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How can I find out about the shaking-table tests?
For general information about the shaking-table tests go to
http://www.ideers.bris.ac.uk/dynamicdesigns/earthquakes.html |
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Can you tell me some details about the earthquake?
The earthquake shake will be a 2-axes shake in the horizontal plane only (x and y directions). Each earthquake generated by the shaking-table will be a sine sweep with a frequency range of about 1-15Hz. |
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 Adam Crewe posted on Tuesday, July 14, 2009 - 05:22 pm
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What will the earthquake tests be for the competition in Korea ?
The shaking table that we will be using is Table A at KOCED Multi platform seismic simulation facility in Pusan. You can find more general details at:
http://en.wikipedia.org/wiki/Earthquake_shaking_table
The table we are using is listed as "Pusan National University (1 of 3)" on this page. The table has the following peak performance values that are appropriate for the tests on your models.
Peak displacment (X or Y axis) +-200mm
Peak velocity (X or Y axis) +-1000mm/sec
Peak acceleration (X or Y axis) +-20m/sec2
The shake we will be using lasts 60 seconds and is an enveloped sine sweep that produces a response spectra roughly the same as the EC8 spectra. In this way your models will subjected to the sorts of forces that could be expected in a real earthquake but by using a sine sweep it is much easier to see the individual modal responses of each of the models being tested.
The shake we will be using will look something like the one shown in the following file. This shows how the acceleration varies with time during the shake. The shake starts at about 15Hz and slowly reduces down to about 2Hz. The peak accelerations levels are between 3 and 5Hz. The table itself moves in a circular motion so all axes of your building will be tested for strength.
For reference the PSD for this shake is shown in this file. (Don't worry if you don't understand this - it is just presenting the same information in a different way)
 PSD for seismic tests when scaled to about 1.2g
PSD.pdf (14.3 k) |
In the final competition, models will be tested on a shaking-table for a series of earthquakes. The first earthquake will be very small. Then the size of the earthquakes will be increased gradually, up to the maximum the shaking-table can produce. (The earthquake shown in the file is scaled to 1.2g which is likely to be one of the largest shakes we will do. The first earthquake will be about 1/20 of this size so all the models should survive this  )
We are not sure exactly what levels of shakes we will test your models at but it is likely to be something like this:
0.05g
0.1g
0.15g
0.2g
0.25g
0.3g
0.4g
0.5g
0.6g
0.7g
0.8g
0.9g
1.0g
1.2g
etc.
Remember that you are trying to design an "Efficient Model" rather than a strong model. For every model, a record will be made of its cost and the size of the earthquake that causes it to fail. An efficiency ratio for your model will be calculated by dividing the size of the largest earthquake it survived by the cost of the model. The team with the model that has the highest efficiency ratio will win the prize for the “Most-Efficient Model”. Therefore a light but well built model can easily do better than a heavyweight model that survives a larger earthquake. |
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