- Thread starter dv8
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many buildings in SD will not withstand large earthquake
Well popeye I totally agree because I thought my statement about my centuries old home was quite innocent enough ..but not for some.
And there lies the answer.
Centuries old construction so often serves the test of time against all adversities using time proven materials and techniques. And maybe your property was built after the last event in the old city. But as the minor recent 4.2 earthquake in Los Alcarrizos reminds us, a danger lurks beneath.
Modern materials (and reinforced concrete has only been around some 150 years) can be stronger if designed, made and used correctly. Used incorrectly, as is probably the case in many Santo Domingo (and other areas) non commercial dwellings and others as the current study mentioned in the OP is uncovering, and another 'Haiti event' beckons at some point, and so counter measures need planning now.
I think we should be glad some planning is happening and hope that the relevant building control bodies in the country as a whole start doing there job properly and stop this poor construction work at source.
And the issue of substandard constructions and their potential consequences should be brought to the general public attention, rather than being brushed aside and disregarded aside as perhaps (I hope not) you are suggesting.
Some people also don't want to understand important issues raised by the OP study which has been and is ongoing....and others go ahead and build and buy property without complete professional advice on issues very relevant to the Dominican Republic and have potential headaches now.
A large part of the damage in porte au Prince was due to the unstable ground that the city was largely built on. That doesn't change the relevance of the report though.
A few years ago, we built a large 'Florida Room' along the back of our house in DR. It's about 35' long and 20' wide. I wanted a cement roof, to keep it cooler, but Mr. AE wasn't comfortable with that expanse of roof without center support columns. The maestro said "no problemo", and I probably would have let him do it, but Mr. AE said he was afraid of an earthquake taking it down and killing someone. [We were in that house when the Haiti quake happened, and it was a weird and scary experience].
Long story short, we bought alu-teja metal roofing. Looks like the terracotta tiles from inside and out, but light. It does hold the heat in there though, sometimes it's cooler inside than out there.
Long story short, we bought alu-teja metal roofing. Looks like the terracotta tiles from inside and out, but light. It does hold the heat in there though, sometimes it's cooler inside than out there.
Any decent supervisory engineer (and the standard of engineer in DR is good) would get samples of the rebar tested for tensile strength. That said reinforcing bar produced in the country does come up to international specifications (http://gerdaumetaldom.com/?lang=en )
And the rebar that is often most important for seismic conditions are often stirrups and links at connections.
If you think Port au Prince ground is dicey, check out Santiago, SFM and La Vega and shudder.
Fact is you can build on any ground anywhere and in seismically active areas with the right design and that includes the right foundations. You will need some special soils investigation with certain ground conditions and I wonder if anyone has ever undertaken seismic refraction testing of soil conditions for major developments in some of the locations within this country where soil liquefaction is possible in a seismic event? As happened in the Haiti quake.
And there are companies providing such testing across the water in Puerto Rico.
Poor assumption
I do not know why you would assume that ..the reinforcing bars are probably used just as correctly here as elsewhere ..there are a very large number of cicil and construction engineers in the DR with degrees both from Dominican and overseas universities and if the proof of the cake is in the eating, there have been precious few problems in Santo Domingo resulting from unstable concrete work. I hate to sound like another on this site but give me evidence of just one. I want to add that of course many of the ZC buildings have no reinforcing not even a RSJ but rely on very hard woods and thick walls , often of rubble placed in an uneven pattern
I do not know why you would assume that ..the reinforcing bars are probably used just as correctly here as elsewhere ..there are a very large number of cicil and construction engineers in the DR with degrees both from Dominican and overseas universities and if the proof of the cake is in the eating, there have been precious few problems in Santo Domingo resulting from unstable concrete work. I hate to sound like another on this site but give me evidence of just one. I want to add that of course many of the ZC buildings have no reinforcing not even a RSJ but rely on very hard woods and thick walls , often of rubble placed in an uneven pattern
it was not an assumption, it was a question, being in the business I know several engineers here. i look at things like rebar. Jeez can't even talk to people on this site without someone getting bent out of shape. i'm done I am not here to argue, sick of it.
you seem to believe that if people disagree with others, it means they are getting bent out of shape.
bulletin for you. this is the internet. gazillions of people read postings, and gazillions of people post. opinions are going to vary, for many reasons. nationality, race, ethnicity, socialization, experiences, you name it.
if you don?t like the notion that people might disagree with you, you might consider seeking your entertainment elsewhere.
A few years back when I was with ex esposa and living in the campo, it fascinated me watching a new municipal building being constructed opposite in the town of Puerto de San Jose, Villa Altagracia.
The covered entry court seemed to be using excessive spans from the earliest days from and engineering perspective. I watched day by day thinking the foundations were far apart, and then that the columns were tall and thin (and less in size than the newly introduced code), and then that there were no ground beam ties, and then there were no beams in the roof slab.
To cap it all the darn roof was not level.....I could visibly see a difference of several inches from one end to the other eying it in with other horizontal surfaces. I went and measure checked it to confirm. It was later spotted by the engine and nothing was done whilst I was there.
The concrete incidentally was batched using a typical mixer and hoist using as dug river gravel and screened river sand and presumably they were mixing cement on a 1:2:4 ratio or thereabouts...but then adding water for ease of working.....excellent quality control lol.
This is probably a typical example of local government at work on it's own projects I'm afraid. They can't supervise there own work let alone monitor other various constructions nationwide and so the 90% figure mentioned in the OP is very believable indeed.
ju10prd yes hydrated lime .. I had almost forgot the qualities in that lime to make the concrete stronger .. I have seen many tests taken by consulting engineers of each concrete truck arriving on site so I think the Dominicans do have a degree of responsibilty when building,, even though it may not be with the workers safety
My experience is new buildings within first 2-3 years have plumbing leaks, cracked cement, and roof and wall leaks. Not to mentioned need painting yearly.
Even if there was a true legal governing for building inspections, one could argue the lack of competent engineers to do so.
I have watched countless 4-6 storey structures being built around me. Its all the same, like watching children build with leggos.
Even if there was a true legal governing for building inspections, one could argue the lack of competent engineers to do so.
I have watched countless 4-6 storey structures being built around me. Its all the same, like watching children build with leggos.
Lime was used very effectively for centuries as a mortar with stonework and there are numerous examples of old buildings throughout the Caribbean and no doubt DR which have stood the test of time and the forces of nature.
As for concrete testing you will indeed see this all the time on new city developments but rarely on the bulk of building work throughout this land, and concrete is normally mixed by cement mixer using local aggregates without the necessary controls. No doubt you are going to tell me that all the new schools built throughout the land including in remote villages had ready mixed concrete delivered with a technician on hand to test the concrete......I don't believe it.....and doubly so after hearing all the OISOE stories.
Equally, what is the use of testing concrete if you don't have a compliance regime that fits the design and the results don't get passed on to future owners of the building within the Owners Manual with O & M information. Would a contractor or commercial developer really take the tough decision to cut out a hole floor pour in a complex cast 28 days before because the strength fell short of the design strength by say 20%. My guess here, unless there is international standard funding and an upstanding checking engineer, is no. The disease that afflicts Obras Publicas has most likely spread despite there being, as you say and I agree, some excellent architects and engineers and decent materials available. Is that not what CODIA and others are making a noise about?
Defend your country as I do often but accept the shortcomings too.
Acceptance of a problem is the first step on the way to resolving it.