Concrete pipelines are one of the most popular underground lifelines used for the transportation of water resources.
Unfortunately, this critical infrastructure system remains vulnerable to ground displacements during seismic and
landslide events. Ground displacements may induce significant bending, shear, and axial forces to concrete pipelines
and eventually lead to joint failures. In order to understand and model the typical failure mechanisms of concrete
segmented pipelines, large-scale experimentation is necessary to explore structural and soil-structure behavior during
ground faulting. This paper reports on the experimentation of a reinforced concrete segmented concrete pipeline using
the unique capabilities of the NEES Lifeline Experimental and Testing Facilities at Cornell University. Five segments of
a full-scale commercial concrete pressure pipe (244 cm long and 37.5 cm diameter) are constructed as a segmented
pipeline under a compacted granular soil in the facility test basin (13.4 m long and 3.6 m wide). Ground displacements
are simulated through translation of half of the test basin. A dense array of sensors including LVDT's, strain gages, and
load cells are installed along the length of the pipeline to measure the pipeline response while the ground is incrementally displaced. Accurate measures of pipeline displacements and strains are captured up to the compressive and flexural failure of the pipeline joints.
Seismic damage to buried pipelines is mainly caused by permanent ground displacements, typically concentrated in the
vicinity of the fault line in the soil. In particular, a pipeline crossing the fault plane is subjected to significant bending,
shear, and axial forces. While researchers have explored the behavior of segmented metallic pipelines under permanent
ground displacement, comparatively less experimental work has been conducted on the performance of segmented
concrete pipelines. In this study, a large-scale test is conducted on a segmented concrete pipeline using the unique
capabilities of the NEES Lifeline Experimental and Testing Facilities at Cornell University. A total of 13 partial-scale
concrete pressure pipes (19 cm diameter and 86 cm long) are assembled into a continuous pipeline and buried in a loose
granular soil. Permanent ground displacement that places the segmented concrete pipeline in compression is simulated
through the translation of half of the soil test basin. A dense array of sensors including linear variable differential
transducers, strain gauges, and load cells are installed along the length of the pipeline to measure its response to ground
displacement. Response data collected from the pipe suggests that significant damage localization occurs at the ends of
the segment crossing the fault plane, resulting in rapid catastrophic failure of the pipeline.
This study characterizes the Doppler signal from simulated microemboli of various sizes in blood mimicking fluid using spectral energy parameters. The goal of this research is to detect microemboli as a non-invasive diagnostic tool, or intra-operatively as a surgical aid. A dual beam diffraction-grating ultrasound probe operating at 10 MHz (Model Echoflow BVM-1, EchoCath, Inc., Princeton, NJ) was used with a flow phantom. Microemboli were polystyrene microspheres in 200 to 1000 micron diameters, in concentrations of 0.1, 0.5, and 1.0 per ml. Average flow velocities were 25, 50, 75, and 100 cm/sec. The distribution of peak values of the power spectrum at 2.5 msec windows was plotted over 15 seconds. The means of the distributions corresponding to the microspheres and background fluid were averaged for the four velocity conditions. Embolic peak spectral power ranged from approximately 12 to 25 dB relative to the background. A detection method based on these measurements is currently being developed.
The acoustic emission (AE) behavior of reinforced concrete beams tested under flexural loading was investigated to characterize and identify the source of damage. This research was aimed at identifying the characteristic AE response associated with micro-crack development, localized crack propagation, corrosion, and debonding of the reinforcing steel.