Index ~~ Background ~~ Purpose ~~ Hypothesis ~~ Materials ~~ Earthquake Machine ~~ Modifications: Overlapping - Height - Buttresses - Base Isolators - Cross Braces - Roofs ~~  Resistant Buildings ~~ Problems ~~ Further Experimentation ~~ Bibliography

EARTHQUAKE RESISTANT BUILDINGS

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PAGE INDEX:

Background

Procedure

Building with base isolator

Building with buttresses

Conclusion

 

BACKGROUND:

Earthquake-proof versus Earthquake Resistant

     

      Engineers would like to make every building earthquake-proof, but can't because it's too expensive. Instead, they recommend making dams and public buildings earthquake-proof. All other buildings should be earthquake resistant to avoid deaths. The cost of repair is a fraction of the cost of earthquake-proofing these buildings (Knowing Earthquakes, p. 2-3). The Transamerica Pyramid Building in San Francisco is earthquake-proof. It swayed more than one foot in the 1989 earthquake but wasn't damaged.

 

The earthequake resistant, pyramid-shaped Transamerica Building in San Francisco ("Design: Tuned Mass Damper")

Transamerica Building, San Francisco

Diagram showing many uses for mass dampers. ("Structural Control System")

(Left) Tuned mass damper system

PROCEDURE

A) A nine layer overlapped building with a cross brace inside was made on the earthquake machine. Straight buttresses and a roof attached with plasticine were added. The handles of the earthquake machine were pulled back to the line then let go. When the machine had stopped shaking, the handles were pulled again and again until the building collapsed. Each pull of the machine was timed to last two seconds. Three trials were done. At the end of each trial, the building was rebuilt. The data for each trial was recorded.

  

 

Nine layer earthquake resistant building made with roof, overlapping blocks, and buttresses

Earthquake building

with buttresses

 

B) A nine layer overlapped building with a cross brace inside was made and a roof was attached using plasticine. The building was built on a marble  base isolator on the earthquake machine. The handles of the earthquake machine were pulled back to the line then let go. When the machine had stopped shaking, the handles were pulled again and again until the building collapsed. Each pull of the machine was timed to last two seconds. Three trials were done. At the end of each trial, the building was rebuilt. The data for each trial was recorded.

 

Nine layer overlapped building, with roof, sitting on marble base isolator

Earthquake resistant

building with base isolators

 

RESULTS (A)

EARTHQUAKE RESISTANT BUILDING WITH BASE ISOLATOR
9 LAYER OVERLAPPED BLOCKS
  nine layer cross braced roof base isolator

cross braced/

roof/

base isolator

  10 20 10 28 36
  12 22 14 28 40
  12 16 16 24 34
average 11.3 19.3 13.3 26.7 36.7
  % improved stability 71 18 136 225

 

 

RESULTS (B)

EARTHQUAKE RESISTANT BUILDING WITH BUTTRESSES
9 LAYER OVERLAPPED BLOCKS
  Nine layer Cross braced Roof Buttresses

Buttresses/

Roof/Cross braced

  10 20 10 12 20
  12 22 14 10 24
  12 16 16 12 18
AVERAGE 11.3 19.3 13.3 11.3 20.7
 

% Improved stability

71 18 0% 83

 

 

CONCLUSION

It is possible to make modifications to a building to make it earthquake resistant.

 

The nine layer overlapped cubic building with buttresses, a roof, and cross braces was 83% more stable than the plain nine layer building. The nine layer overlapped cubic building with cross  braces, a roof and a marble base isolator was 226% more stable then a plain nine layer building. The base isolator is more effective at stabilizing the building than the buttresses because it actually absorbs more of the earthquake's energy.

 

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PROBLEMS WITH THE EXPERIMENT