Vibration Monitoring (VM)

Vibrations in a construction area comes from heavy equipment operations and from blasting operations when employed. Tri-axial accelerometers and seismographs are employed to detect and monitor these vibrations. These may be manually or remotely operated. Remotely operated units have set trigger points, which when reached automatically sends emails to authorized personnel and to a database set-up for that purpose.

Vibration limits are set, in New York City by guidelines based on NYCDOB TPPN 10-88. A Peak Particle Velocity (PPV) of 0.5 Inches per second is the maximum, which when exceeded would mean stopping all work, investigating the reason and mitigating the situation. These vibrations are considered detrimental and may cause damage in prolonged instances.

Older VMs employed in construction are directional and are oriented either in vertical or horizontal positions. Horizontal sensors have pointers which may be directly pointed at the vibration source, or in the general vicinity where the vibration may be coming from and generally measures ground movements. Vertical sensors usually mounted on walls measures the vibrations experienced by the structure itself. Recent developments in Vibration Monitors have multi-directional sensors that automatically orients itself to the plane on which the sensors are mounted, doing away with horizontal or vertical positioning.

Manual VMs are set where a technician oversees its operation. This arrangement allows for the technician to immediately inform the heavy equipment operator, to make adjustments or act on the cause of the vibration triggers.