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THE
GOLDEN GATE BRIDGE - Seismic Retrofit Project
The Golden Gate Bridge built in the 1930s opened to pedestrian
traffic in 1937. The construction was financed by a $ 35 million bond
issue voted by residents of San Francisco, Marin, Sonoma, Del Norte,
Mendocino and Napa Counties. Construction began in January 1933.
A comprehensive seismic evaluation of the existing Golden Gate
Bridge was performed using Program KARMA by engineers at karma2go,
LLC. The bridge was subjected to a magnitude 8.3 earthquake and
its vulnerabilities identified. Based on the nonlinear time history
KARMA analyses results, seismic retrofit schemes were recommended
for the San Francisco Approach Viaduct, the Arch over historic
Fort Point called the Fort Point Arch, the two reinforced concrete
pylons abutting the arch and the South Anchorage Housing which
houses and anchors the suspension span cables at the San Francisco
end. The recommended retrofits were incorporated in the KARMA
models and the retrofitted bridge reanalyzed for the 8.3 magnitude
earthquake. Model images and response animations were generated
with program SWAMI.
CHIRAG-1
OFFSHORE PLATFORMS - Seismic Retrofit Project
Chirag-1 offshore structures are located in the Caspian Sea, Baku,
Azerbaijan. The oil and gas fields of the Caspian Sea are crucial
for the economic strength and growth of Azerbaijan.
Seismic evaluation and retrofit for Chirag-1 twin jacket structures
was performed utilizing program KARMA. Currently it is the largest
oil producing field in the Caspian Sea. The project was conducted
in three phases. Phase I consisted of evaluating the seismic vulnerabilities
of the existing structures. Different retrofit schemes were evaluated
and a final retrofit scheme recommended in Phase II. The Phase
III evaluated the seismic performance of the final retrofitted
structures. A comprehensive seismic risk assessment was part of
Phase II work-scope. Three-dimensional nonlinear KARMA models
were created for this study. These models explicitly included
the nonlinear models of the piles and the surrounding soil. Nonlinear
dynamic time history analyses were performed including soil-structure
interaction. Program SWAMI was used to generate graphics and videos
of response motions.
PAC BELL PARK - Seismic Risk Assessment
Project
Pacific Bell Park, the home of the San Francisco Giants Baseball team,
was the first privately-financed Major League ballpark to be built
since 1962. It is located in the China Basin near downtown San Francisco.
HOK Sport was the architectural firm which also designed Camden Yards,
Jacobs Field, and Coors Field.
K2GO staff performed a comprehensive seismic risk assessment
was performed of the ballpark for the financial institutions.
The project included the following.
- Comprehensive site-specific seismic hazard analysis.
- Creating 3-D fully nonlinear mathematical models of ballpark
sections.
- Performing 3-D nonlinear dynamic time history analyses for
various recorded ground motions simulating various earthquake
magnitudes and distances.
- Quantifying seismic risk, calculating Probable Maximum Losses
(PML), and generating Probability of Exceedance vs. Estimated
Losses Curves.
Pacific
Bell Park
INTERNATIONAL HOUSE - Seismic Retrofit
Project
International House at
the University of California, Berkeley, houses 600 students and visiting
scholars from almost every country in the world. Built in the 1930s
and designed by a prominent local architect George William Kelham,
it sits next to the Memorial Stadium and close to the Hayward fault.
A comprehensive seismic evaluation of the International House
was conducted utilizing program KARMA. This dorm is an eight story
reinforced concrete building. A three-dimensional fully nonlinear
model was created and subjected to several intensities of seismic
motions originating at the Hayward fault.
Three-dimensional linear and nonlinear dynamic time history analyses
were performed utilizing several recorded ground motions simulating
different earthquake magnitudes and distances. Program SWAMI was
used to generate graphics.
CENTRAL
YMCA OF SAN FRANCISCO - Seismic Retofit Project
The original Central YMCA
of San Francisco was destroyed in the 1906 San Francisco earthquake.
It was rebuilt and opened on Thanksgiving Day, 1910.
A comprehensive Seismic Risk Assessment was performed for the
Central YMCA. K2GOs project scope included the following.
- Site-specific hazard analysis
- Establishing project performance criteria
- Creating 3-D fully nonlinear mathematical models of the existing
building and the proposed retrofits.
- Performing 3-D nonlinear dynamic time history analyses for
various recorded ground motions simulating various earthquake
magnitudes and distances.
- Quantifying seismic risk for the existing building.
- Proposing and verifying several retrofit schemes including
risk assessment of the proposed retrofit schemes.
- Optimization, Decision Analysis and final recommendations.
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