Section 573 — Helical Piles

Description

573.01This work consists of designing, providing, and installing helical piles.

Material

573.02Conform to the following Subsection: Helical piles 715.08

Construction Requirements

573.03Submittals. At least 30 days before starting helical pile work, submit the following according to Subsection 104.06(b)(3) :

(a)Product data . Manufacturer’s product data including appurtenances and installation instructions.

(b)Drawin gs and calculations. Drawings and calculations complying with the helical pile capacity shown in the plans. At a minimum, include the following:

(1)Pile number, location, and pattern by assigned identification number;

(2)Pile design load and design calculations. Include the relevant references used for design;

(3)Design notes. Include a description of symbols, terminology, and computer programs used in the design;

(4)Type and size of central shaft;

(5)Helix configuration;

(6)Minimum effective installation torque;

(7)Displacemen t plates or centralizers and their locations;

(8)Minimum and anticipated overall pile length and tip elevation;

(9)Inclination of pile;

(10)Minimum cased length, if applicable;

(11)Cut-off elevation; and

(12)Working drawings for the temporary yoke or load frame to be used for testing. I nclude identification number and calibration test certification for each load cell, test jack pressure gauge, and master pressure gauge. Clearly indicate the serial number of each component of the testing assembly on calibration graphs. Include results from calibration tests conducted by an independent testing laboratory within the previous 60 days.

(c)Equipment. A listing of excavating and drilling equipment with the capacity to install helical piles at the maximum specified diameter to the depth and capacity specified in the plans and conforming to the following:

(1)Torque motor. A torque motor capable of continuous adjustment to number of revolutions per minute during installation and with a torque capacity 15 percent greater than the torsional strength rating of the central steel shaft to be installed. Do not use percussion drilling equipment.

(2)Installation equipment. Installation equipment of rotary type, with hydraulic power -driven torque motor with clockwise and counterclockwise rotation ca pabilities, that can apply adequate downward pressure and torque simultaneously to suit project soil conditions and load requirements, and that can continuously adjust position to maintain proper pile alignment.

(d)Construction methods. A detailed construction sequence for helical pile work describing materials, methods, and equipment to be used. Include the following:

(1)Drilling equipment including the manufacturer’s specifications for the drill rig.

(2)Installation methods to ensure required helical pi le placement and inclination.

(3)Methods of materials handling and disposal.

573.04Production Start -Up Procedures. Conduct a pre -helical pile preparatory phase meeting at least 7 days before the start of helical pile operations according to Subsection 153.06(a) .

573.05Installation of Helical Piles. Install the helical piles according to the approved drawings . Install piles within 1 inch of the position or the line, and within ½ inch of the elevation shown in the plans. Install piles so that the axial alignment is within ¼ inch per foot along the longitudinal axis of the required alignment. Piles will be rejected if any of the following occurs:

(a)Damaged by internal defects or by improper installation;

(b)Unable to provide the design capacity shown in the plans; or

(c)Installed out of tolerance. Correct rejected piles using an approved method according to Subsection 106.01.

573.06Construction Memorandum. Submit a helical pile foundation m emorand um that includes the following for all piles:

(a)Installed tip elevation ;

(b)Installation torque with depth including maximum torque; and

(c)Load tests results. Provide confirmation of the adequacy of the helical pile axial and lateral capacity based on the installation and load test results. Provide a memorandum that bears the seal and signature of a professional engineer according to Subsection 104.06(b)(2) .

573.07Acceptance. Material for helical piles will be evaluated under Subsections 106.02 and 106.03. Construction of helical piles will be evaluated under Subsections 106.02 and 106.04.

Measurement

573.08Measure the Section 573 pay items listed in the bid schedule according to Subsection 109.02 .

Payment

573.09The accepted quant ities will be paid at the contract price per unit of measurement for the Section 573 pay items listed in the bid schedule. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05 .