I am doing my civil engineering and I have this doubt - What is Earth quake force exactly?
I know that it is a lateral force but not able to really understand how it is acting on buildings.
When it is a wave acting on ground, why should we divide in to many zones?
It will be helpful if you can clarify this.
Well! Earth Quake or a seismic Activity is not a wave that induces a direct force or pressure. Earth quake may travel as a wave but it’s not the hit of a wave that creates forces in buildings. The wave only makes a ground movement or acceleration. This acceleration of the ground below the building induces inertial force in the building. I have explained this ground movement and the inertia in the video, explaining about an accelerating bus which induces inertia in the occupants of the bus.
So, to summarise, earth quake is movement of ground and earth quake force is the resulting deflection in the building induced by the inertial force acting at the column beam junctions.
India has 5 seismic zones. Zoning is done in order to estimate the ground acceleration appropriate to the probability of earth quake in a region. This probability of seismic activity is based on the historical data of earth quake and also based on the seismological study of the earth’s crust.
Please comment below if you have further questions on earth quake.
Also see the attached YouTube structural tutorial and like and follow the channel.