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Ground Vibration Analysis
Vibration monitoring is the analysis and measurement of vibrational energy resulting from construcción equipment and demolition activities It can be undertaken before any building work begins (to record background vibration and baseline levels) or during the construction process when continuous or part time monitoring is required.
With vibration monitoring services, the goal is to understand actual ground vibrations at the source and associated attenuations at designation or critical infrastructure and buildings which surround a construction site. If actual ground accelerations exceed pre-designated threasholds at designation or critical infrastructure and buildings, then construction and demolition work may need to be stopped and or adjusted as required.
Alongside this, the monitoring provides accurate data and records that can protect contractors against any related potential claims.
Another benefit of vibrating monitoring is to help identify risk which could result is suitable mitigation to neighboring environments, structures and improvements against long-lasting effects.
Vibration sources and the levels expected
Typical sources of vibration during construction or building work include the demolition of existing structures, heavy vehicle movement, piling, and the removal of large concrete slabs. Examples of property and infrastructure which must be protected include water and gas mains, tunnels, buildings and foundations, roadway and surface alignments, oil and other tanks.
Construction activity can result in varying levels of ground vibration, although they attenuated by the type of ground and distance. In evaluation of the effects of the subject vibrations on the surrounding properties in question, the first order of evaluation is to consider:
- Character of Ground Transmitting Seismic Energy Sources – Both Onsite as a Result of Construction and General “Ambient” Sources in the Vicinity (ie. Trains, Traffic)
- Vibration Energy to Ground vs. Distance from Structures
- Attenuation Factors of the Soils
- Frequency Distribution of Vibration Sources
- Contexting of Energy to Damage – Threshold Limits Graph from USBM RI 8507 and special considerations for sensitive structures.
The location and condition of structures
The response of a building to ground vibrations can be affected by the type of foundation, any underlying conditions and the state of repair of the building. In terms of location, if initial findings indicate that nearby buildings could be at risk, then trial measurements can be carried out to determine the vibration force between the construction site and these buildings.
To mitigate vibration levels, the following approaches can be considered:
- Operate equipment as far away from vibration-sensitive sites as possible
- Adjust demolition, ground-impacting and earthmoving operations at alternate times
- Adjust demolition methods, blasting charges and distances
- Understand actual construction vibration energy, ground attenuation and adjust activities as requried
Pre-existing condition surveys
Pre-construction surveys are powerful tools which can be used to limit liability and risk prior to construction work. By recording pre-existing conditions, contractors have a record of any neighboring structures in the event claims are filed for damages. Usually, high-definition images, nots and measurements can be taken as well as a video to ensure evidence is available upon request.
Development of a monitoring plan for the building(s)
At G3 SoilWorks, our vibration engineering consultants can craft a monitoring plan to ensure the surrounding infrastructure is not damaged during the duration of your construction project.
They'll make sure sophisticated techniques are used to present vibration data, including the frequency spectrum (amplitude as a function of frequency) and time waveform (amplitude as a function of time). The baseline vibration spectrum also makes it possible to identify vibrations that are benign in nature.
Vibration monitoring tools
A number of different tools can be suggested by vibration consultants used to monitor vibrations, including accelerometers, strain gauges, displacement gauges, and seismographs. All of these tools produce a great deal of data which must be correctly evaluated and interpreted.
The equipment usually consists of a sensor unit connected to a recording device, where the signal is processed and stored.
We also provide consultancy on the installation of vibration stations capable of measuring radial, transversal, and vertical ground acceleration, as well as sound pressure levels, which provide critical data for any construction, development, and monitoring endeavors.
Contact the Vibration Engineering Consultants at G3 SoilWorks today
As vibration consultants, G3 SoilWorks can help evaluate and monitor the vibration levels of your construction site, both before and during the project. For more information, contact the team by calling +1 (714) 668-5600, by sending an email to email@example.com, or leaving us a message through our.contact form.