ECIV 724 A Dynamics of Structures. Instructor: Dr. Dimitris C. Rizos 300 Main St. Dept. of Civil and Environmental Engineering (803) 777-6166 email@example.com. Earth Layers. The Main Earth Layers are: Core Lower Mantle Upper Mantle Crust. Earth Layers.
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Dr. Dimitris C. Rizos
300 Main St.
Dept. of Civil and Environmental Engineering
(803) 777-6166 firstname.lastname@example.org
Location: Carrizo Plain area, San Luis Obispo County, California.
Right-Lateral Strike-Slip Faults
R.E. Wallace, U.S. Geological Survey.
Saturated unconsolidated deposits
left-lateral strike-slip fault
San Francisco, April 18, 1906
Guatemala February 4, 1976
Ground Motion has 3 Components
N-S, E-W and Vertical
Horizontal components are of major interest (excessive shear forces)
Vertical component has been traditionally ignored, but may be important.
Strong Motion Accelerograph
A transducer: SDOF highly damped (60-70%)
Known k, m (fn ~ 25 Hz)
Sampling Rate: 1/100, 1/50 sec
(10,000 sampling points)
Niigata, Japan.June 16, 1964, 7.4
Earthquake of July 29, 1967, Caracas, Venezuela.
May 31, 1970, 7.8R
the 1989 Loma Prieta (California)
Parking garage at California State University
Collapsed first and second stories
True for most cases when Soil-Structure Interaction is not an issue
A SDF system is subjected to a ground motion ug(t). The deformation response u(t) is to be calculated.
EQUIVALENT STATIC FORCE
fs(t) is the force which must be applied statically in order to create a displacement u(t).
A response spectrum is a plot of maximum response (e.g. displacement, velocity, acceleration) of SDF systems to a given ground acceleration versus systems parameters (Tn , ).
A response spectrum is calculated numerically using time integration methods for many values of parameters (Tn, ).
Example : Deformation response spectrum for El Centro earthquake
Deformation, pseudo-velocityandpseudoacceleration response spectra can be defined and ploted on the same graphs
n : natural circular frequency
of the SDF system.
Tn < 0.03 s : rigid system
u(t) ≈ 0 D ≈ 0
Tn > 15 s : flexible system
no total displacement
u(t) = ug(t) D = ugo