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City of Santa Ana <br />Environmental Checklist <br />Groundborne vibration typically decreases rapidly with distance. Based on the FTA data (Table 3- <br />19), vibration velocities from typical heavy construction equipment operation that would be used <br />during project construction range from 0.076 to 0.089 inches per second peak particle velocity <br />(PPV) at 25 feet from the source of activity. At 50 feet from the source activity (closest sensitive <br />receiver ST -5), PPV ranges from 0.027 to 0.032 inch per second. <br />Because neither the state nor the local municipalities maintain regulatory standards for vibration <br />sources, potential structural damage and human annoyance associated with vibration from <br />construction activities were evaluated against California Department of Transportation (Caltrans) <br />vibration limits (Table 3 -20). A vibration level of 0.10 inches per second PPV was used to evaluate <br />impacts on nearby receivers because this level represents the boundary between barely perceptible <br />and distinctly perceptible vibration as recognized by Caltrans and others. Because the predicted <br />vibration levels from project construction would be well below applicable vibration thresholds, <br />impacts from groundborne vibration or groundborne noise would be less than significant. <br />Table 3 -19. Typical Vibration Levels for Construction Equipment <br />Approximate peak particle Approximate peak particle <br />velocity at 25 feet velocity at 50 feet <br />Equipment (inches /second) (inches /second) <br />Large bulldozer 0.089 0.032 <br />Loaded trucks 0.076 0.027 <br />Notes: <br />Peak particle velocity measured at 25 feet unless noted otherwise. <br />Root mean square amplitude ground velocity in decibels (VdB) referenced to 1 micro- inch/second. <br />Source: Federal Transit Administration, Transit Noise and Vibration Impact Assessment Guidelines, May <br />2006. <br />Table 3 -20. Reaction of People and Damage to Buildings at Various Continuous Vibration Levels <br />Peak Particle <br />Velocity (PPV) <br />(in /sec) Human Reaction Effect on Buildings <br />0.006 -0.019 Threshold of perception; possibility of Vibrations unlikely to cause damage of <br />intrusion. any type. <br />0.08 Vibrations readily perceptible. <br />0.10 Level at which continuous vibrations <br />begin to annoy people. <br />0.20 Vibrations annoying to people in <br />buildings (this agrees with the levels <br />established for people standing on <br />bridges and subjected to relative short <br />periods of vibration). <br />Recommended upper level of the <br />vibration to which ruins and ancient <br />monuments should be subjected. <br />Virtually no risk of "architectural" <br />damage to normal buildings. <br />Threshold at which there is a risk of <br />"architectural' damage to normal <br />dwelling - houses with plastered wails <br />and ceilings; special types of finish such <br />as lining of walls, flexible ceiling <br />treatment, etc., would minimize <br />"architectural" damage. <br />The Academy Charter High School 3 79 June 2012 <br />Initial Study /Mitigated Negative Declaration ICF00914.11 <br />31 B -157 <br />