Volume 22, Issue 4 (July 1994)
An Excitation System for Dynamic Testing of Large Structures
The service behavior and real performance of engineering materials and systems are best evaluated using data obtained from prototype or full-scale testing, or both. For large engineering structures composed of materials such as concrete, with variable properties, data from such tests are invaluable. Full-scale forced vibration testing is a useful tool for obtaining information on the condition of structural systems. As compared to ambient vibration testing, forced vibration testing can provide more accurate estimates of damping capacity and yield data from which better system identification of structural parameters is possible. However, full-scale forced vibration field testing is much more difficult to achieve when compared with laboratory tests on prototypes. The (large) size of the structure usually means special excitation systems are required. The development and performance characteristics of such an excitation system is described in the article. The system consists of an hydraulic actuator, mounted within a purpose built frame, two pumps, an electronic control unit, and a personal computer. It can be used to induce vertical excitation of highway bridges, long-span floor slabs, and similar structures.