11-20-2019 Council Packet - Laserfiche WebLink

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Prepared by: Bolton & Menk, Inc. ALLEN AVENUE Allen Avenue Improvements ǀ N15.119846 Page 4 storm sewer structures within the project area. The structures are a combination of block-built and precast structures and are in fair to good condition. The catch basin manhole at the northwest quadrant of Allen Avenue and Desoto Street is block-built, has a failing invert, and failing doghouses. Few other structures have doghouses and rings in need of repair. Overall, the system is in good condition and the useful life of the storm sewer system is expected to outlast the pavement improvements described in this report. STREET IMPROVEMENTS The pavement investigation and analysis performed by Braun Intertec included three pavement cores. The analysis indicated that the bituminous pavement section is too thin in most locations to support a mill and overlay rehabilitation. However, it was determined that there is good aggregate base material with thicknesses ranging from 12 inches to 24 inches. As such, full depth reclamation (FDR) is recommended for this project. FDR typically includes the grinding and mixing of the asphalt pavement and aggregate base, spot curb and gutter replacement, and re-paving. It is only recommended when the road section is still structurally sound with a good aggregate base and the subgrade is not susceptible to frost heaving. Curb and gutter that is cracked, weathered, or heaved will be cut out and replaced with new curb and gutter. This is important because cracks and voids in the curb allow water intrusion into the pavement. The more water intrusion that occurs, the faster the pavement and curb will deteriorate. In cases where curb and gutter is in very poor condition on an FDR project, generally when over 50% of the curb needs replacing, it is more economical to replace 100% of the curb and gutter. When this occurs, more extensive impacts to yards, driveways, and private irrigation systems is expected at each property. Preliminary site inspection indicates that approximately 20% of the curb will need to be replaced on Allen Avenue. WATERMAIN IMPROVEMENTS The existing ductile iron watermain is in good condition and is proposed be left in place. Existing water services are also proposed to be left in place. However, existing bolts on gate valve fittings and hydrant fittings will be removed and replaced. These are typically the features that fail first on the water system. Bolt replacement is a proactive way to limit the number of leaks and breaks the system experiences as it ages. STORM SEWER IMPROVEMENTS The storm sewer network is generally in good condition and is proposed to be left in place. However, there is a large storm sewer manhole in the intersection of Allen Avenue and Desoto Street that requires full replacement. Each of the storm sewer manholes in the pavement will be ‘adjusted’ to the new pavement elevation. This typically involves removing the casting, plating the structure until after base course is paved, and re-installing the casting on new rings. Catch basins structures with deteriorated rings will receive a similar adjustment. Doghouses that are deteriorated will receive mud work. SANITARY SEWER IMPROVEMENTS The storm sewer network is in good condition and is proposed to be left in place. Each of the sanitary sewer manholes in the pavement will be ‘adjusted’ to the new pavement elevation. This typically involves removing the casting, plating the structure until after base course is paved, and re-installing the casting on new rings with a new I/I barrier. Benches and inverts that have deteriorated will receive mud work.