The Value of Structural Health Monitoring of a Corroded Reinforced Concrete Beam
Date
2021-12-08
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0002-8983-6271
Type
Thesis
Degree Level
Masters
Abstract
With the increasing number of aging structures worldwide, structural health monitoring (SHM)
has gained a lot of research interest. Structural health monitoring (SHM) can provide real-time
information about a structure’s actual condition, thereby mitigating the risk of failure if the
structural condition is worse than presumed, or extending the service life and saving the
replacement costs if it has an adequate level of safety. Many SHM techniques have been developed
in the past 40 years; however, few of them have been successfully implemented on real structures.
The limited practical application of SHM has been attributed to the lack of mature and
sophisticated SHM techniques and the lack of economic studies to clearly demonstrate the
financial benefits to the structural owners.
Christensen et. al described the theoretical principle of a surface strain-based SHM technique for
reinforced concrete beams in the book “Monitoring Technologies for Bridge Management” in
2011. The SHM technique is designed to estimate the remaining effective cross-sectional area of
the reinforcing bars after corrosion, which can then be used to predict the remaining structural
capacity and service life, as well as the degree of certainty associated with these predictions. As
part of this research project, laboratory experiments were conducted to evaluate the effectiveness
of the surface strain-based SHM technique on nine small-scale reinforced concrete beams. The
experimental and data processing procedures were first calibrated to obtain more reliable results.
The effectiveness of the proposed SHM technique was then determined and quantified using the
errors between the predicted beam capacities using the identified optimal procedures and the actual
failure loads. It was found that the proposed technique did not achieve accurate estimates of the
remaining cross-sectional area of the reinforcing bars or failure load when applied to the small and
slender beams. However, it is believed to have potential to provide better result on large-scale
beams.
The experimental results were also used to demonstrate the value of SHM systems through
reliability and economic analyses. Two monitoring systems with different levels of uncertainty
were created. The standard monitoring system was composed of strain measuring equipment only,
while the enhanced monitoring system included the strain measuring equipment and a cover meter,
used to reduce the uncertainty of the reinforcing bar locations. It was demonstrated that, although
the enhanced SHM system was associated with a higher cost, it consistently provided a higher
reliability index – leading to an extension of service life – and lower annual worth of life cycle
costs (AWLCC) when replacement decisions were based on the respective SHM data.
Description
Keywords
Structural Health Monitoring, SHM, Strain-based, Structural, Corrosion, Corroded Reinforced Concrete Beam, Economic Analysis, Life-cycle Cost, Reliability Analysis
Citation
Degree
Master of Science (M.Sc.)
Department
Civil and Geological Engineering
Program
Civil Engineering