1007. 2(e) 1007. 3(b)
to the manufacturer’s recommendations to control bleed, reduce shrinkage, improve flowability, reduce water content, or retard setting time. Accelerators and admixtures containing chlorides are not allowed.
to AASHTO M 31, Grade 75. Bars with full -length thread meeting the same material requirements are allowed. Provide bars clean of deleterious substances. When mechanical splice systems are required, they must develop the ultimate tensile strength of the bars and maintain the required grout cover over the splices .
of ASTM A252 Grade 3 with an elongation of 15% and have a minimum yield strength of 50 ksi to 80 ksi as used in the design submittal . Pipe casing diameter and minimum wall thickness as indicated. Pipe casings from 5 inches to 12 inches in diameter will be considered micropiles. Material with visual defects such as dents, cracks or tears will be rejected. Use of material classified as mill secondary is acceptable when tests are performed verifying tensile strength and steel chemical composition. Provide flush-joint type pipe casing splices, threads , and joints . Threaded casing joints and welded joints must develop at least the required compressive, tensile, and bending strength used in the design of the micropile. For permanent pipe casing seams and splices that will be shop or field welded the following fabrication and material conditions apply:
• Maximum c arbon equivalency ( CE) of 0.45, according to AWS D1.1 as specified in Section 1005, and according to mill certification .
• Maximums ulfur content 0.05%, according to mill certification.
• Use only complete penetration welds.
• Do not use welded lap splicing.
material that is non- detrimental to the reinforcing steel or grout. Do not use wood or aluminum.
1007.3CONSTRUCTION —
of micropiles, and meeting the following qualifications:
• Micropile contractor has c ompleted at least five projects that demonstrate experience in the construction of micropiles.
• Employ a Professional Engineer registered in the State, with at least 3 years of experience in the design and construction of micropiles and pile load test systems, who is to design the system, verify the proper construction of the testing system