Quantitative evaluation of damages in reinforced concrete beams with acoustic methods

The main aim of this study is to simultaneously and realistically determine the damage initiation and propagation mechanism in strengthened reinforced concrete elements under an increasing loading. In the direction of this aim, AE technique was selected among the nondestructive testing methods. Within the framework of this technique, AE parameter analysis, AE sentry function and AE-SiGMA (Acoustic Emission - Simplified Green's Function for Moment Tensor Analysis) methods were used. Within the scope of this study, 4 specimens were tested, one of them was a reference beam, one of them were shear strengthened beams with CFRP strips applied only to the side surfaces and 2 of them were shear strengthened beams with shape CFRP strips in the different strip widths and spacings. T cantilever beam was selected as experimental specimen. The study was conducted in two parts. First one was the loading of reinforced concrete elements under reversed cyclic loading and determination of the load-displacement relationships and unit deformation values in selected points. Second one was to perform AE measurements simultaneously with experimental work and to realistically monitor damage mechanisms. The acoustic methods used were AE-SiGMA and sentry function techniques and they were firstly applied to strengthened reinforced concrete structures within the scope of this study. The results obtained from two parts were compared and rational findings were reached with an accurate validity.