Civil Engineering Research
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Dr. Pinelli's research interests have focused
on structural dynamics, and earthquake and wind engineering,
more specifically in the area of nonlinear dynamic analysis
of structures, passive control systems and interaction between
structural and nonstructural elements. His research has also
included a strong experimental component. Related interests
are the modeling and optimization of nonlinear mechanical systems.
Dr. Pinelli is also interested in the development of educational
tools based on erector sets.
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See Dr.
Pinelli's
Article in
Florida Tech Today.
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Multiple
Distributed Tuned Mass Dampers: An Exploratory Study
The last decades have seen the
development of important new technologies regarding the control
of the response of structures to dynamic loading. These include
passive control techniques, one of which is the tuned mass
damper (TMD). It is a vibration absorber consisting of a mass,
a spring, and a viscous damper. The motion of its mass activates
the TMD when the natural frequency of the damper is tuned to
be in or near resonance with the predominant frequency of the
main structure. The effectiveness of the TMD's to mitigate
wind-induced motions is well established. A series of
studies have also shown that, when properly optimized, TMD's
can also successfully control seismic vibrations. Recently,
new schemes for the TMD have been proposed. In particular,
it has been shown that multiple TMD's with their frequency
range distributed around the fundamental modal frequency of
a structure can be robust and efficient. However, there is
still no agreement over whether multiple TMD's could successfully
control several modes of a structure.
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The research carried on at Florida Tech,
and funded by the National Science Foundation, explored the feasibility
of controlling various modes of a structure under seismic loading through
the installation of various groups of tuned mass dampers with the frequency
range of each group distributed around a different modal frequency. The
proposed scheme is called multiple distributed tuned mass damper (MDTMD).
A MDTMD could combine the robustness and efficiency already demonstrated
for single mode distributed TMD's (in general referred to as multiple
TMD, or MTMD), with the efficacy of highly damped and high mass devices
proposed for some single TMD's. In addition, since in this type
of installation the mass is distributed among several dampers, each
individual device can be less bulky, and can require less displacement.
The parameters to be varied in the study,
for a given structural model, were the type, properties, and number
of devices to be installed. The sensitivity of the MDTMD's to different
ground motions were investigated. Consequently, a computer and scaled
laboratory structural models were subjected, with and without TMD's,
to a series of dynamic loads through computer simulations and shake
table tests. The shake table was built at Florida Tech.
This exploratory work advanced the understanding
of an important passive control device, and indicated whether or not
TMD's have the potential to be used for multi-modal control.
More information can be found in this paper.
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Public
Hurricane Loss Projection Model
The goal of the project is to develop and
maintain a computer model to assess hurricane risk, and to
project annual expected insured residential losses for specific
sites, zip codes, counties and regions in Florida. These
losses can be estimated for both individual property and
for entire portfolios of residential properties. The proposed
model shall also project insured losses for user defined
scenarios and historical events. |
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The project is funded
by the state of Florida and sponsored by the Florida Department of
Insurance (DOI). It will be developed predominantly by academic
experts at the International Hurricane Center at FIU, and in various
universities in Florida, including Florida Tech, in accordance with
the best available methodologies, techniques, theories and scientific
principles. The proposed model will be developed without bias and
will be non-proprietary and transparent. It will be subject to external
review and will comply with the standards set by the Florida Commission
on Hurricane Loss Projection Methodology (FCHLPM). It is expected
the model and its components will be available to the insurance and
reinsurance industry.
The proposed model can be used to (a)
provide assistance to the Florida Department of Insurance and the insurance
industry in the rate making process; (b) provide a state of the art
non-proprietary wind field model for public use; (c) provide a check
on the assumptions, analysis and results generated by the proprietary
models; (d) help evaluate reinsurance risk for, e.g., the Florida CAT
Fund; (e) assess the efficacy of disaster mitigation strategies.
The model will have meteorological, engineering,
GIS, financial and actuarial components. It will draw upon the expertise
of a team of meteorologists, wind and structural engineers, statisticians,
computer scientists, actuaries, and financial experts from Florida
International University, from the State University System and elsewhere.
The model will consist of three major
components: wind, vulnerability (damage), and insured loss. The vulnerability
component will model the relationship between damage to different
classes of residential structures (and contents) and the maximum sustainable
wind speed generated by the stochastic storms and wind fields. The
impact of terrain roughness on this relationship will be accounted
for. Separate vulnerability functions for structure, content,
and ALE will be developed and validated by using insurance claims data
and engineering data. Uncertainties will be estimated and sensitivity
analysis will be performed.
Hurricane
Wind Gust Structures: Measurement, Characterization and Coastal
Damage Mitigation
Objectives
To measure and characterize ground-level
hurricane wind fields, and to quantify and model the resultant wind
force interaction with man-made coastal structures.
Objective Tasks
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Develop and implement new instrumentation to:
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Create analysis tool for the efficient processing
and dissemination of collected hurricane wind data
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Develop probability based models of:
Methodology
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Develop and deploy new remote access wireless
instrumentation to be installed on mobile wind towers and residential
houses
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Develop software capable of managing and analyzing
the very large full-scale hurricane wind data sets
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Employ data from new instrumentation to define
the gust spatial structure and resultant correlated loads over
the building envelope
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Measure outcomes by direct comparison of new load
models with current code provision and wind tunnel data
Rationale
Given the rapidly increasing population
in Floridašs coastal areas, densely populated areas will continue to
be impacted by hurricane winds. In addition to the immediate public
safety and property loss issues, long-term economic and environmental
recovery will also suffer without a concerted effort to prevent catastrophic
damage to residential and commercial structures and the infrastructure.
Affordable solutions to mitigate damage can only follow from an accurate
quantification of the wind forces causing this destruction. Builders,
coastal home and business owners, the insurance industry, and the state
economy and ecosystem are the potential beneficiaries from this research.
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Wind
Study of Emergency Vehicles
The report presents the results of a
study to define the wind speed limits and conditions beyond which fire
and rescue vehicles should not be operated during a hurricane. For
that purpose, reduced scale models of a typical fire truck, ambulance,
and sports utility vehicle (SUV) were tested in a wind tunnel. For
the fire truck the wind tunnel tests are compared with full-scale measurements
on a real truck and to computer simulations using the Fluent software.
The report presents and compares the results of the different tests:
experimental, field, and numerical. The resulting wind pressure distributions
on the vehicles are used to obtain drag, lift, and side forces, in
addition to overturning, yawing, and pitching moments. Based on the
results of the tests and the analyses, safe wind speeds are found for
the operation of these fire and rescue vehicles.
More information can be found in the
following paper
Wind
Effects on Emergency Vehicles
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