11831 AIRPORT RD WHOLE SITE FILE 2020-01-21

Casing 1. The casing shall be of steel and of ample strength to withstand handling stresses and the external pressure of the caving soil and/or water. 2. The casing shall be watertight, smooth, and clean. 3. The inside diameter of the casing shall provide as a minimum the specified diameter of the shaft. No extra compensation will be allowed for concrete required to fill an oversized casing or an oversized excavation. Construction Sequence All excavation for the foundations in which the drilled shafts are to be constructed shall be completed before shaft construction begins. After shaft construction is completed, all loose or displaced materials shall be removed from around the shafts,leaving a clean solid surface to receive the footing concrete. Shaft Excavation 1. Shafts shall be excavated to the required depth as shown in the Plans or as directed by the Engineer. The excavation shall be completed in a continuous operation using equipment capable of excavating through the type of material expected to be encountered. (Boring Log is available at the office of the Engineer.) The concrete shall be placed immediately after the completion of shaft excavation and cleanout without any undue delay. 2. If the shaft excavation is stopped with the approval of the Engineer, the shaft shall be secured by the installation of a safety cover. It shall be the Contractor's responsibility to ensure the safety of the shaft and the surrounding soil and the stability of the sidewalls. A temporary casing should be used if necessary to ensure such safety and stability. 3. Where caving conditions are encountered, due to soft soils or water intrusion, no further excavation will be allowed until the Contractor selects a method to prevent ground movement. The Contractor may elect to place a temporary casing or use other methods approved by the Engineer. 4. The Contractor shall use appropriate means such as a clean-out bucket, to clean the bottom of the excavation such that a minimum of 50 percent of the base of each shaft will have less than 1 inch of sediment at the time of placement of the concrete. The maximum depth of sediment or any debris at any place on the base of the shaft shall not exceed 27 inches. 5. When unexpected obstructions, which require specioli7ed equipment and/or labor are encountered, the Contractor shall notify the Engineer promptly and the obstructions shall be removed and the excavation continued as directed by the Engineer. Excavation Inspection 1. The Contractor shall provide equipment for checking the dimensions and alignment of each permanent shaft excavation. The dimensions and alignment shall be determined by the Contractor under the direction of the Engineer. 10 Swift II BRT Boeing to Canyon Park Station—Traffic Signal 90%Special Provisions—12/1/2016