Structural Response Studies

GeoSonics/Vibra-Tech’s advanced instrument and comprehensive structure studies are key to making short work of community complaints and compliance concerns.

Low peak particle velocity does not always mean no complaints. People complain about blasting operations for a number of reasons unrelated to ground vibration or airblast, but underlying every complaint is a fear of damage to homes or buildings. The perception of vibration and airblast is typically produced by the structure response to outside forces. Each state, county or city has regulations maintaining levels within limits, but that does not always stop complaints or claims of damage. In such cases, structure response evaluations are completed to ensure that structures are not adversely affected and are not responding in an unexpected manner, and to allow for modifications to blasting plans.

Blasting studies show that racking of the structure and bending of interior walls occur as vibration occurs. In special circumstances multi-story structures will respond differently to outside stimulus. Showing and documenting these effects can demonstrate to regulatory agencies and property owners the impact on their structures.

While a structure has a normal response, further evidence may be necessary to show that vibration is not affecting it, such as crack monitoring. GeoSonics/Vibra-Tech has advanced level instrumentation to show the behavior of cracking in structures. Crack width changes relate directly to crack length, so measurement of width changes shows whether length will change.

GeoSonics/Vibra-Tech’s Re:mote Monitoring systems use crack gauges to measure width and produce recordings that indicate motion and can be used with vibration measurement to show blast vibration stresses. Continual environmental monitoring shows long-term changes produced by temperature and humidity. Mounted on the interior or exterior of structures, the gauges track motion of any type, producing a record to show that vibration is not causing the stress on a structure that would cause defects.

Overall, the motions of the structure are key to making short work of complaints and demonstrating compliance.