The Hong Kong Apartment Complex Fire

 

In the afternoon of Wednesday, November 26, it was windy in the part of Hong Kong where eight 31-story apartment towers called Wang Fuk Court were undergoing renovations.  As has been the custom for hundreds of years, exterior scaffolding made of bamboo was erected around the towers.  To prevent damage to the single-pane windows of the complex, workers had covered the windows with foam-plastic sheets.  Nylon safety nets surrounded the scaffolding.  What could go wrong?

 

The world found out when an unknown cause started a fire in the lower level of one of the scaffolds.  The flames quickly spread from high winds to the flammable plastic sheets over the windows.  Burning debris and flames spread from tower to tower until seven of the eight towers were engulfed.  About 40% of the residents were over 65, and the fire alarms in many of the buildings were later found to be out of order.

 

For the next day or so, the fire defeated efforts of thousands of firefighters to control it.  As of this writing, the confirmed death toll stands at 146, with dozens more missing.  About 4,600 people lived in the complex, so many got out alive.  But many others, probably including most of those who needed mobility assistance to escape, didn't make it.

 

News reports are calling this tragedy a "man-made disaster," and I couldn't agree more.  Authorities have arrested several officials of the construction company in charge of the renovations, Prestige Construction and Engineering Company, and have halted the firm's work on all other projects in order to conduct safety inspections. 

 

Whoever made the choice of protective window panels may have chosen low cost over safety.  In any event, that choice directly contributed to the fire perhaps more than anything else, although final conclusions will have to await a thorough investigation.  The use of nylon for safety netting and bamboo for scaffolding are also questionable, although China has a centuries-old tradition of bamboo scaffolding that has only recently come into question as metal scaffolding gradually supplants it.  Photos of the scene after the disaster seem to indicate that the scaffolding largely stayed in place, but was charred to the point of being structurally unsound.

 

As soon as I learned of this fire, I thought of the 2017 Grenfell Tower fire in London.  In that disaster, a refrigerator caught fire in a lower apartment and the flames spread to flammable exterior insulating sheathing that had been installed in an upgrade some years before.  The fire propagated behind the sheathing and was difficult to extinguish, and before it was all over, 72 people died and many more were injured.  Again, negligent planning and a failure to take account of the flammability of exterior sheathing was at fault, just as it appears to be in the Wang Fuk Court fire.

 

Engineering ethics requires imagination of a particularly informed type:  imagination bolstered by in-depth technical knowledge.  Engineers sometimes have a reputation for being dour pessimists who always jump to the worst-case scenario of a given situation.  But in the case of the Hong Kong fire, engineers were not pessimistic enough.  Nobody apparently imagined what would happen if one of the plastic window-sheathing panels caught fire, especially if it was on a lower floor of a building that happened to be upwind of most of the others on a blustery day. 

 

It's possible that workers were instructed not to smoke or to engage in operations that might lead to a fire.  That's all very well, but not everybody follows instructions. And even the best-intentioned workers can be using equipment that shorts out or otherwise becomes a source of ignition.  Good safety practitioners imagine that something statistically unlikely will nevertheless go wrong, and then draw conclusions from that premise. 

 

Judging from the number of residents listed and the casualty list, it's possible that about 5% of the listed residents died in the fire.  That means that 95% escaped either with no injuries or non-life-threatening ones, while however losing most of their worldly possessions.  No one I know would like to go through an unplanned experience that will strip you of your things and lead to a one-in-twenty chance of death.  So while fire escapes and other built-in safety features allowed most residents to escape the flames, over a hundred didn't.

 

Major renovation projects are routinely inspected by civil authorities, and I can't imagine that this project was an exception.  If a construction firm neglects to take due safety precautions, it is the civil authority's responsibility to step in and halt work if necessary in order for safety hazards to be addressed.  This obviously wasn't done. 

 

I don't know the nature of safety inspection services in Hong Kong, but among those to be held accountable should be whoever permitted the work to proceed.  Such officials can be subject to corruption pressures, and until a tragedy like this occurs, no light is shed on the fact that corners are being cut by paying off inspectors.  I have no reason to believe that this was the case here, but it is certainly an avenue worth investigating.

 

Disasters like this one can have the silver lining of making future safety regulations and inspections much more rigorous.  As the investigations proceed and the chain of causation is revealed, Hong Kong engineers, construction firms, and officials can all learn valuable lessons that are driven home by the horrible example of what can go wrong if safety measures are neglected.  My sympathy is with those who lost loved ones in the fire.  And my hope is that nobody anywhere in the world puts flammable sheathing on high-rises ever again.

 

Sources:  I referred to a BBC report at https://www.bbc.com/news/articles/cdxe9r7wjgro, a report from the news outlet livemint.com at https://www.livemint.com/news/world/hong-kong-apartment-fire-death-toll-climbs-to-146-probe-reveals-fire-code-violations-11764496767266.html, and the Wikipedia article "Grenfell Tower fire.

The JetSet Roof Collapse: Causes Yet Unknown

 

Many prominent people were in the exclusive but crowded venue of the JetSet nightclub on Avenue Independencia in the Dominican Republic's capital city of Santo Domingo late Monday night, April 7.  These included a provincial governor named Nelsy Cruz, ex-Major-League baseball players Octavio Dotel and Tony Blanco, and famed merengue musician Rubby Pérez, whose singing was the main attraction.  An estimated five hundred people were jammed into the building, which occupied a corner block behind some trees and a canopied entryway.

 

Around a quarter to one A. M., someone pointed to the ceiling, saying that they had seen something fall.  Seconds later, a video showed Pérez himself on the stage as he glanced at the ceiling.  Thirty seconds after the first warning sign, the roof over the entire main room of the club collapsed, crushing people under the weight of concrete slabs. 

 

By Friday, the death toll stood at 225, with almost as many injuries.  Pérez, Dotel, Cruz, and Blanco were killed, along with 17 U. S. citizens and numerous residents of other countries.

 

Any time a crowded building collapses with loss of life, especially in the absence of natural causes such as hurricanes or tornadoes, questions are sure to arise about the cause.  While evidence to support a conclusion in which we can put confidence is lacking at this time, the little we know about the circumstances so far can guide cautious speculation.

 

According to news reports, the building was erected in the mid-1970s as a movie theater.  Theaters, coliseums, and other locations for public performances require long unobstructed sight lines, which means that the roof has to be supported only at the edges, with trusses spanning the distance from wall to wall.  Firefighters saw large blocks of concrete among the fallen rubble, and at least one remarked that he saw no "rebar" (reinforcing steel bars) in them. 

 

In the U. S., most spaces at least fifty feet (15 meters) wide or more will have primarily steel trusses supporting the roof, which may have a thin layer of concrete above them for waterproofing.  But the main supporting strength is in the steel trusses. 

 

It's possible to span such distances with a roof made primarily of concrete, but there has to be reinforcing means such as rebar or pre-tensioning cables and thicker concrete beams to support the rest of the roof.  The state of the construction industry in the Dominican Republic in 1975 is unknown to me, but it's possible that the builders of the original structure made the roof just strong enough to support itself.

 

If, as the fireman who saw the concrete slabs speculated, extra weight was added to the roof over the years, such as air-conditioning units or even solar panels, the weight might exceed the carrying capacity of the roof. 

 

Concrete is not like steel, which is homogeneous enough to fail almost as soon as it's overloaded.  Depending on how the concrete was mixed, a piece of concrete that is fundamentally overstressed may hang together for a relatively long time as cracks slowly propagate and stresses reorder themselves to go through the remaining connected pieces of the mix.  Concrete is more likely to fail with a crumble than a bang, although when the most stressed part fails, it usually takes the rest with it pretty fast.

 

This catastrophe recalls the collapse of the Surfside Condominium in a Miami suburb in June of 2021.  Repeated inspections of that structure pointed out serious deterioration in some supporting columns, exacerbated by recent building modifications.  Renovations had been scheduled before the collapse, but the building fell down, taking 98 people to their deaths with it, before they could be done.

 

It is not known at this point (at least by me) whether Santo Domingo required regular building inspections of places where people gather in large crowds.  Even if such inspections were required, it is not easy to inspect a concrete slab underneath layers of roofing material, although there are ways of doing so.  And even if inspections were required, they might not have been done on schedule.  And if they had been done, adverse findings might have been ignored.  The owners of the nightclub are reportedly one of the wealthiest families in the Dominican Republic, so they presumably could have afforded repairs if they were needed.  Now they're going to find out if they can afford the legal nightmares of liability for the two-hundred-plus deaths the collapse of the building caused.

 

If anything good can come out of this tragedy, it may take the form of improvements in building codes and inspections.  Every industrialized nation has followed a long road from basically free-for-all construction methods to increasingly strict regulation of building codes, materials used in construction, design methods, and inspections before, during, and after a building is erected.  While there is an argument to be made that we have now passed the point of diminishing returns in parts of the U. S. and building codes now serve to restrict the housing market more than improve safety, there is a lot more room on the other end of the road where inadequate codes and inspections allow conditions to happen such as the circumstances that led to the JetSet tragedy last week. 

 

Perhaps this horrible accident will stimulate a conversation in the Dominican Republic about building codes, inspections, and where on the tradeoff curves the country wants to reside.  There is always the possibility that some extremely rare and unlikely cause will be found—sabotage, perhaps, or a freakish set of circumstances that can't be predicted.  But currently, the little we know indicates that carelessness and perhaps incremental loading of the roof without an engineer's inspection and approval may be the cause.  If that's the case, then there is something the citizens of the Dominican Republic can do about it:  demand safer buildings, and whatever regulation and enforcement is required to get them.

 

Sources:  I referred to a CNN article at https://www.cnn.com/2025/04/10/americas/what-happened-dominican-republic-collapse-latam-intl/index.html and the Wikipedia article "JetSet nightclub roof collapse." 

 

P. S.  A month or so ago, editor Michael Cook of the website mercatornet.com notified me that his website would soon cease operations.  For over a dozen years, Michael did me the compliment of reprinting many of my blogs, always with my permission, and often with the result that they reached a much wider readership than they otherwise would have.  Originally one of the few conservative family-values-oriented news outlets in Australia, Michael's site recently experienced increased pressure from competition from similar sites and a lack of readership numbers that finally made it uneconomical to continue.  I wish Michael the best in his future endeavors and remind him that all the good things his website did have still been done, and will have unimaginable effects in the future—mostly good ones, I expect.---KDS

Paternoster Lifts and Safety Regulations

Last week my wife and I took a short trip to New Orleans to see the National World War II Museum.  While that institution is full of old technology, I'd like instead to remark on a venerable device I saw not at the museum, but in the parking garage used by the hotel we stayed at downtown. 

 

Folks in "NO" have a different attitude toward old technology than you might find in a forward-looking place like Austin.  For example, on a walk we took on the way to supper one evening, we passed a fenced parking lot.  Just sitting on a grassy area inside the fence were two antique mechanical artifacts, probably left there because they were too heavy to move when the building they were in was torn down.  One was a drum winch and electric motor for an elevator, and the other was a rusty two-cylinder York refrigeration compressor, about four feet high.  In Austin these things would have been hauled away for scrap value decades ago, but somebody decided just to leave them there, maybe for other NO residents to puzzle out what they were.

 

Maybe something of this same attitude has kept the Paternoster elevator going in the parking garage we used.  A Paternoster elevator uses a string of elevator cars suspended from an endless belt which never stops moving.  The elevator compartments just move slowly up or down past each landing, and to use it, you simply step on as one is passing your floor and step off again when you get where you're going.  If you miss your floor, I suppose you can just ride over the top and down again in some types, but then again, maybe not.

 

Paternoster elevators were popular in the early years of the 20th century, especially in Europe where space and funding for new construction was hard to come by, but safety concerns have led to many of them being replaced by conventional elevators in many countries.  That isn't the case for the one I saw, however.

 

This one was more technically called a "belt manlift."  A rubber-coated belt about eighteen inches (0.4 meters) wide traveled around a rotating drum or pulley fastened to the ground floor.  Every six or seven feet (~2 m) there was a steel handhold and a triangular footstand jutting out from the belt.  To use the device to go up, you grabbed a handhold as it was rising past you, stepped onto the footstand, and hung on till it lifted you to your floor.  Then you jumped off.  There were footstands facing the other way for going down.

 

I say "you" colloquially, although the device was behind a locked chain-link cage and intended only for the use of valets who were parking cars.  I don't think it was ever intended for use by ordinary untrained drivers, but the garage was so old, it may have been at one time.  On our last day there, I had the privilege of seeing a young black man in the act of arriving on the ground floor on the manlift.  Once he got off safely and emerged from the cage, I asked him, "You ever have trouble with that elevator?"

 

He paused for a second and said, "Sometimes.  Quite an antique!" 

 

While there are conical plastic guard rings around each hole that the belt goes through from floor to floor, you can easily imagine what could go wrong with either the elevator-car Paternoster or the belt manlift.  When I finally found out after an Internet search what the thing was called, I wondered if it got its name because every time you used it you said a prayer ("Pater noster . . . ").  (Actually, it's from the device's vague resemblance to rosary beads.) 

 

The Wikipedia article on Paternosters says that many countries have banned them altogether because of accidents, some fatal, which typically happen either to children or elderly people.  The valets who use the one I saw are not in these categories. 

 

The way safety customs and regulations change with time is a reflection of larger trends that happen so slowly they are hard to notice.  But these changes go on at different rates in different countries, and even in different parts of the same country, as I've mentioned.  Without doing any research, I'm pretty sure there are no Paternoster elevators or belt manlifts in any Austin parking garages.  The safety inspectors wouldn't put up with it.

 

But why do you find one in New Orleans?  There is no way to be sure, but it may be part of the same attitude toward the past that leaves old refrigeration compressors sitting in parking lots.  Or it may be that the kinds of people who use the belt manlift are not in a position to complain that it's dangerous.  There was that little pause the valet made before he answered my question.  He was probably figuring out that this old guy holding a camera was a tourist, and whatever he said wouldn't get back to anybody important, so it was okay to be frank with him. 

 

At any given time, a culture has a finite amount of resources to expend on new construction and on fixing up old construction.  If that parking garage was about to collapse in an obvious way, I expect the city authorities would have shut it down, or at least insisted on repairs.  But the fact that it has an old and somewhat dangerous belt manlift for the convenience of the valets hasn't seemed to exercise the powers that be to the extent of having it shut down and making the valets take the stairs like I did.  After all, it's behind a cage, there's a big sign explaining that nobody can use it without training, there's a pair of ropes next to the belt you can yank on to stop the motor, and the valets seem to want the convenience enough to put up with the hazards. 

 

But some time or other, the parking garage will get torn down, and the belt manlift will go with it, unless the future owner decides to keep the big pulley on display as a mute memorial to outdated technology that one era thought was safe enough, and the next thought was too dangerous to use.

 

Sources:  I referred to the Wikipedia articles "Paternoster lift" and "Belt manlift."  The parking garage in question is near the corner of Gravier Street and Camp Street in downtown New Orleans. 

The Moroccan Earthquake and Building Codes

Last Friday, at 11:11 PM local time, the city of Marrakech in Morocco was hit by a 6.8-magnitude earthquake.  Within a day, the fatality count exceeded 2,000 and continues to rise as this is written (Sunday morning).  Photos from Marrakech and surrounding cities near the Atlas Mountains show cracked and toppled towers and piles of rubble, especially in small villages where enforcement of building codes is lax. 

 

According to an Associated Press report of the disaster, Morocco lies on the intersection of the African and Eurasian tectonic plates.  Earthquakes tend to cluster where plates collide, but compared to some plate-intersection regions, strong earthquakes in northwest Africa are relatively rare.  When they occur, though, they tend to cause massive destruction.  In 1960, a Moroccan earthquake of magnitude 5.8 caused thousands of deaths as well.   

 

As earthquakes go, a magnitude 5.8 event is not the worst possible.  The world's record quake in terms of magnitude was a 9.5-magnitude event along a long fault in Chile in 1960.  Bearing in mind that quake magnitudes are logarithmic—a 6.0-magnitude quake has ten times the amplitude of movement of a 5.0-magnitude one—a magnitude-5.8 quake in the U. S. might not even cause any fatalities, depending on how densely populated the region was and the nature of the buildings involved.  For example, in 1973 the 5.8-magnitude Point Mugu earthquake in Ventura County, California caused several injuries and over $1 million in damage, but no one died as a result.

 

Just quoting the magnitude of an earthquake doesn't tell you everything about how it will affect a given building.  For that, you need something called the modified Mercatili intensity scale.  This scale runs from I (not felt) to XII (third stage of extreme), and why Mercatili chose to use Roman numerals is not known (unless he felt a patriotic need as an Italian to use Roman numerals).  For a given magnitude of quake, there is a maximum Mercatili number it can cause on the surface, because obviously the farther away you are from the epicenter, the less shaking you will experience.  According to Wikipedia, a magnitude-6.8 quake can cause a Mercatili shaking of up to IX (nine, for those unfamiliar with Roman numerals).  This can cause damage even in wood-frame structures, which are much more tolerant of earthquakes than unreinforced masonry and rock buildings.  But typically, such a quake causes only shaking to Mercatili number VII (seven), which according to geophysicist Kelly Martin can be withstood by most small U. S. residential buildings, although with some minor damage but no fatalities.

 

And that is one of the key reasons why Morocco suffered so much damage in last week's magnitude-6.8 quake.  By its nature, masonry not reinforced with steel reinforcement bars ("rebar"), which is a very traditional form of building, is poorly adapted to resist earthquakes.  If the wall or building is basically one heavy block put on top of another with only gravity to hold them down, the tensile stress that occurs when the bottom layer of masonry moves under the huge inertia of the masonry above makes the joints between the blocks fail.  It's not much different than piling up a pile of children's blocks on a towel, and then pulling the towel.  It doesn't take much of a pull to make the whole pile come apart and fall down.

 

That being the case, why don't countries like Morocco enforce building codes so that most structures can withstand a Mercatili shaking of VII or more?  The authorities in Morocco are in the best position to answer that question, but I can speculate.

 

One factor is money, or more specifically, per-capita GDP.  Making a masonry building resistant to earthquakes is not a simple undertaking.  It requires expertise, skilled craftsmen who know how to translate the engineering requirements into reality, and money to pay for extra things like braces, rebar, and other features that will not add anything to the perceived value of the structure unless and until an earthquake occurs. 

 

For numerous reasons, these factors all militate against the likelihood of your average citizen moving into an earthquake-resistant house in a place like Morocco.  If the citizen has a certain amount of money, and one contractor says he can build a 1,500-square-foot place for that amount, and a second contractor says he can build an earthquake-resistant building for the same amount, only it will be 1,000 square feet, well, most people are going to go for the bigger building.  Much has been made about fatalism in Muslim countries, which is allegedly the habit of attributing disaster to God's will.  By my judgment, there is at least as much fatalism in the U. S. concerning disasters, but what we have here is building codes that are actually enforced, plus a tendency not to make houses out of pure masonry, brick, or stone.

 

Asking Moroccans to build wooden houses would be like asking to go waterskiing in Death Valley:  the requisite materials are simply not available.  So why aren't building codes for masonry buildings enforced to make them more resistant to earthquakes?

 

One big problem in very old countries like Morocco is that a lot of the buildings are decades or centuries old.  One famous structure that was damaged in last week's earthquake, Marrakesh's Koutoubia Mosque with a 226-foot-high tower, was built in the 12th century A. D.  It reportedly suffered damage, but the extent is not known and the tower apparently did not fall down.  Even U. S. building codes typically do not require retrofitting of existing structures until they are sold or extensively modified.  If an old structure of importance is judged to be an earthquake hazard in the U. S., more typically it is just torn down and replaced.  But you don't just tear down a historic mosque.

 

Our sympathies are with the survivors of the Moroccan earthquake, who will no doubt plea for the government and King Mohammed VI to do something to prevent such fatalities next time.  But as next time may not be for a long time, it's quite possible that any efforts to improve building codes, or to remedy hazards in existing buildings, may be forgotten before the next major quake comes along.

 

Sources:  I referred to an Associated Press article by Sam Metz and Mosa'ab Elshamy that was carried in the Los Angeles Times at https://www.latimes.com/world-nation/story/2023-09-09/morocco-earthquake-kills-600-damages-historic-buildings.  I also referred to articles at https://www.quora.com/What-magnitude-earthquake-can-an-average-building-withstand,

https://www.usgs.gov/faqs/can-megaquakes-really-happen-magnitude-10-or-larger, and the Wikipedia articles on specific earthquakes mentioned and the modified Mercatili intensity scale.

Mistake in Yellow and Gray

Texas has always been a forward-looking state, where things are always going to get better and history doesn't count for much.  The spirit of the state is well expressed by GM engineer and inventor Charles F. Kettering, who said in 1948, "My interest is in the future because I am going to spend the rest of my life there."  So it's natural to expect that this bias toward novelty would show up in architecture. 

The problem with novelty in architecture is that most of the time, a new building is surrounded by older buildings.  And if the style of the new building is too radically different than its surroundings, the overall effect cannot be a happy one, regardless of how elegant or coordinated the new building is on its own.  When you leave out elegance and coordination and design a building's appearance in a manner that seems to have taken every minute of a half-hour's thought, well—you get the new Local apartment building here in San Marcos, Texas. 

I should explain something about the way San Marcos has grown from a town of less than 10,000 people in 1950 to its present estimated population of over 60,000.  Like most county seats in Texas, settlement started out around the county courthouse in the town square.  Many of the original buildings around the square still stand, and the immediate area of the square is a historic district, as is a quarter-mile or so of old homes along the main road that extends southwest of downtown, and much of the newer construction in town is several miles farther southwest in that direction.  Going northeast in the opposite direction from the old residences, you encounter one- and two-story commercial buildings, a 1970s-era bank building or two, a few auto repair shops, a gas station, and so on, until you reach the San Marcos River, fed by nearby Spring Lake, which has evidence of human habitation going back 9,000 years.  While there are not any architectural gems in the couple of blocks northeast of town, the buildings were all pretty consistent with each other, and the historic small-town atmosphere still lingered in that district to some extent.

That is, until the Local started going up a mere two blocks away from the courthouse square.  Here is a view taken from a parking garage a few blocks north of the area I'm speaking of:

The brownish copper dome to the extreme right is the county courthouse, no longer in active use but preserved for its historic and architectural beauty.  Almost even in height with the courthouse is the six-story thing on the left that looks like something an architecture undergraduate turned in at the last minute. 

In researching the history of the Grenfell Tower building in London that caught fire on June 14, I learned that its architectural style is known by the technical name of "brutalist."  I'm not sure that the Local's style has the dignity of a name, but I think brutalist will do until a better one comes along.  Here's a closeup of its sole concession to the fact that it's going to be on public display to thousands of people for years or decades to come: the yellow and gray—patterns—or whatever they are:

Good architecture treats space and the people who occupy it with respect, framing and transitioning to make mechanical necessities such as columns and cornices things of beauty.  The Local is just a box for housing students, and one gets the feeling that the designers came close to leaving it a solid uniform light gray, and then had a twinge of conscience, plus maybe some leftover yellow and dark gray panels (there's no sign of paint anywhere outside), and so they determined on the alternating design that reminds me of nothing more than a surveyor's stadia rod, or the way old 1960s space-flight rockets were painted with alternate black and white squares so the engineers could tell if they were spinning after launch.  Both patterns were designed for high visibility, and I suppose you could say the Local has that.  But they could have made it any color or no color at all, and it would still be highly visible anyway, towering six stories above the surrounding one- and two-story buildings.

Engineers were no doubt involved in the design of this structure.  If you look carefully just to the right of the old-fashioned-design streetlight in the second picture above, you can see evidence that electrical engineers were involved:  a set of junction or transformer boxes connecting to large steel conduits that run up outside the first two parking-lot floors of the building.  I suppose this side is the rear, but it looks pretty much the same from any angle, so who can tell?  Trying to make one side of this building inconspicuous is like trying to hide an elephant under a napkin—the thing can't be done. 

This is not the first or the only apartment building in downtown San Marcos.  The red-brick structure visible to the left in the second picture probably is, or was, an apartment building, but it was built in a scale and style commensurate with the rest of that section of town.  With the huge increase in population in the last decade brought on by the explosion of enrollment at Texas State University (of which I am an employee, therefore indirectly part of the problem), the city has broken out in a rash of apartments ranging from the marginally tasteful—the old First Baptist Church was converted into apartments in a way that at least made some concessions to the appearance of its surroundings—to the esthetic horror that is the topic of this blog. 

There may be no place on Earth where the Local would fit in and look normal, but if there is, I'm pretty sure I wouldn't want to live there.   And nothing I'm saying should be construed as a criticism of the safety, structural integrity, or legality of the building under discussion.  There are lots of things that are legal that nevertheless shouldn't be done.  Downtown San Marcos was not exactly an architectural showplace, but it at least had a semblance of coherence and a flavor of the town's historic roots.  The Local has changed all that.  I will probably teach students who live in the Local, and that's okay—everybody has to live somewhere.  But I'll still always think of it as the Mistake in Yellow and Gray.

Sources:  The photos were taken by the author on June 15, 2017.  The Kettering quote is from a Forbes magazine interview and can be found at https://todayinsci.com/K/Kettering_Charles/KetteringCharles-Quotations.htm.

Tragedy in Taiwan: Collapse of the Golden Dragon Building

On Saturday, Feb. 6, a magnitude-6.4 earthquake shook the island nation of Taiwan.  Nearly all the high-rises in the southern city of Tainan withstood the quake without serious damage, partly because of new building codes enacted after a more severe earthquake in 1999 killed 2400 people.  But in the Feb. 6 quake, a 17-story building containing 96 apartments completely collapsed, trapping victims inside and causing the majority of the deaths involved.  As of Feb. 11, the confirmed death toll in the quake stood at 55, but many bodies probably remain in the ruins of the Golden Dragon apartment building, which was erected in 1994 before the new building codes took effect.  On Feb. 9, the building's developer and two associates were arrested and charged with professional negligence causing death.  Prosecutors claimed that shoddy construction was responsible for the building's collapse, saying that cans of polystyrene foam were used as fillers in the reinforced-concrete structure and that steel reinforcing bars were too short. 

Building a structure that can resist earthquakes is a challenge that modern structural engineers tackle routinely.  Very few steel-framed high-rises are seriously damaged by earthquakes, because the type of steel used in them has a certain amount of "give" which allows the stresses of a shaking foundation to bend but not break supporting members.  The only exception is the unusual case when an earthquake's period coincides with a building's resonant frequency and vibrations build up until something snaps.

Reinforced concrete is another matter entirely.  Concrete has excellent compressive strength, but it's brittle and doesn't bend easily.  If you try to bend it, parts of it are put into tension, and pure (unreinforced) concrete has almost no tensile strength, so it cracks when subjected to the pulling forces that bending causes. 

Many decades ago, construction engineers figured out how to embed "rebar"—steel reinforcing bars—in concrete to provide the tensile strength that concrete alone cannot provide.  Properly apportioned and applied, reinforcing bars can make concrete-framed structures just as strong as steel ones, with the advantage that setting up molds and pouring beams and floors can be a lot cheaper than assembling a steel frame.  So many buildings for which cost is an issue, such as apartment complexes, are made of reinforced concrete.

However, making such a structure earthquake-resistant is a challenge, especially if it was not originally designed that way.  A personal anecdote will illustrate this.  I attended the California Institute of Technology in Pasadena from 1972 to 1976.  That institution began its existence in 1891 as a vocational school funded by businessman Amos Throop.  By 1912, the main building on campus was Throop Hall, a reinforced-concrete-and-brick structure that stood until a 1971 magnitude-6.6 quake seriously damaged it.  Engineering studies showed that the structure was fatally flawed with regard to earthquake resistance, and would probably collapse in another quake of the same or greater magnitude.  So despite its historic associations, it was condemned and fell to the wrecking ball during my freshman year there. 

The problem of what to do with existing structures when building codes change is difficult, and municipal authorities rarely condemn buildings that are not obvious ongoing hazards simply because of a building-code change.  The Golden Dragon apartment building may have been erected in compliance with the codes as they stood in 1994, but emotions are running high after the disastrous collapse, and the developers will have to argue in court as to whether they behaved responsibly during the construction of their building.

One way to enable reinforced-concrete structures to withstand earthquakes is to make ductile joints between the horizontal and vertical members of the structure.  This will allow the building to "follow" horizontal ground movement without imposing fatal strains on the supporting walls.  The fact that lightweight material such as plastic foam was used as fill may not necessarily indicate shoddy construction.  And the length of rebars is something that may or may not have had anything to do with the building's collapse.

The good news coming out of this tragedy is that more buildings didn't collapse, as for example happened in Haiti in 2010.  What few building codes existed there were not enforced, and although there were few structures more than three or four stories high, over 200,000 of them collapsed and the death toll exceeded 100,000.  As a rapidly developing nation, government officials in Taiwan did the responsible thing following the 1999 earthquake and imposed building codes that required buildings to withstand a certain level of earthquake shocks.  The fact that only one major high-rise collapsed, and that one a pre-1999 structure, says that the new building codes have been largely effective.

In addition to investigating the construction of the ill-fated Golden Dragon, Taiwan officials may want to consider a program of inspections of pre-1999 structures with an eye toward preventing more such tragedies in the event of a larger earthquake.  Even if the conclusion is that things are okay, this would be a reassuring thing to find out.  And if some other structures are like time bombs waiting to be set off by a large earthquake, the time to find that out is now, not when the next big one hits. 

Sources:  I referred to news items from Agence France-Press carried by the Australian Broadcasting Company at http://www.abc.net.au/news/2016-02-11/taiwan-court-hears-of-critical-flaws-in-quake-hit-high-rise/7160954 and UK's Daily Mail at http://www.dailymail.co.uk/wires/afp/article-3439998/Taiwan-developer-grilled-collapse-quake-building.html.  I also referred to the Wikipedia articles on earthquake engineering and the California Institute of Technology.