| Term: | Thumper: Urban, two-axis shaker |
| Definition: | University of Texas at Austin earthquake engineering mobile shaker equipment, built on an International model 4300 truck. Has a moderate force output, which makes it ideal for testing in urban areas. The maximum force output is about 27 kN. The direction of shaking with this machine can be changed between vertical and horizontal in about four hours at the test site. The direction of shaking in horizontal mode can be transverse or inline with the vehicle. |