EOSC 114 Lecture Notes - Lecture 7: Seismic Wave, The Vibrations, Tuned Mass Damper
17 Jul 2016
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Document Summary
Horizontal ground motion are most damaging to buildings. P-waves are the least destructive, duration and amplitude is the smallest. M9 earthquakes can cause several minutes of shaking. A quantitative measure of the maximum ground motion produced by the earthquake. Moment magnitude: describes fault size, slip, and strength. A qualitative estimate of how ground motion affects population and structures. Excluding landslides, earthquake faults and waves rarely break the ground surface. Sometimes there can be crack, but rarely open space. Wood is flexible and a low and squat geometry is generally better. If you shake a structure hard enough or long enough, it will fail. A key design factor to control is resonance. Complex structures (almost all structures) will have many modes of vibration, but will have one or perhaps a few dominant modes (or resonances) If the "forcing" vibrations are tuned to one of the primary resonant frequencies of the structure it breaks.
