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Science Nation: Engineering Innovative Seismic Retrofits That Don't Break the Bank

4 minutes

(Describer) Streams of light collide to create a globe filled with water. Title: Science Nation. A two-story building frame stands.

(man) Six, five, four, three, two, one, start.

[clattering]

(Describer) Part of the building shakes.

(male narrator) On a hot, late summer afternoon at Georgia Tech's Structures Lab, it's time to get shaking.

(Describer) A flat machine shakes.

[rumbling]

This is no act of nature. It's a highly controlled, calibrated shake test. And this building is wired to the hilt.

(Describer) Reginald DesRoches:

We're really concerned about two- to five-story buildings that are used for office buildings, apartment buildings-- any sort of structure you might find very common in the U.S. Nine, eight...

(Describer) Results are monitored in a truck beside the structure.

(narrator) With the National Science Foundation's support, structural engineer Reggie DesRoches and a team at Georgia Tech want to document how older, reinforced concrete buildings respond under moderate to strong earthquake conditions and validate how to best retrofit them to withstand a temblor.

(Describer) The machine shakes the structure again.

(DesRoches) The project goal is to understand how they behave, and also look at ways to retrofit them, to rehabilitate them so they perform better and don't collapse during earthquakes.

(narrator) The Georgia Tech team built this concrete structure with their shake test plans in mind. It's divided into four sections, so that each can be rigged for different retrofits and more tests could be done. The shaker itself is a portable unit attached to the building's roof.

(Describer) On the roof, it shakes a weight side-to-side.

[buzzing, clanging]

(DesRoches) It impulses a load laterally onto your building, representing what would happen in an earthquake.

(narrator) During our visit, a bolt needed for structural stiffening came loose during the first strong test. They quickly fixed it, and we're back in business. The retrofits varied, mixing combinations of mortar, high strength steel rods, and carbon fiber sheets that wrap around the columns and pillars. Another was a brace using a shape-memory alloy to keep the structure strong and stiff. Even under hard shaking, it barely moved at all.

(DesRoches) We tried several retrofits. All worked to a different extent. This project focused on trying to find ways to retrofit less disruptively than the current approaches. Meaning you don't need to evacuate buildings for long extended periods to retrofit it. It doesn't alter the building's aesthetics dramatically, and it's easy and economical to do.

(narrator) DesRoches wants to give building owners looking to upgrade the information they need to choose an effective retrofit.

(DesRoches) People think there's nothing to do about earthquakes other than hope you're not in the building. Actually, there are straightforward ways you can retrofit a structure, so it either doesn't collapse, whereas it would without retrofitting, or has a much better performance.

(Describer) The machine shakes again.

[rumbling]

(narrator) Tests like these, and the retrofits to follow, could mean a huge difference, making older structures in quake zones safer than ever before.

(Describer) The globe turns beside the title.

For Science Nation, I'm Miles O'Brien.

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Researchers at the state-of-the-art Structural Engineering and Materials Laboratory at the Georgia Institute of Technology are using a full-scale model building to test new ways to protect structures from earthquakes and potentially save lives. The three-story concrete building is based on designs common through much of the 20th century. It has been subjected to round after round of simulated temblors to test if materials such as carbon fiber or new shape-memory alloys can be used to reinforce the structure so it would remain standing in moderate to strong earthquakes. With support from the National Science Foundation, structural engineer Reginald DesRoches and his team have developed a series of retrofits of varying cost and intrusiveness to give building owners in quake-prone areas a range of choices for hardening their property.

Media Details

Runtime: 4 minutes

Science Nation
Episode 1
4 minutes
Grade Level: 7 - 12
Science Nation
Episode 2
4 minutes
Grade Level: 7 - 12
Science Nation
Episode 3
4 minutes
Grade Level: 7 - 12
Science Nation
Episode 4
4 minutes
Grade Level: 7 - 12
Science Nation
Episode 5
4 minutes
Grade Level: 7 - 12
Science Nation
Episode 6
4 minutes
Grade Level: 9 - 12
Science Nation
Episode 7
4 minutes
Grade Level: 9 - 12
Science Nation
Episode 8
4 minutes
Grade Level: 9 - 12
Science Nation
Episode 9
4 minutes
Grade Level: 7 - 12
Science Nation
Episode 10
4 minutes
Grade Level: 10 - 12