Optical fibers are used in different areas and in many applications. In Civil
Engineering, they have been used for the structural monitoring as an alternative to traditional
electrical sensors. This work aims to study the feasibility and application of sensors based on
optic fibers to monitor large civil engineering structures. Three different types of experimental
tests were carried out to evaluate the results where specimens were instrumented with
electrical and optical strain gages. The first type of tests was simple tensile tests where steel
bars were submitted to monotonic loading untilcollapse. In the second type of test, the
automation of a triorthogonal joint gage, that is a typical instrument used for monitoring
concrete dams. Finally, was studied the last type of tests was compression tests carried out
with cylindrical concrete specimens for determining Young modulus. Regarding the use of
optical sensors, there were many problems with the optical data acquisition system; so three
different data acquisition units were used to carry on the tests. Concerning the accuracy of
the results, it was observed that the results obtained with optical sensors were similar to the
electrical sensors results. However, when the optical sensors were submitted to large
deformations, signal loss occurred due to the interruption of the light flow.
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