Nepal Earthquake Nischal

8/16/2019 Nepal Earthquake Nischal

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The Spire of the temple, as a lumped mass, caused excessive vibrational stresses on the structure before

collapsing. Most of the remaining intact temples have had the spires broken off…


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It seems that most of the high-rise apartmental complexes such as the one pictured above have not

been properly designed for earthquake resistance. Many developed huge cracks on the load bearing

columns and re-entrant corners. The cracks propagated from corner to corner of windows. The above

apartment doesn’t seem to have band lintel beams as we can see cracks propagating vertically.


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Again, cracks originated from re-entrant corners of doors and windows. However, they have not spread

vertically across the floors in this case.


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Huge cracks seen across the asphalt roads that propagated a few meters into the ground.


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Notice the scale of soil settlement seen on the footpath and the connecting land.


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Here, an entire section of the road got settled, also notice the crack line running along the road on the

top left corner of the photo.


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We can see the front-side of the monument leaning towards the street on a closer look.


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This crack runs across the building and then falls vertically on the diagonally opposite corner as shown

below. So, an entire diagonal half is leaning on the street.


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A crack that runs vertically along the entire building from the ground, this might have been caused by

the vibrations coming from the adjacent attached building.


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The Front section of several buildings facing the road collapsed. The upper floor levels of these buildings

were extended onto the streets to gain more floor space. The extended portions behaved like

cantilevers and thus they were vulnerable to the earthquake.


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Many buildings that were attached together like this have sustained heavy damages when they

hammered against each other during the vibrations.


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There used to be huge temples on top of these two pyramid pedestals. I used to take the stairs to the

top of the pedestal and enjoy the view of the streets…


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Temporary supports added on the buildings. Which I think will remain for next 5-10 years, until the

government forces the inhabitants to repair the buildings.


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Traditionally built buildings with lime concrete, mud mortar and wood were more vulnerable. In the

above photo, we can see the cracks propagating from corners to corners. This was the most common

type of failure mechanism seen in the buildings.


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Cracks running across the floor and connecting

vertically adjacent windows and doors on the ground floor.


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A closer observation showing the re-entrant corner cracks, connecting the corners of the door and the

window


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Again mostly corner to corner cracks, traditionally built structures were extremely vulnerable


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Again scaffoldings installed to relieve

stress on the buildings


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Cracks running through the plinth

Cracks resulting from the lack of proper lintel reinforcements; runs through all of the adjacent doors and

windows.


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A house made from modern construction materials, i.e., reinforced cement concrete, and brick –cement

mortar


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However, it has suffered huge damages, with vertical cracks running from the plinth to the roof. This

could have happened as result of the adjacent buildings being physically connected. Expansion joints

with enough spacing to allow building sway aren’t present.


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A possible case of progressive collapse, where one part of building initially collapses. This imbalances the

stability of the remaining portion, which eventually results in collapse of the remaining portions. It’s

something similar to the collapse seen on the house of cards, whereby removing one card leads to

collapse of all the remaining. Framed structures with redundant structural members are resistant to this

effect.


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Again, installed scaffoldings to

distribute stresses, and to provide

lateral confinement.


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The crack separated the two adjacent buildings which were previously monolithically attached. This

separation crack runs vertically through the entire building.


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Another picture of re-entrant cornercrack


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New cracks seen on the Tri-Chandra College building. It is actually a very old building, and has survived

an 8.1 magnitude earthquake that struck Nepal about 80 years ago…


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The picture above is the Dharahara Tower of Kathmandu city, I took this one off the internet. The

picture shown below is all that remains. The failure mechanism is quite interesting. If you see clearly, the

tower broke off at its base and also it broke at an angle, I would assume the angle to be somewhere

close to 45 degrees.


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You would naturally expect a cantilever to

develop the maximum bending moment

and shear forces at the point of its support.

Which is why, the tower broke off near the

ground. Also, since it broke at an angle

close to 45 degree, the mode of failure was

Shear.


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Finally the cracks seen in my house…

This crack runs through the entire base of the parapet wall on the terrace.


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I am not sure if the crack shown in the above picture runs across the width of the wall…

Cracks on the arched entrance door


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Cracks on the wall just below the sun-roof of my house shown on the picture above and below…

There were cracks on other numerous places which included ones on a few of the window corners, and

marble flooring on the corridors… Other than this, all of the load bearing walls and columns on the


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ground/plinth level of my house has settled by a few millimeters probably because the underlying soil

got densified. You could say that my entire house has settled into the ground…

As a note, most of the modern houses in Kathmandu are constructed using reinforced cement concrete

slabs, beams and columns, and brick-cement mortar walls. However, my house has only reinforced

concrete slabs, all the loads are transferred to the ground through brick-cement mortar walls andcolumns. So, it isn’t the most earthquake resistant structure out there…

Only older traditionally built houses use timber, mud-mortar and lime concrete. They are definitely

extremely vulnerable to earthquakes.

~Nischal P N Pradhan

Nepal Earthquake Nischal

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