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.

Building Codes, Earthquakes, and Haiti

Two weeks ago tomorrow, the worst earthquake in two centuries hit Port-au-Prince, Haiti. The official death toll has exceeded 100,000 and it is likely that millions are homeless and will have to leave the city temporarily or permanently. The survivors have my sympathy and prayers, along with hopes that this terrible tragedy will have a few positive outcomes. One of the best possible outcomes would be a change in the way the city and country are rebuilt.

Laws concerned with how buildings are constructed can be traced back to the Code of Hammurabi promulgated around 1800 B. C. Its provisions were simple: if a building collapsed on its owner and killed him, the builder lost his head. This was a powerful, if negative, incentive, but it lacked something in the area of specificity. In the U. S., Baltimore was the first city to adopt a prescriptive code that not only laid out penalties for poor construction, but described what good construction was. This was around 1904. Since then, advances in structural engineering and materials science have given us the tools to predict how almost any structure will behave under a wide variety of anticipated natural disasters, from hurricanes and floods to earthquakes. But the problem in Haiti was that this knowledge, even in the rare instances when people possessed it, was rarely applied.

Amid the rubble of Port-au-Prince, the tallest building in Haiti—the Digicel building, completed about a year ago—still stands with only minor cosmetic damage. Why? It was constructed according to American building codes to withstand a magnitude-7 earthquake—and it did. A plainer argument for enforcement of building codes could not be imagined.

If Haiti has any building codes, I was unable to ascertain exactly what they amount to or where they apply. A project that was ongoing in 2007 under the auspices of the Organization of American States (OAS) put up a website that stated Haiti has no national building code, and was focused on developing one. According to news reports, any building codes that exist are merely on paper, and people use cinder blocks that are basically home-made, reportedly weighing only about 12% of what the same size block would weigh if it was made under U. S. standards. Reinforcing bar is used sparingly, if at all, and when people need more room they just go down to the homemade cinder-block store and pile another story or two onto their house. Radical libertarians might do well to study Haiti as an example of what happens when government absents itself completely from the supervision of private and even public construction. Things can go well for a while, but when an earthquake hits, the devastation is nearly total.

And while engineers, to the extent they were involved at all in Haitian construction practices, deserve blame for not building better buildings, an individual engineer can do only so much in a regulatory, economic, political, and cultural environment that militates so strongly against good construction. Digicel was able to build according to American codes because it had the money and expertise to do so. The average Haitian in a country with the lowest per-capita income in the Western Hemisphere cannot afford to pay that much, unless he wants to live in an earthquake-proof building the size of a phone booth.

What will have to change if the next earthquake is not to produce equal devastation?

Clearly, the people will need to demand that the government get serious about building codes. Unfortunately, there is little precedent in recent history for the Haitian government getting serious about anything besides corruption and self-serving behavior on the part of its politicians. But perhaps the shock engendered by this tragedy will make people understand that corruption has a price, and the price is one that Haitians can no longer afford. Something like that happened after the notorious 1911 Triangle Shirtwaist disaster, in which 146 garment workers died when a New York City sweatshop caught fire. That tragedy inspired the creation of the American Society of Safety Engineers and led to important legislation regarding worker safety.

But clearly those aspects of Haitian culture which take a laissez-faire attitude toward future-directed regulation of any kind, including building codes, must change if Haitians are to live in safer buildings in the future. How this can happen is a problem for politicians, diplomats, the hundreds of non-governmental organizations (NGOs) that have poured many millions of dollars into Haiti over the last few decades, and most of all the citizens, who alone can demand better of their government than they have received heretofore. We have the knowledge of how to build safer buildings, though it is perhaps not distributed very widely in Haiti. What was lacking, and what I hope will arise in the future, is the will to reach a compromise between the total lack of building codes that went on before the earthquake, and an American-style set of codes that would put new construction totally out of reach for all but the richest Haitians. This requires ingenuity, political smarts, and good will on all sides, but it can happen. I only pray that it will.

Sources: I used Wikipedia’s article on building codes and news items on Haiti found at http://www.infrastructurist.com/2010/01/20/earthquakes-dont-kill-peoplebad-buildings-do-more-on-haitis-building-codes/ and http://www.mcclatchydc.com/world/story/82915.html.