Automatic Vibration Monitoring
As an alternative or supplement to the manually operated seismograph, we provide automatic units (see Vibration Monitoring specifications), which are installed on a long-term basis. When the seismograph is installed it is set to record within a certain criteria. The typical setting is 1.92 in/sec PPV with a threshold of 0.5 in/sec PPV. The threshold is set at a much lower limit in order to ensure that 1.92 in/sec PPV is not exceeded. 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 instrumentation used are component instruments. When installed the seismograph shall continuously monitor construction vibration from a secure location with a power source and requires periodic weekly visits to remove the recordings for analysis.
We install and remove our equipment, perform a weekly visit in order to remove the records obtained for analysis and interpretation, 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.
Examples of event graphs we produce can be found here:
Event Graph 1 JPG PDF
