DESIGN PROCEDURES FOR SHOCK ISOLATION SYSTEMS OF UNDERGROUND PROTECTIVE STRUCTURES. VOLUME IV. RESPONSE OF TWO-DEGREE-OF-FREEDOM ELASTIC AND INELASTIC SYSTEMS.
NEWMARK HANSEN AND ASSOCIATES URBANA ILL
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The purpose of this study is to develop simple rules for the designer so that he may be able to predict the maximum responses of two-degree-of-freedom elastic and inelastic systems under various types of ground shock excitation. The true responses of two-degree-of-freedom systems both in the elastic range and in the inelastic range, when subjected to five different forms of ground excitation are compared with the modal response of the same systems. Simple expressions are given for linear two-degree-of-freedom mass and spring combinations from which modal parameters can be obtained. From these modal parameters, and the response spectra for one-degree-of-freedom systems for various excitations, as presented in Vol. III AD-444 989 of this series of reports, one can determine bounds and probable values of the response. A detailed study is reported of a two-degree-of-freedom system subjected to a step velocity pulse at the base, having various combinations of elastic and inelastic response. In addition, a series of solutions of two-degree-of-freedom systems are presented for comparison with various approximate rules for determining bounds to the response in the various springs of the system. Author
- Structural Engineering and Building Technology