Mass Transit Monitoring

John V. Dinan Associates provides subway monitoring, which requires there be an inspector/technician on the site during construction activities. Once our seismologist(s) are on site, they shall install the required geophones in the predetermined locations and set the seismograph(s) to record at a certain criteria.

The typical criteria for projects adjacent to mass transit structures is 0.5 in/sec PPV with a threshold of 0.05 in/sec PPV. These settings change based on projects requirements, the conditions of adjacent structures, whether the project is in a historic district, and if the adjacent structures are historic landmarks. The seismograph shall continuously monitor construction vibration while our technician ensures that the threshold value is not exceeded.

We install and remove our equipment, provide the vibration monitoring readings on a daily basis, and render a weekly report and opinion, in triplicate, for your records. In our weekly reports we state the source of vibration, include the actual data/graphs that list the date and time of each recording, and provide a conclusion based on the vibration levels.

The main purpose of vibration monitoring is to measure, record, and analyze the vibration levels at a specific location. From this we are able to determine the possible effect of these vibrations and confirm that the vibration levels are below the specified threshold.