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Determining the Effects
of Low-Cycle Fatigue on the Seismic Performance of Rebar and Couplers for
Critical Bridge Members ($200,000): May 2005 – December 2005. I Left my Academic Position before completing the
project. Submitted to California
Department of Transportation in response to RFP and funded in April 2005. In
seismic events, the longitudinal reinforcement in concrete elements may undergo
large strain reversals of typically one to five fully reversed cycles. This
causes significant changes to the mechanical properties of the steel
reinforcement and couplers, and as a result the strength and ductility of the
concrete element changes. The purpose of this study is to develop a computer
simulation based on a developed analytical model to assess the vulnerability
of concrete bridge elements after seismic events and to verify this model
using experimental tests. |
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Knowledge Based Computer
Support Environment for the Reuse of Design Information in Structural Design
($25,600): December 2002 – April 2005: Using previous designs to
generate new designs is desirable because it saves time and effort, and
because the concept has proven effective in previous situations. In this
research, a conceptual model is developed to support the use of prior
experiences to generate a solution for a new problem by using the entire
previous design or part of it as a template to generate a new one through the
use of innovative case adaptation techniques. The model works like a large
spreadsheet to establish relations between various design parameters and
supports the interface with a library of design tools to calculate the
configuration of the new design based on its loads and structural
configurations. |
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Seismic Evaluation of
the Performance of Retrofitted and Repaired Brick Walls by Means of Expansive
Epoxy Injection (Approx. $50,000):
March 1998 - August 2000: A pioneer technique to
repair unreinforced masonry walls cracked during past seismic events, or to
retrofit existing brick walls to meet the current code requirements, is
subjected to experimental investigation. Such walls are very common in
historical buildings. The walls are injected by ceramic foaming material
developed by Delta Plastics Company.
After the material is shot into walls, it expands, bonds and hardens
like rock. Unlike Carbon fiber, this injection technique does not affect the
appearance of these historical walls and consequently it preserves their
historical value. The seismic performance and ductility of the plain brick
walls were first measured by applying cyclic loads on them to failure. The
broken walls were repaired using the Ceramic Foam and tested again. In
addition, unbroken walls strengthened with Ceramic Foam and composite Carbon
Fiber material were tested. Performance of all walls were studied and
compared to prove the effectiveness of the Ceramic Foam material in the
retrofittingand repairing of walls. Video clips of the tests can be viewed at
my web site See Testing [Video here or
YouTube] and Report. |
