Shake Tables

Derek Jacobs & Julia Johnson

What is a shake table?

• Used to replicate earthquakes• Can also used for noise & vibration

tests• Their most basic form, shake tables

consist of a flat plate that moves by computer control

• Shake tables come in a large variety of sizes and capabilities

Performance Features

• Shake tables can have many different features – Degrees of freedom– Capacity (weight of structure that can be

supported)– Frequency range– Stroke range– Velocity range

How do they work?

• Table Hardware– System of pistons & motors under the plate– May or may not be sensors in the table itself

• Control Hardware & Software– System of connections that transfer commands

from a computer to the table– One of many types of software programs

chosen for a given table

Shake tables from around the world University of California San Diego

• Large high performance shake table

• Enables large scale experiments to be performed– Full scale buildings– Single and multiple

column bridge bents– Life line structures– Nuclear containment casks– Seismic isolation systems

Shake tables from around the world University of California San Diego

• Properties– Single DOF w/ capability

of upgrading to six DOF– Capacity:

• Horizontal force: 6.8MN• Overturning Moment:

50MN-m• Vertical Payload: 20MN

– Frequency range: 0-20Hz

– Stroke range: ± 0.75m– Velocity range: ±1.8m/s

Shake tables from around the world Rensselaer Polytechnic Institute

• 2-D shake table• Provides periodic or

random shaking determined by input signal

• Used in conjunction with centrifuge

• Can facilitate the investigation into the response of scale geotechnical or soil structure systems

Shake tables from around the world Rensselaer Polytechnic Institute

• Properties– 965mm x 660mm– 2 DOF– Capacity: 50 kN– Frequency range: 0-350

Hz– Stroke: 6.35mm– Velocity Range:

±1.1m/s– Centrifugal acceleration

max: 100g

Shake tables from around the world State University of New York -Buffalo

• Dual-movable tables– Used for real time

testing of structures up to 120’ long and 30’ high

– Tables can be used fully in-phase or totally unrelated

– Can test large variety of scale structures from buildings to road segments

Shake tables from around the world State University of New York -Buffalo

• Properties– Size: 3.6m x 3.6m– 6 DOF– Capacity:

• Vertical payload: 50 tons each

• Overturning moment: 46ton-meter

– Frequency range: 1-50Hz

– Stroke: ±150m, ±150m, ±75m

– Velocity Max: 1.25m/s, 1.25m/s, 0.5m/s

– Acceleration Max: ±1.15g w/ 20 ton specimen

Shake tables from around the world Miki City, Japan

• Worlds largest shake table

• Offers a wide variety of testing capabilities:– RC structures– Soil pile-structure– Wooden Structures

• Part of the E-Defense • 5 actuators in each

horizontal axis and 14 in the vertical axis

Shake tables from around the world Miki City, Japan

• Properties– 20m x 15m– 3 DOF– Capacity:

• Payload: 12 MN• Overturning moment: 150

MN-m– Stroke:

• ±100cm Horiz.• ±50cm Vert.

– Velocity• ±200cm/s Horiz.• ±70cm/s Vert.

– Acceleration• ±900cm/s2 Horiz.• ±1,500cm/s2 Vert.

Shake tables from around the world University of Nevada Reno

• Biaxial multiple shake table facility

• 3 identical biaxial shake tables

• Used for research on long, specially distributable structural and geotechnical systems

Shake tables from around the world University of California Berkley

• First of its kind• Properties

– 20ft x 20ft– 3 DOF– Capacity: 100kip– Acceleration Range:

±1.5g– Stroke: 10.5 ft, 8.66

ft

References

• http://nees.buffalo.edu• http://nees.buffalo.edu• http://nees.unr.edu• http://nees.rpi.edu• http://nees.org• http://www.bosai.go.jp/hyogo/

• Make Your Own!– http://www.exo.net/~donr/activities/Shake_Tab

le.pdf