University of Texas at Austin earthquake engineering mobile shaker equipment capable of generating large dynamic forces in any of three directions (vertical, horizontal in-line, and horizontal cross-line). The shaking system is housed on an off-road, all-wheel-drive vehicle. The shaking direction is selectable from the operator's cab. The maximum force output is about 267 kN in the vertical mode and about 134 kN in each horizontal mode. In addition to the significant 3D load-generation capabilities of T-Rex, this machine also has the capability of pushing cone penetrometers and other custom-made vibration and/or pressure-sensing instrumentation into the ground using a hydraulic ram located at the rear of the vehicle.