CCEER-17-07: Analytical Investigation into Bridge Column Innovations for Mitigating Earthquake Damage
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Authors
Nada, Hisham
Sanders, David H.
Issue Date
2017-06-01
Type
Report
Language
Keywords
CCEER
Alternative Title
Abstract
Current seismic bridge design is based on columns designed to be the sacrificial elements during earthquake excitation. This
design philosophy capacity protects the bridge foundations, connections and superstructures while causing a lot of damage to
the columns during large seismic events. Despite that this concept proved to be successful in bridge collapse prevention and
life safety, it causes excessive residual displacement, extensive concrete cracking, cover spalling, rebar buckling, and
residual strains in concrete and steel reinforcement. Conventionally designed and detailed reinforced concrete bridge
columns can achieve large inelastic deformations without significant loss of vertical or lateral load capacity, but may have
significant post-earthquake damage. In many cases, this damage required long-term closure of highways while expensive
repairs, or even complete replacement, are carried out. The past two decades witnessed extensive research that developed
new design and detailing methods to include new design details and new materials. Despite the extensive effort exerted in
such detailing and innovations, little application has been observed in real bridge construction and few code provisions have
been changed to include limiting bridge damage. As Nevada is considered the second most seismically active state in the
continental U.S and possesses a highway system at full capacity in many locations and has limited redundancy in other
places, it is essential to develop bridge designs that limit or eliminate the damage. This report spans the gap between the
research and practical application of the new innovations to actual bridges with specific Nevada bridges in mind.
Innovations included Engineered Cementitious Composites (ECC), Strength Memory Alloys (SMA), prestressing and
debonding reinforcement. It investigates the behavior, advantages and disadvantages of each proposed detail and answers
the question whether such innovation will be useful to bridge design and damage mitigation through a sophisticated
analytical study of a full-scale model that is exposed to different earthquake excitations matching different Nevada design
response spectrums. Analytical results and column detail recommendations are provided.
Description
Report No. CCEER-17-07
Citation
Publisher
License
In Copyright