Shock and Vibration Application Brief
University of Connecticut
The University of Connecticut assesses a bridge's structural
integrity through vibrational monitoring.
A 100-foot section of a Connecticut Turnpike bridge collapsed and fell
into the Mianus River, killing three people and critically injuring
three more. Hundreds of thousands of drivers had to find alternate
routes for almost three months while repairs were made. The repairs
alone cost the state of Connecticut over $23 million after insurance.
Additional funds were disbursed to investigate why the collapse had
occurred in the first place, since the bridge had passed inspection
only nine months earlier.
Structurally Deficient Bridges
It has been estimated that 35% of this country's 590,000 bridges were
considered structurally deficient or functionally obsolete because of
increased age and larger-than-expected service loads. Recent collapses
or near-collapses have forced governments to develop extensive
rehabilitation programs. Regulations require that bridges be inspected
every two years, except old and high-risk bridges, which must be
inspected more frequently. Current inspection techniques depend on
human beings to recognize structural imperfections. A need to improve
inspection techniques is evident.
Flexible and Powerful Analysis Software Required
Researchers at the University of Connecticut are studying the
feasibility of assessing a bridge's structural integrity through
vibrational monitoring. Structural imperfections in nuclear power
plants and in offshore engineering structures are commonly detected
using the evaluation of dynamic characteristics; since bridges have
dynamic loads, it seems reasonable to evaluate them using these methods
also. A full-scale prototype monitoring system developed at the
University of Connecticut and at Vibra-Metrics, Inc. in Hamden,
Connecticut provides a method of non-destructive evaluation for
assessing a bridge's structural condition. It was initially tested on
a laboratory bridge model and is currently being tested on a
Connecticut bridge. This project requires that they use software
sufficiently flexible and powerful to provide them with answers, yet
easy enough to learn that it will not slow them down.