Agenda - Council - 06/27/2017 - Laserfiche WebLink

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under pressure (jetting) or puddling will not be permitted to facilitate jacking/augering operations. If any installation is augered, the head shall be approved by the Engineer and the auger shall be located six inches (6") behind the lead edge of the casing or carrier pipe. The jacking system shall be provided with an integral grout pipe and casing pipe. A one inch (1") grout pipe shall be tack welded to the front edge of the first length of casing pipe. The grout pipe shall be extended with the casing pipe, but not fastened to the casing pipe during the remaining jacking operations. After the pipes are through to the receiving pit, the grout pipe shall be cut free from the casing pipe. The grout pipe shall be pulled back through the embankment applying positive piston pressure on the grout along the outside of the casing pipe throughout the pulling operation. A cement slurry grout mix with as little water as possible shall be used. Bentonite shall not be used to fill voids. The Engineer shall approve grout and backfill material prior to placement of any material. Deviation from the pipe grade, as provided by the Engineer, in excess of five tenths of a percent (0.05%) may be cause for removal and relaying of the pipe by the Contractor with no additional compensation allowed therefore. If a void develops, the jacking or boring operation shall be stopped immediately and the void shall be filled by an approved method. The Contractor shall take the following precautions when boring: Extend casing through entire distance bored. Check grade and alignment after each casing section is installed. Coordinate operations to provide continuous support to surrounding earth materials. Excavation shall be carried on in such a manner as to provide adequate support to surface structures and roads above and adjacent to the boring and not create any hazards to overhead traffic and other activities. These contract documents do not guarantee the extent to which rocks, boulders, or other obstructions, regardless of size, may be encountered during boring operations. No extra compensation will be made for removal of rocks, boulders or other natural or manmade obstructions encountered during trenchless construction or excavation. All voids caused by boring shall be filled by pressure grouting. The grout material shall consist of sand cement slurry of at least two (2) sacks of cement per cubic yard and a minimum of water to assure satisfactory placement. All slurry shall be pre -approved by the Engineer prior to use by the Contractor. The Contractor shall take the following precautions when jacking: The jacking machine shall be capable of controlling line and grade. Progressively push carrier pipe through completed casing. Page 13