Project Title
Surveillance of the Performance of Elastomeric Bearings
on Maryland Concrete Bridges
Research Problem Statement and Objectives
Elastomeric bridge bearings are much easier to install
in a bridge in comparison to other types of bearings and require minimum
maintenance. This type of bearing has
been used for decades by the Maryland State Highway Administration (MDSHA) on
prestressed or reinforced concrete bridges.
Based on manufacturers’ reports, elastomeric bearings should not undergo
marked stiffening at low temperatures when the thermal contraction of the
bridge deck is at maximum. Such
stiffening could be deleterious to the bearing and/or structure. Correctly-designed and installed elastomeric bridge
bearings can be confidently expected to function efficiently for at least two
decades. However, reports from other
states have stated problems of some cases using elastomeric bearings.
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NCHRP Report 449, Test Methods for Elastomeric Bridge
Bearings, contains the findings of a study undertaken to develop
performance-related specifications for elastomeric bridge bearings. This report will be a good source for
obtaining information about the problem, laboratory
testing and mathematical analysis associated with
type of bearings. The emphasis
will be collecting as much field information (structure type, bearing
type, size, grade, deformation measurements, degree of delamination, bulging,
cracking, etc) as possible to assemble a matrix on deterioration modes
versus potential causes. The field information will
be supplemented with material acceptance test reports, design method
or policy used and bearing details. The variables (some independent
some interdependent) that can cause bearing deterioration is large in number therefore
much information will have be collected to arrive at most probable
causes by bridge.
II. Implementation
Summary
The proposal is divided into
four tasks:
1
Identify problematic bridge bearings
2
Detect deterioration modes of the elastomeric bearings
3
Find the causes of deterioration and categorize them
4
Summary and Conclusion
