STRUCTURAL STEEL PRODUCTS

Transcription

1 STRUCTURAL STEEL PRODUCTS I) Bars and Plates Used as members themselves or to form other members. Plates are also used for connecting members AISC Manual - Part 1: Dimensions and Properties

2 TABLES FOR THE GENERAL DESIGN AND SPECIFICATION OF MATERlALS 2-49 Table 2-5 Applicable ASTM Specifications.' for Plates and Bars, Plates and Bars. FyMin. F u over over over over over over over over Yield Tensile to to to 5 to 6 to Steel ASTM Stress Stress' 0.75 to to to to a over Type Designation (ksi) (ksi) inc! inc!. inc!. inc!. inc!. incl. incl. a Carbon A529 A Gr b b b b Gr Gr High- Gr Strength A572 Gr Low- Alloy Gr Gr Corrosion A Resistant High Strength Low-Alloy A Quenched and Tempered A514' Alloy Quenched and TempereD Low-Alloy A852' = Preferred material spoclfication o = Other applicable materiai specification, the avaiiabiiity of which should be confirmed prior to specification o = Material specification does not apply Minimum unless a range is shown. b Applicable to bars only above 1-in. thickness, Avaiiable as plates only. b b

3 II) Hot Rolled Structural Shapes Formed from hot blocks of steel (billet steel) that are passed through rolls several times until final shape is obtained. W-shape is by far the most common structural shape Part 1 of AISC Manual contains dimensions and main properties of many common shapes.

4 2-48 GENERAL DESIGN CONSIDERATIONS Table 2-4 Applicable ASTM Specifications for Various Structural Shapes FyMin. F Applicable Shape Series u Yield Tensile HSS 't:l Steel ASTM Stress Stress' l: ::> Type Designation (ksi) (ksi) W M S HP C MC L Reel. 0 Pipe A " ~~ Carbon A500 ~ A501 A529' A53 Gr. B Gr. B Gr. C Gr. A Gr. B Gr Gr. 55 Gr Gr ' A572 Gr Gr. 60' High Gr. 65' Strength Gr.1 & II 50' 70' Low A618 ' Gr.11I Alloy h 60 h A A ' Corrosion ' Resistant A242 46' 67' High 50' 70 ' Strength A Low-Alloy A = Preferred material specification D = Other applicabie material specification, the availability of which should be confirmed prior to specification o = Material specification does not apply , Minimum unless a range is shown. b For shapes over 426 Iblft, only the minimum of 58 ksi applies., For shapes with a fiange thickness less than or equal to 1\-i in. only. To improve weldability, a maximum carbon equivalent can be specified (per ASTM Supplementary ReqUirement S78). If desired, maximum tensile stress of 90 ksi can be specified (per ASTM Supplementary Requirement S79) d If desired, maximum tensile stress of 70 ksi can be specified (per ASTM Supplementary Requirement S91)., For shapes with a flange thickness less than or equal to 2 in. only. t ASTM A618 can also be specified as corrosion-resistant; see ASTM A618., Minimum applies for walls nominally }.I-in. thick and under For wall thicknesses over}.l in., F y =46 ksi and F u =67 ksi. h If desired, maximum yield stress of 65 ksi and maximum yield-to-tensile strength ratio of 0.85 can be specified (per ASTM Suppiementary Requirement S75). ; A maximum yield-to-tensile strength ratio at 0.85 and carbon equivalent formula are included as mandatory in ASTM A For shapes with a fiange thickness greater than 2 in. only. k For slmpes with a flange thickness greater than 1\-i in. and less than or equal to 2 In. only. I For slmpes with a flange thickness less than or equal to 1)2 in. only. AMERICAN INSTITUTE OF STEEL CONSTRUCTION

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6 W-Shapes Dimensions i) Designation W 21 x 201 approx. depth in inches weight in lbs / ft tabulated in decreasing order by depth and weight, and then by flange width. ii) A, d, t w, b f, t f (self explanatory) iii) k = distance from outer face of flange to web toe of fillet (includes radius) k 1 = same as k measured from center of web in the perpendicular direction T = d - 2k (useful in some calcs.)

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8 W-Shapes Properties i) Compact Section Criteria:, constants related to local buckling of the flange or web (more on this later) ii) Elastic properties: I = moment of inertia S = section modulus r = radius of gyration iii) Plastic Properties: Z = plastic modulus (similar to S but for a fully plastic section more on this later) iv) Lateral Torsional Buckling Criteria:, constants related to lateral torsional buckling of beams (more on this later) v) Torsional Properties: J = torsional constant C w = warping constant

9 III) Built-up sections Plates or combinations of plates and rolled shapes welded together to form a structural shape.

10 IV) Cold-Formed Sections Formed by bending thin sheets of metal unlike hot rolled sections, they are not standarized design covered by AISI (American Iron and Steel Institute) most common section used in buildings is a coldformed steel deck V) Bolts VI) Welding Materials

11 Additional Information Not all shapes listed in the AISC Manual are available in all grades of steel. For current availability of steel products see January issue of Modern Steel magazine Standard Mill Practices see AISC pp 1-9. Provides limits on dimensions and tolerances for steel products. Steel Prices: - Plates A36 or A572 Gr 50: ~ 34 /lb (large quantities) - Rolled shapes (A36, A572 Gr 50, A992): ~ 34 /lb (large quantities) Current Cost Distribution * Material costs -- 25% * Fabrication labor costs -- 35% * Erection labor costs -- 25% * Other costs -- 15%

12 Typical Grades of Structural Steel AISC Manual Tables 2-4 and available steel for structural shapes, plates and bars Approved steels for buildings - AISC Spec. section A3.1 (pp ) AISC Manual pp through 2-27: General info. on steels and availability. Read article entitled Are You Properly Specifying Materials? by Charles J. Carter (on course web page)