NEHRP Clearinghouse

Use of Energy as a Design Criterion in Earthquake-Resistant Design.
Uang, C. M.; Bertero, V. V.
National Science Foundation, Washington, DC., November 1988, 57 p.
Identifying Number(s)
The conventional derivation of an energy equation for the seismic response of structures is reviewed and compared with an alternative definition which is physically more meaningful. The following engineering parameters computed using these two definitions are compared: (1) the profiles of energy time histories for short and long period structures, which are shown to be significantly different; (2) input energy spectra based on a constant ductility ratio for which significant differences exist for both the short and long period ranges, although for periods in the range of practical interest in building design the difference is small for most of the recorded ground motions. It was also found that the maximum input energy is closely correlated to the strong motion duration. The reliability of using input energy spectra derived for a single-degree-of-freedom system to predict the input energy to multi-story buildings is illustrated by correlating the analytical prediction with the experimental results of a six-story steel frame. Finally, the uniqueness of the energy dissipation capacity of a structural member is evaluated. Test results for three types of structural members--steel beams, reinforced concrete shear walls, and composite beams--are examined, with the conclusion that the energy dissipation capacity is not unique but is highly dependent on the loading and deformation paths.
; Energy dissipation; Ductility; Dynamic response; Earthquake resistant structures; Beams (Supports); Earthquake engineering; Structural vibration; Earthquakes; Energy methods; Walls; Design criteria; Mathematical models; Structural analysis; Seismic waves