Posted by Per Corell on November 06, 2002 at 00:06:15:
In Reply to: Re: Can we not produce earth quake safe buildings ? posted by d on November 05, 2002 at 14:03:21:
Guess this is the first thing to consider , - the strength. Esp. when it show that the materials seem veak or a breakdown show the use of bad materials . Also the use of more flexible reinforcememt are obvious , but isn't it the rigid structures, together the heavy weights and the cracking up of rigid "boxex" that caurse the structures to pancake.
If building elements are not allowed to move seperatly and when heavy materials are allowed as "filers". When each part of the structure "live it's own life" don't support or is supported with other members as the "structure" are rather a form then an element with internal strength or ability to flex.
Guess the real problem as you point out, are not about newbuild buildings but those standing there for decates ,and the solution for new and old buildings will be two different things.
Still ------- is there even any real solutions with structures where each part will be seperated so no strength are left with building elements that acturly live their own life indepandant of other parts of a structure. Most old buildings was in a way forced to the worse possible structure, as if any member shuld have any function it would be fighting gravity when builded causing huge trouble for the craftmen placing members ontop eachother locked with otheres in what is often a "card house" building with only horisontal and vertical members . As in a "card house" the only way to have two walls standing is to lean the vertical edges towerds eachother ,no diagonals possible except those that act as "building jig" for the much heavyer stone members , ------- guess the list can continue.
What I promote is even very different than the damper systems with modern buildings ; I point to the nature of an earthquake ,that often are seen as "earth waves" ; waves that move along the surface of the ground as waves in the sea, where the way we tradisionaly se an earthquake is like a chaos of shakings ,fact is that there are a system in earthquakes, that could make it possible tom maby avoid the consentration of forces within a rigid structure ; to solve the problems with pancaking of tradisional structures will be a fight against the chaos forces that could even mean that weakening a building instead od reinforcing it, could even produce a more safe structure , ------ but often this would be more expensive than removing the old one and replace it with a modern lightweight structure.
With the structure in the graphic, each member will be allowed to tilt, independant of all other members it's movements will be forced guided by the assembly slots ,so "lifting one end of a beam and a build up of forces could even make a lock in fragile filler material explode, so each member will be allowed to move ; or isn't this just where a great deal of the problem show , that when a structure are not allowed to flex ,then the forces _will_ be pointed to the weakest points , the joinst the corners , the brick walls that othervise would be the place where the forces in rigid combined frame-wall structure is concentrated.
This is why I ask about the nature of earthquakes, as if they are waves ,then in theorie you could place several beams in a structure as in the graphics , in top of eachother, each holding several floors, and case one "corner" of the structure lift due to an earthquake wave, the motion will be absorbed within the structure, by being used too flex the structure , instead of breaking it apart.
---- Guess it's not the earthquake, but the gravity that acturly destroy a house and make it pancake.
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