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City of Pleasanton 2023-2031 (6th Cycle) Housing Element Update CEQA Findings of Fact and Statement of Overriding Considerations FirstCarbon Solutions 111 Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480022/FOF/21480022 Pleasanton Housing Element FOF.docx Department, to implement these measures to limit construction-related vibration impacts. For any future development projects that would necessitate the use of large vibratory rollers within 30 feet of an off-site structure, or the use of heavy construction equipment (i.e. construction equipment with a peak particle velocity [PPV] at 25 feet [inches per second] rating of 0.051 or greater as shown in Table 3.11-3 in Section 3.11, Noise, in the Program EIR] within 15 feet of an off-site structure, the project sponsor shall retain a Noise Specialist to prepare a Construction Vibration Reduction Plan for submittal to the City’s Director of Community Development for review and approval that identifies specific techniques, such as the depth and location of temporary trenching, that would reduce potential vibration impacts to less than significant for any impacted structures. Upon approval by the City, the construction vibration reduction measures shall be incorporated into the construction documents. A note shall be provided on grading and building plans indicating that, during grading and construction, the property owner/developer shall be responsible for requiring contractors, to be monitored via on-site inspection by the Community Development Department, to implement these measures to limit construction-related vibration impacts. Facts in Support of Findings: The City has not adopted specific thresholds for groundborne vibration impacts; therefore, for purposes of this analysis, the FTA’s vibration impact criteria are utilized to analyze vibration impacts. Short-term Construction Vibration Impacts to Off-site Receptors: Construction activity can result in varying degrees of ground vibration, depending on the equipment used on the site. Operation of construction equipment causes ground vibrations that spread through the ground and diminish in strength with distance. Buildings in the vicinity of a construction site respond to these vibrations with varying results, ranging from no perceptible effects at the low levels to slight damage at the highest levels. Vibration-induced structural damage could only occur when certain types of construction activity (e.g., blasting and pile-driving) take place close to existing structures, while vibration-induced disruption/annoyance could occur during more common types of construction activity (e.g., truck movements) at greater distance from the activity area. Impact pile drivers that could be used in the site preparation phase of construction would produce the greatest groundborne vibration levels. Impact pile drivers produce groundborne vibration levels ranging up to 0.644 inch per second (in/sec) PPV at 25 feet from the operating equipment. Potential construction vibration levels from future development projects could exceed the FTA’s damage threshold criteria. For example, the threshold criteria for structures of non-engineered timber and masonry construction is 0.2 in/sec PPV. Therefore, mitigation would be required to reduce this potential impact. Construction vibration sources can be mitigated to acceptable levels either at the source or on the adjacent property by using alternate equipment, employing adequate setbacks, or digging temporary trenches between the source and the receptor. For example, at a distance of 200 feet, vibration levels from an impact pile driver would attenuate to 0.02 in/sec PPV. Therefore, in compliance with