Earthquake proof buildings

[Aisha]

How do earthquake-proof buildings work?

[gregpreed]

I am no expert and this is a total guess. It could be a combination of things really like a strengthened base and a larger surface area etc. However I think the main factor would be a structure made out of flexible material that took in the shocks. A building that would move with the quake taking less force and therefore most like to withhold the movements or shocks. -- You could think of it in terms of a pencil - what happens when you bend a wood pencil? It snaps. If the pencil were made out of plastic or a "bendy" material it wouldn't snap - it would move with the force and go back into its original position after the force was no longer applied. If you have any disagreements with the above email me! [email protected]

[GeorgeR]

They are built around a rigid structural frame that is not dependent on the earth surface (foundations) for support. They can be moved around like a rigid "box" without collapsing. The Turkish earthquake last year revealed how not to do it (insufficient cement in the concrete), but the subsequent one in Tawain showed lots of intact buildings which had survived, but at precarious angles. Here, in Portugal we need a certificate for new buildings, to confirm that the design is earthquake proof.

[Ed Ancona]

Houses and buildings can be made earthquake resistant, but earthquake proof -- mother nature can always go you one up. The standard frame construction residence can be made resistant by fastening 3/4 inch plywood to the vertical studs to make a rigid box which will not collapse into an oblique parallelogram under the shaking. Also the base plate upon which the studs sit must be bolted to the concrete foundation so the house will not slide off. The 'cripple wall,' the short structure which elevates the main floor a foot or so above the foundation, must also be reinforced against collapse with a 3/4 inch ply facing. Such construction is now standard in California, and many houses are being thus retrofitted. Bookcases, tall furniture and water heaters should be strapped to the walls so they will not fall over. Cabinet doors can be equipped with 'baby latches' so they will stay closed to prevent your valuable dishes from sliding out onto the floor. An automatic shutoff valve should be put in the gas line.

[Ed Ancona]

...further to earthquakes: Different soil conditions can affect the vulnerablilty of structures to an earthquake. Alluvial soil, the softer soil deposited by old rivers and streams, can liquify during earthquake shaking allowing even a rigidly constructed building to fall sideways as the supporting soil gives way. Some of the pictures from the Kobe earthquake showed this. If you can, build your house on a solid rocky hill, but first check with the geologists to be sure that you're not over a known large fault. (Isn't there something in the Bible about not building your house on sand?)