Energy Absorption and Conversion, Vibration Isolation, Dampening, Oscillation, Advanced Building Technologies, Building Codes and Code Enforcement

Posted by PITHOCRATES - March 7th, 2012

Technology 101

Springs and Shock Absorbers on a Car provides Vibration Isolation from the Shocks of the Road

Roads aren’t perfect.  They have their bumps.  And their potholes.  Especially in the north.  Where they use salt to melt snow and ice.  Which get to the reinforcing steel within the concrete.  Causing it to corrode.  Further stressing and cracking the concrete.  Allowing water to get underneath the concrete.  Where it expands as it freezes, heaving and cracking the road.  Then there’s the normal heating and cooling.  That can buckle and crack blacktop.  Heavy truck traffic that stresses and hammers our roads.  Even sinking slightly into our asphalt roads making tire ruts.  And then there are railroad crossings.  Sewers and manholes that aren’t flush with the surface.  There’s a lot out there to make for a rough ride.  Yet in a new car you barely feel any of this.  And you can drink a cup of coffee while driving without it splashing out of the cup.  Why?

Because the shocks from the rode are isolated from the passenger compartment.  Air-inflated rubber tires smooth out much of that rough ride.  By compressing to absorb some bumps.  Then expanding back to their original shape.  Springs handle the larger bumps.  Which compress underneath the car as the tires hit a large bump.  Absorbing the energy from that impact before it reaches the passenger compartment.  By using it to compress a spring.  Then the energy in that compressed spring releases and the spring expands until it can expand no longer.  Placing the stretched spring into tension.  The stored energy in the tensioned spring compresses it again.  And this continues back and forth until the energy fully dissipates.  Or is absorbed in a shock absorber.  That dampens the oscillation of the spring.  Bringing it back to a steady-state quickly.  Further smoothing out the ride.

A car is a magnificent piece of engineering.  From converting a fuel into motive power.  To brakes slowing a car down by converting kinetic energy into heat via the friction of brake pads or shoes on rotors or drums.  To the isolation and dampening of the road forces imparted to the car.  It’s a remarkable control and conversion of energy.  That provides for a comfortable ride.  And a smooth ride.  Smooth enough to enjoy a cup of coffee while driving.  Without being too distracted from the business of driving.

Tuned Mass Dampers prevent Dangerous Oscillations in Buildings that can lead to Structural Failures

But a car moving over a road is not the only way energy transfers between the earth and something manmade.  Sometimes the earth moves.  And energy is transferred into something stationary.  Manmade structures like buildings and bridges.  During earthquakes.  And some of these stationary things get damaged.  Some even collapse.  Depending on how we constructed them.  And how similar they are to a car.

Tectonic plates are trying to move.  But the friction between these plates as they jam into each other holds them in place.  Until the pressure builds so much that the plates shift.  Causing an earthquake.  Sending seismic waves through the earth.  In active seismic regions structures need to be like cars.  They need isolation and dampening from the shockwaves caused by shifting tectonic plates.  For during a seismic event these shockwaves ‘grab’ these structures by their foundations and shake them.  This energy applying great forces on these buildings.  Energy that needs to go somewhere.  Because of the conservation of energy principle.  We can’t create it.  Nor we can destroy it.  At best we can redirect it.  Absorb it.  Or convert it.  Like converting the forward movement of a car (kinetic energy) into heat (created during braking).  Or the conversion of kinetic and potential energy of moving springs into heat (via shock absorbers). 

Waves have an amplitude and a frequency.  They oscillate.  That is, they vibrate.  And have energy.  Which is why we build buildings and bridges to move.  To bend and sway.  To dissipate this energy.  For if they were too rigid the forces could instead lead to a structural failure.  However, if they move too much and the external force is in ‘resonance’ with the building’s natural frequency of movement, this oscillation can grow.  Producing great vibrations.  (Like a car driving without any shock absorbers.)  And great forces on the structural integrity of the building.  Itself leading to a structural failure.  That’s why high rises include dampening systems.  Such as tuned mass dampers.  A great mass suspended within a building and restrained by hydraulic cylinders.  Such as the tuned mass damper atop Taipei 101 in Taiwan.  So when the building sways in one direction the mass swings in the opposite direction.  Thus dampening the oscillation of the building.

Free Market Capitalism allows a Higher Standard of Living and Creates the Kind of Wealth that can build Safe Houses and Buildings

Smaller buildings may use springs-with-damper base isolators.  Which does the same thing springs and shocks do for a car.  Isolates the structure from vibrations.  But using the proper building materials to allow a building to move or withstand destructive forces without structural failure provides most seismic protection.  And this is nothing new.  The Machu Picchu Temple of the Sun in Peru is an early example of good seismic engineering.  Peru sits on the Ring of Fire.  A highly seismic region that circles the Pacific Ocean.  The Inca were highly skilled stone cutters.  They built the Machu Picchu Temple of the Sun without mortar.  Because of this the stone can move during seismic events.  Which has let it stand through the millennia.  Today we use mortar.  And reinforcing steel to strengthen our masonry construction (these blocks can’t move but when the walls they make crack the steel inside keeps them from collapsing).  As well as other advanced building technologies.  And ever evolving building codes and code enforcement to make sure builders meet the exacting standards of these technologies.  To keep these buildings from collapsing and killing hundreds of thousands of people.  Which is why in the most modern and advanced cities in seismic regions survive some of the worst seismic events with minimal loss of life.  Where they count deaths in the hundreds instead of the hundreds of thousands.  As they did before we used these advanced building technologies.

The countries and regions sitting on the Ring of Fire (New Zealand, Indonesia, the Philippines, Japan, Alaska, California, Mexico, Peru and Chile) use some of the most advanced building technologies.  And can withstand some of the most severe earthquakes.  With little loss of life.  Now compare that to the impoverished country of Haiti.  Their 2010 earthquake was devastating, claiming 230,000 lives.  Because they have no such building codes or code enforcement.  Or advanced building technology.  Because Haiti is not a nation of free market capitalism.  Or the rule of law.  But one of political corruption.  And abject poverty.  Are they predisposed to be impoverished?  No.  Because countries can change.  If they embrace free market capitalism.  And the rule of law.

Chile was one such country at one time.  Corrupt.  And anti-capitalistic.  During the heyday of Keynesian economics.  Where nations said goodbye to the gold standard.  And ramped up their printing presses.  Igniting hyperinflation.  Including the Chileans.  But they changed.  Thanks to the Chicago Boys.  Chilean economists schooled in the Chicago school of economics.  With a little help from Milton Friedman.  Perhaps the most esteemed member of the Chicago school. Economic reforms produced solid economic growth.  A prosperous middle class.  And advanced building technologies, building codes and code enforcement.  So when Chile suffered a more powerful earthquake than Haiti did that same year Chile measured their death toll in the hundreds.  Not the hundreds of thousands as they did in Haiti.  And the major difference between these two nations?  Chile has a higher standard of living than Haiti.  And has less poverty.  Because Chile embraces free market capitalism.  Which creates the kind of wealth that can build safe houses.  And safe buildings.  For everyone.  Not just the ruling elite.


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Japan’s Nuke Plants/Coastal Communities withstood the Earthquake but not the Tsunami

Posted by PITHOCRATES - March 12th, 2011

The Awesome Power of Water

Japan’s most powerful earthquake caused a lot of damage.  But the tsunami’s damage may be even greater.

In 1923 the 8.3 magnitude Kanto quake killed 140,000 people.  In 1995 the 7.2 magnitude Kobe quake killed 6,400 people.  The 8.9 magnitude that just hit may have even killed fewer people.  The official count just recently exceeded 1,000.  But we’ll never know.  Japan’s buildings may have withstood this quake.  But the tsunami that followed made coastal communities just disappear. 

In Minamisanriku some 10,000 are missing.  That’s more than half of its population.  And that’s just one coastal community.  Others no doubt suffered the same fate.  The water just came in so fast (see The town that drowned: Fresh pictures from the port where 10,000 people are missing after it was swept away by the megaquake by Jo MacFarlane posted 3/12/2011 on the UK’s Daily Mail).

It only took a few minutes for the 30ft wave to wash the town away with terrifying force. The locals desperately tried to escape to higher ground. But most did not stand a chance.

During an earthquake you can stand in a doorway.  If the building survives you’ll probably be okay.  But there’s not much you can do when a 30 foot wave races toward you.  Other than run away.  To high ground.  Because a 30 foot wave is about as tall as a 3 story building. That’s a lot of water.  And nothing will stop it.

Never let a Good Crisis go to Waste

First it was an environmentalist looking to exploit the Japanese earthquake in the name of global warming.  Now an American congressman wants to exploit the earthquake to hinder the growth of nuclear power (see Japan quake disaster shows U.S. at risk of Chernobyl-type event by Alexander Bolton posted 3/12/2011 on The Hill).

Rep. Edward Markey of Massachusetts, the senior Democrat on the House Natural Resources Committee, warned Saturday that the U.S. is vulnerable to the type of nuclear accident that has sent waves of fear through northeast Japan…

Markey said he hoped the Japanese would act swiftly to bring the situation under control and avoid a Chernobyl-style disaster.

I’m glad he made this statement.  Because I don’t know if the Japanese knew the full extent of what they were facing.  I mean, they’re only up to their elbows in it.  How could they see things as clearly as a politician in Washington?  I’m sure the Japanese ambassador will bestow him with gifts, grateful for this erudite observation.

Chernobyl-style disaster?  I doubt it.  He’s comparing apples to oranges.  Different reactor design (the Chernobyl reactor was a unique Soviet-era design considered to be the most dangerous reactor type in the world).  Different technology.  Different safety precautions.  And, due to its physical size, no containment vessel.  Nothing at all like the Japanese reactors.  Or the American ones.

Japan’s reactors did okay during the earthquake.  Their problems didn’t really start until coastal areas disappeared in the wake of the tsunami.  Yeah, it’s possible that the US Pacific coast could suffer a similar seismic event.  It does sit on the Ring of Fire.  But earthquake-tsunami one-two punches are more probable in Japan than they are on the US Pacific coast.  What happen in Japan could happen in the US.  Just as a meteorite could crash into a nuclear reactor.  Anything is possible.  But the odds favor certain events in certain places. 

Here’s a newsflash.  Life is dangerous.  Driving in a small, fuel-efficient car is dangerous.  Your odds are greater dying in one of those cars than in a nuclear accident.  But we’re not going to stop building small cars, are we?  And neither should we use what’s happening in Japan to further hinder an already hindered industry.

Is it Chernobyl bad or Three Mile Island Bad?

So what is the danger with those nuclear reactors in Japan?  A lot of people are opining.  And they’re not saying the same thing.  So who do we believe?  Depends on which experts you trust more (see Health risk from Japan reactor seems quite low: WHO posted 3/12/2011 on CNBC).

The World Health Organization (WHO) said Saturday that the public health risk from Japan’s radiation leak appeared to be “quite low” but the WHO network of medical experts was ready to assist if requested.

So CNBC has a source that says it may not be that bad.  While The New York Times has a source that says things are bad and can get worse (see Danger Posed by Radioactivity in Japan Hard to Assess by William Broad posted 3/12/2011 on The New York Times).

“The situation is pretty bad,” said Frank N. von Hippel, a nuclear physicist who advised the Clinton White House and now teaches international affairs at Princeton. “But it could get a lot worse.”

Even Japanese officials appear to be contradicting each other (see Japanese Government Confirms Meltdown posted 3/12/2011 on Stratfor).

Japan’s Nuclear and Industrial Safety Agency (NISA) said March 12 that the explosion at the Fukushima Daiichi No. 1 nuclear plant could only have been caused by a meltdown of the reactor core, Japanese daily Nikkei reported. This statement seemed somewhat at odds with Japanese Chief Cabinet Secretary Yukio Edano’s comments earlier March 12, in which he said “the walls of the building containing the reactor were destroyed, meaning that the metal container encasing the reactor did not explode.”

How about hearing from a guy that isn’t there but went through his own nuclear reactor crisis.  In Pennsylvania (see Three Mile Island Meltdown: Richard Thornburgh’s Advice for Japan by Eleanor Clift posted 3/12/2011 on The Daily Beast).

Richard Thornburgh is watching the developments in Japan with a keen sense of déjà vu. He had been in office as Pennsylvania governor only 72 days when he was confronted with a potentially catastrophic event at the Three Mile Island nuclear reactor near Harrisburg. It was resolved without cost to human life, or the environment, which by no means is certain in Japan.

Though what occurred in Japan is the result of a natural disaster, the Republican says, the challenge officials face is identical: “To get a grip on what the facts are.”  That’s difficult when you’re dealing with complicated technology and an abundance of experts, often with their own agendas…

Thornburgh’s advice to his counterparts in Japan is to “just keep plowing ahead on getting a grip on the facts. Make sure the right experts are in place. The quality of the facts is going to determine the quality of the outcome…”

Watching the television coverage of Japan disaster and the ominous news of an explosion at one of its nuclear power plants, he cautions that “there’s nothing inherently unsafe about an explosion—it depends what exploded.” The Japanese have paid careful attention to safety and standards, unlike the Russians, who confronted a similar catastrophe with their reactor at Chernobyl in 1986. When he visited Chernobyl years earlier, Thornburgh recalls, it didn’t even have a containment facility.

So what exactly did explode (see Nuclear power industry watches warily as Japan’s aging reactor is hit hard by Joel Achenbach posted 3/12/2011 on The Washington Post)?

The explosion was not nuclear. Industry officials said it was created by the release of hydrogen gas that mixed with oxygen and exploded.

The building around the reactor vessel is partially destroyed, but Japanese officials say the primary vessel and the reactor core within are intact.

“If the reactor vessel is breached . . . then this radioactive stuff starts coming out in copious amounts,” said Robert Alvarez, a former senior adviser to the Department of Energy who studies nuclear power at the Institute for Policy Studies in Washington.

Well, perhaps we know this much.  A non-nuclear explosion occurred.  There is no real radioactive fallout.  And we can compare and contrast what we know now about what we knew then. 

As at Fukushima, the Three Mile Island accident was triggered by a disruption of water flow to the reactor. Several instruments failed and operators did not realize that pressure was building inside the reactor. A heavy secondary containment shield ultimately prevented all but a tiny amount of radiation from escaping into the environment.

The Chernobyl disaster, in contrast, was caused by a crude reactor design and at least six fatally flawed decisions by operators during a risky test. A huge power spike and the bad decisions drove the reactor out of control. An explosion then blew the reactor apart and spewed radioactive debris for a week.

Unlike U.S. and Japanese nuclear plants, Chernobyl lacked the heavy shielding that eventually halted the Three Mile Island disaster – and that all of Japan desperately hopes will prevent Fukushima Daiichi’s unit one from melting down.

Yes, there’s uncertainty.  But it appears that what’s happening in Japan is less Chernobyl.  And more Three Mile Island.  If it turns out this way this won’t be so bad after all.  And it will say a lot about Japan’s nuclear power industry.  For Three Mile Island didn’t get hit with an earthquake AND a tsunami.

Right now all eyes are on the nukes.  People are holding their breath.  Once they secure the power plants, though, it will be anticlimactic.  For the real work will then only begin.  The cleanup.  The rebuilding.  And the wakes. 

God give the Japanese strength.


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