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20 Buildings Suspended in Mid-Air

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ashepard
ashepard  
1/15/2014 1:48:02 PM
User Rank Urban Legend
Re: Sacrificial first floor
@Richheap,

     I agree with you - foundation isolation with "slip and slide" instead of connecting the building to the ground. Once the pads to allow the ground to move under the building are in place than stilts seem like a good idea.  

    A tuned mass near the roof of a very tall building works for shear loads like wind but not during an earthquake. The earthquake frequency is way too high, compared to the wind. Plus its best to have passive safety measures instead of active ones. Why? less maintenace and they work during blackouts or power failures. 

   In my opinion there is still alot of work to be done with non metal, non stone materials. 

Toby
Toby  
1/15/2014 5:23:52 AM
User Rank Urban Legend
Housing for practical purposes
@Rich: I first came across these sort of buildings visiting Honduras in the early 90's. It was a town on the edge of a hot steamy jungle and when I asked why build on the water, the reason given was that the flies were so bad most days that being out over the water was the only relief and made living there possible. 

It was indeed a big improvement over the airborne assault on the land but still pretty squalid as an option.

richheap
richheap  
1/15/2014 4:33:48 AM
User Rank Staff
Re: Sacrificial first floor
Hmmm... well, I'm not sure it's that simple Venks. Even if these stilts give buildings more flexibility in an earthquake then that's no guarantee they'd be able to support the weight above. I think it's more common to have foundations that allow the building on top to slide from side to side so the building is at less risk of cracking. If stilts were the best solution to protecting building in earthquakes then people in Japan would be using them a lot more.

Venks
Venks  
1/15/2014 4:11:52 AM
User Rank Urban Legend
Re: Sacrificial first floor
@ashepard: Thanks for your indepth analysis and explanation. That piece of information will surely help us a lot. I believe you have indepth knowledge of structural analysis of buildings. Thanks once again.

The Kansai International Airport case looks to be equally fascinating as well. Just like Petronas towers, Burj Dubai is also built with most part of its weight being on the lower floors.

ashepard
ashepard  
1/14/2014 3:44:59 PM
User Rank Urban Legend
Re: Sacrificial first floor
@Venks

    Hi. Why not use stilts?  Cost keeps stilts from being used in some areas. Extra material and new techniques scare some. Many keep the earthquake energy from entering the building by using pads that allow the foundation to slide under the building. This way the earth moves but the building does not. Stilts are harder to use with this technique unless the foundation is built with stilts above it. How? Deep foundation is built at least three feet longer on each side than the building. Pads to allow for slipping are installed. Second foundation ring is built on top of the pads. Its size is smaller so the building can move over the first, lower, foundation freely. Then stilts can be built.

   Sound too difficult? Kansai International Airport is supported on hydraulic jacks that lift the building off its foundation to keep it level. The airport has a central four story building that is 312m long with two 677m wings. Yes, stilts on foundation does work.

 Japan does things right so testing is needed. Welding, not bolting, the cross members and supports are critical. Building in dampening systems helps reduces the energy a building picks up from an earthquake. For example

   Japan has a long building history. Wood will bend without breaking, unlike concrete. Just south of you is Pentros towers in Indonesia. They used concrete pillar design effectively, with most of the building mass at the bottom. I could be wrong, but earthquakes are common in Japan because Japan is moving east away from China against the pacific plate.

   Typhoons and tsunamis highlight the need for water to move through the first floor in Japanese homes. Tradition of keeping the bones of relatives in the home for a number of years highlights the need to keep people *and* valuables safe.

   I hope this helps. Thank you for reading.

 

Venks
Venks  
1/14/2014 2:12:19 PM
User Rank Urban Legend
Re: Sacrificial first floor
Yeah, I got it @ashepard and @Rich. Thanks for your explanations. That pretty much clears my doubt.

But having said that, Is that the solution for us to henceforth build all the structures in Japan using such construction techiniques. If this helps us during earthhquake time then why not use it? I will have to find out more on this.

ashepard
ashepard  
1/14/2014 1:48:13 PM
User Rank Urban Legend
Re: No. 11!
@richheap

    Yes the sunlight is very important. Because of the earths tilt, how much sun - full sun, shade or little sun, varies. In the forrest trees help keep regulate this. Building have sharp edges so planing is tricky but not impossible. 

   I would not grow crops or berries that attract animals. I would suggest flowers. The U.S.A. and now the world has a honey bee population problem. Bees are disapearing. One way to fix this is with multiple flower types that bloom at different periods. Yea mother nature thought of it first. 

   Bees? City? What about population risk.  Honey bees are just one of hundreds of different species of bee. They are different from carpenter bees, killer bees, ground bees, bumble bees, wasps or mud dobbers.

   Just like folks are rasing chickens in the city, people are crating hives in the city.

  
Nicole Ferraro,

   (grins)  Once the flood waters come in people are living on the water. Homes on stilts?  Lots of folks in the byou do it because the land is soo swampy. 

 

Lastly the biggest city I can think of that is built entirely stilts is Venice, Italy. The biggest city built on stilts in the ground is Boston City. Well we call them Pillings but the building rests on poles, not earth.  

 

  Just saying. 

 

richheap
richheap  
1/14/2014 12:00:08 PM
User Rank Staff
Re: No. 11!
Hi Nicole. I wondered that too, but actually the answer's pretty simple. Can you see the side of the building? Well, those are corridors with the front doors into the flats. The sticking out flats have their front doors facing onto those corridors, but they aren't visible in this photo.

richheap
richheap  
1/14/2014 4:20:46 AM
User Rank Staff
Re: No. 11!
You could put plants in spaces under raised parts of buildings as long as they get enough light. I'm no gardening expert, but light is pretty important.

Nicole Ferraro
Nicole Ferraro  
1/13/2014 6:18:32 PM
User Rank Staff
Re: No. 11!
Great ideas, ashepard. Another thought is those spaces can also be filled with greenery -- whether shrubs or full gardens.

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