US builders rarely use de­signs that with­stand earth­quakes


When the shak­ing started at 5:46 a.m., Ya­suhisa Itakura, an ar­chi­tect at a big Ja­panese con­struc­tion com­pany in Kobe, was sit­ting at his desk fin­ish­ing a re­port he had toiled over all night. His of­fice swayed, but the books stayed on their shelves and noth­ing fell off his desk.

“I thought to my­self, this earth­quake is not that big,” Itakura said.

It was, in fact, cat­a­strophic. The Great Han­shin earth­quake of Jan. 17, 1995, killed more than 6,000 peo­ple in and around the in­dus­trial port city.

Itakura had been cush­ioned from the vi­o­lence of the earth­quake be­cause his three-story of­fice build­ing was sit­ting on an ex­per­i­men­tal foun­da­tion made from rub­ber – an early ver­sion of an en­gi­neer­ing tech­nique called base iso­la­tion.

The tech­nique that pro­tected Itakura’s build­ing is used in roughly 9,000 struc­tures in Ja­pan to­day, up from just two dozen at the time of the Kobe earth­quake. Thou­sands of other build­ings in the coun­try have been fit­ted with shock-ab­sorb­ing de­vices that can greatly re­duce dam­age and pre­vent col­lapse.

Chile, China, Italy, Mex­ico, Peru, Turkey and other coun­tries vul­ner­a­ble to earth­quakes have adopted the tech­nolo­gies to vary­ing de­grees.

But with no­table ex­cep­tions, in­clud­ing Ap­ple’s new head­quar­ters in Sil­i­con Val­ley, the in­no­va­tions have been used only spar­ingly in the United States. Seis­mic safety ad­vo­cates de­scribe this as a missed opportunit­y to save bil­lions of dol­lars in re­con­struc­tion costs af­ter the in­evitable Big One strikes.

Earth­quakes are of course nat­u­ral phe­nom­ena. But the amount of dam­age they cause is a func­tion of de­ci­sions made by politi­cians, engi­neers and busi­ness ex­ec­u­tives. Ja­pan and the United States, two of the world’s most tech­no­log­i­cally ad­vanced coun­tries, have the same prob­lem – how to pro­tect peo­ple and so­ci­ety from earth­quakes – and yet they have re­sponded in very dif­fer­ent ways.

Ja­pan, through both gov­ern­ment man­dates and its en­gi­neer­ing cul­ture, builds stronger struc­tures ca­pa­ble of with­stand­ing earth­quakes and be­ing used im­me­di­ately after­ward. The United States sets a min­i­mum and less pro­tec­tive stan­dard with the un­der­stand­ing that many build­ings will be badly dam­aged.

The two ap­proaches re­flect dif­fer­ent at­ti­tudes to­ward risk, the role of gov­ern­ment and col­lec­tive so­cial re­spon­si­bil­ity. Anal­o­gous to Amer­ica’s de­bate over health in­sur­ance, the U.S. phi­los­o­phy has been to make more re­silient build­ings an in­di­vid­ual choice, not a gov­ern­ment man­date.

“Do we want to be more like Ja­pan and are we will­ing to pay the price?” said Joyce Fuss, pres­i­dent of the Struc­tural Engi­neers As­so­ci­a­tion of Cal­i­for­nia. “A lot of peo­ple would say ‘no’ and maybe some peo­ple would say ‘yes.’ ”

In­her­ent in the U.S. ap­proach to seis­mic en­gi­neer­ing is a risk cal­cu­la­tion: Many Amer­i­can engi­neers op­er­ate on the as­sump­tion that a build­ing, which might be used for 50 years be­fore it is torn down and re­placed with a new one, has a rel­a­tively small chance of be­ing hit by a huge earth­quake.

“If you spend the money to­day and the earth­quake hap­pens to­mor­row, then con­grat­u­la­tions, you’ve done a good job,” said Ron Ham­burger, an Amer­i­can struc­tural engi­neer who is per­haps the lead­ing au­thor­ity on the build­ing code. “But the fact is, truly sig­nif­i­cant dam­ag­ing earth­quakes will af­fect a place like San Fran­cisco or Los An­ge­les maybe once ev­ery 100 to 200 years.”

“How lucky do you feel?” he added.

In cities like San Fran­cisco, where the median price of a home is well above $1 mil­lion, the no­tion of mak­ing con­struc­tion costs even more ex­pen­sive is likely to be un­pop­u­lar, even if the goal is to pre­serve the city in the long run.

Large earth­quakes are around 10 times more com­mon in Ja­pan than in the con­ti­nen­tal United States, ac­cord­ing to Hiroo Kanamori, an emer­i­tus pro­fes­sor of seis­mol­ogy at the Cal­i­for­nia In­sti­tute of Tech­nol­ogy.

But seis­mic his­tory sug­gests that Cal­i­for­nia may be due for large earth­quakes, which of­ten come in clus­ters.

In North­ern Cal­i­for­nia, the past five ma­jor earth­quakes along the Hay­ward fault, the jagged crack in the earth that runs through the heav­ily pop­u­lated cities of Berkeley and Oak­land across the bay from San Fran­cisco, have oc­curred on av­er­age ev­ery 140 years.

The last one was 151 years ago. (Seis­mic his­tory has also shown that pre­dict­ing earth­quakes is a fool’s er­rand.)

The last ma­jor earth­quake in the con­tigu­ous U.S., which caused $20 bil­lion of dam­age to the Los An­ge­les area, was a quar­ter of a cen­tury ago.

“The land has been peace­ful in Amer­ica,” said Masayoshi Nakashima, pres­i­dent of the In­ter­na­tional As­so­ci­a­tion for Earth­quake En­gi­neer­ing. “Young gen­er­a­tions in par­tic­u­lar are not nec­es­sar­ily fa­mil­iar with the re­al­ity of earth­quakes.”

The de­bate over whether to build more re­silient build­ings in the United States has been held largely out of pub­lic view, among engi­neers and other spe­cial­ists.

But at stake is whether places like Sil­i­con Val­ley, Seat­tle, Salt Lake City, San Fran­cisco or Los An­ge­les might be forced to shut down af­ter a di­rect hit – and for how long.

A fed­eral study last year found that a quar­ter of the build­ings in the San Fran­cisco Bay Area would be sig­nif­i­cantly dam­aged af­ter a mag­ni­tude-7 earth­quake, a dis­as­ter that would be com­pounded by the fact that 9 out of ev­ery 10 com­mer­cial build­ings and 8 out of 10 homes in Cal­i­for­nia are not in­sured for earth­quakes.

“Cities won’t be us­able for many months, if not years,” said H. Kit Miyamoto, a mem­ber of the Cal­i­for­nia Seis­mic Safety Com­mis­sion, a gov­ern­ment body that ad­vises the state Leg­is­la­ture and the gov­er­nor on earth­quake is­sues. “Throw­away build­ings equal a throw­away city.”

In a se­vere earth­quake, most Amer­i­can build­ings are de­signed to crum­ple like a car in a head-on col­li­sion, dis­si­pat­ing the en­ergy of the earth­quake through dam­age. The goal is to pre­serve lives, but the build­ing – like a car af­ter an ac­ci­dent – may be use­less.

Ham­burger, the struc­tural engi­neer, es­ti­mates that half of all build­ings in San Fran­cisco could be deemed un­oc­cu­pi­able im­me­di­ately af­ter a ma­jor earth­quake.

Some cities like San Fran­cisco are con­sid­er­ing rules that would re­quire build­ings to be more rigid, sim­i­lar to those in Ja­pan. There is no such thing as earth­quake-proof con­struc­tion, but ex­perts say Amer­i­can build­ings could be much more re­silient for lit­tle ad­di­tional cost.

A mul­ti­year fed­eral study con­cluded that fix­ing build­ings af­ter an earth­quake costs four times more than build­ing them more strongly in the first place. The United States is los­ing an es­ti­mated $4 bil­lion for ev­ery year that it de­lays a stronger build­ing code for earth­quakes, the study cal­cu­lated.

Miyamoto, who was raised in Ja­pan but now lives in Cal­i­for­nia, said there was in­creas­ingly sharp dis­agree­ment be­tween Ja­pan and the United States over seis­mic en­gi­neer­ing.

“The Ja­panese are com­pletely flab­ber­gasted about how we de­sign out here,” he said.

Pro­tect­ing tall build­ings

from earth­quakes is among the high­est-stakes endeavors for engi­neers. The col­lapse of even one sky­scraper could have cat­a­strophic ef­fects. Tall build­ings are also per­haps the big­gest bone of con­tention be­tween Amer­i­can and Ja­panese engi­neers.

Most new high-rises in the United States are built around a re­in­forced con­crete core, a tech­nique that Ja­panese engi­neers shun be­cause they say it per­forms un­pre­dictably in an earth­quake. Tall build­ings in Ja­pan are al­most al­ways built with steel.

Ja­pan, of course, still has many vul­ner­a­bil­i­ties, some of which were made clear when the 2011 To­hoku earth­quake cre­ated a tsunami that breached sea walls, killing an es­ti­mated 16,000 peo­ple and spread­ing ra­di­a­tion from a dam­aged nu­clear re­ac­tor.

The coun­try has many older build­ings con­structed be­fore ma­jor changes to a 1981 build­ing code, and even the coun­try’s seis­mic in­no­va­tions are of vary­ing qual­ity and ef­fec­tive­ness, as high­lighted by rev­e­la­tions last year that a man­u­fac­turer of seis­mic shock ab­sorbers fal­si­fied its per­for­mance data.

But over­all, Ja­panese engi­neers say, earth­quakes over the past two decades have proved the ef­fec­tive­ness of the coun­try’s stricter regulation­s and in­no­va­tions.

Kobe and the To­hoku earth­quake of 2011 led to a surge in de­mand for more ro­bust build­ings, with con­sumers will­ing to pay a pre­mium for the lat­est tech­nolo­gies. One com­pany has de­vel­oped in­flat­able air bags that de­ploy un­der­neath a wooden home when a large earth­quake is de­tected.

Of Ja­pan’s 9,000 ba­seiso­lated struc­tures, 4,300 are mul­ti­story build­ings, many of them of­fices, con­do­mini­ums and gov­ern­ment build­ings, and 4,700 are houses, ac­cord­ing to the Ja­pan So­ci­ety of Seis­mic Iso­la­tion.

Base iso­la­tion is ad­ver­tised on Ja­panese tele­vi­sion and on the Tokyo sub­way, tout­ing the seis­mic sys­tems of newly con­structed con­do­mini­ums. Nice Corp., a Ja­panese con­struc­tion com­pany, says a seven-story base-iso­lated build­ing costs 13% to 15% more than a con­ven­tional one.

Amar­nath Kasala­nati, the as­so­ciate direc­tor of the Pa­cific Earth­quake En­gi­neer­ing Re­search Cen­ter at the Univer­sity of Cal­i­for­nia, Berkeley, says it is para­dox­i­cal that more build­ings in the United States do not use in­no­va­tive seis­mic tech­nolo­gies, since Amer­i­can sci­en­tists and engi­neers were early lead­ers in the field.

Kasala­nati es­ti­mates that there are 175 ba­seiso­lated build­ings in the United States, mostly mu­se­ums, hos­pi­tals and older build­ings like the city halls of San Fran­cisco and Los An­ge­les that were retro­fit­ted with iso­la­tors.

One U.S. com­pany that helped de­velop seis­mic iso­la­tion de­vices has shipped 70% of the 20,000 de­vices it has pro­duced over­seas.

One no­table build­ing in the United States that uses the de­vices is Ap­ple’s gi­ant new head­quar­ters in Sil­i­con Val­ley.

Steve Jobs, the Ap­ple co-founder, died be­fore con­struc­tion be­gan on the build­ing. But when he in­tro­duced plans for the cir­cu­lar, glass-sheathed struc­ture, he de­scribed it as a “lit­tle like a space­ship.”

As seen on a rare tour, the four-story orb, which holds 12,000 peo­ple and is about as wide as the Pen­tagon, is the Roll­sRoyce of base-iso­lated build­ings.

The build­ing, which has a con­crete foun­da­tion that re­sem­bles a bath­tub, is not at­tached to the ground – if cranes or he­li­copters ex­isted that were pow­er­ful enough, they could lift it up.

At the base of the build­ing’s nearly 700 sup­port col­umns are stain­less steel pucks that sit on top of mas­sive steel saucers. When an earth­quake causes the ground to shake, the pucks slide across the saucers as much as 4 feet, slowed by fric­tion.

The net ef­fect for oc­cu­pants is that when the ground jolts back and forth, the build­ing moves sig­nif­i­cantly less.

One of the de­sign­ers of the build­ing was Jony Ive, the man who was re­spon­si­ble for the look and feel of Ap­ple prod­ucts such as the iPhone and iPad.

A na­tive of Bri­tain, Ive said he found the threat of earth­quakes “ut­terly alarm­ing” when he moved to Cal­i­for­nia in the 1990s and was sur­prised by the Cal­i­for­nian non­cha­lance to­ward them.

Ive said he and Jobs never con­sid­ered us­ing a con­ven­tional foun­da­tion for the build­ing.

“We would have seen it as ut­terly bizarre not to pro­tect our in­vest­ment,” he said.


Los An­ge­les City Hall was retro­fit­ted with base iso­la­tors to help cope with fu­ture earth­quakes. But most US build­ings in quake-prone re­gions lack earth­quake-re­sis­tant in­no­va­tions. One rea­son is that builders aren’t re­quired to use them.

Newspapers in English

Newspapers from USA

© PressReader. All rights reserved.