06 16 20 PWA_02_02 Exh2 - IS-MND

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L w FAIRVIEw BRIDGE REPLACEMENT AND STREET IMPROVEMENTS INITIAL STUDY/MITIGATED NEGATIVE DECLARATION `J' (9TH STREET TO 16TH STREET) PROJECT MAY 2020 SANTA ANAL CALIFORNIA • NB No. 4: A 171 ft long barrier along the right-of-way and private property line on the southbound side of Fairview Street between West 9th Street and West 12th Street was analyzed to shield Receptor R-23. NB No. 5: A 705 ft long barrier along the right-of-way on the northbound side of Fairview Street between West 9th Street and West 12th Street was analyzed to shield Receptors R- 24, R-25, and R-40. • NB No. 6: A 184 ft long barrier along the right-of-way and private property line on the southbound side of Fairview Street between West 12th Street and the Santa Ana River was analyzed to shield Receptor R-46. Based on the NADR, NB Nos. 2 through 5 were determined to be reasonable, and NB Nos. 1 and 6 were determined to be not reasonable because the estimated construction cost exceeded the total reasonable allowance. NB Nos. 2, 3 (at 12 ft and 14 ft high), 4, and 5 would require the property owner to donate their right-of-way (permanent and temporary easement) in order to achieve reasonableness. The property owners and nonowner occupants were sent a noise barrier survey letter during the IS/MND public review period to request each owner's or occupant's opinion on whether or not they would prefer a noise barrier and what height they would prefer the barrier to be, based on the range of feasible and reasonable heights listed in Table 3.1 of the NADR (Appendix A of this IS/MND). NB No. 3 (at 14 ft high) was determined to be feasible and reasonable and would be constructed as part of the proposed Project. b. Would the project result in generation of excessive groundborne vibration or groundborne noise levels? Less Than Significant Impact. Construction. Construction of the proposed Project could result in the generation of groundborne vibration. This construction vibration impact analysis discusses the level of human annoyance using vibration levels in vibration velocity decibels (VdB) and will assess the potential for building damages using vibration levels in peak particle velocity (PPV, measured in inches per second [in/sec]) because vibration levels calculated in root -mean -square (RMS) are best for characterizing human response to building vibration, while vibration level in PPV is best used to characterize potential for damage. The Transit Noise and Vibration Impact Assessment" indicates that a vibration level up to 102 VdB (an equivalent to 0.5 in/sec in PPV) is considered safe for buildings consisting of reinforced concrete, steel, or timber (no plaster), and would not result in any construction vibration damage. For a nonengineered-timber and masonry building, the construction vibration damage criterion is 94 VdB (0.2 in/sec in PPV). 52 United States Federal Transit Administration. 2018. Transit Noise and Vibration Impact Assessment Manual. September. Website: https://www.transit.dot.gov/sites/fta.dot.gov/files/docs/research- innovation/118131/transit-noise-and-vibration-impact-assessment-manual-fta-report-no-0123_0.pdf (accessed October 2019). 3-82 R:\WKE1702\ISMND\Final ISMND\Fairview Street Bridge Final ISMND.docx (05/26/20)