Hot rolled and slit steel tee bars

IS 1173: Scope Summary and Key Specifications

• Scope: Covers rolled steel beams, channels, and angle sections as per Indian Standard dimensions and properties.

• Sectional Properties (Clause 3.1):

  • ( a ) = Sectional area (cm²)
  • ( w = 0.785 \times a ) = Weight (kg/m)
  • ( C_{xx} ), ( I_{xx} ), ( I_{yy} ) = CG distance and moments of inertia about principal axes
  • ( e_{xx} ), ( e_{yy} ) = Distances to extreme fibers
  • ( Z_x ), ( Z_y ) = Section moduli about X-X and Y-Y axes
  • ( r_{xx} ), ( r_{yy} ) = Radii of gyration
  • ( D ) = Angle between web and flange (degrees)

• Classification (Clause 4.2):
  | Classification | Abbreviation |
  |----------------|--------------|
  | ISNT | NT |
  | ISDT | DT |
  | ISLT | LT |
  | ISMT | MT |
  | ISHT | HT |

• Rounding off: As per IS 2-1960, maintain significant digits consistent with specified values.

This standard aligns with IS 808 (Part I) for medium weight sections and reflects Indian manufacturing practices.

flowchart LR
    A[Steel Sections] --> B[Beams]
    A --> C[Channels]
    A --> D[Angles]
    B --> E[Properties: a, w, Ixx, Iyy, Zx, Zy]
    C --> E
    D --> E

IS 1173: Key Definitions, Symbols, and Classification

1. Letter Symbols (Clause 3.1)

2. Classification (Clause 4.2)

3. Weight Calculation Formula

[ w = 0.785 \times a \quad \text{(kg/m)} ]

Notes:

• Dimensions and properties are aligned with IS 808 (Part I) for medium weight sections.
• Rounding off complies with IS 2-1960.

flowchart LR
    A[Sectional Area (a)] --> B[Weight w = 0.785 × a]
    B --> C[Moment of Inertia Ixx, Iyy]
    C --> D[Radius of Gyration rxx, ryy]
    D --> E[Section Modulus Zx, Zy]

This summary aids in understanding symbols, classification, and key formulas for IS 1173 sections.

IS 1173 - Letter Symbols & Key Specifications

1. Letter Symbols (Clause 3.1)

2. Abbreviated Reference Symbols (Clause 4.2)

3. Key Formulas

• Weight per meter:
  [ w = 0.785 \times a \quad (\text{where } a \text{ in cm}^2, w \text{ in kg/m}) ]

• Modulus of Section:
  [ Z_x = \frac{I_{xx}}{e_{xx}}, \quad Z_y = \frac{I_{yy}}{e_{yy}} ]

• Radius of Gyration:
  [ r_{xx} = \sqrt{\frac{I_{xx}}{a}}, \quad r_{yy} = \sqrt{\frac{I_{yy}}{a}} ]

4. Example from Table 1 (ISNT

IS 1173 - Classification Summary

Clause 4.2: Classification & Abbreviated Symbols

Key Symbols & Formulas (Clause 3.1)

Notes:

• Dimensions and properties are aligned with IS 808 (Part I)-1973 for medium weight sections.
• Weight calculation uses steel density factor 0.785 (approximate density in kg/cm³).
• Rounding off values should follow IS 2-1960 rules.

IS 1173: Dimensions and Properties Summary

Key Letter Symbols (Clause 3.1)

Important Notes

• Weight formula:
  [ w = 0.785 \times a \quad \text{(kg/m)} ]
• Dimensions and weights are tabulated in Table 1 (Clause 5.1) for Indian Standard Tee Bars.
• Section properties are expressed in SI units.
• Rounding off values must follow IS 2:1960 rules.

Classification Abbreviations (Clause 4.2)

Typical Calculation Flow for Section Properties

flowchart TD
    A[Sectional Area (a)] --> B[Calculate Weight (w)]
    B --> C[Find Centroid (Cxx)]
    C --> D[Calculate Moments of Inertia (Ixx, Iyy)]
    D --> E[Calculate Extreme Fibre Distances (exx, eyy)]
    E --> F[Calculate Section Modulus (Zx, Zy)]
    F --> G

IS 1173: Tolerances on Dimensions

• Reference Standard:
  Tolerances on dimensions for Indian Standard Tee Bars are governed by IS 1852:1973 (Rolling and cutting tolerances for hot-rolled steel products).

• Key Points on Tolerances (Clause 5.2):

  • Dimensional tolerances (thickness, width, length) must comply with IS 1852 limits.
  • These tolerances ensure uniformity and interchangeability of steel sections.

Typical Tolerances from IS 1852 (Summary)

Exact values depend on the specific product and size.

Important Symbols from IS 1173 (Clause 3.1)

Summary Diagram: Section Properties

graph LR
A[Sectional Area (a)] --> B[Weight (w)]
B --> C[Centroid (Cxx)]
C --> D[Moments of Inertia (Ixx, Iyy)]
D --> E[Section Modulus (Zx, Zy)]
E --> F[Extreme Fibers (exx, eyy)]
F --> G[Angle D between web & flange]

For detailed tolerances, always refer to IS 1852:1973 alongside IS 1173.

IS 1173: Marking and Designation - Key Points

1. Abbreviated Reference Symbols (Clause 4.2)

For shop marking and drawings, the following abbreviations are used to denote Indian Standard sections:

These abbreviations must be mutually understood by fabricator, producer, and drawing office.

2. Key Letter Symbols & Formulas (Clause 3.1)

3. Rounding Off (IS 2-1960)

• Final values from tests or calculations must be rounded off as per IS 2-1960.

IS 1173: Manufacturing and Trade Practices - Key Points

1. Sectional Properties of Indian Standard Tee Bars (Clause 3.1, Table 1)

• Parameters:
  • Sectional Area (a) in mm²
  • Weight (kg/m)
  • Size (h × b) in mm
  • Thickness of Web (tw) & Flange (tf) in mm
  • Radii at root (Tr) & toe (Tt) in mm
  • Slope of Flange (D°)
  • Centre of Gravity position (Cxx) in mm
  • Moments of Inertia (Ixx, Iyy) in 10⁶ mm⁴
  • Radii of Gyration (rxx, ryy) in mm
  • Moduli of Section (Zxx, Zyy) in 10³ mm³

2. Abbreviated Reference Symbols (Clause 4.2)

3. Important Formulae (Clause 3.1)

• Weight per meter:
  [ w = 0.785 \times a ] where (a) = sectional area in cm², (w) in kg/m.

• Modulus of section:
  [ Z_x = \frac{I_{xx}}{e_{xx}}, \quad Z_y = \frac{I_{yy}}{e_{yy}} ]

• Radius of gyration:
  [ r_{xx} = \sqrt{\frac{I_{xx}}{a}}, \quad r_{yy} = \sqrt{\frac{I_{yy}}{a}} ]

4. Manufacturing Notes

• Dimensions and properties align with IS 808 (Part I)-1973 for medium weight sections.
• Rounding off numerical values follows IS 2-1960.

Summary Table Snapshot (Example for ISNT Tee Bars)

| Designation | Weight (kg/m) | Size (h×b

IS 1173: References to Related Standards & Key Specifications

1. Abbreviated Reference Symbols (Clause 4.2)

For shop marking and drawing office, IS sections can be abbreviated as:

Note: These symbols refer only to Indian Standard Sections.

2. Key Letter Symbols & Formulas (Clause 3.1)

3. Related IS Codes

• IS 808 (Part I) - 1973: Dimensions for hot rolled steel beams (MB series).
• IS 2 - 1960: Rules for rounding off numerical values.
• IS 1173: Specification for rolled steel beam, channel, and angle sections (revised).

Summary Diagram

Key Formulas and Specifications from IS 1173 Annexures and Tables

Letter Symbols (Clause 3.1)

• a = Sectional area (cm²)
• w = Weight (kg/m) = 0.785 × a
• Cxx = Distance of CG from top flange (mm)
• Ixx, Iyy = Moments of inertia about X-X and Y-Y axes (mm⁴)
• exx, eyy = Distance to extreme fibre from X-X and Y-Y axes (mm)
• Zxx, Zyy = Section modulus about X-X and Y-Y axes (mm³)
• rxx, ryy = Radius of gyration about X-X and Y-Y axes (mm)
• D = Angle between web and flange (degrees)

Important Table: Nominal Dimensions and Properties of Indian Standard Tee Bars (Excerpt)