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MICHIGANDEPARTMENT OF TRANSPORTATION

SPECIAL PROVISIONFOR

PROOF ROLLING

DES:DJP 1 of 2 C&T:APPR:MF:JTL:05-16-02

a. Description. Proof rolling shall be preformed as requested by the Engineer, to verify theuniformity of support and to identify unstable areas which might require remedial construction(undercutting and replacement). The use of a proof roller as described herein is for testing purposesonly, and is not intended as a requirement for compaction of the subgrade.

b. Equipment. The proof rolling shall be performed by a tractor drawn or self-propelledpneumatic-tired proof roller. The proof roller shall consist of four pneumatic-tired wheels mounted on arigid steel frame. The wheels shall be evenly spaced in one line across the width of the roller andshall be arranged in such a manner that all wheels will carry approximately equal loads when operated

over an uneven surface. The maximum spacing between adjacent wheels shall not exceed the timewidth. The tires shall be operated at an inflation pressure of 344.7 kilopascals (50 pounds per squareinch) 13.8 kilopascals ( 2 pounds per square inch). The proof roller shall have a suitable body forthe ballast loading and operated at a gross loading of 222.41 kilonewton 4.5 kilonewton (25 tons 1000 pounds). Ballast to obtain the required weight shall consist of ingots, concrete blocks, sandbags,or other approved material with a uniform known weight, so the total weight of the ballast used can bereadily determined at all times. There shall be a sufficient amount of ballast available at the projectsite to load the proof roller to the requires weight of 222.41 kilonewton (25 tons).

c. Construction Method. The proof roller shall be operated in a systematic manner so a recordmay be easily kept of the area tested and the working time required for the testing.

The proof roller shall be operated at a speed between 4 kilometers per hour (2.5 miles per hour)and 8 kilometers per hour (5 miles per hour) while testing the subgrade.

One complete coverage by the proof roller is defined as the complete coverage by the tire tread ofthe roller over the entire surface area being tested. Unless otherwise specified or required by theEngineer, one complete coverage of the proof roller shall be made on a complete subgrade ofembankments and cut sections with the following exceptions and additions:

For embankments more than 1.8 meters (6 feet) in depth below subgrade, the proof rolling shallalso be conducted on the layer of fill 0.91 meters (3 feet) below the subgrade.

The proof roller shall not be operated within 4.6 meters (15 feet) of any bridge abutment of

retaining wall.

Where proof rolling shows the subgrade to be unstable or to have less than the specified density,such areas shall be corrected by the Contractor.

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DES:DJP 2 of 2 05-16-02d. Measurement and Payment. Proof Rolling will be measured in hours for the roller,

including tractor, is operated for testing purposes. The time will be measured to the nearest 1/4hour. No measurement will be made for the time required for servicing and repairing theequipment or when moving from one testing site to another. The Contractor will be paid half ofthe actual time required for moving the roller around a structure location if it is necessary to

transport the roller on special equipment.

Unstable conditions encountered during Proof Rolling operations, which result from thefailure of the Contractor to attain and maintain the specified density and moisture requirementsshall be corrected by the Contractor at the Contractors expense. Unstable conditionsencountered when the specified density and moisture requirements have been attained, shall becorrected and will be paid for at the contract unit prices for the items involved or as extra work.There will be no adjustment in the contract unit price, regardless of the percentage of increaseor decrease above or below the contract quantity for the item ofProof Rolling.

Contract Item (Pay Item) Pay Unit

Proof Rolling Hour

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DES:DJP 2 of 2 05-16-02CS 50015, JN 46273