Civil Engineering Reference
In-Depth Information
19
Seismic reliability of deteriorating reinforced
concrete (RC) bridges
P. GARDONI, University of
Illinois at Urbana-Champaign, USA and
D. TREJO, Oregon State University, USA
DOI
: 10.1533/97808577098986.4.514
Abstract
: The chapter discusses different deterioration mechanisms that
affect the performance and reliability of bridges. Focus is on reinforced
concrete (RC) and post-tensioned (PT) bridges. First, a general
discussion is provided on different forms of deterioration along with an
overview of the underlying physical phenomena and their infl uencing
factors, which include material properties and environmental conditions.
Then, the chapter focuses specifi cally on corrosion mechanisms and
provides a quantitative assessment of the effects of corrosion on the
performance and reliability of RC bridges. Finally the chapter suggests
future directions on the topics presented.
Key words
: corrosion, deterioration, reliability, bridge.
19.1 Introduction
Structures are designed such that they meet some minimum level of safety.
The American Association of State Highway and Transportation Offi cials
(AASHTO) provides guidance on safety factors and reliability require-
ments for both newly designed and in-service bridge structures. Although
signifi cant research has been performed to assess the effects of deterior-
ation of materials, less research has been performed to assess the infl u-
ence of this deterioration on structure performance. Structures, and more
specifi cally reinforced concrete (RC) and post-tensioned (PT) bridge
structures, are exposed to various environmental conditions. These envi-
ronmental conditions can lead to deterioration of the concrete and/or
reinforcement. This chapter provides:
•
a review of the mechanisms of deterioration that can occur in RC and
PT structures;
•
a review of types of structural damage resulting from the deterioration
mechanisms, as the type of damage will provide pertinent information
necessary to compute time-variant reliability;
•
a discussion on the time-variant reliability of bridges; and
514
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