By Vanessa Ko
Posting in Cities
HONG KONG -- Would you want to be caught in a Hong Kong skyscraper during an earthquake?
HONG KONG -- Hong Kong is known for its tall buildings that locals work and live in.
But whenever an earthquake devastates another city somewhere in the world, it begs the question (as one peers down a window on the 50th floor): What if it happened here?
Hong Kong has never required that buildings be designed to withstand earthquakes. Only last month did a government consultation for a proposal begin the process of implementing such legislation.
Although Hong Kong is not prone to quakes, laws mandating seismic resistance exist in most modernized cities and countries worldwide, such as Shanghai, South Korea, Thailand, Australia, France, Germany and New York City, where the likelihood of tremors is about the same, according to the Hong Kong government’s proposal.
“Hong Kong is probably, in this part of the world, the only region that doesn’t have an earthquake resistant design requirement,” said Greg Wong, a structural and geotechnical engineer who formally headed the Institution of Engineers, a local trade group.
The thought of a major earthquake in the city seems frightening, given the height of so many buildings. But they have been strengthened to withstand the extreme winds of typhoon season, which poses a real concern each year. Buildings are designed to sway when hit by these storms.
Wong said it is improbable for a strong earthquake to hit at the same time as a severe typhoon, or when there is a maximum loading of furniture and people, which would be the only times when an unstudied structural test would emerge. But as these events tend to affect different parts of a building, it still makes sense to factor in earthquakes separately.
The entire country of China requires buildings to be earthquake resistant, and it only makes sense, because certain areas are seismically active — and the rule has been applied countrywide. Hong Kong, a region with separate laws from China, has been late to begin implementing legislation because of the general low risk.
But over the past half-century, as buildings have gotten taller and more crowded, and as building codes evolve, Wong says it is a “rational” move to include earthquake resistance into the code.
Moreover, recent earthquakes, like the one that devastated China’s Sichuan province in 2008, one on the East Coast of the United States in 2011 and the earthquake in Italy in May of this year, show how unpredictable the incidents could be — although on faults, none of these places had strong seismic activity.
The government’s proposal says that only a small additional cost would be incurred for a building’s design to include earthquake resistance, whereas studies show that the projected cost savings from probable damage over a year, if U.S. resistance standards are used, would be 80%, while injuries or casualties would fall from around 150 to almost nonexistent.
Wong also points out that enhancing the structure to counter the effects of earthquakes would be only a small fraction of the cost of the entire development. He estimates that putting up a building in Hong Kong costs only one-third of the price to buy the plot of land, and spending on reinforcing the concrete and steel would be minuscule.
As far as engineers are concerned, bringing the code up to international standards is important, but the urgency is not there for Hong Kong.
“I tell people, ‘You don’t need to panic,’ ” Wong said. “ ‘It doesn’t mean if an earthquake comes tomorrow your building will fall down.’ ”
Photo: Vanessa Ko
Nov 21, 2012