****GENERAL REWRITE. – PLEASE READ CAREFULLY.****

HIGH STRENGTH / NON –HIGH STRENGTH FASTENERS

GENERAL

This IM pertains to inspection, sampling and testing, of high strength and non-high strength fasteners for of all specified applications. Fasteners shall be furnished to projects as specified in Article 4153.06 of the Standard Specifications and any other supplemental or specified requirements. Only high strength fasteners for steel structures and special requirements shall be required to meet the Rotational Capacity Testing requirements as described in section D of this IM.

ACCEPTANCE

A. High Strength Fasteners (Bolt, Nut, & Washer)

1A. The manufactures of bolts, nuts and washers shall furnish a certified mill report with each shipment to the project. The mill test report shall include the following

a. Heat-analysis and heat number and type

b. hardness, tensile and yield strengths and proof load

c. Rotational capacity test results for the assemblies(bolts, nuts and washers)

d. Zinc coating methods and measured coating thickness

e. Chemical analysis

f. Signed and certified

2A. Ensure that:

a. Bolts meet the requirements of ASTM A-325 type 1 or type 3

Note: Type 1 is regular carbon steel/ alloy steel and type 3 is a weathering steel

b. Nuts shall meet the requirements of ASTM A563 grade DH or DH3

c. Washers shall meet the requirements of ASTM F436- Hardened steel washers, type 1 or type 3

d. Galvanizing shall meet the requirements of ASTM B695 class 55, type 1 or ASTM F2329

Note: All threaded components (bolts and nuts ) shall be coated by the same zinc-coating process. The suppliers option is limited to only one process per item with no mixed process in a lot

e. For weathering steel fasteners use ASTM A325 type 3, nuts ASTM A563 grade DH3 and washers ASTM F436 type 3

f. Threads for bolts shall be rolled or cut and shall be the coarse thread series as specified in ASME B 1.1 and shall have class 2A tolerance and the dimensions as specified in ASME B18.2.1

g. Threads for the nuts shall conform to the dimensions for the united coarse thread series as specified in ASME B1.1 and shall have class 2B tolerance, Threads shall be formed by tapping or machining.

Note: Hot dip zinc-coated nuts shall be tapped oversize after zinc-coating

Note: Zinc-coated nuts (hot dip or mechanically deposited shall be provided with additional lubricant and shall be clean and dry to the touch.

**Note: Nuts shall be proof load tested after zinc-coating and overtapping.

h. Grade Identification and Marking

1. Type 1 bolt shall be marked “A325

2. Type 3 bolts shall be marked “A325” with the “A325” underlined

3. Markings shall be located on the top of the bolt head and shall be either raised or depressed

4. Bolts which are not marked shall be considered as non-comforming and subject to rejection.

5. Nuts made to the requirements of grade “DH” shall be marked with the grade symbol “DH” on one face. Heavy hex nuts made to the requirements of grade “DH3” shall be marked with grade symbol “DH3” on one face.

6. Washers shall be marked with a symbol to identify the manufacturer. Additionally, weathering steel washer type 3 shall be identified with the symbol “3” in addition to the symbol of the manufacturer.

3A. Sampling And Testing

Bolts		Nuts & Washers
No. of Pieces in a Production Lot	Min. No. Sampled & Tested	No. of Pieces in a PO Lot	Min. No. Sampled & Tested
800 and under	1	800 and under	1
801 to 8,000	2	801 to 8,000	2
8,001 to 35,000	3	8,001 to 22,000	3
35,001 to 150,000	8	Over 22,000	5
150,001 and Over	13

B. Contracting Authority Sampling and Testing

The inspector will sample bolts, nuts, and washers at the production rate listed above. Samples will be sent to the Office of Materials, Ames, Iowa, for acceptance testing. A copy of the Manufacturer-Certified Test Report, Mill Test Report, and rotational capacity test must be forwarded with the sample.

C. Re-tests

Fasteners which fail to meet the requirements of any specified ASTM Specification shall be rejected or, at contractor option, will be re-sampled and tested at two times the original rate. All additional samples shall conform to the specifications or the production lot will be rejected.

NOTE: High strength bolts and nuts that have been torqued, shall not be re-used. This includes both black and galvanized bolts and nuts.

D. Small Quantities

If a production lot represents less than 20 fasteners (bolts, nuts, or washers), the District Materials Engineer may, without sampling, accept the small quantity lot on a basis of Manufacturer-Certified Test Report Certification.

E. Rotational Capacity Test

For Steel Structures:

1. The manufacturer, supplier or distributor of fasteners shall perform rotational capacity tests prior to shipment.

2. Rotational capacity test report shall be documented and shall include the rotational lot number.

3. For steel structures, the contractor shall perform field rotational capacity acceptance tests prior to assembly. For shop assembly, the Structural Materials Engineer may waive this requirement.

Site storage for fasteners is important. Storage shall be in a sealed container within a sheltered storage shed. Storage containers shall be covered (sealed) at all times. Bolts, nuts, and washers shall be free of moisture, dust, dirt, and / or any contaminants.

4. Specification 4153.06 requires a Rotational Capacity (RC) Test for high strength fasteners. This test confirms component compatibility and the presence of adequate lubrication.

5. A pre-bolting meeting shall be held to establish a clear understanding of the Rotational Capacity Test, bolting procedures, turn-of nut methods, and the inspection process.

6. Black bolts and nuts shall be clean, free of contaminants and “oily” to the touch when delivered, stored and installed.

7. Galvanized nuts shall be checked to verify lubrication.

8. High strength fasteners shall be mechanically galvanized in accordance with the requirements of ASTM B695 or Class 55, type 1 or ASTM F2329 with zinc bath temperature not exceeding 850ºF

9. All rotational capacity tests shall be conducted in accordance with Appendix A or B, whichever is applicable.

10. Fasteners, bolts, nuts and washers shall be from domestic origin melted and manufactured in the USA.

EQUIPMENT CALIBRATION REQUIREMENTS FOR ROTATIONAL CAPACITY TEST

1. Torque Wrench: Torque Wrench shall be calibrated at least every six months by the Iowa DOT and / or by an approved / certified testing agency. The contractor shall furnish and use an inspected and calibrated torque wrench, which shall be capable of accurately measuring torque.

2. Bolt Tension Measuring Device (Skid-More): Bolt Tension Measuring Device shall be calibrated by the Iowa DOT and / or by an approved / certified testing agency. Calibration of the bolt tension measuring device shall be performed at least every six months.

Calibration of the Torque Wrench and the Bolt Tension Measuring Device (Skid More)can be performed separately or combined as long as neither calibration have not exceeded the six-month period.

Note: Lot Definition: A lot shall be a quantity uniquely identified heavy hex structural bolts or nuts of the same nominal size and length produced in a single heat of material and processed at one time by the same process in the same manner.

4A. ASTM A490 bolts are specifically excluded from the Iowa DOT specifications.

5A. For quenched and tempered steel bolts and studs with diameters greater than 1 1/2” but with similar mechanical properties as A325, refers to specifications ASTM A449

B. Non-High Strength Fasteners (Bolts, nuts and washers)

1b. The manufactures of bolts, nuts, and washers shall furnish certified mill test report with each shipment to the project. The mill test report shall include the following

a. ASTM designation, bolt head style hex or heavy hex.

b. Grade A or B.

c. Size and length

d. Heat number

e. Hardness, tensile and yield strengths

f. zinc-coating methods and measured coating thickness

g. signed and certified

2b. Ensure that

a. Bolts shall meet the requirements of ASTM A307, class A or class B with a full diameter body, hexagonal bold heads and nuts

*Note: A307 specification covers three grades of carbon steel bolts and studs or rods in sizes 1/4” through 4”. Grade C was replaced by ASTM F1554

b. Threads shall be rolled or cut , and shall be the coarse thread series as specified in ASME B1.1 and shall have class 2A tolerance and the dimensions in accordance with ASME B18.2.1

c. Nuts shall meet the requirements of ASTM A563

Grade DH or Grade A, heavy-hex

**Note: Nuts made to the requirements of ASTM A194/A194M, Grade 2H are an acceptable equivalent for grade DH nuts ASTM A 563 when the zinc-coating, overtapping, lubrication and rotational capacity testing have been performed in accordance with A563 requirements.

d. Threads for nuts shall conform to the dimensions for coarse thread series as specified in ASME B1.1 and shall have class 2 B tolerance and the dimensions as specified in ASME B18.2.1.

Note: Hot dip zinc coated nuts shall be tapped oversize after zinc coating

Note: Zinc coated nuts (hot dip mechanically deposited) shall be provided with additional lubricant and shall be clean and dry to the touch.

e. Washers shall meet the requirements of ASTM F436, Type 1

f. Grade identifications:

1. Grade A shall be marked 307A

2. Grade B shall be marked 307B

3. Marking shall be located on the top of the bolt head

4. Bolts or studs which are not marked shall be considered as non-conforming and shall be subject to rejection

3B. Sampling And Testing

Bolts		Nuts & Washers
No. of Pieces in a Production Lot	Min. No. Sampled & Tested	No. of Pieces in a PO Lot	Min. No. Sampled & Tested
800 and under	1	800 and under	1
801 to 8,000	2	801 to 8,000	2
8,001 to 22,000	3	8,001 to 22,000	3
Over 22,000	5	Over 22,000	5

b. Black bolts and nuts shall be clean, free of contaminants and oily to the touch.

c. Fasteners shall be galvanized in accordance with the requirements of wither ASTM F2329 with zinc bath temperature not to exceed 850°F or to the requirements of ASTB B 695, class 55, type 1.

d. Fasteners, bolts, nuts and washers shall be from a domestic origin, melted and manufactured in the USA.