7.0 hits Haiti? 2

[msquared48]

What's goin' on?

Somehow, I never thought of this region as prone to earthquakes of this magnitude. Very strange to me.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[concretemasonry]

Code changes will not have an immediate effect because there is no real government or enforcement people or mechanism. Most of the common construction was residential away from the downtown.

There rest of the Carribean has successfully practiced good construction for hurricanes and what seismic history there has been using the locally available materials. Even something as simple as vertical steel along and opening and a bond beam as a top course makes a big difference where the construction is controlled by tradition and performance and not by cost cutting.

Codes are not the only answer. - I was involved in the damage assessment starting a day after the Northridge quake and found many problems ranging from poor construction practices to solidly grouting walls where not needed that tended to concentrate loads and prevent distribution to the rest of the structure. The hospital and addition there was a prime example.

In Haiti and similar areas the real human disasters are in residential structures and depend on good construction practices since the buildings are not engineered unless they are commercial.



Engineer and international traveler interested in construction techniques, problems and proper design.

 

[msquared48]

News

ASCE urges donations, volunteers for Haiti relief
January 19, 2010

RESTON, VA. — The American Society of Civil Engineers urged its members and partners to join it in supporting the relief efforts organized the American Red Cross. ASCE also encouraged its members to consider volunteering to help at the scene, especially structural engineers or individuals who speak French or Creole. ... Read full article

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[rmw]

Four years ago to the day of the earthquake I visited Haiti (Port-Au-Prince) for several days. Then I visited the DR for several days. I have never seen two countries that share a common island so diametrically different. The differences were staggering. Haiti is one of the few countries that I have visited that I have no real desire to return to. I'd go back to the DR in a heartbeat.

I wish I had a solution for the situation that they are in but I don't. And we as engineers function by analyzing problems and coming up with solutions. Sorry, in this case, I'm stumped.

rmw

 

[dik]

== PRELIMINARY EARTHQUAKE REPORT ==

***This event supersedes event AT00398542.


Region: HAITI REGION
Geographic coordinates: 18.428N, 72.875W
Magnitude: 6.1 M
Depth: 9 km
Universal Time (UTC): 20 Jan 2010 11:03:44
Time near the Epicenter: 20 Jan 2010 06:03:44
Local standard time in your area: 20 Jan 2010 11:03:44

Location with respect to nearby cities:
41 km (26 miles) WNW (301 degrees) of Jacmel, Sud-Est, Haiti
49 km (31 miles) WSW (257 degrees) of Carrefour, Ouest, Haiti
59 km (36 miles) WSW (257 degrees) of PORT-AU-PRINCE, Haiti


ADDITIONAL EARTHQUAKE PARAMETERS
________________________________
event ID : US 2010rsbb

This event has been reviewed by a seismologist at NEIC
For subsequent updates, maps, and technical information, see:

http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2010rsbb.php

or

http://earthquake.usgs.gov/

 

[ewh]

Haiti does not need loans to rebuild, as they have no economy to pay the loans back. What they need are grants to help them to their feet.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[CPENG78]

The events that have taken place are truly sad and are actually one of the primary reasons of why I became an engineer. I was born in Guatemala and lived there until I was 10 yrs old. Like someone mentioned earlier, the prefered (most economically feasible) construction materials are either adobe (for homes) or concrete (for taller structures). When I was living over there, I saw floods, earthquakes, volcanic activity, water distribution problems, roadways in poor conditions or no roadways at all. And of course too much death for problems that can be solved engineering wise. This was the case about 20 years ago. I don't know what the present state of infrastructure is there now. I'm sure that many advancements have been made but I must mention that not too long ago, approximately back in 2004 an article came out from a Guatemalan Newspaper describing how poor roads converted a short drive into a 10 hr trip. I don't recall the exact text but that was the point of the article.

Now I live in the US and like Concretemasonry points out, we have our own construction technique problems. I saw many of those issues in the Northridge earthquake as well. Like many of you, I see pictures and video of what remains in Haiti and there is lack of proper reinforcement. Not enough rebar in relation to what appears to be the physical size of the member, no shear reinforcement, in some cases no reinforcement at all.

I also agree with others that having stricter codes is not the issue or the problem here. The problem is having enforcement of those codes. Unfotunately I also believe the problem runs deeper than some us can grasp. Like many Latin American countries more education is needed in Haiti, not just in earthquake preparedness but also in general. By the way, no disrespect is meant, I know Latin American countries have great engineers and other great professionals but we need more. Adding to the problem is the corruption that plagues many goverments of the world.

It is frustrating to know that what can be avoided with good engineering judgement can not be accomplished because of political reasons. I really hope for the best for the people of Haiti. My condolences to anyone that is part of this forum and has lost anyone to this tragedy.

I do want to mention one more point and request your input. I believe that at some point one of the reporters mentioned that beyond the immediate epicenter, there were pocketed areas of damage with areas of minor or no damage at all. I would assume that this could be attributed to the different soil profiles in these areas and how the energy was transmitted thru those profiles. Any thoughts.

 

[dgillette]

CPENG78 - First, for a very large part of the Haitian population, maybe even a majority, I think the choice is not between poorly constructed housing and proper construction, but between poorly constructed housing and NO housing. To people who literally eat patties of soil for the small amount of nutrients in them, steel is quite expensive. Doesn't matter what the building codes say if you can't afford to follow them. It may be a perfectly rational decision to live in an adobe house with say, 1 percent chance of collapse due to earthquake each year, rather than living in no house at all or a hovel built from sticks and tarps.

Second, it is fairly common to see areas of severe damage interspersed with areas of little damage, like you describe. Structures on rock or on thin soil above rock tend to be loaded by lower peak acceleration, generally shorter-period motion, and fewer strong cycles compared to those on alluvial or other soils, because of the dynamic response. It was seen in the Loma Prieta, where areas of fill along the waterfront experienced much worse shaking than areas on rock much closer to the epicenter. In the 1925(?) Santa Barbara EQ, downtown Santa Barbara CA, on thick alluvium, was severely damaged, whereas higher ground a short way north, on bedrock or a thin layer of soil above bedrock, experienced much less damage. Think of Jello in an iron pan. One reason the Mexico City earthquake was so destructive, even though the epicenter was very far from Mexico City, was the thick lacustrine sediments.

rmw - I too would go back to DR in a heartbeat. Great people, great coffee, great merengue music by Cuatro Cuarenta. Haven't been to Haiti.

Regards,
DRG

 

[msquared48]

The 6.1 was downgraded to a 5.9, as if that will change anything.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[CPENG78]

Dgillette,
I agree with you that for some it may be a matter of no housing at all, in fact for the great majority that is the case. I lived in an Adobe house in Guatemala. But like I also mentioned, the problems run deeper than a code, even code enforcement that I mentioned, but also lack of education and so much corruption. Yes, there is no point in code or code enforcement if you can not afford it but the corruption of some governments does not allow for even there own presidential palace to be safe from such a disaster, not alone a hospital (which its just a shame). The intent of my statement was not to provide a simplied analysis of the problems but rather mention some of the problems that plague our countries of the world and that I have noticed as someone who resides in the US but comes from another country. When it comes down to it and more than anything - I am angry for the loss of human life, its just not acceptable even when reality hits. Like RMW, I am also stumped.

 

[msquared48]

The western end of the faultline runs into Kingston, Jamaica. I've been to Puerto Rico, but not Jamaica. I assume the construction there is much like Haiti and similar results could be expected when the western end of the fault rips.

Positive thoughts, huh? I wonder if they will get the message...

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[alehman]

I think the real problem is population. The nationwide population density is 362/sq km. For comparison, DR is 208. Jamaica is 252. GDP per capita is $790. DR is $8,672, Jamaica is $8,967. There simply are not enough resources to support their population at anywhere above a poverty lifestyle.

Alan
“The engineer's first problem in any design situation is to discover what the problem really is.” Unk.