CCFSS Library (1939 - present)

Abstract

The damping capacities of seven model steel structures, each consisting of a heavy steel platform supported on four columns, have been determined from forced vibration tests. The vibrations were produced by an eccentric-mass vibration generator, and the amplitudes ranged from small displacements up to slightly greater than yield displacement. The tests were terminated at the higher amplitudes once fatigue cracks formed in any of the joint welds in the columns. For vibration amplitudes up to a critical amplitude slightly less than yield displacement, the damping factors of the structures were constant, independent of amplitude, and ranged between .15 and .25~ for different structures. At vibration amplitudes greater than the critical amplitude, the damping factors of the structures became functions of amplitude. For example, the damping factor of one test structure increased from .15 to 1.~ as the displacement amplitude increased from 1.1 to 1.4 inches. The last structure tested revealed that a few cycles of vibration at amplitudes greater than the critical amplitude would increase these values slightly. Finally, the results summarized above are compared with the results of: {i) experimental work conducted by Lazan; {ii) reversed loading tests conducted on cantilever beams of similar construction to those tested in the work described in this report; and (iii) experimental work conducted by Hanson.

Department(s)

Civil, Architectural and Environmental Engineering

Sponsor(s)

American Iron and Steel Institute

Research Center/Lab(s)

Wei-Wen Yu Center for Cold-Formed Steel Structures

Publisher

American Iron and Steel Institute

Publication Date

01 Jan 1971

Document Version

Final Version

Rights

© 1971 American Iron and Steel Institute, All rights reserved.

Document Type

Technical Report

File Type

text

Language(s)

English

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