Geoscience Reference
In-Depth Information
3. Mobile laboratories
3.1. NEES FACILITIES AT UCLA (http://nees.ucla.edu,
PROF. JOHN WALLACE, PI)
NEES at UCLA includes mobile dynamic excitation shakers and a fully mobile
data acquisition laboratory. Capabilities include satellite Internet transmission as
well (thus allowing for tele-participation). In addition, a CPT truck is available for
estimation of soil properties in-situ (material below is extracted from the website
http://nees.ucls.edu).
3.1.1. Eccentric mass shakers
Three eccentric mass shakers have been developed to enable forced vibration testing of
full-scale buildings.
1. MK-14A: An omni-directional eccentric mass vibrator capable of low frequency,
highamplitudeharmonicloading.Ithasanoperatingfrequencyrangeof0.1-4.2Hz
and maximum load of 20kips.
2. MK-15:Twouni-directionaleccentricmassvibrators(Figures5.11and5.12)witha
wide frequency range (0-25Hz) and large forcecapability (100kips).
For all three eccentric vibrators (MK-14A-5500 and MK-15's), a wireless control option
wasaddedtoenabletheoperator(inthemobilecommandcentre)toremotelycontrolthe
shakers. Furthermore, synchronization between the MK-15 shakers is possible with the
use of the new Vector motor drives. Two or more vibrators, spaced apart on a struc-
ture, can provide the tested structure with torsional as well as translational forcing, or
Fig. 5.11. MK-15eccentric mass shaker during UCSD Elliot Field testing
