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Dear Friends & Colleagues,
For nearly 35 years, CSI software has been the
universal choice of sophisticated engineering professionals for
structural design and retrofitting. Today, as our nation enters
this critical infrastructure rebuilding era, CSI stands ready to
deliver the most productive and practical software available in
the market—as we have since 1975. Offering advances in every
facet, from powerful information processing to efficient numerical
simulation, CSI products offer unmatched technology for engineering
modeling, analysis, design, and project documentation.
The structural engineering profession is being
summoned to rebuild our nation's freeways, bridges, schools, hospitals,
and the infrastructure that drives our economy— to create
jobs and to put America back to work. CSI’s commitment to
the development of state-of-the-art structural engineering software
has never been stronger. Reflecting more than three decades of development
experience, CSI's innovations will continue to set the industry
standard.
Please contact
us or click
here to learn more about CSI software products and
training services. We look forward to hearing from you!
Sincerely,

Ashraf Habibullah, President & CEO
Computers & Structures, Inc.
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In the evaluation of the dynamic
response of a structure, the engineer often must calculate the free
vibration modes of the system. Traditionally this has been accomplished
by conducting an Eigen analysis to produce the structural mode shapes
and corresponding frequencies. These modes are then used to conduct
the dynamic analysis.
Depending on the characteristics of the dynamic
loading, many Eigen modes may have low participation and may contribute
little or nothing to the dynamic response of the structure. This
makes the Eigen analysis-based procedure inefficient because a significant
numerical effort is wasted in calculating trivial modes.
In contrast, the Ritz analysis does not produce
“exact Eigen vectors," rather Load Dependent Ritz (LDR)
vectors. As the name suggests, these vectors are dependent upon
the characteristics of the dynamic loading that is being applied.
The net effect is that the only vectors calculated are ones which
produce non-trivial contributions to the response of a structure
when subjected to that dynamic load.
Ritz procedure offers computational efficiency
because it requires calculation of fewer vectors and because the
dynamic analysis algorithm also processes fewer vectors during the
solution and recovery.
In an Eigen-based dynamic solution, several hundred
modes may be needed for large systems to capture the mass participation
percentage (typically 90 percent) required by many design regulations.
The results then need further corrections due to missing mass vectors.
The Ritz-based dynamic solution needs far fewer modes to achieve
the required mass participation, and the missing mass is always
automatically included in every set of Ritz vectors.
It is also important to note that although Ritz
vectors are not Eigen vectors, they are all linear combinations
of the Eigen vectors; therefore, the method always converges to
the exact solution. The effectiveness of Ritz vectors is appreciable
for any dynamic loading, but is most noteworthy when evaluating
the effect of vertical ground motion, multiple-support excitation,
or even the application of localized forces such as footfall or
machine vibration.
The power of the Ritz technology has been effectively
applied in linear and nonlinear applications, making Ritz an aspect
of structural dynamics worthy of study.
For more technical information on Ritz vectors
please see the CSI Analysis Reference Manual. |
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SAP2000/Bridge combines a versatile
and intuitive bridge object-based user interface with the potency
of CSI’s analytical engine, SAPFire®, to produce
the most versatile and productive software package for designing,
rebuilding and retrofitting our bridges and freeways. For more information
about this product click
here.
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Lovers of Urdu poetry, especially
our friends and colleagues in South Asia, will be pleased to know
that Computers & Structures is sponsoring a festive afternoon
celebrating the life and poetry of Mirza Ghalib, the beloved and
perhaps greatest poet of the Urdu language. The event, held at the
Indian Community Center in Milpitas, California, will feature highlights
of Ghalib’s life and will study the impact of his renowned
poetry. Various participants will present selected readings from
his famous Diwan-e-Ghalib. For more information about ICC, click
here.
To download a flyer about the event, click
here. |
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Due to popular demand, new dates
have been announced for SAFE and SAP2000/Bridge online training.
You will experience live over-the-web training led by an expert
CSI software instructor. Space is limited, so register early.

Introduction to SAFE v12- Reinforced Concrete
| DATE |
TIME
(Pacific) |
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| Thursday, April 9 |
1:00 pm - 2:30 pm |
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| Thursday, April 23 |
10:00 am - 11:30 am |
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| Thursday, May 7 |
10:00 am - 11:30 am |
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| Thursday, May 21 |
1:00 pm - 2:30 pm |
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Introduction to SAFE v12 Post-Tensioned
Concrete
| DATE |
TIME
(Pacific) |
|
| Friday, April 10 |
8:00 am - 9:30 am |
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| Friday, April 24 |
1:00 pm - 2:30 pm |
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| Friday, May 8 |
10:00 am - 11:30 am |
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| Friday, May 22 |
1:00 pm - 2:30 pm |
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Seismic Design of Bridges Using SAP2000
Bridge
| DATE |
TIME
(Pacific) |
|
| Thursday, April 9 |
10:00 am - 12:00 pm |
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| Thursday, April 23 |
1:00 pm - 3:00 pm |
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| Thursday, May 7 |
1:00 pm - 3:00 pm |
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| Thursday, May 21 |
10:00 am - 12:00 pm |
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The Fourth International
Structural Engineering Seminar was hosted by CSI Caribe
in Caracas, Venezuela, February 2-11, 2009. Engineers from all over
Latin America attended the ten-day training which covered the concepts
of concrete design, shear wall design, pushover analysis, nonlinear
analysis, sequential construction, and slab and foundation design.
For more information about CSI Caribe, click
here.
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Computers and Structures, Inc. proudly
sponsored the 6th Annual Undergraduate Student Seismic Design Competition
at the 2009 EERI Annual Conference held in Salt Lake City, Feb 11-14,
2009. The event, organized by EERI's Student Leadership Council,
drew 100 of the best of the next generation of earthquake engineers
from 18 universities throughout the country. They designed, analyzed,
and fabricated scale models of high-rise office buildings, using
CSI software in most cases. The competition room was filled to capacity
with cheering onlookers, both students and professionals. The students
made presentations describing their creative and innovative designs
and then conducted shaking table tests on the models.
The teams were ranked by their overall performance
index, with Cal Poly San Louis Obispo placing first, Brigham Young
University placing second, and Oregon State University placing third.
Two special awards were also given: the Charles Richter Competition
Spirit Award went to a one-man team from Brigham Young University,
and the Egor Popov Innovative Design Award was given to the University
of California Davis. For more information about the seismic design
competition, click here.
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Computers & Structures, Inc.
has proudly presented a matching grant to the Engineers Alliance
for the Arts (EAA). The grant supports EAA in their mission to
instill passion and enthusiasm for structural engineering by introducing
students to the technical, creative and artistic aspects of the
profession. EAA’s eight week Student Impact Project brings
members of the structural engineering profession together with high
school students to teach them about art and engineering. These engineers
make an incredible impact on the lives and futures of talented young
people while bringing the profession to the forefront in a meaningful
and exciting way.
Individuals and organizations are invited to make
tax deductible donations to EAA. CSI will match all donations, dollar
for dollar, that are received by June 30, 2009. For details please
contact EAA Executive Director Antigone Trimis at 415.846.5743.
For more information about EAA click
here. |
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