Soil Dynamics
Lecture 16
Diaphragm Theory - Part II
In a Problem Format
Question #01.
Rigid diaphragms distribute the lateral force to the resisting elements proportional
to the,
A. relative rigidities of these elements.
B. tributary areas of these elemen

Soil Dynamics
Lecture 18
Diaphragm Theory - Part III
In a Problem Format
Question #01.
A wood residence has a wood structural panel roof diaphragm (which is shown in
plan view below). Two retail stores are separated by a common wood shear wall,
parallel t

Lecture #17
What is a shear wall ?
Consider the simple analogy of a typical residential interior stud wall.
Consider a 12 long by 8 high stud wall sitting on a concrete slab.
A stud wall is built from 2x 4 wooden or steel studs placed every 16
on center,

Soil Dynamics
Lecture 15
Diaphragm Theory - Part I
In a Problem Format
Question #01.
Which of the following are known as resisting elements?
A. Columns.
B. Shear walls.
C. Connections.
D. All the above.
Answer to #01.
D.
Elements that resist story shears

Soil Dynamics
Lecture 14
Seismic Codes
California Building Code - Part IV
In a Problem Format
List of Symbols.
- ap is the in-structure component of the amplification factor.
- Ca is the seismic response coefficient for proximity.
- Cp is the horizontal f

Soil Dynamics
Lecture 13
Seismic Codes
California Building Code Part III
In a Problem Format
List of Symbols.
- ap is the in-structure component of the amplification factor.
- Ca is the seismic response coefficient for proximity.
- Cp is the horizontal fo

Soil Dynamics
Lecture 12
Seismic Codes
California Building Code Part II
In a Problem Format
List of Symbols.
- ap is the in-structure component of the amplification factor.
- Ca is the seismic response coefficient for proximity.
- Cp is the horizontal for

Soil Dynamics
Lecture 11
Seismic Codes
California Building Code Part I
In a Problem Format
List of Symbols.
- ap is the in-structure component of the amplification factor.
- Ca is the seismic response coefficient for proximity.
- Cp is the horizontal forc

Soil Dynamics
Lecture 10
A Review of some Basic Concepts
of
Vibrations
Question #01.
For a single-degree of freedom system, the natural period T is,
I. The inverse of the natural frequency,
II. Equivalent to the linear natural frequency,
III. Expressed in

Soil Dynamics
Lecture 09
The Behavior of Surface Soil Layers
under
Earthquake Loading
The vibration of the surface layer due to an earthquake ensues from the upward
propagation of the shear waves from below. The behavior of the surface stratum was
studied

Soil Dynamics
Lecture 08
Earthquakes
Definitions.
Epicenter
Focal depth
Hypocentric distance
Focus point of rupture of a fault
1. Shallow-focus: 0 to 70 km deep;
(constitute about 75% of all earthquakes);
2. Intermediate-focus: 70 to 300 km deep;
(constit

Soil Dynamics
Lecture 07
Stress Waves in a Semi-Infinite Media
Luis A. Prieto-Portar, August 2006.
Rayleigh waves.
The stress waves we studied in Lecture #6 dealt with waves within bodies that are
infinite, elastic and isotropic.
There is another type of

Soil Dynamics
Lecture 06
Stress Waves in Infinite Media
Luis A. Prieto-Portar, August 2006.
The equation of motion of a stress wave in an elastic medium.
Consider an element of an elastic medium, as shown below, with all the possible
stresses on each of

Soil Dynamics
Lecture 05
Elastic Stress Waves in Bars
Luis A. Prieto-Portar, August 2006.
The propagation of stress in an elastic medium.
When stress is applied to a body, that stress will propagate away from the point of
application via stress waves. Di

Soil Dynamics
Lecture 04
Systems with Two-Degrees of Freedom
Luis A. Prieto-Portar, August 2006.
The figure at right shows a simple
non-damped mass and spring system
with two-degrees of freedom.
This simple system can be excited
into vibration in two dif

Soil Dynamics
Lecture 03
Measuring Vibrations
Luis A. Prieto-Portar, August 2006.
A rotating mass type of excitation.
Some machines have intentionally designed eccentric weights that shake their frames
in a forceful manner. For example, steel sheet-pilin

Soil Dynamics
Lecture 02
Simple Vibrations
Luis A. Prieto-Portar, August 2006.
Some simple initial definitions:
- A free vibration is any system that vibrates under the action of forces that are part of,
or are inherent to the system itself.
- A forced v

Soil Dynamics
Lecture 01
General Concepts
Most of geotechnical and foundation design is based on the soils behavior under static
loads. Important structures however, require that highly competent engineers know
how to analyze structures under complex dyna