GTS Technologies -- Geophysical

GTS performed a vibration monitoring assessment study along two sections of roadway in eastern Pennsylvania where the road is scheduled for major widening and improvements. This construction activity and the revised roadway will place traffic much closer to buildings, some of which are historic structures. Potential damage to these structures required an assessment of the future vibration energy that would exist along the new roadway.

GTS identified 25 properties along the two sections of roadway that were constructed with materials that could be sensitive to increased roadway vibrations. For each of these properties, three recording vibration accelerometers were installed at differing distances between the structure and the roadway to define the current level of vibration and to define the vibration energy decline curve with increasing distance. Several hundred vibration events were recorded and time stamped in the memory of each accelerometer. Later GTS returned to three sites with a tripod mounted heavy drop weight and repeated the vibration monitoring using the energy produced by the drop weight. The energy of the drop weight could be precisely calculated and therefore a correlation between energy release and vibration impact could be calculated at three different distances from the drop weight.

The field vibration data were analyzed using Instantel software called Blastware, and, using the recorded waveform data from the accelerometers, the maximum ground velocities were calculated. The FEMA NONLIN program was used to determine the response of a structure to ground motion, either linear or nonlinear, for one to three degrees of freedom. This program was used to gage the level of structural response due to traffic-induced vibrations compared to non-traffic vibrations. The model assumed a two-story structure with stone and mortar exterior walls.

The results of the field survey and modeling analysis verified that the proposed roadway improvements would not result in excessive vibrations that could potentially damage the buildings.



	GTS performed a vibration monitoring assessment study along two sections of roadway in eastern Pennsylvania where the road is scheduled for major widening and improvements. This construction activity and the revised roadway will place traffic much closer to buildings, some of which are historic structures. Potential damage to these structures required an assessment of the future vibration energy that would exist along the new roadway. GTS identified 25 properties along the two sections of roadway that were constructed with materials that could be sensitive to increased roadway vibrations. For each of these properties, three recording vibration accelerometers were installed at differing distances between the structure and the roadway to define the current level of vibration and to define the vibration energy decline curve with increasing distance. Several hundred vibration events were recorded and time stamped in the memory of each accelerometer. Later GTS returned to three sites with a tripod mounted heavy drop weight and repeated the vibration monitoring using the energy produced by the drop weight. The energy of the drop weight could be precisely calculated and therefore a correlation between energy release and vibration impact could be calculated at three different distances from the drop weight. The field vibration data were analyzed using Instantel software called Blastware, and, using the recorded waveform data from the accelerometers, the maximum ground velocities were calculated. The FEMA NONLIN program was used to determine the response of a structure to ground motion, either linear or nonlinear, for one to three degrees of freedom. This program was used to gage the level of structural response due to traffic-induced vibrations compared to non-traffic vibrations. The model assumed a two-story structure with stone and mortar exterior walls. The results of the field survey and modeling analysis verified that the proposed roadway improvements would not result in excessive vibrations that could potentially damage the buildings. Top of Page	METHODS Electrical Resistivity Terrain Conductivity Very Low Frequency Spontaneous Potential Seismic Refraction Ground Penetrating Radar Magnetometry Vibration Monitoring Soil Resistance Testing CASE HISTORIES Archaeology Bedrock Delineation Ground Penetrating Radar Groundwater Availablity Mining 1 Mining 2 Sinkhole Investigations Sinkhole Investigations 2 Soil Resistance Testing Underground Storage Tanks Vibration Monitoring
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