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City of Santa Ana Addendum to the <br />MainPlace Mall Transformation Project Fashion Square Commercial Center Final EIR <br />Table N-5: Existing Project Area Noise Levels <br />Leq <br />Lmin <br />Lmax <br />Site <br />Location <br />(dBA) <br />(dBA) <br />(dBA) <br />Time <br />At the northeast corner of the <br />1 <br />parking structure near JC <br />72.1 <br />68.1 <br />81.3 <br />1:24 p.m. <br />Penny <br />At the northeast corner of the <br />2 <br />parking structure along Main <br />64.4 <br />56.2 <br />76.2 <br />1:37 p.m. <br />St <br />130 feet east of the Broadway <br />3 <br />and Main Place Dr/Memory <br />65.7 <br />62.4 <br />73.0 <br />1:53 p.m. <br />Lane intersection <br />Along Main Place Dr, 890 feet <br />4 <br />north of the east -west segment <br />71.9 <br />96.4 <br />77.5 <br />2:09 p.m. <br />of Main Place Dr <br />Source: Acoustical Assessment, 21J19 <br />Construction Vibration <br />Construction has the potential to result in varying degrees of temporary groundborne <br />vibration, depending on the specific construction equipment used and the operations <br />involved. Vibration can result in human annoyance when construction vibration rises <br />significantly above the threshold of human perception for extended periods of time. <br />Building damage from vibration generated by construction equipment can also occur. <br />However, the Federal Transit Administration (FTA) guidelines show that a vibration level <br />of up to 0.20 in/sec is considered safe and would not result in any construction vibration <br />damage. <br />Table N-6 lists vibration levels at 25 feet for typical construction equipment. As shown, <br />vibration velocities from typical heavy construction equipment operations range from <br />0.003 to 0.089 in/sec PPV at 25 feet from the source of activity. The nearest offsite <br />sensitive receptors are the residential uses approximately 300 feet to the north and the <br />nearest existing structures could be approximately 25 feet from the closest active <br />construction zone. As shown in Table N-6, at 25 feet the vibration velocities from <br />construction equipment would not exceed 0.089 in/sec PPV, which is below the FTA's <br />0.20 PPV threshold for structural damage. Therefore, vibration impacts associated with <br />construction of the proposed Project would be less than significant. <br />104 <br />