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OCTA I Santa Ana/Garden Grove Fixed Guideway Project <br />FNNoise and Vibration Technical Analysis Re-evaluation in Support of Minor Design Modifications <br />COMBINED EFFECT (INCREASE IN SPEED AND ALIGNMENT SHIFT) <br />Table L lists the vibration levels calculated for the proposed alignment. This table reflects the <br />change in vibration levels associated with the increase in speed and the change in centerline <br />location. <br />Table L: Proposed Modified Project Train Operation Vibration Levels <br />NSA <br />Rec. <br />Land Use <br />Cat. <br />Transit Vehicle Speed <br />(mph) <br />Vibration Level (VdB) <br />Vibration Impact (without <br />inclusion of recommended design <br />feature) <br />II. Engineered concrete and masonry (no plaster) <br />R1 <br />2 <br />45 <br />58 <br />None <br />1 <br />R2 <br />2 <br />45 <br />68 <br />None <br />R3 <br />2 <br />45 <br />68 <br />None <br />2 <br />R4 <br />2 <br />45 <br />68 <br />None <br />R5 <br />2 <br />45 <br />70 <br />None <br />3 <br />R6 <br />2 <br />45 <br />71 <br />None <br />R7 <br />2 <br />45 <br />63 <br />None <br />R8 <br />3 <br />45 <br />66 <br />None <br />4 <br />R9 <br />3 <br />45 <br />59 <br />None <br />5 <br />R11 <br />3 <br />45 <br />63 <br />None <br />6 <br />R10 <br />2 <br />45 <br />71 <br />None <br />7 <br />R12 <br />2 <br />45 <br />71 <br />None <br />8 <br />R13 <br />2 <br />45 <br />70 <br />None <br />9 <br />R15 <br />1 2 <br />1 45 1 <br />66 <br />1 None <br />10 <br />R14 <br />1 2 <br />1 45 1 <br />65 <br />1 None <br />Source: URS (February 2012) and HDR (June 2016). <br />The impact threshold for Land Use Category 2 is 72 VdB and for Land Use Category 3 is <br />75 VdB. As shown, the vibration levels are below the impact threshold at all receptor locations. <br />Therefore, no minimization design features are required. <br />Construction Vibration Analysis <br />Construction activity can result in varying degrees of ground vibration, depending on the <br />equipment and methods employed. Ground vibrations from construction activities do not often <br />reach the levels that can damage structures. A possible exception is the case of fragile <br />buildings, many of them old, where special care must be taken to avoid damage. Table M lists <br />FTA's Construction Noise Vibration Damage Criteria. <br />Table M: Construction Vibration Damage Criteria <br />Building Category <br />PPV (in/sec) <br />Approximate Lv <br />I. Reinforced -concrete, steel or timber (no plaster) <br />0.5 <br />102 <br />II. Engineered concrete and masonry (no plaster) <br />0.3 <br />98 <br />III. Non -engineered timber and masonry buildings <br />0.2 <br />94 <br />IV. Buildings extremely susceptible to vibration damage <br />0.12 <br />90 <br />Source: FTA (May 2006). <br />Peak particle velocity (PPV): The maximum instantaneous positive or negative peak of the vibration signal <br />12 <br />