, architects and fabricators, aided by materials scientists and software designers, are building soaring facades, arching canopies and delicate cubes, footbridges and staircases, almost entirely of glass. They’re laminating glass with polymers to make beams and other components stronger and safer — each of the Sears Tower sheets is a five-layer sandwich — and analyzing every square inch of a design to make sure the stresses are within precise limits. And they are experimenting with new materials and methods that could someday lead to glass structures that are unmarked by metal or other materials.
“Ultimately what we’re all striving for is an all-glass structure,” said James O’Callaghan of Eckersley O’Callaghan Structural Design, who has designed what are perhaps the world’s best-known glass projects, the staircases that are a prominent feature of some Apple Stores.
Through it all, they’ve realized one thing. “Glass is just another material,” said John Kooymans of the engineering firm Halcrow Yolles, which designed the Sears Tower boxes.
It’s a material that has been around for millennia. Although glass can be made in countless ways to have any number of specific uses — to conduct light as fibers, say, or serve as a backing for electronic circuitry, as in a laptop screen — structural projects almost exclusively use soda-lime glass, made, as it has always been, largely from sodium carbonate, limestone and silica.
“For years, the basic composition of soda-lime glass has not changed much,” said Harrie J. Stevens, director of the Center for Glass Research at Alfred University. It’s the same glass, more or less, that is used for the windows in your home and the jar of jam in your fridge — and that old elixir bottle you bought at an antique store.
It’s basic stuff, but far from simple. “Of course, glass is an unusual material,” said James Carpenter of James Carpenter Design Associates, who has designed glass facades and other structures and was a consultant for the glassmaker Corning in the 1970s. “Since we don’t really know what it is.”
Although there has long been debate as to whether glass is a solid or liquid, it is now usually described as an amorphous solid (there is no evidence that it flows, extremely slowly, over time as a liquid). The noncrystalline structure is achieved by relatively rapid cooling below what is referred to as the glass transition temperature, around 1,000 degrees Fahrenheit for the soda-lime variety.
Cooled further and cut, pristine glass is very strong. But like a new car that plummets in value the moment it is driven off the lot, glass starts to lose its strength the instant it’s made. Tiny cracks begin to form through contact with other surfaces, or even with water vapor and carbon dioxide.
“If you take the freshly made surface and blow on it with your breath, you’ve reduced the strength of glass by a factor of two,” said Suresh Gulati, a mechanical engineer and self-described “strength man” who retired in 2000 after 33 years at Corning but still works for the company as a consultant.
Even one gas molecule can break a silicon-oxygen bond in glass, generating a defect, said Carlo G. Pantano, a professor of materials science at Pennsylvania State University. While glass is very strong in compression, tensile stresses will make these tiny fissures start to grow, bond by bond. “That’s what makes glass break,” Dr. Pantano said. “And if it doesn’t break, it weakens it.”
Protective coatings are one way to avoid new cracks, although they can affect transparency, which is the main reason for using glass in the first place. Changing the glass recipe can also make it harder for cracks to form and propagate. “There is some evidence that you can modify the composition to make it innately stronger,” Dr. Stevens said, although that risks altering other properties or making the glass too costly. (And glass projects are not cheap to start with; the glass in the Sears Tower project cost more than $40,000 per box.)
The manufacturing process can be modified, too, to keep the surfaces of the glass as pristine as possible. In one technique, used for laptop glass, molten glass is pumped into a V-shaped trough, spills over on both sides and flows down the outside of the V, joining together at the bottom into a sheet that continues to move downward as it cools. This way, each side of the sheet is a “melt surface,” exposed only to the air and not touched by any part of the equipment.
For structural purposes, glass is often strengthened the old-fashioned way — by tempering. This puts the surface under compression, so that even more tensile force is needed for cracks to grow.
For flat glass, heat tempering is most often used. William LaCourse, a professor at Alfred, said the process took advantage of one property of glass — that when it cools slowly it becomes denser. By rapidly cooling the exterior of a sheet (usually with air), the surface stays less dense. “Inside it’s still hot, and tries to cool to a more dense structure,” Dr. LaCourse said. “This pulls the surface into compression.”
In chemical tempering, sodium ions in the surface are replaced with potassium ions, which are about 30 percent larger. It’s like taking a suitcase full of summer-weight clothes and replacing the top layer with winter-weight items; the suitcase will bulge at the seams when you try to close it. Glass cannot bulge at the seams, so the surface becomes compressed.
Tempered glass may take longer to crack, but it can still break. Because surface compression must be balanced by interior tension, when tempered glass does break it forms many more smaller pieces than untempered glass, as more fracture lines release more energy. “The more it is strengthened the more pieces it will fly into,” Dr. Gulati said. An extreme example of this is a Prince Rupert’s drop, a small glass ball with a long tail formed by dropping molten glass into water. You can pound on the ball end with a hammer and it will not break, but snip off the tail and the ball will explode into tiny pieces as the tensile forces are released.
In structural applications, breaking into smaller pieces is often preferred, because these have less chance of causing injury. But tempering alone is usually not enough.
A primary concern when building with glass is what happens if and when a component breaks — what engineers call “post-failure behavior.” Unlike steel or other materials, glass does not deform or otherwise give advance warning of failure. If breakage occurs, maintaining the integrity of the structure is paramount so that people on or below it are safe.
That’s where lamination comes in. In a typical project, glass sheets (one-half-inch thick in the Sears Tower project) are bonded with thin polymer interlayers. The interlayers add strength and, should one of the glass layers break, keep the structure together, and the pieces from falling.
But lamination makes fabricating glass for structural uses very difficult. Since cutting into tempered glass causes it to break, each sheet must be polished and drilled for the connecting fittings before it is tempered. Tolerances are extremely small, to avoid potentially destructive stresses in the assembled structure.
“It’s doable,” said Lou Cerny of MTH Industries, who managed the installation at the Sears Tower, where the tolerances were one-sixteenth of an inch. “There’s just not a lot of people who want to get involved in it.”
No wonder, then, that those who build with glass look forward to a day when their structures will be unencumbered by metal or other materials.
“My goal has always been to reduce the amount of fittings in glass,” said Mr. O’Callaghan, whose Apple staircases use stainless steel and, occasionally, titanium to join the glass components.
Already, some engineers are using different glass shapes to reduce the dependence on metal. Rob Nijsse, a professor at the Delft University of Technology in the Netherlands and a structural engineer with the firm ABT Belgium, has used large sheets of corrugated glass, mounted vertically, for window walls in a concert hall in Porto, Portugal, and a museum being built in Antwerp, Belgium. The shape helps stiffen the glass against wind loads.
Other designers think about using different kinds of glass. “There are so many amazing types of glass available,” Mr. Carpenter said. “There’s an enormous potential to transfer some of their characteristics into architectural uses.”
Using a glass that does not expand much when heated, for example, would enable components to be welded together, forming, in effect, a continuous piece of glass. Conventional soda-lime glass expands too much, so welding introduces stresses that can lead to failure.
Researchers at Delft have experimented with welding glass components. But low-expansion glass is much costlier than soda-lime glass.
Other engineers are starting to use adhesives to join glass directly to glass. Lucio Blandini, an engineer with Werner Sobek Engineering and Design in Stuttgart, Germany, used adhesives to create a thin glass dome, 28 feet across, for his doctoral thesis in a clearing in Stuttgart. “I think adhesives are the most promising connection device,” Dr. Blandini said. “It allows glass to keep its aesthetic qualities.” His firm is using adhesives in parts of structures being built at the University of Chicago and in Dubai.
But the long-term strength and reliability of adhesives has not been proved, so most people who work in glass think an all-glued structure is a long way off.
“We have way too many lawyers in this country,” said Mr. Cerny, the installer at the Sears Tower. “It’ll be awhile before we see that.”
How Termites Inspired Mick Pearce's Green Buildings
When I mention the words “high-rise office building” what do you think of? Probably an enclosed glass and steel box, stripped of detail, perfect in its photogenic, modernist simplicity.
This is a classic example of surfing for free on a gradient, discussed in my last two essays, and the termites' lesson was not lost on Mr. Pearce. When the developers of the Eastgate office building asked him to design a structure with a passive climate control system in 1996, he employed some of these principles. The complex is actually two buildings that shelter an interior atrium (right). Heat gain is reduced by limited glazing, deep overhangs, and building mass, and the architect took advantage of night cooling, thermal storage and convective air currents to moderate temperatures.
The owner of the building, the Melbourne City Council, estimates that CH2 achieves an 80 percent reduction in typical energy use and a 70 percent reduction in water use.
The remaining water is piped into basement storage where it is cooled through a phase change apparatus and distributed when needed. The phase change apparatus is made up of 10,000 stainless steel spheres containing salts with a high freezing point (15 degrees C) which are frozen at night and then used to chill the water for distribution during the day, much like ice cubes chill your drink as they melt. This newly cooled water is pumped from the basement to chilled beams at every level of the building. These beams are arrayed copper pipes that drop cool air down later in the day when the effects of the night purge have worn off.
Perhaps, like me, you also imagine its occupants: hunched at their desks, panting for fresh air and light, mesmerized by the hum of overhead fluorescent fixtures gone buggy. In fact, our cultural understanding of “high-rise” seems to include its occupants being divorced from their natural surroundings, sequestered in a technologically advanced, artificial environment.
A lot of us have been wondering just how advanced our current model really is.
Mick Pearce is an African architect who has tried to change that model, demonstrating his ideas in two signature buildings, the Eastgate Building in Harare, Zimbabwe, and the Council House 2 Building in Melbourne, Australia. Both buildings employ common-sense passive systems for climate control based on gradients, and both were inspired by the work of a tiny insect, the termite.
The termite is one of nature's more accomplished builders, erecting the tallest structures on our planet (when measured against the size of the builder), and maintaining a constant temperature inside despite wide temperature swings outside.
The mounds that they build are extremely durable structures of mud, often employing sophisticated buttressing and, in the case of so-called compass mounds, a precise shape and siting that optimize the effects of the sun.
The compass mounds of Australia are shaped like large blades, narrow at the top and gently curved to a narrow boat-shaped footprint. They get their name from their consistent north-south orientation, and it is this orientation and shape that allow them to optimize their environment. When the sun angle is low and temperatures are chilly the mound receives the maximum exposure to its flanks and gains heat needed to warm the nest. When the sun is overhead, in the heat of the day, the narrow blade edge receives very little sunlight and unwanted heat gain. Shape saves energy, again, in the natural world.
What impressed Mr. Pearce about the local African mounds was the climate control. Despite a daily fluctuation from 40 degrees C to less than 0 degrees C, the termites are able to maintain a constant inside temperature of 30 degrees C.
Within thick, insulating walls they accomplish this by creating and constantly maintaining a draft of air from low openings to top holes. They make use of the so-called stack effect, convective airflow from cool to warm. The termites are constantly tweaking these openings for optimum performance, sometimes adding wet mud that aids cooling with its evaporative effects.
During the day the heavy building mass and rock storage in the basement absorb the heat of the environment and human activity. At night, cool air is allowed into the bottom of the building and starts the convective flow that vents the hot daytime air through roof vents. This cool air is also stored and then distributed the next day into offices via hollow floors and baseboard vents.
These passive techniques, although not able to supply all of the climate control for the building, contributed to some impressive building conservation statistics. The approximately 32,000 square meter building was built with 10 percent of the typical ventilation costs for the area, 35 percent less energy costs, and 10 percent fewer typical capital costs, translating to a savings of $3.5 million for a $36 million building.
Ten years later, Mr. Pearce had perfected some of the principles tried at Eastgate, this time in a more contained, 10 story, 12,500 square meter building in Melbourne, Council House 2 (CH2). The use of gradients is also key to this design.
Like Eastgate, CH2 is cooled by a timely management of the difference in temperature between night air and day air. In this case, a whole side of the building is opened up to direct air intake through automatic shutters made from recycled wood (left).
This “night purge” vents the warmer air directly from the office and shop spaces and cools down the overhead mass of concrete. The warm air rises up to openings in the ceiling and then travels through hollow floors to a vertical shaft and eventually to roof vents. This passive treatment alone is enough to keep the spaces comfortable for a part of the day. Cooled fresh air rises up through floor registers throughout the day.
CH2 also uses another temperature gradient of a fluid, water, to condition the air in the building. First, water is “mined” from the sewage supply of the city, triple filtered and then put to work flushing toilets, watering plants and conditioning the air. The AC water is run down the outside of the structure through five 15-meter “shower towers” (below) which create evaporatively cooled air for induction into the lower commercial spaces.
This building also uses thermal mass to absorb heat, reduces heat gain by a strategic placement of glazing, and produces power and heat by photovoltaic and thermal solar panels and a gas-fired cogeneration plant. It also hosts an equivalent amount of plant leaf surface to the site (to replace what theoretically was lost by development of the land), which oxygenates the air indoors and out. The building receives a fresh air change every half hour, and the owner claims a 10.9 percent improvement in worker productivity as the biggest payback from the $11 million (Australian) ventilation system. This increased productivity is calculated to be worth over $2 million (Australian) a year in staff time and means that the investment will likely pay for itself in 5-6 years. What a difference a difference makes!
While one architect's successful use of gradients inspired by nature is the main theme to this essay I believe there are more building lessons to be learned from the termites. These fascinating creatures don't build these mounds alone, or use any forethought, and they certainly don't understand the methods they are using. They take humble materials, however, and build 25-foot high structures that require a stick of dynamite to remove. Moreover, they maintain precise living conditions for millions of inhabitants in a complex and ordered society. They do this with brains the size of a pinhead. This is the power of the super organism, of which I will write next time.
Tom McKeag teaches bio-inspired design at the California College of the Arts and University of California, Berkeley. He is the founder and president of BioDreamMachine, a nonprofit educational institute that brings bio-inspired design and science education to K12 schools.
Termite mounds - CC license by librarianidol and brewbooks; Eastgate Building - CC license by garybembridge; Council House 2 - CC license by avlxyz and avlxyz