Historic Structural Steelwork

Name: Historic Steel Mechanical Properties and Design Stresses
Brand: Community
SKU: 69725046-8ca5-4424-bb01-9d48180d8d1c

This listing brings together the data an engineer needs to assess steelwork in existing Australian buildings and structures built from the early 1900s to the 1970s.

Community

Historic steel mechanical properties and design stresses

The steel specification and the design basis (working or permissible stresses) in force in Australia for a given year of construction, from the iron and imported British steel of the 1800s to the Australian grades of the 1970s and the start of limit states design to AS 4100 in 1990.

Set the year the steelwork was made or erected: drag the red line on the timeline, click the timeline, or use the left and right arrow keys (with Shift for ten years). Where the Year of construction box is shown, you can also type the year.
Choose Imperial or SI with the Units switch at the top of the timeline (or the Units box, where shown).
The timeline marks the year across the steel, the design basis, the section series and the strength values, and the row in force for that year is highlighted in each table. In a year when a specification or code changed, the summary says so: check both rows.

The steel follows the date of construction, not the section series. For the dimensions and section properties of the sections themselves, see the companion listing Historic Steel Section Properties (Australia).

Historical data: not a capacity. These are the properties specified and the stresses permitted at the time, transcribed from the standards, codes and handbooks of the period. They show what the original designer could assume. They are not the strength of the steel in a structure today and are not design values under current standards. Steel of unknown origin should be taken as unidentified (see the notes) unless it is tested. The engineer assessing the structure is responsible for the values used.

In force in the year entered

Notes for assessment

Unidentified steel. Unless a full test to AS 1391 is made, the yield for design is taken as not more than 170 MPa (AS 1250-1981 cl 2.1.4); AS 4100-1990 cl 2.2.3 keeps 170 MPa and adds a tensile strength not more than 300 MPa; its Commentary (C2.2) calls this a severe assumption and recommends testing. The earlier codes held (AS CA1-1968, AS CA1-1972 and AS 1250-1975, rule 2.1.4) allowed unidentified steel only where its properties and weldability would not adversely affect strength and serviceability, with no value given. AS 1250-1972 is not held.
No specified yield before July 1955. AS A1-1928 and AS A1-1940 specified tensile strength only; the yield point was recorded in test reports. A minimum yield first appears in AS A1 Amendment No. 1 (July 1955). Any yield for older steel is an inference from tensile strength or a test.
Weldability. AS A1-1928 and AS A1-1940 limit only phosphorus and sulphur. The first carbon and carbon equivalent limits are in AS A149-1965 (C not more than 0.25%, C + Mn/6 not more than 0.42%; Table 1). Do not assume older steel is weldable.
Tensile upper limits removed in 1970. Amendments of September 1970 to AS A149 (No. 3), AS A135 (No. 2) and AS A151 (No. 3) deleted the upper limit of tensile strength, leaving a minimum only. Yield and elongation were not changed.
Iron or steel. A structure built before 1890 is almost certainly wrought iron; after 1910, with sizes to BS 4, mild steel may be assumed; between 1890 and 1910 either is possible: determine the material unless very conservative stresses are used. A small boring settles it: a measurable carbon content means steel. Cast iron shows an asymmetric shape, mould joint lines and a pitted surface (Bates 1984, sections 2.1 and 9.4).
Iron working stresses for checking (Bates 1984, section 6.3). Wrought iron beams: tension and bending tension 5.25 tons/in² (81.1 MPa), bending compression 4.0 tons/in² (61.8 MPa), shear 5.0 tons/in² (77.2 MPa) (factor of safety 4). Cast iron beams: tension 1.2 tons/in² (18.5 MPa), compression 6.4 tons/in² (98.8 MPa), shear 1.6 tons/in² (24.7 MPa) (factor of safety 5).
Imported British steel after 1948. BS 15:1948 first specified a yield: 16 tons/in² (247 MPa) up to 3/4 in (19.1 mm), 15 tons/in² (232 MPa) over 3/4 in (19.1 mm) to 1 1/2 in (38.1 mm), 14.75 tons/in² (228 MPa) over 1 1/2 in (38.1 mm), tensile 28 to 33 tons/in² (432 to 510 MPa) (Bates 1984, section 2.5).
Design intent, not capacity. The design basis rows give the working stresses the original designer could use. They are not the strength of the member and are not values for assessment under current standards.
Steel may be older than the building. Stock, second-hand and imported steel was common. Check the row before the year entered as well.

How to read the tables

From is the first year of each row. The row in force for the year entered is the last row whose From year is not later than that year. Where the source gives the month of a change, the Period column shows it. In a year when a row starts, the summary flags it: check both rows.
Values are as printed in the source named in the Source column, in its units. Ranges are minimum to maximum.
Yield: before July 1955 the Australian specifications for sections (AS A1) gave no minimum yield. Where a row shows no yield, none was specified.
The design basis rows give the working (permissible) stresses of the code or handbook named. Formulas are given as printed, with L/r the slenderness ratio and L/b the ratio of unrestrained length to flange width.
AS 4100 (from October 1990) is limit states design: the row gives design capacities with a capacity factor φ, not working stresses, so its entries are not comparable with the rows above. The other steels tables (AS A135 Class A, AS A135 Class B and AS A151) appear only for years 1965 to 1971: use them where the steel was ordered to one of those standards instead of AS A149.
SI values are converted from the printed imperial values and rounded to three significant figures.
Timeline: it plots the values in the tables on one time scale. In the steel band orange, with an orange top edge and the tag Fy, means a minimum yield was specified, and grey means no specified yield (tensile strength only, or no standard); in the design band aqua means a code held and grey handbook practice. The strength chart is in tons/in² (values printed in lb/in², ksi or MPa converted) or in MPa. The yield line is the thinnest thickness band with a specified yield (1/4 in to 3/4 in; Grade 250 to 0.5 in from 1971 and to 12 mm from 1990). The bending line stops in April 1968: from then the codes give bending as 0.66 Fy, which depends on the grade; and from October 1990 AS 4100 gives a design capacity (φ fy Ze), not a stress. The section series bars are guidance only, and fade where the end of the period is approximate. On a narrow screen the timeline is small: use the tables.

Sources

W. Bates, Historical Structural Steelwork Handbook, British Constructional Steelwork Association, 1984 (sections 2.1 to 2.5, 6.3 and 9.4).
Dorman, Long & Co, pocket handbook, 1906 (printed pages 44, 64 and 180) and 1924 (printed pages 15, 70, 112 and 248).
Redpath, Brown & Co, handbook, 1928 (printed page x).
Australian Commonwealth Engineering Standards Association, Australian Standard Specification No. A.1-1928, Structural Steel and Australian Standard Rolled Steel Sections for Structural Purposes, with the April 1931 amendment notice (Part 1, clauses 1 and 5).
Standards Association of Australia, Australian Standard No. A.1-1940, Structural Steel (Excluding Plates) and Australian Standard Rolled Steel Sections for Structural Purposes, with Amendment No. 1 (July 1955) and Amendment No. 2 to AS A1-1956 (April 1965).
Standards Association of Australia, S.A.A. Code for Structural Steel in Building, AS CA1-1933 (clauses 61, 81 and 91).
Standards Association of Australia, SAA Code for Structural Steel in Building, AS CA1-1939, with the war emergency relaxation memorandum of September 1941 (rules 61, 81 and 91, Table III and Appendix D).
Standards Association of Australia, Interim Code for the Use of Structural Steel in Building, SAA Int 351 (first printed June 1952; April 1956 reprint) (clauses 3, 7 to 11 and 26, Tables I and IV, Appendix C).
Standards Association of Australia, SAA Steel Structures Code, AS CA1-1968, with Amendment No. 1 (July 1968), Amendment No. 2 (September 1969) and corrigenda (rules 1.6, 2.1, 4.5, 5.2, 5.3, 5.11, 5.12, 6.1.1 and 7.1, Table 11, Appendix C).
Standards Association of Australia, SAA Steel Structures Code, AS CA1-1972 (imperial), with Amendment No. 1 (March 1973).
Standards Association of Australia, Mild Steel for General Structural Purposes, AS A149-1965, with Amendments No. 1 (April 1967), 2 (November 1968) and 3 (September 1970) (clauses 5 and 6, Tables 1 and 2).
Standards Association of Australia, Notch Ductile Steel for General Structural Purposes, AS A135-1965, with Amendments No. 1 (April 1967) and 2 (September 1970) (Tables 1 to 3).
Standards Association of Australia, Structural Steel of High Yield Stress (Welding Quality), AS A151-1966, incorporating Amendments 1 and 2, with Amendment No. 3 (September 1970) (clause 5, Tables 1, 2 and 4).
Standards Association of Australia, Structural Steels: Ordinary Weldable Grades, AS A186-1971 (preface, Tables 2 and 4, Appendix B).
Standards Association of Australia, SAA Steel Structures Code, AS 1250-1975, incorporating Amendment No. 1 (rules 1.6, 2.1.4, 5.2, 5.10, 5.11.1, 6.1.1 and 7.1).
Standards Association of Australia, SAA Steel Structures Code, AS 1250-1981 (clauses 1.6 and 2.1.4).
Standards Australia, Steel structures, AS 4100-1990, copy incorporating Amendments 1 to 3 (preface; clauses 1.1, 1.4, 2.1, 2.2.3, 5.2.1, 5.6.1.1, 5.11.4, 5.13.3, 6.2.1, 6.3.3 and 7.2; Table 3.4), and its Commentary, AS 4100 Supp1-1990 (section C2.2).
Standards Australia, Hot-rolled structural steel bars and sections, AS 3679-1990, with Amendment No. 1 (December 1991) (preface, Tables 1 and 3).
Standards Australia, MP 84-2000, Evolution of Australian Standards for structural steel.
S. Kotwal, The Evolution of Australian Material Standards for Structural Steel, Steel Construction, Journal of the Australian Institute of Steel Construction (now the Australian Steel Institute), Vol 33 No 2, June 1999 (the paper reissued as MP 84-2000).
John Lysaght (Australia), The Lysaght Referee, 18th edition 1950 and 20th edition 1957 (allowable stress tables).
The Broken Hill Proprietary Co Ltd and Australian Iron & Steel Pty Ltd, BHP-AIS Hot Rolled Carbon Steel Sections and Plates, 1969.

The values are facts compiled from these publications. The publications remain the work of their publishers. Standards Australia documents are cited for their facts only; no pages or tables are reproduced.

Not covered in this release

Plates (AS A33-1937 and AS A33-1955 are held but not tabulated), rivets, bolts, pins, castings and the stresses for connections.
Weather resistant steels, hollow section steels, AS A186 plate values, and the metric AS 1204 (1972 to 1990) in detail.
Editions after the first: AS/NZS 3679.1:1996 and later, AS 4100 after 1990 (later editions and amendments may change the values).
Limit states design in detail: AS 4100 member rules are summarised as their main expressions only.
Wrought and cast iron beyond the summary values in the notes.
Capacity of members. This listing gives the specified properties and the design basis of the period only.

When an existing steel structure is assessed, altered or reused, two questions come first: what are the members, and what steel and design rules were they made to? For Australian steelwork from the early 1900s to the 1970s, neither answer is easy to find. The section lists changed several times, a section of the same nominal size and weight can have different properties from one list to the next, and the steel specifications and design codes changed independently of the sections. The information sits in handbooks and standards that have long been out of print, and those handbooks contain misprints. The two listings in this collection answer those questions. Both start from the year the steelwork was made or erected. Historic Steel Section Properties (Australia) The dimensions and section properties of more than 900 hot rolled sections in five imperial series: the British Standard sections of 1903 and 1904, the revised British list of 1921, the first Australian Standard list (AS A1-1928), its 1940 revision as rolled by BHP, and the AS A1:1965 range that brought in universal beams and columns. It covers beams, channels, equal and unequal angles, tees, zed bars, taper flange beams, universal beams, universal columns and bearing piles. 1. Set the year on the timeline (drag the red line, click it, or use the arrow keys). Only the section series in use in that year are offered. 2. Choose the series, the section type and the units (imperial as printed, or SI converted). 3. Choose the designation. Its row is highlighted in each table and the section is drawn to scale. Expand a table to compare sections. The Source, flags and notes table shows where each value comes from, the other sources that list the section, any differences between them, and the result of the property check. Historic Steel Mechanical Properties and Design Stresses The steel specification and the design basis in force in Australia for a given year of construction, from the iron and imported British steel of the 1800s to limit states design to AS 4100 in 1990. Set the year on the timeline and the page gives a summary for that year and highlights the row in force in each table: the specified tensile strength and, from July 1955, the minimum yield; the code or handbook practice in force; and the working stresses of the period. The timeline shows the steel specifications, the design codes, the section series and the strength values on one time scale. Where a specification or code changed during the year, the summary says so, so that both can be checked. A separate table covers the other steels that could be ordered between 1965 and 1971. Where the data comes from All values are transcribed from the original publications. The section data comes from Dorman Long (1906 and 1924), Redpath Brown (1928), the Australian Standards AS A1-1928, AS A1-1940 and AS A1-1965, BHP handbooks of 1952, 1961 and 1969, the Lysaght Referee (1950 to 1972) and Bates, Historical Structural Steelwork Handbook (1984). The steel and design data comes from the Australian Standards for structural steel and steel design from 1928 to 1990 (including AS A1, AS A149, AS A186, AS 3679, AS CA1, SAA Int 351, AS 1250 and AS 4100), the British Standard values printed in the period handbooks, and those handbooks themselves. Every table was read twice, independently, from images of the printed pages, and the two readings were compared cell by cell. Each source was checked against the others. Where a source prints a figure that arithmetic and other sources show to be a misprint, the corrected value is listed, marked *, and the printed figure is given in the notes. The section properties were also recalculated from the listed dimensions, and the result is shown for each section. SI values are converted from the imperial values and rounded to three significant figures. Limits These are historical values for review and assessment. Rolled sections varied between mills, editions and years, and steel was often imported, reused or held in stock. Identify each section by measuring it on site, and confirm the steel by testing where the assessment depends on it. The listings give section properties, specified material properties and period design stresses. They do not give member capacities, and the engineer assessing the structure is responsible for the values used. Not yet covered: metric sections (from 1974), hollow sections, AS A1-1965 T-bars and piling sections, plates, and safe load tables.