9-47 Section 906. Structural Steel
906.01 General Requirements
Finished rolled shapes must be free from imperfections that affect strength and durability in accordance with ASTM A6/A6M . Rolled shapes must have a smooth and uniform finish. Straighten rolle d shapes in the mill if necessary before shipment.
906.02 Testing
Test s tructural steel materials in accordance with the specified ASTM, AASHTO , or Department methods, as modified by this section. Mechanical ly test structural steel products in accordance with ASTM A6/A6M and AASHTO T 244.
906.03 Mill Inspection
Mill inspection is waived unless otherwise specified. If required, the Department will conduct mill inspection in accordance with Division 1, subsection 707.02, and subsection 906.01. Notify the Department before beginning rolling to allow time for inspection. Provide Mill Test Reports in accordance with subsection 707.02.
906.04 Structural Steel
Perform i mpact testing in accordance with AASHTO M270 and at the temperatures required for Zone 2. Non-fracture critical main members must meet the tension component impact test requirements at Frequency (H) in accordance with AASHTO T243, regardl ess of the direction of stress in the member . Main members identified in the contract by the Engineer as fracture critical must meet the fracture critical tension component impact test requirements at F requency (P) in accordance with AASHTO T243. The Department considers the average flange thickness to be the governing thickness for wide-flange beams, wide-flange tees, and channel shapes . The Department considers the required leg thickness to be the governing thickness for angles . Take test specimens for these shapes at one-third the distance from the outer edge of the flange or leg to the web or heel. Fill plates, less than ⅜ inch thick, may be fabricated from steel conforming to ASTM A1011/A1011M or ASTM A606/A606M. MDOT Standard Specifications for Construction Section 906 9-48 906.05. Foundation Piles The piling manufacturer must p rovide a certified mill test report showing the physical properties of the steel. Foundation piles must meet the following requirements for the type of pile required. If the Engineer determines that the pile cutoffs are in good condition, pile cutoffs that meet size and thickness requirements will be accepted without mill test reports . If submitting pile cutoffs without mill test reports, provide the Engineer with two copies of an affidavit stating that the material provided meets the contract requirements.
A.Steel H -Piling and Special Sections. Steel H -piling and special sections must meet the requirements of AASHTO M270, Grades 50 or 50W, or ASTM A690/A690M .
B.Steel Shells for Cast -in-Place Concrete Piles. Steel shells for cast-in-place concrete piles must have the nominal outside diameters (ODs) and meet or exceed minimum shell metal thickness shown on the plans . Steel shells must meet the requirements of ASTM A252 /A252M Grade 3 welded and seamless steel pipe piles except the yield strength must be a minimum of 50 ksi (Grade 3 Modified) . Spiral weld steel shells are allowed. If shell thicknesses greater than the minimum stated on the plans are provided to increase strength and rigidity during driving due to the equipment selected or distortion caused by soil pressures from driving adjacent piles when the driving sequence shown on the plans is not followed, the extra costs will be considered as included in the pay item. If shell thicknesses greater than the minimum stated on the plans are necessary to obtain proper pile penetration in unforeseen soil properties or distortion caused by soil pressures from driving adjacent piles when the driving sequence as noted on the plans is followed, the extra costs will be paid for as extra work. Use watertight pipe shells to exclude water during the placement of concrete. Do not use fluted shells.
C.Pile Points . Pile points must conform to the dimensions shown on the plans . Provide certification that the steel used for the f abrication of the points meets one of the following:
1.AASHTO M270 Grade 50 or Grade 50W;
2.SAE Grade 1016 through Grade 1027; or
3.SAE Grade 1030. MDOT Standard Specifications for Construction Section 906 9-49 D. Pile Protection. Provide asphalt or ultraviolet -stabilized, extruded, corrugated polypropylene sheets for pile protection. The asphalt must conform to ASTM D449/A449M, Type II . The polypropylene sheets must conform to Table 906- 1. The polypropylene sheets must be preformed and scored to fold around and conform to the shape of the piling. The length of each sheet must be at least 4 feet. Table 906- 1: Polypropylene Sheet Specifications Property Specification Test Method Specific gravity 0.906 ASTM D1505 Melt flow 0.5 g/10 min ASTM D1238 Tensile at yield 4,000 psi ASTM D638 Flexural modulus 195,000 psi ASTM D790 Elongation at break >500% ASTM D638 Heat deflection temperature at 66 psi 190⁰F ASTM D648 Notched Izod at 73 °F No break ASTM D256 Rockwell hardness 75 R Scale ASTM D785
906.06 Steel Sheet Piles
For permanent steel sheet piling, the steel piling manufacturer must provide the Department with a certified mill test report that shows the physical properties of the steel. Sheet piles must meet the following requirements for the type of pile required. If the Engineer determines that the pile cutoffs are in good condition, pile cutoffs that meet the size and thickness requirements will be accepted without mill test reports . If submitting pile cutoffs without mill test reports, provide the Engineer with tw o copies of an affidavit stating that the material provided meets the contract requirements.
A.Temporary Steel Sheet Piling . Temporary steel sheet piling must meet the requirements of AASHTO M202 or AASHTO M270, Grade 36, Grade 50, or Grade 50W.
B.Permanent St eel Sheet Piling . Permanent steel sheet piling must meet the requirements of AASHTO M270, Grade 50.
906.07 High -Strength Steel Bolts, Nuts, and Washers for Structural Joints
Structural bolts must meet the requirements of ASTM F3125/F3125M, Grade A325, Type 1. Nuts must meet the requirements of ASTM A563, Grade DH or AASHTO M292, Grade 2H . Washers must meet the requirements of ASTM MDOT Standard Specifications for Construction Section 906 9-50 F436/F436M for circular, beveled, clipped circular, and clippe d beveled washers. Bolts, nuts, and washers must be hot -dip galvanized in accordance with AASHTO M232 . Galvanized nuts must be tapped oversize in accordance with ASTM A563 and meet supplementary requirements S1 and S2.
906.08 Pins and Link Plates for Steel Bridge Construction
Link plates for steel bridge construction must meet the requirements of AASHTO M270 , Grade 50 or Grade 50W, and pins must meet the requirements of ASTM A276 /A276M UNS designation S21800 or S20161 annealed stainless steel with 50 ksi yield point . Provide washers made from austenitic stainless steel meeting the chemical requirements of ASTM A276/A276M UNS designation S31600, S31603, S21800, or S20161. The longitudinal Charpy V -notch impact values for pin and link plate materials in redundant structures must meet the requirements for high-strength structural steel in subsection 906.04 and require impact testing at Frequency (P). Use the steel yield point stress value shown in the certified mill test report to determine the testing temperature. The steel may require heat treatment to meet the Charpy V -notch impact requirements. The longitudinal Charpy V -notch impact values for pin and link plate materials in non-redundant structures must average 30 foot -pounds when tested at the lowest anticipated service temperature (LAST) specified for the MDOT region location of the structure in accordance with Table 906-2 . Table 906- 2: Lowest Anticipated Service Temperatures by MDOT Region Region LAST Superior −25°F North −20°F Grand and Bay −15°F Southwest, University, and Metro −10°F
906.09 Shear Developers
Select steel shear connectors from the Qualified Products List . Steel shear connectors must be designed for end welding to steel beams and girders with automatically timed stud welding equipment . Provide steel shear connectors as shown on the plans. Provide an arc shield (ferrule) with each stud. The arc shield must be made of a heat -resist ant ceramic or material that will not adversely affect the welds, MDOT Standard Specifications for Construction Section 906 9-51 cause excessive slag, or crumble or break from thermal or structural shock during welding. Furnish flux for welding with each connector that is attached to the end of the connector or combined with the arc shield for automatic application in the welding operation. Steel shear connectors must meet the requirements of AASHTO M169 for cold finished carbon steel, cold drawn bar, Grade 1015 or Grade 1020, either semi -killed or fully killed . If usi ng flux -retaining caps, provide cold-rolled steel caps of a low carbon grade for welding that meet the requirements of ASTM A109/A109M . Tensile properties, as determined by tests of bar stock after drawing or of finished connectors , must conform to the minimum requirements shown in Table 906-3 . Table 906- 3: Steel Shear Connector Tensile Properties Property Specification (minimum) Tensile strength 60 ksi Yield strength 50 ksi Elongation 20% in 2 inches Reduction of area 50% Determine tensile properties in accordance with AASHTO T244 for mechanical testing of steel products . Use the 0.2% offset method to determine the yield strength. Finished connectors must be uniform in quality and condition and free from injurious laps, fins, seams, cracks, twists, bends, or other defects . Use cold drawing, cold rolling, or machining to finish.
Source: Michigan Standard Specifications for Construction, 2020 Edition. Pages 857–861 of 1,146.