1 / 23

Plate movement

Plate movement.

micheal
Télécharger la présentation

Plate movement

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Plate movement

  2. Earthquake = sudden release of energy in the Earth’s crust that creates seismic waves. They are measured by the Richter Scale, which is an exponential scale. Magnitude 3 and below are very weak and barely felt, magnitude 7 and above cause serious damage over large areas. The damage and severity of shaking depends on the earthquake’s depth.

  3. Surface waves travel along the surface of the Earth after P waves and S waves.

  4. Earthquake Engineering The purpose is to mitigate earthquake hazards. This is done through: Preventingnon-structural damage in frequent minor ground shaking Preventingstructural damage and minimizingnon-structural damage in occasional moderate ground shaking Avoidingcollapse or serious damage in rare major ground shaking

  5. Earthquake Engineering • Damage to structures may result from different seismic effects. • Ground failure (surface faulting and vibration of soil) • Vibrations transmitted from the ground to the structure. • Structural engineers are most concerned with the vibration of the structure in response to ground shaking at it’s foundation.

  6. Seismic Structures • 2012 EERI Seismic Design Competition - Stanford University – YouTube • UTAustin - Seismic Design Competition 2011 – YouTube • JohnsHopkins - Seismic Design Competition 2011 – YouTube • UCLA - Seismic Design Competition 2011 - YouTube

  7. Seismic Effects – Ground Failure • Soil instability during earthquakes can cause significant damage. Soil response depends on the characteristics of the soil layers, depth of the water table, and intensity/duration of ground shaking. • Liquefaction is when unconsolidated soil acts like a liquid. This can undermine the foundations of structures, causing very serious damage. Ex: Haiti

  8. Seismic Effects – Ground Failure • Liquefaction works when earthquake waves cause water pressures in increase in the sediment, which causes the sand grains to lose contact with each other.

  9. Seismic Effects – Ground Failure • Typical effects of liquefaction include: • Loss of bearing strength – soil cannot support structures • Lateral spreading of soil – ground slides down gentle slopes or structures move around on a buried liquefied layer • Ground oscillation – the surface layer, riding on a buried liquefied layer, is thrown back and forth by the shaking. • Settlement – when liquefied ground re-consolidates after the earthquake, the ground surface may settle or subside as the liquefied soil becomes more dense.

  10. Seismic Effects – Ground Vibration • The seismic performance (degree of damage) of a structure depends on: • type of foundation • configuration of the structure • structural material • design and construction details

  11. Seismic Effects – Ground Vibration • The main points to remember are that the whole structure-foundation system should work as a unit, and that the superstructure be tied or anchored properly to the foundation.

  12. Design Proposal • Some items to research for your design proposal are: • Base isolation systems • Shear wall system • Building elevation control • Friction pendulum bearing

More Related