| Summary: | 碩士 === 淡江大學 === 土木工程學系 === 85 === In recent years, large number of highrise buildings are built
due to the rapid economic development and highly use of land. At
the same time, more complex structure system design causes
eccentricity which also change many building behavors.
Amongthem, special aeroelastic phenomenon would be handled and
solved by method of wind engineering.
The purpose of this article is to apply a building model which
includes alongwind, acrosswind and torsional motion under the
wind tunnel test to investigate the aeroelastic behavior of
shape a square highrise building in different flow fields.
Damping rations, torsional / lateral frequency ratio and
eccentricity are used as the experimental parameters.
According to the experimental result, the acrosswind dynamic
responses show peak values at critical velocity when building
has eccentricity in the acrosswind axis in BL1 flow field. The
peak values amplified with the increase of eccentricity, but
reduced as the frequency ratio close to 1.0. In BL2 flow field,
the aeroelastic effect weakened due to presence of the stronger
tubulence. Hence, the acrosswind dynamic responses do not have
peak near critical velocity as in BL1. When eccentricity
increases, as thstiffness center moves down wind of geometry
center, building''s dynamic respones increase especially near
critical velocity. When the torsional / lateral frequency ratio
approache unity, responses will further increase.
In the aspects of acrosswind vibration and vortes shedding, we
find that the strenght of vortex and the lock-in phenomenon is
also more apparent will increase with increase eccentricity.
Moreover, when the stiffness center towards down wind and the
frequency ratio approache 1.1, the increase of vortex strength
becomes more obvious.
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