09/27/2004 Council Packet - Laserfiche WebLink

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• • Company STS Project # Date Page 2 With respect to vibration effects from pile driving, we have reviewed actual seismograph data taken adjacent to pile driving operations. This material was provided to us courtesy of LH Bolduc Company and Carl Bolander and Sons Company. The seismograph tests indicate that the frequency of the vibrations is less than 2 cycles per second and the maximum particle velocity recorded, ever as close as 15 to 20 feet from the pile driver, is generally less than 1 inch per second. On this basis, there should be no damage to the nearest house, which is 70 feet from one end of the bridge. It should be noted that the human body is quite sensitive, and thus occupants of the house might feel some small vibrations, or some crockery may rattle during the pile driving, but the effects on the structure should be none or negligible. STS will provide a continuously recording seismograph to the site during all pile driving operations. We will also establish pre - existing vibration levels in the neighborhood resulting from street traffic such as garbage or delivery trucks. During construction, vibration levels (amplitude and frequency will be recorded at the closest house to the pile driving operations and at any nearby home where a complaint is made. If vibration levels exceed 1 inch /sec particle velocity, modifications to the pile driving will be necessary. Records of vibration events will be submitted to the City upon completion of the piling operations, or as any issues or complaints arise. The pre - condition survey, and pre - construction noise and vibration studies can be initiated upon your request. The results of these surveys can be forwarded to the City if you desire. If we can be of further service, please call us. Sincerely, STS CONSULTANTS, LTD. James H. Overtoom, P.E. Principal EngineerNice President JHO/ cc: Mr. Jeff Shopek — Loucks and Associates, Inc. C623B001.doc