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Tri-Directional Test Facility


The tri-directional test facility is a computer-controlled apparatus capable of applying cyclic loads simultaneously in three directions. It is used to examine the strength of structural components or assemblages under the application of a variety of loading conditions, such as might occur during an earthquake or hurricane. This is one of the largest such facilities in the world, both in terms of load capacity and capability to handle, full-scale specimens.

Specifications / Capabilities:

The facility can apply forces or displacements in three orthogonal directions and moments or rotations about three orthogonal axes. Specimens up to 3.3 m in height and 3 m in length or width may be tested. The forces are applied by six closed-loop, servo-controlled hydraulic actuators that receive commands from a computer. Operating under computer control, the facility simultaneously maintains specified loads and/or displacements in each of the six degrees of freedom. Loads may be applied up to 2,000 kN in the vertical direction and 900 kN in each of the two horizontal directions.

Scientific Opportunities / Applications:

Loads may be cyclic or unidirectional depending on the type of loading condition being simulated. The facility has been used to study shear walls, precast concrete connections, and structural steel sub-assemblages subjected to reverse cyclic lateral loading. This facility supports EL's role in conducting research for seismic design and construction standards in the National Earthquake Hazards Reduction Program.

Access Information:

The facility is used in a variety of EL research projects and collaborative projects with other agencies. It also is available on a cost reimbursable basis for independent research but must be operated by EL staff.


Name: John L. Gross
Phone: 301-975-6068
Materials & Construction Research Div.
100 Bureau Drive, Stop 8611
Gaithersburg, MD  20899-8611