Title: Distributed Sensing in Large Reinforced Concrete Shear Test

Author(s): Jack J. Poldon, Neil A. Hoult, and Evan C. Bentz

Publication: Structural Journal

Volume: 116

Issue: 5

Appears on pages(s): 235-245

Keywords: curvature; digital image correlation; fiber-optic strain sensors; large beams; shear; shear strains; stirrups

DOI: 10.14359/51716765

Date: 9/1/2019

Abstract:
A large reinforced concrete (RC) beam designed to fail in shear was experimentally tested and monitored with distributed sensing technologies. Fiber-optic sensors (FOS) were used to monitor the strain along the flexural and shear reinforcement, and digital image correlation (DIC) was used to measure strains and displacements on the concrete surface. Measurements from the distributed sensing technologies were found to be in agreement with conventional sensors when tensile elongation and midspan deflection were analyzed prior to the development of extensive shear cracks. Results showed that cracking on the concrete surface was correlated with peaks in the FOS strain data for both the flexural and shear reinforcement. Combined distributed measurement (CDM) plots presented the full beam response at a given load. A method of monitoring the distributed shear strain was proposed and used to assess the behavior with increasing load and showed that prior to failure, approximately 45% of the beam displacement was due to shear strain. The presented measurement technique using FOS and DIC is shown to enable a more detailed study of shear failures, specifically, in a fashion that enables the quantification of the individual response of reinforcing steel and concrete under loading.