Equivalent Number of Loading Cycles for the Seismic Testing of Passive Energy Dissipation Devices.
Equivalent Number of Loading Cycles for the Seismic
Testing of Passive Energy Dissipation Devices.
Sadek, F.; Riley, M. A.
U.S. National Conference on Earthquake Engineering, 7th
Proceedings. (7NCEE). Theme: Urban Earthquake Risk.
Earthquake Engineering Research Institute (EERI). July
21-25, 2002, Boston, MA, 1-10 pp, 2002.
structural engineering; earthquakes; earthquake
engineering; structural control; passive energy
dissipation devices; prototype testing; earthquake
Prototype testing of passive energy dissipation devices
is required to verify their response characteristics and
demonstrate their capacity to withstand the design
loads. These tests usually consist of loading the
devices with a defined number of cyclic loads, with
frequency and amplitude based on the design properties.
The objective of this research was to develop
recommendations for the required number of
sine-wave-equivalent loading cycles that a device will
be subjected to during the design earthquake. For this
purpose, several linear and nonlinear
single-degree-of-freedom (SDOF) structures were analyzed
with a large number of earthquake records and the
required number of cycles was computed based on two
criteria. The first criterion is the equivalent total
energy, where the energy dissipated by the passive
energy dissipation device during seismic excitation is
equal to that absorbed by the device during cyclic
testing. The second criterion is the equivalent
cumulative displacement, where the cumulative
displacement experienced by the device during seismic
excitation is equal to that experienced by the device
during cyclic testing. Two sets of earthquake records
were included in this study: a general set and a
near-source set. The results of the various analyses
indicated that the number of loading cycles computed
using the displacement criterion is significantly larger
than that based on the energy criterion. Comparing the
number of cycles computed for linear and nonlinear
structures, it is found that increased nonlinearity
results in a smaller number of cycles using both
criteria, due to the energy dissipated through inelastic
action. The results also indicate that similar numbers
of cycles are required for near-source and far-field
ground motions in the short-period range, while for
longer periods (T > 1 s), near-source excitations
require fewer cycles.