Lecture 29

Namaskar, yesterday we talked about seismic waves and their frequency, what kind of frequency is generated. So, today we will talk about how it will affect the buildings, so let us move to the next slide. So, first of all, let us look at some earthquakes, which were very big earthquakes, and we can say that they were large magnitude earthquakes, and how many people died in them, so this is a list, which you will see, this is till 2010, after that also, many earthquakes have come, have come in India as well, in our country as well, the one that came in Nepal, in 2015, it was 7.6, so there was a lot of damage in that as well, and many people died, although it was not as much damage as was expected, but if we talk about the frequency and see about it, then how the buildings will vibrate, as we have said that low frequency waves and high frequency waves are there, so because of that, in which place the shorter buildings and taller buildings are there, that vibrates you. So, these are some examples of this, so these are the buildings of different heights, means whose height is different, which we talk about multi-storey buildings, shorter buildings which we say, so only one floor is made or two floors are made, but if it is a multi-storey building, then we put it in the category of high-rise buildings. So, what happens is, it is your sway, we say its shaking, so the buildings shake, when the earthquake waves pass through the earth crust and its material, so we have taken this information earlier as well, that different frequencies, one and the other is its motion, which propagates, its characteristics are different, which does push and pull, up and down, side by side, elliptical, so in this way, the vibrations, due to which the acceleration, ground acceleration will be different and due to that, your different buildings will affect it. So, it sways like a pendulum, means if you have this building, then it will sway like a pendulum. So, if you have this building, then it will sway like a pendulum. So, this can be the way to save the oscillation. So, if you have this building, then it will sway like a pendulum. So, but the best examples which one can easily work out and provide the safety to the houses.