However, shear cracks become dominant as the cracking process progresses. It is found that both tensile and shear cracks are generated around the reinforcement in the low loading stages. First, bending tests are performed on reinforced concrete beams. Cracking process is quantitatively evaluated and visualized by applying a moment tensor analysis to the AE waveforms detected during the fracture. =, number = 3,įracture tests are conducted on two types of reinforced concrete specimens under cyclic loadings. The moment tensor analysis showed that shear cracks start to appear and play a primary role when the Kaiser effect fails.
Cyclic loading using flac3d crack#
Crack orientations determined from eigenvectors obtained by decomposition of moment tensor components and crack more » directions presented as crack-opening vectors for tensile cracks and fault-motion vectors for shear cracks were in good agreement with the visual observation of the surface cracks.
Moment tensor analysis, a quantitative AE waveform analysis based on the moment tensor modeling of cracks, was applied to classify crack types and to determine crack orientations in the fracture process of a rigid reinforced concrete frame.
The Kaiser effect, thus, becomes a very effective method for estimating the level of deterioration in concrete structures. However, it fails after the width has reached this value and with the onset of shear cracks. It was revealed that the Kaiser effect exists so long as the width of tensile cracks is smaller than about 0.15-0.20 mm (0.006-0.0078 in.). From the tests, it was shown that different AE sources could be clearly discriminated by comparing the AE parameter data with the results of visual observation and crack width measurement. The results were compared with visual observation and the measured value of crack widths and deflections. The growth of tensile cracks, shear cracks and bond failure of the reinforcement in an L shaped rigid frame of reinforced concrete was monitored by AE. The results obtained, comprising total and differential settlements and bending moments, were used for the final design of the proposed pile foundation and can be used for similar practical applications.A fundamental study was made of the acoustic emission (AE) behavior of reinforced concrete structures under cyclic loading. The outcome of a probabilistic seismic hazard assessment was used to estimate target input motions resulting in maximum bending moments of 114 kN.m and maximum settlement of 21♹ mm for piles under dynamic conditions. Field pile load test data for a static analysis were used for validation of the Flac3D model. The foundation system was modelled using the finite-difference-based geotechnical program Flac3D to carry out detailed DSSI analysis. by 1♵ m thick pile cap connecting together 89 piles, each pile being 800 mm in diameter and 26 m long. For the particular in situ soil profile, a pile group foundation is proposed comprising a 24♱ m dia. This paper presents an actual field study and dynamic soil–structure interaction (DSSI) analysis for an oil tank foundation design in weak soil strata for the Kafza site in Iraq, which is located in a seismically active region. Seismic analysis and design of pile foundations in weak soil strata to support oil tanks are of great importance to geotechnical practitioners.
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