Civil Engineering Made Easy: Measuring the Damage in Nepal

Date: April 25th, 2015
Magnitude: 7.8M or 8.1M
Type: Thrust
Dead: 8,452
Injured: 19,009
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:

nepal earthquake

A man cries as he walks on the street while passing through a damaged statue of Lord Buddha a day after an earthquake in Bhaktapur, Nepal April 26, 2015. Rescuers dug with their bare hands and bodies piled up in Nepal on Sunday after the earthquake devastated the heavily crowded Kathmandu valley, killing at least 1,900, and triggered a deadly avalanche on Mount Everest.  REUTERS/Navesh Chitrakar      TPX IMAGES OF THE DAY      - RTX1AAS7
REUTERS/Navesh Chitrakar

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.

Building foundations are crucial to a structure’s integrity. Notice these two diagrams:as1as3

 

SpringsFixed 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) :

nepal

 

 

 

_47397578_earth_quake466x352Structural 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!

Nepal’s lax building standards require decent enforcement and its infrastructure needs better upgrades. Crooked politics and government corruption feed off the ignorance of ingenuity, safety, and growth. Nepal will need money to rebuild; if World Bank or IMF loans are used, this small and poor South Asian country will need to reform its government and stop corruption before another earthquake stops it.

 

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