AS 1250-1981

1 - AS 1250-1981 SAA STEEL STRUCTURES CODE
4 - PREFACE
5 - CONTENTS
6 - SECTION 1. SCOPE AND GENERAL
6 - 1.1 SCOPE.
6 - 1.2 STANDARDS.
6 - 1.3 NEW MATERIALS OR METHODS.
6 - 1.4 DESIGN AND SUPERVISION.
6 - 1.4.1 Design.
6 - 1.4.2 Supervision.
6 - 1.5 DEFINITIONS.
6 - 1.5.1 General.
6 - 1.5.2 Administrative Definitions.
6 - 1.5.2.1 Approved
6 - 1.5.2.2 Building Authority
6 - 1.5.2.3 Contractor
6 - 1.5.2.4 Engineer
6 - 1.5.3 Technical Definitions.
6 - 1.5.3.1 Beam or girder
6 - 1.5.3.2 Dead load
7 - 1.5.3.3 Footing
7 - 1.5.3.4 Foundation
7 - 1.5.3.5 Gauge
7 - 1.5.3.6 High strength bolt
7 - 1.5.3.7 Live load
7 - 1.5.3.8 Load factor
7 - 1.5.3.9 Partition
7 - 1.5.3.10 Pitch
7 - 1.5.3.11 Strut
7 - 1.5.3.12 Substructure
7 - 1.5.3.13 Tensile strength
7 - 1.5.3.14 Wind forces
7 - 1.5.3.15 Yield stress
7 - 1.5.4 Welding Terms.
7 - 1.6 NOTATION.
9 - SECTION 2. MATERIALS
9 - 2.1 STRUCTURAL STEEL.
9 - 2.1.1 Australian Standards.
9 - 2.1.2 Other Structural Steels.
9 - 2.1.3 Acceptance of Steels.
9 - 2.1.4 Unidentified Steel.
9 - 2.2 FASTENERS AND ELECTRODES.
9 - 2.2.1 Steel Bolts, Nuts and Washers.
9 - 2.2.2 Rivets.
9 - 2.2.3 Electrodes.
9 - 2.3 STEEL CASTINGS.
9 - 2.4 CONCRETE.
10 - SECTION 3. GENERAL DESIGN REQUIREMENTS
10 - 3.1 LOADS.
10 - 3.2 DESIGN METHODS.
10 - 3.2.1 General.
10 - 3.2.2 Simple Design Method.
10 - 3.2.3 Fully Rigid Design Method.
10 - 3.2.4 Semi-rigid Design Method.
10 - 3.2.5 Experimentally Based Design.
11 - 3.3 OTHER DESIGN CONSIDERATIONS.
11 - 3.3.1 Loading Combinations.
11 - 3.3.2 Stability.
11 - 3.3.3 Lateral Forces.
11 - 3.3.4 Lateral Restraining Systems.
11 - 3.3.4.1 General.
11 - 3.3.4.2 Forces.
11 - 3.3.4.3 Stiffness.
11 - 3.3.4.4 Multiple restraints.
12 - 3.3.4.5 Parallel restrained members.
12 - 3.3.4.6 Attachment of restraints.
12 - 3.3.4.7 Critical flange or chord.
12 - 3.3.5 Deflection.
12 - 3.3.6 Fatigue.
12 - 3.3.7 Corrosion Protection.
12 - 3.3.8 Brittle Fracture.
13 - SECTION 4. GEOMETRICAL PROPERTIES
13 - 4.1 GENERAL.
13 - 4.2 GEOMETRICAL PROPERTIES FOR CALCULATING
13 - 4.3 PLATE THICKNESSES.
13 - 4.3.1 Plate and Flange Outstands.
13 - 4.3.2 Flanges and Plates-Unsupported Widths.
13 - 4.3.3 Circular Hollow Sections.
13 - 4.4 HOLES.
13 - 4.4.1 Effective Diameters.
13 - 4.4.2 Combinations of Holes.
14 - 4.5 SECTIONAL AREAS OF BOLTS, SCREWED TENSION RODS AND RIVETS.
14 - 4.5.1 Bolts and Screwed Tension Rods.
14 - 4.5.2 Rivets.
14 - 4.6 MAXIMUM SLENDERNESS RATIOS.
15 - SECTION 5. DESIGN OF BEAMS
15 - 5.1 GENERAL.
15 - 5.2 MAXIMUM PERMISSIBLE STRESS.
15 - 5.3 MAXIMUM PERMISSIBLE COMPRESSIVE STRESS.
15 - 5.4 MAXIMUM PERMISSIBLE STRESS IN A BEAM BENT ABOUT THE AXIS OF MAXIMUM STRENGTH.
15 - 5.4.1 Equal-flange I-beams or Channels.
15 - 5.4.2 Laterally Unsupported Angle Sections.
15 - 5.4.3 Other Sections.
18 - 5.5 ELASTIC CRITICAL STRESS.
18 - 5.6 BENDING STRESSES FOR CASED BEAMS.
18 - 5.7 PURLINS AND GIRTS.
18 - 5.8 EFFECTIVE SPAN OF BEAMS.
20 - 5.9 EFFECTIVE LENGTH OF BEAMS FOR LATERAL BUCKLING.
20 - 5.9.1 General.
20 - 5.9.2 Restraints.
20 - 5.9.2.1 Torsional end-restraints.
20 - 5.9.2.2 Intermediate lateral restraints.
20 - 5.9.3 Beams without Intermediate Lateral Restraints.
20 - 5.9.3.1 Restrained against torsion.
20 - 5.9.3.2 Partially restrained against torsion.
20 - 5.9.4 Cantilevered Beams without Intermediate Lateral Restraints.
20 - 5.9.5 Beams with Intermediate Lateral Restraint.
20 - 5.9.5.1 Lateral restraint at intervals.
20 - 5.9.5.2 Continuous lateral restraint.
20 - 5.9.6 Beams with Critical Flange Loading Unrestrained Laterally.
20 - 5.10 SHEAR.
20 - 5.10.1 Maximum Shear Stress.
20 - 5.10.2 Average Shear Stress in Rolled I-beams and Channels, Plate Girders, Box-sections, Rectangular and Circular Hollow Section
22 - 5.10.3 Shear Stresses in Other Sections.
22 - 5.10.4 Effective Sectional Area.
22 - 5.11 BEARING STRESSES.
22 - 5.11.1 Maximum Permissible Stress.
22 - 5.11.2 Dispersion of Force through Flange to Web.
22 - 5.12 FLANGE DETAILS.
22 - 5.12.1 Flange Splices.
22 - 5.12.1.1 Butt welds.
22 - 5.12.1.2 Cover plates.
22 - 5.12.2 Curtailment of Flange Plates.
22 - 5.12.3 Connection of Flanges to Web.
22 - 5.13 WEB DETAILS.
22 - 5.13.1 Web Plates.
22 - 5.13.1.1 Minimum thickness.
24 - 5.13.1.2 Web panel-maximum dimension.
24 - 5.13.1.3 Splices in webs.
24 - 5.13.1.4 Side reinforcing plates.
24 - 5.13.2 Load-bearing Web Stiffeners.
24 - 5.13.2.1 All sections.
24 - 5.13.2.2 Plate girders.
24 - 5.13.2.3 Design for concentrated force.
24 - 5.13.2.4 Design for torsional end-restraint.
24 - 5.13.3 Intermediate Web Stiffeners for Plate Girders.
24 - 5.13.3.1 Vertical stiffeners.
24 - 5.13.3.2 Horizontal stiffeners.
25 - 5.13.3.3 External forces on intermediate stiffeners.
25 - 5.13.3.4 Connection of intermediate stiffeners to web.
25 - 5.13.3.5 Outstand of all web stiffeners.
25 - 5.14 SEPARATORS AND DIAPHRAGMS.
26 - SECTION 6. DESIGN OF STRUTS
26 - 6.1 AXIAL STRESSES IN UNCASED STRUTS.
26 - 6.1.1 Struts Loaded Concentrically.
26 - 6.1.2 Built-up Struts.
26 - 6.1.3 Slender-leg Struts.
26 - 6.2 AXIAL FORCES IN CASED STRUTS.
26 - 6.3 EFFECTIVE LENGTH OF STRUTS.
26 - 6.3.1 General.
28 - 6.3.2 Sidesway Prevented.
28 - 6.3.3 Sidesway Not Prevented.
28 - 6.4 ECCENTRICITY FOR STRUTS.
28 - 6.4.1 Location of Beam Reaction.
28 - 6.4.2 Continuous Struts.
28 - 6.5 SPLICES.
28 - 6.5.1 Ends of Struts Prepared for Full Contact.
28 - 6.5.2 Ends of Struts Not Prepared for Full Contact.
28 - 6.5.3 Arrangement of Splices.
28 - 6.5.4 Minimum Forces.
28 - 6.6 STRUTS WITH TWO OR MORE MAIN COMPONENTS IN CONTACT.
28 - 6.7 STRUTS WITH TWO SEPARATED COMPONENTS.
28 - 6.7.1 Design Forces for Connections.
28 - 6.7.2 Struts Composed of Two Components Back-to-back.
29 - 6.7.3 Laced Struts.
30 - 6.7.4 Battened Struts.
30 - 6.7.5 Starred Angles.
31 - 6.8 CAPS AND BASES FOR STRUTS.
31 - 6.8.1 Concentric Forces.
31 - 6.8.2 Eccentric Forces and Non-rectangular Plates.
31 - 6.8.3 Connection to Bases.
31 - 6.8.4 Encased Grillage Beams.
31 - 6.9 BEARING STRESSES.
32 - SECTION 7. DESIGN OF TENSION MEMBERS
32 - 7.1 AXIAL STRESSES IN TENSION MEMBERS.
32 - 7.2 TENSION MEMBERS SUBJECTED TO BENDING.
32 - 7.3 DISTRIBUTION OF FORCES.
32 - 7.3.1 End Connections Providing Uniform Force Distribution.
32 - 7.3.2 End Connections Providing Non-uniform Force Distribution.
33 - 7.4 TENSION MEMBERS WITH TWO OR MORE MAIN COMPONENTS.
33 - 7.4.1 General.
33 - 7.4.2 Design Forces for Connections.
33 - 7.4.3 Tension Members Composed of Two Components Back-to-back.
33 - 7.4.4 Lacing of Tension Members.
33 - 7.4.5 Battening of Tension Members.
33 - 7.5 CONNECTIONS.
33 - 7.5.1 Minimum Connections.
33 - 7.5.2 Splices.
34 - 7.5.3 Pin Connections.
34 - 7.6 BEARING STRESSES.
35 - SECTION 8. COMBINED STRESSES
35 - 8.1 ENERAL.
35 - 8.2 INDIVIDUAL MOMENTS AND FORCES.
35 - 8.3 DIRECT STRESS COMBINATIONS.
35 - 8.3.1 Axial Compression and Bending.
36 - 8.3.2 Axial Tension and Bending.
36 - 8.3.3 Biaxial Bending.
37 - SECTION 9. DESIGN OF CONNECTIONS
37 - 9.1 MINIMUM DESIGN FORCE ON CONNECTIONS.
37 - 9.2 CHOICE OF FASTENERS.
37 - 9.3 COMBINED CONNECTIONS.
37 - 9.4 CONNECTION STIFFENERS.
37 - 9.5 STRESSES IN BOLTS, SCREWED TENSION RODS, RIVETS AND PINS.
37 - 9.5.1 Forces on Bolts and Rivets.
37 - 9.5.2 Maximum Permissible Stresses.
37 - 9.5.3 Combined Stresses.
37 - 9.6 DESIGN DETAILS FOR FASTENERS.
37 - 9.6.1 Minimum Pitch.
38 - 9.6.2 Minimum Edge Distances.
38 - 9.6.2.1 General.
38 - 9.6.2.2 Minimum edge distance in direction of component of force.
38 - 9.6.3 Maximum Pitch.
38 - 9.6.4 Maximum Edge Distance.
38 - 9.6.5 Locking of Nuts.
38 - 9.6.6 Long-grip Rivets.
38 - 9.7 DESIGN DETAILS FOR PINS.
38 - 9.7.1 General.
38 - 9.7.2 Bending Stresses in Pins.
38 - 9.8 WELDS.
38 - 9.8.1 General.
38 - 9.8.2 Maximum Permissible Stresses in Welds.
38 - 9.8.3 Butt Welds.
38 - 9.8.3.1 Continuous incomplete-penetration butt welds.
38 - 9.8.3.2 Intermittent complete-penetration butt welds.
39 - 9.8.4 Fillet Welds.
39 - 9.8.4.1 Transverse spacing.
39 - 9.8.4.2 Intermittent fillet welds-general.
39 - 9.8.4.3 Intermittent fillet welds, built-up members.
39 - 9.9 PACKING.
39 - 9.9.1 Bolts or Rivets Through Packing.
39 - 9.9.2 Packing in Welded Construction.
40 - SECTION 10. PLASTIC DESIGN
40 - 10.1 GENERAL.
40 - 10.2 BEAMS.
40 - 10.3 TENSION MEMBERS.
40 - 10.4 STRUTS.
40 - 10.5 MEMBERS SUBJECTED TO COMBINED BENDING AND AXIAL FORCE.
40 - 10.5.1 General.
40 - 10.5.2 Moment Capacities.
40 - 10.5.3 Struts.
40 - 10.5.3.1 Slender struts.
40 - 10.5.3.2 Stocky struts.
40 - 10.5.4 Low Load-ratio Members.
40 - 10.6 SHEAR.
40 - 10.7 STABILITY.
41 - 10.8 MINIMUM THICKNESSES.
41 - 10.8.1 Compression Outstands.
41 - 10.8.2 Unsupported Widths.
41 - 10.8.3 Webs in Shear.
41 - 10.9 LATERAL RESTRAINTS.
41 - 10.10 WEB STIFFENING.
41 - 10.10.1 Excessive Shear Forces.
41 - 10.10.2 Concentrated Loads.
41 - 10.10.3 Plastic Hinges.
41 - 10.11 LOAD CAPACITIES OFCONNECTIONS.
42 - SECTION 11. FABRICATION AND ERECTION
42 - 11.1 GENERAL.
42 - 11.1.1 Inspection.
42 - 11.1.2 Supply.
42 - 11.1.3 Correction of Faults.
42 - 11.1.4 Identification.
42 - 11.2 TOLERANCES.
42 - 11.2.1 General.
42 - 11.2.2 Straightness.
42 - 11.2.3 Length.
42 - 11.2.4 Full Contact Splices.
42 - 11.2.4.1 Machine ends.
42 - 11.2.4.2 Grouted ends.
42 - 11.2.4.3 Butt-welded ends.
42 - 11.2.5 Struts Not Prepared for Full Contact.
42 - 11.3 FABRICATION PROCEDURES.
42 - 11.3.1 General.
42 - 11.3.2 Cutting.
42 - 11.3.3 Welding.
42 - 11.3.3.1 General.
43 - 11.3.3.2 Electrodes.
43 - 11.3.4 Holes for Bolts and Rivets.
43 - 11.3.4.1 Sizes.
43 - 11.3.4.2 Alignment.
43 - 11.3.4.3 Finishing.
43 - 11.3.4.4 Punching.
43 - 11.3.4.5 Flame cutting.
43 - 11.3.5 Bolting.
43 - 11.3.5.1 High-strength bolts.
43 - 11.3.5.2 Other steel bolts.
43 - 11.3.6 Riveting.
43 - 11.3.7 Flattening Ends of Circular Hollow Sections.
43 - 11.3.8 Pinned Joints.
43 - 11.3.9 Surface Preparation.
43 - 11.4 ERECTION.
43 - 11.4.1 Equipment Support.
43 - 11.4.2 Setting Out Tolerances.
43 - 11.4.2.1 Level and alignment of beams.
44 - 11.4.2.2 Alignment and plumbing of struts.
44 - 11.4.3 Safety During Erection.
44 - 11.4.4 Grouting at Supports.
44 - 11.4.4.1 Strut bases and beams.
44 - 11.4.4.2 Bedding of grillages on concrete.
44 - 11.4.4.3 Grouting.
45 - APPENDIX A - DEFLECTION
45 - A1 NOTES ON DEFLECTION.
45 - A1.1 General.
45 - A1.2 Estimation.
45 - A1.3 Special Conditions.
45 - A1.4 Conclusion.
45 - A2 DEFLECTION LIMITS FOR SPECIFIC CASES.
45 - A2.1 Beams.
45 - A2.2 Purlins, Girts, Secondary Members.
45 - A2.3 Industrial Buildings.
46 - APPENDIX B - FATIGUE
46 - B1 GENERAL.
46 - B2 LOADS AND STRESS CONCENTRATIONS.
46 - B3 LOADING CONDITIONS AND TYPE AND LOCATION OF MATERIAL.
46 - B4 MAXIMUM PERMISSIBLE STRESSES.
46 - B5 RIVETED AND BOLTED CONNECTIONS.
46 - B5.1 Connections Made with Bolts Complying with AS 1252 and Subject to Tensile Fatigue Loading.
47 - B5.2 Other Mechanical Fasteners Subject to Tensile Fatigue Loading.
47 - B5.3 Rivets, Bolts and Threaded Parts Subjected to Cyclic Loading in Shear.
52 - APPENDIX C - MINIMUM YIELD STRESSES FOR STEEL TO AS 1163, AS 1204 AND AS 1205
54 - APPENDIX D - LIST OF REFERENCES ON THE ELASTIC FLEXURAL-TORSIONAL BUCKLING OF STEEL BEAMS
55 - APPENDIX E - EFFECTIVE LENGTH OF STRUTS
55 - E1 EFFECTIVE LENGTH OF STRUTS IN RECTANGULAR FRAMES.
55 - E1.1 General.
55 - E1.2 Sidesway Prevented.
55 - E1.3 Sidesway Not Prevented.
55 - E1.4 Notation.
56 - E1.5 Application.
56 - E1.5.1 Assumptions.
56 - E1.5.2 Use of charts.
56 - E2 EFFECTIVE LENGTH OF STRUTS IN TRIANGULATED FRAMES.
58 - INDEX
62 - NOTATION

Applies to the design, fabrication, erection, repair and alteration of steel structures, including foot and service bridges, but does not apply to road and rail bridges, material less than 3 mm thick, steel for which the design yield stress exceeds 450 MPa, and cold-formed structures (see AS 1538).

This standard applies to the design, fabrication, erection, repair and alteration of steel-work in structures, including foot and service bridges. The standard does not apply to the following structures and materials:(a) Road and railway bridges.(b) Material less than 3 mm thick.(c) Steel for which the value used in design FY exceeds 450 MPa.(d) Cold-formed members other than those com-plying with AS 1163.NOTES:1. The use of cold-formed steel sections in structures is covered by AS 1538. Reference should also be made to Addendum No 1 to BS 449 (PD 4064), and the AISI* Cold-formed Steel Design Manual.2. Packings may be of any thickness.

First published as AS CA1-1933.
Second edition 1939.
Revised and redesignated as Int 351-1952.
Revised and issued as AS CA1-1968.
Fourth edition AS CA1-1972 (imperial).
AS 1250 first published 1972 (metric).
AS CA1-1972 and AS 1250-1972 revised, amalgamated and issued as AS 1250-1975.
AS CA1-1972 withdrawn 1976.
Third edition AS 1250-1981.
AS 1250-1981 withdrawn 1991.
Available as superseded standard - June 1992.