700-160Section 712 — Drilled Shaft Foundations
712.1Description
1 Construct drilled shafts of reinforced concrete cast in cylindrically excavated holes that extend into soil or rock to support the structure and applied loads . 2 For the purposes of this specification: • Drilled shafts are cast -in-place shafts with reinforcing steel and have a diameter 30 in. or greater . • Construction casing refers to casing that remain in- place. Temporary casings are removed prior to or during the concreting process.
712.2Materials
1 Provide Class 4000DS as specified in Section 701 . Adjustments to the mix design may be requested when characteristics of materials, job condition, weather, test results, or other circumstances warrant. All adjustments are subject to acceptance by the OMR . Make accepted adjustments at no additional cost to the Department. 2 Furnish reinforcing steel conforming to Section 703.
712.3Construction
712.3.1 Equipment 1 Use excavation and drilling equipment with adequate capacity including power, torque, and down thrust to excavate a hole of both the maximum diameter and to a depth 10 ft beyond the depth shown on the Plans . 2 Ensure that the excavation and over -reaming tools are of adequate design, size, and strength to perform the work shown in the Plans or described herein. Use equipment that is well maintained and in good working condition. The BCE will be the sole judge of whether the drilling equipment is appropriate and in good working condition. Provide sufficient equipment to enable prosecution of the work according to the project schedule and completion of the work in the specified t ime. 3 When the material encountered cannot be drilled using conventional earth augers with soil or rock teeth, drill buckets, and/or under -reaming tools, provide special drilling equipment including, but not limited to, rock core barrels, rock tools, air tools, blasting materials, and other equipment as necessary to construct the excavation to the size and depth required. Obtain written concurrence of the RCE and BCE before performing excavation by blasting. Due to variations in rock strength, provide equipment capable of drilling rock up to 25% stronger than the maximum compressive strength shown on the Plans