Lateral Seismic Loading 1

[sammy3]

What is the theory behind energy dissipation between a flexible structure vs. a stiffened structure in regards to seismic design? How does this theory apply to a statically loaded system (flexible vs. stiffened structure).

 

[bjb]

I am far from an expert on this, but my understanding is that the important factor is the ductility of the structure. In an earthquake it is probable that things will be stressed beyond the yield point, and energy is dissipated when the structure deforms in a plastic manner. If the structure is not ductile, it doesn't have the ability to deform in a plastic manner, so things will tend to fracture. The demand for ductility is not as great for a static load (such as wind is usually assumed to be) I believe because you don't get load reversals. With load reversals you get a hysteresis loop, and I believe the bigger the loop the more energy dissipation, which is a good thing.

In terms of building stiffness, it is my understanding that a stiffer building has a shorter period, and therefore is subject to higher accelerations and therefore higher forces from an earthquake.

Like I said, I am no seismic expert but these are my general understandings. Usually, my buildings are in low seismic areas.