How to Rebuild After an Earthquake

How to Rebuild After an Earthquake

Given that Durres and the surrounding areas were hit by a strong earthquake a week ago, causing many damage in buildings and people, we are taking notes on a New York Times article about a devastating earthquake that stroke Nepal a few years ago.

Why did so many buildings crumble in Durres’s recent earthquake, even those that were built under modern building codes? Lax enforcement fueled by corruption and indifference probably played a part, but so did a lack of public awareness about how to build structures that can sway and shake in an earthquake and absorb some damage without collapsing. Albania is not a wealthy country, even so, there are ways to build in an earthquake-prone area that can make homes less likely to fail.

Here are tips offered by two experts: Maggie Stephenson, who worked for the United Nations on postearthquake reconstruction in Pakistan and Haiti, and Bijay Krishna Upadhyay, community director and training specialist at the National Society for Earthquake Technology-Nepal.

(Photo by Armend NIMANI / AFP)
  1. Build to last.

Whenever possible, people should build permanent homes from the start, rather than improvising temporary shelter and then trying to improve it later. That approach rarely yields structures with integrity.

  1. Choose the ground wisely.

Soil conditions under a structure make a big difference in how it fares in an earthquake. Soft or muddy soil amplifies ground movement and makes foundations less stable. Hard or rocky soil is generally better, though in mountainous areas, steeply sloping ground can be prone to slides, and rock outcrops or cliffs uphill from a building site can break loose in a quake.

Mr. Upadhyay offered a simple test for soil integrity: Dig a hole one meter square and one meter deep, and then put the extracted soil back in. If it does not refill the hole to the top or higher, he said, the ground is weak.

  1. Plan ahead, and plan conservatively.

Following a prepared plan and a budget will more likely yield a robust structure, with its doors and windows, columns and walls placed sensibly and safely. Making it up along the way — a common practice in rural construction — can lead to unbalanced, incomplete buildings and skimping on materials when money runs out.

Unless a trained engineer is involved, stick to tried-and-true design principles and proportions, and avoid more modern features like a “soft story” — an open ground floor with columns but no walls — because they can make a building vulnerable to collapse.

  1. Check the quality of materials.

Weak materials will result in a weak construction. Ms. Stephenson suggested several simple field testing methods.

To check the strength of bricks, drop two of them from a height of four feet and see if they crack or break. For steel reinforcing rods, try to bend one of them into a square; if it does not bend three times, it may contain carbon and be too brittle for the purpose.

  1. Anchor the building well.

The stronger the foundation, the more force a building can generally withstand in an earthquake, provided it is well anchored to the ground. For a single-story masonry house, foundation footings should be at least two and a half to three feet deep and wide.

“It is as if you had a plant that’s not really dug down into the ground. If it has got shallow roots, you can rip it out easily.”

  1. Tie the building together.

Masonry buildings need horizontal bands built into them that can tie the walls together and make the building move as a unit in an earthquake. There should be horizontal bands at the floor level and at the tops and bottoms of windows, and there should be at least one for every two meters of wall height.

The corners of the building should also have vertical reinforcement.

  1. Columns must be secured.

Many buildings collapse because they are built with columns of varying sizes that are not anchored properly.

  1. Avoid top-heaviness.

Heavy roofs are dangerous in earthquakes. Roofing materials like stone and ceramic tile should be avoided. Corrugated metal, which has become much more common in rural areas, is much lighter and much safer.

  1. Keep water away from the foundation.

Standing or flowing water can weaken a masonry building’s foundation and walls, especially when cheap bricks and other materials of uncertain quality have been used. Good drainage is a must to protect the building’s integrity.

Source: nytimes.com

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