Experimental verification of a container crane structure modal parameters which are numericaly obtained by using the Finite Element Method is presented. To validate the numericaly calculated natural frequencies and vibration mode shapes, and to define the modal damping values, a full-scale forced vibration experiment was performed. The simplest possible experiment was chosen to obtain these objectives. Some kind of intersection between forced vibration test, with the control of the input (forcing function), and step relaxation test, with the release of the structure from a statically deformed position, was made. Instead of releasing the deformed structure, the crane was forced into the specific vibration mode with limited operational movements, using inertial forces of the masses in motion. Therefore, the input excitation was not directly controlled, but was more or less under control. Ambient vibration testing, due to wind loading and due to forcing with crane motion, was also performed and is briefly presented.
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