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RECOMMENDED VIBRATION LIMITS FOR RESIDENTIAL STRUCTURES Seismological research by the USBM, OSM, foreign investigative groups, and individual seismologists have established criteria relating the occurrence of structural damage to certain frequencies and levels of ground motion USBM Report of Investigations (RI) 85072 states that residential stmcnues are most prone to damage as a result of vibration energy within the frequency range of 412 hertz. Within this range, a 0.5 inch per second maximum particle velocity is recommended to preclude'tlueshold' damage to the plaster-on wood-lath ulterior portions of older structures. Threshold damage is defined by the USBM as the loosening of paint, small plaster cracks at joints between construction elements, or the lengthening of old plaster cracks. A mardmum of 0.75 inch per second is recommended for the protection of modem drywall interior construction. The damage threshold is normally considerably higher for load-bearing or other structural portions of a house. Above 12 hertz, the allowable vibration level increases as the frequency increases, up to 40 hertz Above 40 hertz, a constant 2.0 inches per second level is recommended to protect the interior walls and ceilings of structures, regazdless of construction material. A graphic representation of the USBM recommended criteria is shown in the velocity versus frequency curve on the following page. The vibration analysis of the recordings are plotted on graphic representations at the end of this report. It should be noted that it is almost impossible, in actual practice, to visually determine if the recorded peak vibration on a typical seismogram is actually within the Bureau's 4-12 hertz range. This is because ground vibration is usually a complex mixture of many frequencies which cannot be accurately separated by visual analysis of a seismogram. RECOMMENDED VIBRATION LIMTPS FOR ENGINEERED STRUCTURES Engineered structures such as commercial buildings, which contain no plaster or gypsum-board walls, are much stronger than plaster-on-wood residential construction and can safely withstand peak particle velocities in excess of the U. S. Bureau of Mines limits. The generally accepted criteria to protect .. engineered or unplastered commercial structures from short duration vibrations is 4.0 inches per second. These limits assume that the structures of concern are in good structural condition. Stnrctures that are not in good condition will necessitate a downward revision of the acceptable vibration limits. Engineered structures such as train tracks, asphalt paved roads, and bridges can safely withstand peak particle velocities in excess of 4.0 inches per second. The ground vibration effects of the proposed quarry on the roadways, bridges and railroad tracks in the vicinity will be infinitesimally small when compared to the everyday dynamic compaction forces of vehicular or Vain traffic. 2. Siskind, David et al, "Structural Response and Damage Produced by Ground Vibration From Blasting", U. S. Bureau of Mmes, RI 8507, 1980. 13 -.