All structures vibrate, but those vibrations become of concern when their amplitude becomes excessive. Structural dynamics addresses those issues pertaining to the structure itself that may lead to unwanted vibration. The key parameters include stiffness, resonance frequencies and damping, all of which may be under the control of a designer. The "tools" for structural analysis include vibration measurement and experimental modal analysis (where a structure actually exists), or finite element modeling (where a structure might not yet exist). The structure of interest may be as large as a building, a floor in a semiconductor plant, or a piping system, or as small as the stage in a microscope or other sensitive piece of equipment. Staff at Colin Gordon & Associates offer many years experience in structural dynamics analysis and mitigation design for a wide range of project types, including vibration-sensitive equipment, pipelines, cranes of several types, and buildings. Consulting and Design Services: Measurement of structural vibrations In situ assessment of stiffness, resonance frequency and damping Finite element modeling of complex structural systems Experimental modal analysis