Biaxial Seismic Simulator

Biaxial Seismic Simulator with a Laminated Shear Stack option

For reproducing realistic earthquake events in a laboratory with a moderate research budget using a compact system

Digital Model Table

Earthquakes are a problem of great significance to Australia. History shows that earthquakes may occur in places with no previous seismic activity. Australian cities are at risk as they comprise old infrastructure made of unreinforced brick and masonry, which is particularly susceptible to earthquake damage. Moreover, large areas in Australian cities are underlain by soils which may experience strength loss and turn to a fluid-like state (liquefaction) in an earthquake. Reinsurance companies rate an earthquake in Sydney in their 20 top risk exposures worldwide.

Research is needed to understand how infrastructure responds to earthquakes, using seismic simulators to conduct controlled laboratory tests in which large models are subjected to earthquake loading.

Most earthquake damage is caused by a combination of significant horizontal and vertical shaking. However, the seismic simulators used by many researchers move in just one horizontal direction, posing limitations on the relevance and usefulness of the results they generate.

This low cost shaking table has been developed by UNSW and incorporates advanced actuation and control technology.

It enables combined horizontal (lateral) and vertical (heave) motions providing a higher level of simulation realism when compared with uniaxial simulators which move in just one horizontal direction.

The Biaxial Seismic Simulator is ideal for researchers wanting to:

  • enter the earthquake engineering testing field at a low cost
  • upgrade current testing capabilities which may be limited to shaking horizontally
  • make research discoveries that are more relevant and that will have greater impact than possible using other low cost simulators which only shake horizontally

The Biaxial (H and V) Seismic Simulator, unloaded and with combined H and V sine sweepsThe cost of the Biaxial Seismic Simulator is kept low through its use of only two actuators with the same horizontal alignment. This simple design makes the simulator very compact and easy to anchor to a strong floor, and it occupies a relatively small space. The installation costs are far less than required for a six degrees-of-freedom system.

One of the actuators causes the vertical motion using a scissor mechanism, sometimes referred to as the Scott Russell mechanism. The other actuator causes the horizontal motion. https://en.wikipedia.org/wiki/Scott_Russell_linkage

The first simulator of this type has been installed at UNSW. One current project using the simulator involves the development of a new technology to make tailings liquefaction resistant in the event of an earthquake. It is being run in parallel to an ARC funded project led by UWA that also involves UNSW, UniSA, UoW and six mining companies. Another current project is an investigation, with Yokohama National University, into the seismic behaviour of stone walls of Japanese castles.

For further information on the seismic simulator, enquiries on sales and rescaling the simulator’s design and specifications to suit your needs, or to get involved in related research projects please contact Associate Professor Adrian Russell at UNSW (a.russell@unsw.edu.au). Technical information on the simulator at UNSW is contained in the brochure.

The Biaxial Seismic Simulator, unloaded and with combined horizontal and vertical sine sweeps

Earthquake testing of a drystone retaining wall

The purpose built laminated shear stack

The purpose built laminated shear stack with a CPT penetrometer mounting frame attached. Each of the 10 laminates has an adjustable stiffness