625CRIBBING

625.1DESCRIPTION—This work is constructing precast reinforced concrete or metal cribbing as

indicated.

625.2MATERIAL—

• Class A Cement Concrete. Section 704

• Reinforcement Bars. Section 709.1

• Steel Welded Wire Fabric. Section 709.3

• Premolded Expansion Joint Filler. Section 705.1

• Asphalt Material. Asphalt Cement RC-1, Section 702

• Drift Bolts. 3/4-inch diameter, galvanized steel, of the required length. Certify as specified in Section

106.03(b)3

• Casings for Drift Bolts . 1 1/4 inch inside diameter, galvanized steel pipe. Certify as s pecified in Section 106.03(b)3.

• Rock. Rock or rock spalls not exceeding 8 inches in their greatest dimension, or stone backfill, as specified in Section 613.2. Obtain backfill from available excavation , if possible, otherwise p rovide foreign borrow material. Provide backfill of acceptable quality, sound, free from structural defects and foreign substances. Unless backfill is from an approved Type A source, submit samples to the LTS.

of the cribbing members to the Department for review and acceptance. Use a concrete design mix which when molded, cured, and tested in accordance with Department procedures, has a minimum 28 -day compression cylinder strength of 5,000 psi. Fabricate and cure sufficient test cylinders, for design verification and for production control of members, in the same manner as the cribbing membe rs. Do not ship cribbing until it has attained the minimum 28-day compressive strength. One day's p roduction will represent a lot. Lot acceptance will be based upon average strength of at least one set of cylinders. Mix concrete with an air content of 5.5% (± 1.5%), a minimum cement factor of 7.0 bags per cubic yard of concrete, and a slump between 1 1/2 inches and 2 1/2 inches. Use a minimum quantity of water per bag of cement to obtain workable concrete of the specified minimum strength. Do not exceed 5 gallon of water per bag of cement. Mix and proportion concret e, as specified in Section 704. Place concrete and cure, in accordance with AASHTO M 170. Embed the casings for drift bolts and lift hooks in the members where required. Do not place more than two handling lift hooks in each member. Use members true to form, free from depressions, spalls, patched or plastered surface edges. Cracked or otherwise defective crib members will be rejected. Fully enclose the equipment and facilities for manufacture of the members in a building available for Department inspection. Crib members will be inspected for acceptance before being placed in the work. Mark each member with the following information:

• Date of Manufacture

• Name or trademark of the manufacturer.

• Letter "F" on face of each stretcher

Certify each project shipment of concrete cribbing, as specified in Section 106.03(b)3.

• Galvanized Metal Sheets and Base Plates: AASHTO M 218, U.S. Standard or thicknesses (gages) as required, but not thinner than No.16 gage, except for base plates do not use thinner than No. 1 gage.

• Galvanized Bolts and Nuts : 5/8-inch diameter and 1 3/4-inch minimum length, bolts, furnished by the manufacturer.

improper holes or otherwise defective. Maintain a minimum forming radius of 3/4 -inch. However, for units formed with less than 3/4-inch radius, galvanize after forming. Completely fabricate individual members before shipment.

start work until written acceptance is received.

Class A Cement Concrete - Section 704

625.3CONSTRUCTION—

with 1/4-inch expansion joint filler over the full bearing area. Satisfactorily and firmly compact the cribbing foundation. Do not place the cribbing members until the foundation is accepted. Handle and place crib members carefully. Remove and replace cracked or damaged members. Fill the interior of the bins and the space behind the cribbing with rock. Thoroughly compact the rock in layers having a maximum depth of 12 inches. Erect the units and place and compact the backfill simultaneously.

face. Below this elevation, excavate trenches 18 inches in width, to the dep th required, for all bin sides. Provide acceptable bearings at the bin corners, firm and to grade, before the crib erection. Place metal base plates, if required, and erect the units. Do not drill, punch, or use drift pins to correct manufacturing defects. Handle members carefully. Hold members securely in place using bolts and nuts provided. Remove and replace members that become deformed or damaged. Field coat metal cribbing with asphalt material, when indicated. Satisfactorily backfill the bins and the space behind the cribbing.

the applicable parts of Section 1001.3.

625.4MEASUREMENT AND PAYMENT—

Measured on the completed cribbing face.

Measured on the completed cribbing face.

For the class indicated.

For the type indicated and if required for backfilling.