Annex C(Clauses 18.6.2.2 and 22.1.2)

NBC 2016 (SP 7:2016) Volume 1

2016 · PDF page 950

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Moments of Resistance for Rectangular and T-sections

C-1 The moment of resistance of rectangular sections or T-sections in which neutral axis lies within the flange may be obtained as follows:

M _ {\mathrm{u}} = f _ {\mathrm{pb}} A _ {\mathrm{ps}} \left(d - 0. 4 2 x _ {\mathrm{u}}\right)

where

$M_{\mathrm{u}} =$ moment of resistance of the section,

$f_{\mathrm{pb}} =$ tensile stress in the tendon at failure,

$f_{\mathrm{pe}} =$ effective prestress in tendon,

$A_{ps} = \text{area of pretensioning tendons in the tension zone,}$

$d =$ effective depth to the centroid of the steel area, and

$x_{\mathrm{u}} =$ neutral axis depth.

For pre-tensioned members and for post-tensioned members with effective bond between the concrete and tendons, values of $f_{\mathrm{pb}}$ and $x_{\mathrm{u}}$ are given in Table 11. It shall be ensured that the effective prestress after all losses is not less than $0.45f_{\mathrm{pu}}$ , where is the characteristic tensile strength of tendon. Prestressing tendons in the compression zone should be ignored in the strength calculations when using this method.

Table 11Conditions at the Ultimate Limit State for Rectangular Beams With Pre-Tensioned Tendons or With Post-Tensioned Tendons Having Effective Bond (Clause C-1)

Sl No.

\frac{A_{ps} \cdot f_{pu}}{bd \cdot f_{ck}}

$^{1)}$ The neutral axis depth in these cases is too low to provide the necessary elongation for developing $0.87 f_{pu}$ stress level. Hence, it is essential that the strength provided exceeds the required strength by 15 percent for these cases.

PART 6 STRUCTURAL DESIGN — SECTION 5 CONCRETE: 5B PRESTRESSED CONCRETE

LIST OF STANDARDS

The following list records those standards which are acceptable as ‘good practice’ and ‘accepted standards’ in the fulfillment of the requirements of the Code. The latest version of a standard shall be adopted at the time of enforcement of the Code. The standards listed may be used by the Authority for conformance with the requirements of the referred clauses in the Code.

In the following list, the number appearing in the first column within parentheses indicates the number of the reference in this Subsection.

IS No. Title

(1) 4845 : 1968 Definitions and terminology relating to hydraulic cement 6461 Glossary of terms relating to cement concrete:

(Part 1): 1972 Concrete aggregates

(Part 2): 1972 Materials (other than cement and aggregate)

(Part 3): 1972 Concrete reinforcement

(Part 4): 1972 Types of concrete

(Part 5): 1972 Formwork for concrete

(Part 6): 1972 Equipment, tools and plant

(Part 7): 1973 Mixing, laying, compaction, curing and other construction aspects

(Part 8): 1973 Properties of concrete

(Part 9): 1972 Structural aspects

(Part 10): 1973 Tests and testing apparatus (Part 11): 1973 Prestressed concrete

(Part 12): 1973 Miscellaneous

(2) 269 : 2015 Specification for ordinary Portland cement (sixth revision)

8041 : 1990 Specification for rapid hardening Portland cement (second revision)

455 : 2015 Specification for Portland slag cement (fifth revision) 1489 Specification for Portland pozzolana cement:

(Part 1): 2015 Fly ash based (fourth revision)

(Part 2): 2015 Calcined clay based (fourth revision)

8043 : 1991 Specification for hydrophobic Portland cement (second revision)

12600 : 1989 Specification for low heat Portland cement

12330 : 1988 Specification for sulphate resisting Portland cement

(3) 12600 : 1989 Specification for low heat Portland cement

IS No. Title

(4) 6452 : 1989 Specification for high alumina cement for structural use (first revision)

(5) 6909 : 1990 Specification for supersulphated cement (first revision)

NATIONAL BUILDING CODE OF INDIA 2016

(6) 383 : 2016 Specification for coarse and fine aggregates for concrete (third revision)

(7) 1785(Part 1): Specification for plain hard drawn steel wire for prestressed concrete: Part 1 Cold drawn stress relieved wire (second revision)

6003 : 2010 Specification for indented wire for prestressed concrete (second revision)

2090 : 1983 Specification for high tensile steel bars used in prestressed concrete (first revision)

6006 : 2014 Specification for uncoated stress relieved strand for prestressed concrete (second revision)

14268 : 1995 Specification for uncoated stress relieved low relaxation seven ply strand for prestressed concrete

(8) 432 Specification for mild steel and

(Part 1): 1982 medium tensile steel bars and hard-drawn steel wire for concrete reinforcement: Part 1 Mild steel and medium tensile steel bars (third revision)

1786 : 2008 Specification for high strength deformed steel bars and wire for concrete reinforcement (fourth revision)

1566 : 1982 Specification for hard-drawn steel wire fabric for concrete reinforcement (second revision)

(9) 4082 : 1996 Recommendations on stacking and storage of construction materials and components at site (second revision)

(10) 516 : 1959 Method of test for strength of concrete 5816 : 1999 Method of test for splitting tensile strength of concrete (first revision)

(11) 1489 Specification for Portland (Part 1): 2015 pozzolana cement: Part 1 Fly ash based (fourth revision)

(12) 455 : 2015 Specification for Portland slag cement (fifth revision)

(13) 3812 (Part 1): Specification for pulverized fuel ash: Part 1 For use as pozzolana in cement, cement mortar and concrete (third revision)

(14) 12089 : 1987 Specification for granulated slag for manufacture of Portland slag cement

(15) 4925 : 2004 Specification for concrete batching and mixing plant (first revision)

(16) 4926 : 2003 Code of practice for ready-mixed concrete (second revision)

(17) 2386 (Part 3): Methods of test for aggregates for concrete: Part 3 Specific gravity, density, voids, absorption and bulking

(20) 9103 : 1999 Specification for admixtures for concrete (first revision)

(22) 516 : 1959 Method of test for strength of concrete

PART 6 STRUCTURAL DESIGN — SECTION 5 CONCRETE: 5B PRESTRESSED CONCRETE

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PART 6 STRUCTURAL DESIGN

Section 6 Steel

BUREAU OF INDIAN STANDARDS

Section 6(m) Working Stress Design

SECTION 6(m) WORKING STRESS DESIGN
17 WORKING STRESS DESIGN ... 82
SECTION 6(n) DESIGN AND DETAILING FOR EARTHQUAKE LOADS
18 DESIGN AND DETAILING FOR EARTHQUAKE LOADS ... 85
SECTION 6(p) FATIGUE
19 FATIGUE ... 89
SECTION 6(q) DESIGN ASSISTED BY TESTING
20 DESIGN ASSISTED BY TESTING ... 98
SECTION 6(r) DURABILITY
21 DURABILITY ...101
SECTION 6(s) FIRE RESISTANCE
22 FIRE RESISTANCE ...102
SECTION 6(t) FABRICATION AND ERECTION
23 FABRICATION AND ERECTION ...107
ANNEX A ANALYSIS AND DESIGN METHODS ...114
ANNEX B DESIGN AGAINST FLOOR VIBRATION ...115
ANNEX C DETERMINATION OF EFFECTIVE LENGTH OF COLUMNS ...116
ANNEX D ELASTIC LATERAL TORSIONAL BUCKLING ...121
ANNEX E CONNECTIONS ...124
ANNEX F GENERAL RECOMMENDATIONS FOR STEELWORK TENDERS AND CONTRACTS ...128
ANNEX G ...131
LIST OF STANDARDS ...132

PART 6 STRUCTURAL DESIGN — SECTION 6 STEEL

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National Building Code Sectional Committee, CED 46

This Code (Part 6/Section 6) covers the structural design aspects of steel structures in buildings.

This Section covers the use of hot-rolled structural steel sections and steel tubes in buildings. It covers the design by limit state method and plastic theory, and also enables design by working stress method.

This Section is based on IS 800 : 2007 ‘Code of practice for general construction in steel (third revision)’ and IS 806 : 1968 ‘Code of practice for use of steel tubes in general building construction (first revision)’.

This Section was first published in 1970 and was subsequently revised in 1983 and 2005. In the 2005 version, the detailed design provisions were not included as IS 800 : 1984 ‘Code of practice for general construction in steel (second revision)’ was under revision at that time. This Section, therefore, then referred to the 1984 version of IS 800 with the remarks that the latest version would prevail, as and when published. It, however, covered the philosophical aspects of limit state design which was being introduced in the revision of IS 800. IS 800 was subsequently revised and published as IS 800 : 2007 and hence, became the prevailing version for use under this Section.

In the revision of IS 800 in 2007, in view of the development and production of new varieties of medium and high tensile structural steels in the country, the scope of the standard was modified permitting the use of any variety of structural steel provided the relevant provisions of the standard were satisfied. IS 800 : 2007 makes reference to the latest Indian Standards available for rivets, bolts and other fasteners. The standard is based on limit state method, reflecting the latest developments.

This revision of the Section is intended to bring it in line with the revised version of IS 800 : 2007 read with its Amendment No. 1 and to take care of further improvements and incorporations required. In this revision, therefore, the following major modifications have been made:

a) The table on tensile properties of structural steel products has been updated by including yield stress values of bolts of sizes 3.6 to 6.8 mm as per IS 1367 (Part 3) ‘Mechanical properties of fasteners made of carbon steel and alloy steel – bolts, screws and studs (fourth revision)’ and aligning the corresponding provisions of the table with those given in IS 2062 : 2011 ‘Hot rolled low, medium and high tensile structural steel (seventh revision)’.

b) Provisions relating to mechanical properties of structural steel have been elaborated.

c) Provisions related to effective wind pressure on exposed circular tube members have been included.

d) Provisions related to requirement of temperature stress analysis have been updated.

e) Provisions related to slender cross-sections have been updated, with the inclusion of two new figures on effective sections of slender members under pure and flexural compression.

f) The table on deflection limits has been suitably updated with respect to the load nomenclature of the load and their combinations.

g) The term ‘imposed load’ has been substituted for ‘live load’ in coherence with the use of terminology in other published standards.

h) Warping restraint conditions in the table on effective lengths for simply supported beams have been clarified.

j) The provision on assessment of conditions under which fatigue assessment is to be done, is covered comprehensively in 19.2.1.2 ‘Necessity for Fatigue Assessment’, which takes care of 13.5.1 of IS 800 : 2007 as well.

k) Provisions related to design of end panels in stiffened web panels have been updated.

m) Provisions related to design for earthquake loads relating to load and load combinations, response reduction factor for various types of frames, connections in the critical zones of frames, and bracing members have been updated.

n) The nominal bearing pressure between the column base plate and the support has been updated to bring

PART 6 STRUCTURAL DESIGN — SECTION 6 STEEL

it line with the corresponding provisions of IS 456 : 2000 ‘Code of practice for plain and reinforced concrete (fourth revision)’.

p) Provisions related to design of single angle struts loaded through one leg have been revised.

q) Provisions related to non-ductile braced and moment resisting frames have been included.

r) Provisions on ductile designing with respect to column base connections have been updated.

s) Reference design conditions under fatigue for S-N curve have been modified.

t) Provisions on clearances related to fabrication procedures have been updated.

u) Sketches of the restraint conditions under table on effective lengths of single stepped columns have been updated.

w) Certain terminologies, symbols and figures have been updated based on the changes incorporated.

y) List of Indian Standards cross-referred in this Section has been updated.

The revised Section will enhance the confidence of designers, engineers, contractors, technical institutions, professional bodies and the industry and will open a new era in safe and economic construction in steel.

In the earlier versions of this Code, the provisions relating to the use of steel tubes in general building construction was based on IS 806 : 1968 ‘Code of practice for use of steel tubes in general building construction’, which was complementary to IS 800. The design using tubular steel in structural applications may be carried using the limit state design provisions in this Section until IS 806 is revised as per limit state design method.

The design of cold-formed steel members is based on the provisions of IS 801 : 1975 ‘Code of practice for use of cold formed light gauge steel structural members in general building construction’. The standard is currently under revision to be based on the limit state design practice. Until the revised IS 801 is published, the cold formed steel members may be designed using the current IS 801, based on the working stress method.

All standards, whether given herein above or cross-referred to in the main text of this Section, are subject to revision. The parties to agreement based on this Section are encouraged to investigate the possibility of applying the most recent editions of the standards.

For the purpose of deciding whether a particular requirement of this Section is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 2 : 1960 ‘Rules for rounding off numerical values (revised)’. The number of significant places retained in the rounded off value should be the same as that of the specified value in this Section.

PART 6 STRUCTURAL DESIGN

Section 6 Steel

SECTION 6(a) GENERAL

1 SCOPE

1.1 This Code (Part 6/Section 6) covers the structural design aspects of steel structures in buildings. This Section applies to general construction using hot rolled steel sections and steel tubes joined using riveting, bolting and welding. Cold formed light gauge steel sections, etc, are covered in separate standards. This Section covers the design by limit state method and plastic theory, and also enables design by working stress method.

1.2 This Section gives only general guidance as regards to the various loads to be considered in design. For the actual loads, such as dead, live, snow, wind and earthquake loads and load combinations to be used, reference may be made to Part 6 ‘Structural Design, Section 1 Loads, Forces and Effects’ of the Code.

1.3 Fabrication and erection requirements covered in this Section are general and the minimum necessary quality of material and workmanship consistent with assumptions in the design rules. The actual requirements may be further developed as per other standards or the project specification, the type of structure and the method of construction.

1.4 For seismic design, recommendations pertaining to steel frames only are covered in this section. For more detailed information on seismic design of other structural and non-structural components, reference may be made to 5 of Part 6 ‘Structural Design, Section 1 Loads, Forces and Effects’ of the Code and other special publications on the subject.

2 TERMINOLOGY

For the purpose of this Section, the definitions given below shall apply.

2.1 Accidental Loads — Loads due to explosion, impact of vehicles, or other rare loads for which the structure is considered to be vulnerable as per the user.

2.2 Accompanying Load — Live (imposed) load acting along with leading imposed load but causing lower actions and/or deflections.

2.3 Action Effect or Load Effect — The internal force, axial, shear, bending or twisting moment, due to external actions and temperature loads.

2.4 Action — The primary cause for stress or deformations in a structure such as dead, live, wind, seismic or temperature loads.

PART 6 STRUCTURAL DESIGN — SECTION 6 STEEL

2.5 Actual Length — The length between centre-to-centre of intersection points, with supporting members or the cantilever length in the case of a free standing member.

2.6 Beam — A member subjected predominantly to bending.

2.7 Bearing Type Connection — A connection made using bolts in ‘snug-tight’ condition, or rivets where the load is transferred by bearing of bolts or rivets against plate inside the bolt hole.

2.8 Braced Member — A member in which the relative transverse displacement is effectively prevented by bracing.

2.9 Brittle Cladding — Claddings, such as asbestos cement sheets which get damaged before undergoing considerable deformation.

2.10 Buckling Load — The load at which an element, a member or a structure as a whole, either collapses in service or buckles in a load test and develops excessive lateral (out of plane) deformation or instability.

2.11 Buckling Strength or Resistance — Force or moment, which a member can withstand without buckling.

2.12 Built-Up Section — A member fabricated by interconnecting more than one element to form a compound section acting as a single member.

2.13 Camber — Intentionally introduced pre-curving (usually upwards) in a system, member or any portion of a member with respect to its chord. Frequently, camber is introduced to compensate for deflections at a specific level of loads.

2.14 Characteristic Load (Action) — The value of specified load (action), above which not more than a specified percentage (usually 5 percent) of samples of corresponding load are expected to be encountered.

2.15 Characteristic Yield/Ultimate Stress — The minimum value of stress, below which not more than a specified percentage (usually 5 percent) of corresponding stresses of samples tested are expected to occur.

2.16 Column — A member in upright (vertical) position which supports a roof or floor system and predominantly subjected to compression.

2.17 Compact Section — A cross-section, which can develop plastic moment, but has inadequate plastic rotation capacity needed for formation of a plastic collapse mechanism of the member or structure.

2.18 Constant Stress Range — The amplitude between which the stress ranges under cyclic loading is constant during the life of the structure or a structural element.

2.49Fire Exposure Condition

a) Three-sided fire exposure condition — Steel member incorporated in or in contact with a concrete or masonry floor or wall (at least against on surface).

NOTES

1 Three-sided fire exposure condition is to be considered separately unless otherwise specified (see 22.10).

2 Members with more than one face in contact with a concrete or masonry floor or wall may be treated as three-sided fire exposure.

b) Four-sided fire exposure condition — Steel member, which may be exposed to fire on all sides.

2.50 Fire Protection System — The fire protection material and its method of attachment to the steel member.

2.51 Fire Resistance — The ability of an element, component or structure, to fulfil for a stated period of time, the required stability, integrity, thermal insulation and/or other expected performance specified in a standard fire test.

2.52 Fire Resistance Level — The fire resistance grading period for a structural element or system, in minutes, which is required to be attained in the standard fire test.

2.53 Flexural Stiffness — Stiffness of a member against rotation as evaluated by the value of bending deformation moment required to cause a unit rotation while all other degrees of freedom of the joints of the member except the rotated one are assumed to be restrained.

2.54 Friction Type Connection — Connection effected by using pre-tensioned high strength bolts where shear force transfer is due to mobilization of friction between the connected plates due to clamping force developed at the interface of connected plates by the bolt pre-tension.

2.55 Gauge — The spacing between adjacent parallel lines of fasteners, transverse to the direction of load/stress.

2.56 Gravity Load — Loads arising due to gravitational effects.

2.57 Gusset Plate — The plate to which the members intersecting at a joint are connected.

2.58 High Shear — High shear condition is caused when the actual shear due to factored load is greater than a certain fraction of design shear resistance (see 15.2.2).

2.59 Imposed (Live) Load — The load assumed to be produced by the intended use or occupancy including distributed, concentrated, impact, vibration and snow loads but excluding, wind, earthquake and temperature loads.

2.60 Instability — The phenomenon which disables an element, member or a structure to carry further load due to excessive deflection lateral to the direction of loading and vanishing stiffness.

2.61Lateral Restraint for a Beam — See 2.34.

2.62 Leading Imposed Load — Imposed load causing higher action and/or deflection.

2.63 Limit State — Any limiting condition beyond which the structure ceases to fulfill its intended function (see also 2.86).

2.64 Live Load — See 2.59.

2.65 Load — An externally applied force or action (see also 2.4).

2.66 Main Member — A structural member, which is primarily responsible for carrying and distributing the applied load or action.

2.67 Mill Tolerance — Amount of variation allowed from the nominal dimensions and geometry, with respect to cross-sectional area, non-parallelism of flanges, and out of straightness such as sweep or camber, in a product, as manufactured in a steel mill.

2.68 Normal Stress — Stress component acting normal to the face, plane or section.

2.69 Partial Safety Factor — The factor normally greater than unity by which either the loads (actions) are multiplied or the resistances are divided to obtain the design values.

2.70 Period of Structural Adequacy under Fire — The time (t), in minutes, for the member to reach the limit state of structural inadequacy in a standard fire test.

2.71 Permissible Stress — When a structure is being designed by the working stress method, the maximum stress that is permitted to be experienced in elements, members or structures under the nominal/service load (action).

2.72 Pitch — The centre-to-centre distance between individual fasteners in a line, in the direction of load/stress.

PART 6 STRUCTURAL DESIGN — SECTION 6 STEEL

2.73 Plastic Collapse — The failure stage at which sufficient number of plastic hinges have formed due to the loads (actions) in a structure leading to a failure mechanism.

2.74 Plastic Design — Design against the limit state of plastic collapse.

2.75 Plastic Hinge — A yielding zone with significant inelastic rotation, which forms in a member, when the plastic moment is reached at a section.

2.76 Plastic Moment — Moment capacity of a cross-section when the entire cross-section has yielded due to bending moment.

2.77 Plastic Section — Cross-section, which can develop a plastic hinge and sustain plastic moment over sufficient plastic rotation required for formation of plastic failure mechanism of the member or structure.

2.78 Poisson's Ratio — It is the absolute value of the ratio of lateral strain to longitudinal strain under uniaxial loading.

2.79 Proof Stress — The stress to which high strength friction grip (HSFG) bolts are pre-tensioned.

2.80 Proof Testing — The application of test loads to a structure, sub-structure, member or connection to ascertain the structural characteristics of only that specific unit.

2.81 Prototype Testing — Testing of structure, substructure, members or connections to ascertain the structural characteristics of that class of structures, substructures, members or connections that are nominally identical (full scale) to the units tested.

2.82 Prying Force — Additional tensile force developed in a bolt as a result of the flexing of a connection component such as a beam end plate or leg of an angle.

2.83 Rotation — The change in angle at a joint between the original orientation of two linear member and their final position under loading.

2.84 Secondary Member — Member which is provided for overall stability and or for restraining the main members from buckling or similar modes of failure.

2.85 Semi-Compact Section — Cross-section, which can attain the yield moment, but not the plastic moment before failure by plate buckling.

2.86 Serviceability Limit State — A limit state of acceptable service condition exceedance of which causes serviceability failure.

2.87 Shear Force — The in-plane force at any transverse cross-section of a straight member of a column or beam.

2.88 Shear Lag — The in plane shear deformation effect by which concentrated forces tangential to the surface of a plate gets distributed over the entire section perpendicular to the load over a finite length of the plate along the direction of the load.

2.89 Shear Stress — The stress component acting parallel to a face, plane or cross-section.

2.90 Slender Section — Cross-section in which the elements buckle locally before reaching yield moment.

2.91 Slenderness Ratio — The ratio of the effective length of a member to the radius of gyration of the Cross-section about the axis under consideration.

2.92 Slip Resistance — Limit shear that can be applied in a friction grip connection before slip occurs.

2.93 S-N Curve — The curve defining the relationship between the number of stress cycles to failure ( $N_{sc}$ ) at a constant stress range ( $S_{c}$ ), during fatigue loading of a structure.

2.94 Snow Load — Load on a structure due to the accumulation of snow and ice on surfaces such as roof.

2.95 Snug Tight — The tightness of a bolt achieved by a few impacts of an impact wrench or by the full effort of a person using a standard spanner.

2.96 Stability Limit State — A limit state corresponding to the loss of static equilibrium of a structure by excessive deflection transverse to the direction of predominant loads.

2.97 Stickability — The ability of the fire protection system to remain in place as the member deflects under load during a fire test.

2.98 Stiffener — An element used to retain or prevent the out-of-plane deformations of plates.

2.99 Strain — Deformation per unit length or unit angle.

2.100 Strain Hardening — The phenomenon of increase in stress with increase in strain beyond yielding.

2.101 Strength — Resistance to failure by yielding or buckling.

2.102 Strength Limit State — A limit state of collapse or loss of structural integrity.

2.103 Stress — The internal force per unit area of the original cross-section.

2.104 Stress Analysis — The analysis of the internal force and stress condition in an element, member or structure.

2.105 Stress Cycle Counting — Sum of individual stress cycles from stress history arrived at using any rational method.

2.106 Stress Range — Algebraic difference between two extremes of stresses in a cycle of loading.

2.107 Stress Spectrum — Histogram of stress cycles produced by a nominal loading event design spectrum, during design life.

2.108 Structural Adequacy for Fire — The ability of the member to carry the test load exposed to the standard fire test.

2.109 Structural Analysis — The analysis of stress, strain, and deflection characteristics of a structure.

2.110 Strut — A compression member, which may be oriented in any direction.

2.111 Sway — The lateral deflection of a frame.

2.112 Sway Member — A member in which the transverse displacement of one end, relative to the other is not effectively prevented.

2.113 Tensile Stress — The characteristic stress corresponding to rupture in tension, specified for the grade of steel in the appropriate Indian Standard, as listed in Table 1.

2.114 Test Load — The factored load, equivalent to a specified load combination appropriate for the type of test being performed.

2.115 Transverse — Direction along the stronger axes of the cross-section of the member.

2.116 Ultimate Limit State — The state which, if exceeded can cause collapse of a part or the whole of the structure.

2.117 Ultimate Stress — See 2.113.

2.118 Wind Loads — Load experienced by member or structure due to wind pressure acting on the surfaces.

2.119 Yield Stress — The characteristic stress of the material in tension before the elastic limit of the material is exceeded, as specified in the appropriate Indian Standard, as listed in Table 1.

3 SYMBOLS

Symbols used in this section shall have the following meanings with respect to the structure or member or condition, unless otherwise defined elsewhere in this Section:

A

\left| A _ {\mathrm{c}} \right|

A _ {\mathrm{e}}

4 UNITS

For the purpose of design calculations the following units are recommended:

a) Forces and loads, in kN, kN/m, kN/m²;

PART 6 STRUCTURAL DESIGN — SECTION 6 STEEL

b) Unit mass, in kg/m³;

c) Unit weight, in $\mathrm{kN / m^3}$ ;

d) Stresses and strengths, in N/mm² (MN/m² or MPa); and

e) Moments (bending, etc), in kNm.

For conversion of one system of units to another system, accepted standard [6-6(1)] may be referred.

5 STANDARD DIMENSIONS, FORM AND WEIGHT

The dimensions, form, weight, tolerances of all rolled shapes, all rivets, bolts, nuts, studs, and welds and other members used in any steel structure shall conform to accepted standards $[6-6(2)]$ , wherever applicable.