Astrophysicist and author Ethan Siegel, writing for Forbes, just helped to expose a longtime myth about good ole’ Galloping Gertie, a bridge that (in)famously collapsed just a few short months after opening to public traffic.

To help jog your memory, here is footage uploaded to YouTube of the bridge twisting and bouncing around:

The story we learned in Physics class back in school was that Galloping Gertie’s fatal flaw was related to “resonant frequency” — the same phenomena responsible for wine glasses shattering when exposed a tone of specific frequency. Siegel proposes an alternative explanation:

But it wasn’t resonance that brought the bridge down, but rather the self-induced rocking! Without an ability to dissipate its energy, it just kept twisting back-and-forth, and as the twisting continued, it continued to take damage, just as twisting a solid object back-and-forth will weaken it, eventually leading to it breaking. It didn’t take any fancy resonance to bring the bridge down, just a lack of foresight of all the effects that would be at play, cheap construction techniques, and a failure to calculate all the relevant forces.

This wasn’t a total failure, however. The engineers who investigated its collapsed began to understand the phenomenon quickly; within 10 years, they had a new sub-field of science to call their own: bridge aerodynamics-aeroelastics. The phenomenon of flutter is now well-understood, but it has to be remembered in order to be effective. The two bridges currently spanning the Tacoma Narrows’ previous path have shorn up those flaws, but London’s Millennium Bridge and Russia’s Volgograd Bridge have both had “flutter”-related flaws exposed in the 21st century.

Don’t blame resonance for the most famous bridge-collapse of all. The true cause is much scarier, and could affect hundreds of bridges across the world if we ever forget to account for, and mitigate, the fluttering effects that brought this one down.

Read all of Siegel’s piece for the details…

Wowzers! That’s my general response to a controversy that has been brewing over the last several weeks among marketers responsible for promoting architecture, engineering and construction professional services.

It all started when Professional Services Management Journal (PSMJ) published a list-based article called, “8 Reasons You Shouldn’t Do A/E Marketing,” which started out as follows: (more…)

Disruption is a word that is overused in Silicon Valley, and elsewhere in the tech world. The idea is that sometimes a new player comes along with an approach to doing things in such a radically different way that it disrupts the entire industry.

With advancements such as building information modeling (BIM), virtual/augmented reality (VR/AR), semi-private cloud-sharing of information, drone photography, the Internet of Things (IoT), prefabrication and/or modular construction, 3D printing, robotics, artificial intelligence (AI), and so on and so forth… — the construction industry of the next couple decades will look absolutely nothing like the previous couple decades.

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Financial Times’ Matthew Klein has proposed an interesting alternative theory about the skilled labor shortage in the US that has impacted all sectors of the construction industry, but especially the residential market.

He posits that by looking at homebuilding data in Japan, the implication is that the US isn’t facing a labor shortage so much as it is dealing with sub-par productivity. Despite the fact that Japan’s population is less than 40% of US population, only 14% more homes have been built in the US since 1992.

Surely an aging society without a reservoir of cheap (and often illegal) immigrant labour would have fewer builders as a share of the labour force than a relatively youthful and foreigner-friendly country such as the US. Unsurprisingly, there has been a glut of articles over the past few years warning of “labour shortages” due to the combination of aging and falling immigration rates, with the implication that this has been restraining construction and inflating house prices.

Reality is the other way around. Despite radically different demographics and essentially no immigration, Japan has consistently employed a much larger share of its workers in the construction industry than the US, although the share has dropped over time. Even at the peak of America’s housing bubble, only about 5.5 per cent of workers were employed in construction. In Japan last year, more than 7 per cent of employees worked in construction — and that’s a lot lower than in the early 2000s…

Another way of putting all of this is that America built about the same number of housing units in 2016 as in 1992, but somehow required about 46 per cent more people to do it. Japan built 31 per cent fewer houses in 2016 than in 1992, but its construction workforce had fallen by 19 per cent. Productivity deteriorated in both countries, but productivity fell much further in America than in Japan.

Patrick Sisson, writing for Curbed, wrote a wonderful article: How air conditioning shaped modern architecture — and changed our climate. He states:

Air conditioning enabled our great modernist buildings to rise, but it’s also fueled today’s energy and environmental crisis. AC helped create a new building typology, one that environmentally conscious architects and designers are trying to move beyond with new designs and passive-cooling techniques.

“Modern buildings cannot survive unless hard-wired to a life-support machine,” says University of Cambridge professor Alan Short. “Yet this fetish for glass, steel, and air-conditioned skyscrapers continues; they are symbols of status around the world on an increasingly vast scale.”

Interestingly (at least to me), the development and implementation of air conditioning and mechanical ventilation was not primarily driven by a desire for improved occupant comfort. Instead, the focus was health:

The new class of white-collar workers who occupied these upper-level offices suffered through humid summers not just because they didn’t know any better, but because Victorian social mores didn’t place much stock in personal comfort. In fact, the adoption of mechanical ventilation systems, which were invented by Benjamin Franklin Sturtevant in the 1860s and became more common in taller buildings towards the end of the 19th century, was due in large part to the problems of heat and light—coal- and gas-powered lamps and heaters quickly filled rooms with toxic smoke—and the belief that poor health was caused by miasma, or dirty air.

Still, at the time, ventilation was less about a comforting breeze and more about sanitation—removing humid, fetid air from crowded workshops and workspaces. By the mid-1890s, designers and architects in New York needed to file their building plans with the Bureau of Light and Ventilation. The 21-story American Surety Building in New York, built in 1896, included a ventilation system, but only for the lower seven floors. Workers on these levels couldn’t open their windows due to the dirt, muck, and grime of the city streets.

I find it amazing that a little over 100 years after Carrier installed the first building air conditioning system that we have seemingly come full circle.

Inhabitat’s Kristine Lofgren reports that the order form and website for Tesla’s new solar roofing system is now live. In a previous article, Inhabitat had the following to say:

The seamless look of the new technology is thanks to “integrated front skirts and no visible mounting hardware” according to Tesla’s website. Electrek said these features come from Zep Solar, a mounting equipment company SolarCity acquired before Tesla’s acquisition. Zep Solar engineers designed the rail-less system Solar City employed to slash solar installation times in half.

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Earlier this week, I shared an article that touted all the amazing benefits to be gained from prefabricating some assemblies offsite. So how long will it be before the entire construction industry shifts to a paradigm in which building consists primarily of assembling prefabricated components?

FMI, a management consulting firm that specializes in nonresidential construction, recently conducted a survey of 200 firms on their knowledge, use and strategy for implementing Building Information Modeling (BIM) and prefabrication. ENR’s Jim Parsons shares some insight from one of the study’s authors:

Right now, it is hardly surprising that contractors’ opinions and results are mixed, Hoover says. “We’re in a messy transition of baby boomers who want to hold on to old ways and new people coming in,” she says. “The better companies are luring younger workers who can deal with technology and understand change, and they’re the ones who will make prefabrication happen.”

Indeed, Hoover says prefabrication’s growth in construction may well be inevitable as its advantages continue to overshadow current work practices. “If you’re not willing to do things that will reduce schedule by 50%, reduce risk and improve safety, you’ll be out of it,” she adds.

Ultimately, what may attract more GCs and specialty contractors to understanding, adopting and improving their prefab mind-set is the same trend that affects other aspects of the industry—labor.

In other words, the “this is the way we’ve always done it” mentality is still a major driver of key construction strategic decisions.

Upper floors in skyscrapers have incredible views, but with those views comes the occasional unnerving sensation that the building is swaying in the wind. The Ladders’ Jane Burnett writes:

In a University of Exeter statement on the study, Dr Antony Darby, Head of Civil Engineering at the University of Bath, commented on how well people tolerate movement in different situations: “Just like sea sickness, our propensity to motion induced discomfort is situation and environment dependent. For example, people at a concert in a grandstand will accept completely different level of vibration than those in a hospital operating theatre.” […]

According to the statement, “despite looking rigid in appearance, tall buildings can flex in response to external forces, and strong winds can make them vibrate or sway at low frequencies, sometimes with bursts of motion at random intervals,” adding that studies have shown that some people can detect the movement, which can at times result in “motion sickness and causing fear.”

Building sway is one thing, and having experienced it personally, it is a strange and disconcerting sensation — one does not typically expect a multi-million dollar luxury residence to shift with the wind, unless one is at sea and said residence is in fact a boat. But I must admit I was caught a little off guard when the article veered off in the direction of “sick building syndrome” — a phenomenon more typically linked to indoor air quality and HVAC system performance:

A 2008 article by the Air & Waste Management Association called “Linking Noise and Vibration to Sick Building Syndrome in Office Buildings” said that “in recent years, several studies have linked excessive noise and vibration in the office to illnesses, such as headaches, dizziness, irritability, and stress. This is similar to the more well-known indoor air quality triggers associated with sick building syndrome…”

As I tell my kids, “you learn something new every day, if you allow for the opportunity…”