Date: April 25th, 2015
Magnitude: 7.8M or 8.1M
Aftershocks: 250 as of May 18, 2015
But why was the damage that severe? The New York Times reported that the earthquake “has ignited public alarm that the collapses exposed not only flaky concrete and brittle pillars, but also a system of government enforcement rotted by corruption and indifference.” A lot of the blame was placed on “bribery, lax law enforcement and a lack of land-use controls” in a “rapidly urbanizing society.”
The evidence couldn’t be clearer. Looking at a variety of photos form the earthquake, we can run a (very) quick analysis on the structural integrity of Nepal’s damaged buildings. Here are just two:
Here are some themes we find in the photos:
1) Unstable building foundation.
2) Poor structural integrity of homes and buildings.
3) Lack of code enforcement.
Fixed building bases will topple the structure whereas isolated ones absorb ground movements from seismic forces. Take NORAD, for example. All their structures buried deep inside the Cheyenne Mountain rest on gigantic springs that are designed to absorb any impacts from nuclear attacks to massive earthquakes. Here’s another photo from Nepal showing how a fixed-base foundation caused this building to collapse (eerily similar to the drawing above) :
Structural integrity is key to a structure’s lifespan. In both photos showing the destruction in Nepal, there are bricks and debris everywhere. But where’s the steel? Rebar? beams? Considering that they’re nowhere to be found, it’s no wonder that these buildings were so prone to damage and collapse. Generally, engineering standards suggest using reinforced concrete columns for support, rather than piled up pieces of bricks. These types of columns usually have strands of rebar (reinforced steel bars) wrapped with a thick layer of concrete around all sides. And if you want to get really fancy, you can always use pre-stressed concrete beams!
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