Abstract: The present disclosure provides systems and methods for determining residual tension of a target bolt. An example method may include modeling ratios of times-of-flight of longitudinal waves and times-of-flight of shear waves as a function of tension for a plurality of test bolts. The modeling may include receiving data from longitudinal wave and shear wave transducers, analyzing the data to assess certain quality characteristics, and using a machine learning algorithm to create the model. The example method may further include determining a ratio of a time-of-flight of longitudinal waves and a time-of-flight of shear waves in a target bolt. The example method may further include determining residual tension in the target bolt based on the model and the ratio of a time-of-flight of longitudinal waves and time-of-flight of shear waves in the target bolt.

Abstract: An apparatus for orienting an accelerometer on a post-tensioned rod is provided. The apparatus includes a first open channel having a first sidewall forming a substantially half cylinder shape along at least a portion of a length of the first open channel, and a first axis along a length of the first open channel. The apparatus further includes a second open channel having a second sidewall forming a substantially half cylinder shape along at least a portion of a height of the second open channel, and a second axis along a height of the second open channel. The apparatus further includes a stopper wall having an inner surface disposed internal to a top end of the second channel. The inner surface of the stopper wall is substantially perpendicular to the second axis. The first axis is substantially perpendicular to the second axis. The first and second channels are contiguous.

Abstract: The present disclosure provides systems and methods for estimating the strength of a concrete foundation. The disclosed systems and methods can be used to estimate compressive strength of below-grade concrete without excavation. A method of estimating compressive strength may include determining compressive strength measurements corresponding to surface wave speeds for a plurality of concrete test specimens, determining a speed of surface waves in the concrete foundation, and estimating compressive strength of the concrete foundation based on the compressive strength measurements and corresponding surface wave speeds for the plurality of concrete test specimens and the speed of surface waves in the concrete foundation.

Abstract: A system for estimating tension in a post-tensioned rod is provided. The system includes an impact device for transversely-impacting a post-tensioned rod, an accelerometer configured to generate data indicative of a vibrational response in the post-tensioned rod, and a receiver communicatively coupled to the accelerometer. The receiver includes a display, at least one input device, a communication module, a processor, and one or more memory devices coupled to the processor. Instructions stored on the one or more memory devices, when executed by the processor, cause the processor to receiver the data indicative of a vibrational response in the post-tensioned rod, process the received data to determine a difference between a first and a second modal frequency corresponding to the vibrational response, and store the difference between a first and second modal frequency corresponding to the vibrational response.

Abstract: The present disclosure provides systems and methods for non-destructively estimating the thickness of buried concrete without excavation. An example method may include placing one or more first accelerometers at a plurality of vertical positions below the surface of the ground at an approximate first distance from a vertical edge of the buried concrete each time. The method may further include, for each position in the plurality of vertical positions, generating a dispersive wave in the buried concrete and determining a time of arrival of the dispersive wave at the one or more first accelerometers. The method may further include estimating the thickness of the buried concrete based on at least the times of arrival of the dispersive waves at the one or more first accelerometers.

Abstract: The present disclosure provides systems and methods for non-destructively estimating the thickness of buried concrete without excavation. An example method may include placing one or more first accelerometers at a plurality of vertical positions below the surface of the ground at an approximate first distance from a vertical edge of the buried concrete each time. The method may further include, for each position in the plurality of vertical positions, generating a dispersive wave in the buried concrete and determining a time of arrival of the dispersive wave at the one or more first accelerometers. The method may further include estimating the thickness of the buried concrete based on at least the times of arrival of the dispersive waves at the one or more first accelerometers.

Abstract: The present disclosure provides systems and methods for non-destructively estimating the thickness of buried concrete without excavation. An example method may include placing one or more first accelerometers at a plurality of vertical positions below the surface of the ground at an approximate first distance from a vertical edge of the buried concrete each time. The method may further include, for each position in the plurality of vertical positions, generating a dispersive wave in the buried concrete and determining a time of arrival of the dispersive wave at the one or more first accelerometers. The method may further include estimating the thickness of the buried concrete based on at least the times of arrival of the dispersive waves at the one or more first accelerometers.

Abstract: A system for estimating tension in a post-tensioned rod is provided. The system includes an impact device for transversely-impacting a post-tensioned rod, an accelerometer configured to generate data indicative of a vibrational response in the post-tensioned rod, and a receiver communicatively coupled to the accelerometer. The receiver includes a display, at least one input device, a communication module, a processor, and one or more memory devices coupled to the processor. Instructions stored on the one or more memory devices, when executed by the processor, cause the processor to receiver the data indicative of a vibrational response in the post-tensioned rod, process the received data to determine a difference between a first and a second modal frequency corresponding to the vibrational response, and store the difference between a first and second modal frequency corresponding to the vibrational response.

Abstract: The present disclosure provides systems, methods, and apparatuses for estimating tension in post-tensioned rods, such as anchor rods that support structural steel to concrete. A method of estimating tension in a target post-tension rod may include selecting a plurality of post-tensioned rods and modeling tension for the plurality of post-tensioned rods as a function of frequency differences between a first and a second modal frequency and cantilever length of each rod. The method may further include measuring the length of a cantilever of the target post-tensioned rod, determining first and second modal frequencies of the target post-tensioned rod, and determining a frequency difference between the first and second modal frequencies. The method may further include estimating tension in the target post-tensioned rod based on at least the model.

Abstract: The present disclosure provides systems and methods for non-destructively estimating the thickness of buried concrete without excavation. An example method may include placing one or more first accelerometers at a plurality of vertical positions below the surface of the ground at an approximate first distance from a vertical edge of the buried concrete each time. The method may further include, for each position in the plurality of vertical positions, generating a dispersive wave in the buried concrete and determining a time of arrival of the dispersive wave at the one or more first accelerometers. The method may further include estimating the thickness of the buried concrete based on at least the times of arrival of the dispersive waves at the one or more first accelerometers.

Abstract: The present disclosure provides systems and methods for non-destructively estimating the thickness of buried concrete without excavation. An example method may include placing one or more first accelerometers at a plurality of vertical positions below the surface of the ground at an approximate first distance from a vertical edge of the buried concrete each time. The method may further include, for each position in the plurality of vertical positions, generating a dispersive wave in the buried concrete and determining a time of arrival of the dispersive wave at the one or more first accelerometers. The method may further include estimating the thickness of the buried concrete based on at least the times of arrival of the dispersive waves at the one or more first accelerometers.

Abstract: An apparatus for orienting an accelerometer on a post-tensioned rod is provided. The apparatus includes a first open channel having a first sidewall forming a substantially half cylinder shape along at least a portion of a length of the first open channel, and a first axis along a length of the first open channel. The apparatus further includes a second open channel having a second sidewall forming a substantially half cylinder shape along at least a portion of a height of the second open channel, and a second axis along a height of the second open channel. The apparatus further includes a stopper wall having an inner surface disposed internal to a top end of the second channel. The inner surface of the stopper wall is substantially perpendicular to the second axis. The first axis is substantially perpendicular to the second axis. The first and second channels are contiguous.

Abstract: The present disclosure provides systems, methods, and apparatuses for estimating tension in post-tensioned rods, such as anchor rods that support structural steel to concrete. A method of estimating tension in a target post-tension rod may include selecting a plurality of post-tensioned rods and modeling tension for the plurality of post-tensioned rods as a function of frequency differences between a first and a second modal frequency and cantilever length of each rod. The method may further include measuring the length of a cantilever of the target post-tensioned rod, determining first and second modal frequencies of the target post-tensioned rod, and determining a frequency difference between the first and second modal frequencies. The method may further include estimating tension in the target post-tensioned rod based on at least the model.