Dimensions for Hot Rolled Steel Beam, Column, Channel and Angle Sections

IS 808 Scope: Key Formulas, Tables & Specifications

1. Scope Overview (Clause 3.1 & 5.1, 5.2)

• IS 808 covers Indian Standard Sections for columns and heavy beams.
• Includes designations, dimensions, mass, and sectional properties.
• Shift angles for angle sections are tabulated (Tables 5.1 & 5.2).

2. Key Sectional Properties Symbols (Clause 4.2.2)

3. Typical Sectional Properties Table (Excerpt from Table 3.1)

IS 808: Classification and Designation of Sections

1. Symbols for Sectional Properties (Clause 4.2.2)

2. Classification of Sections (Clause 5.1 & 5.2)

3. Key Table: Sectional Properties of Columns & Heavy Beams (Excerpt)

| Designation | Mass (kg/m) | Area (cm²) | D (mm) | B (mm) | t (mm) | Flange slope (°) | Ix (cm⁴) | Iy (cm⁴) | rx (cm) | ry (cm) | Zx (cm³) | Zy (cm³) | |-|-|-|-|-|-|-|-|-|-|-|-| | SC 100 | 20.0 | 25.5 | 100 | 100 | 0.9 | 98 | 436 | 136 | 4.13 | 2.31 | 87.2 | 27.2 | | SC 150* | 37.1 | 47.4 | 152 | 152 | 7.9 | 98 | 1970 | 700 | 6.45 | 3.84 | 259

IS 808: Key Data for Columns and Heavy Weight Beams (Clauses 5.1.2 & 3.1)

1. Indian Standard Column Sections (ISSC)

• Designations: SC 100 to SC 250
• Dimensions: Square sections (e.g., 100x100 mm to 250x250 mm)
• Flange slope ~ 98°
• Web thickness (T): 0.9 mm to 10 mm approx.
• Typical sectional properties include:
  • Area (A): 25.5 cm² to 109 cm²
  • Moment of inertia (I): 436 cm⁴ to 12,500 cm⁴
  • Radius of gyration (rₓ): 4.13 cm to 10.7 cm
  • Section modulus (Z): 27.2 cm³ to 260 cm³

2. Indian Standard Heavy Weight Beams (ISHB)

• Designations: HB 150 to HB 450
• Dimensions: Flanged beams with depths 150 mm to 450 mm, flange width 150-250 mm
• Flange slope: 94°
• Web thickness: 0.6 mm to 13.7 mm
• Sectional properties:
  • Area (A): 34.5 cm² to 118 cm²
  • Moment of inertia (I): 1,460 cm⁴ to 40,300 cm⁴
  • Radius of gyration (rₓ): 6.29 cm to 18.5 cm
  • Section modulus (Z): 57.6 cm³ to 242 cm³

Important Notes:

• Heavier sections (*) are made by spreading rolls; flange width increases.
• HB sections can also be used as columns.
• Mass should be specified when ordering heavier sections.

Typical Section Properties Table Extract (Example):

IS 808: Key Formulas, Tables & Specs for Beam Sections

1. Sectional Properties (Clause 2.1, Table 2.1: Medium Flange Beams)

2. Sectional Properties (Clause 3.1, Table 3.1: Column/Heavy Weight Beams)

IS 808: Equal Leg Angle Sections - Key Specifications & Formulas

Designation & Dimensions (Clause 6.2):

• Equal leg angles are designated as L A×A × t (e.g., L 100×100×7).
• A = leg length, t = thickness (mm).

Key Sectional Properties (from Tables 5.1 & 5.2):

Typical Formula for Section Modulus (Z):

[ Z_x = \frac{I_x}{y_{max}}, \quad Z_y = \frac{I_y}{x_{max}} ]

Where:

• (I_x, I_y) = moments of inertia
• (y_{max}, x_{max}) = max distance to extreme fiber from centroid

Example (from Table 5.1):

Unequal Leg Angles - IS 808 Key Points

Designation Format (Clause 6.2):

• Unequal leg angles are designated as:
  L A B × t
  where A = longer leg (mm), B = shorter leg (mm), t = thickness (mm)
  Example: L 200 100 × 10

Key Parameters from Table 6.1 (Unequal Leg Angles)

Typical Formulas

• Area:
  [ A = t \times (A + B - t) ]

• Moment of Inertia (approximate):
  [ I_x = \frac{t B^3}{12} + A t \left(\frac{B}{2}\right)^2, \quad I_y = \frac{t A^3}{12} + B t \left(\frac{A}{2}\right)^2 ]

• Section Modulus:
  [ Z = \frac{I}{y_{\max}} ]

Summary

• Use Table 6.1 for precise sectional properties of unequal leg angles.
• Designation includes leg lengths and thickness.
• Properties include mass, area, centroid location, moments of inertia, radii of gyration, and section moduli.
• Unequal leg angles have asymmetrical properties; centroid and moments differ along each axis.

graph TD
    A[Unequal Leg Angle L A B × t] --> B[

IS 808 Channel Sections Summary

Key Tables (Clause 4.1 & 4.2)

• Table 4.1: Dimensions, Mass & Sectional Properties of Sloping Flange Channels (Medium, Junior, Light Weight).
• Table 4.2: Dimensions, Mass & Sectional Properties of Parallel Flange Channels.

Important Parameters:

Typical Formulae:

• Moment of inertia (I): Provided in tables for both axes.
• Section modulus (Z): ( Z = \frac{I}{y_{max}} ) (from centroid to extreme fiber).
• Radius of gyration: ( r = \sqrt{\frac{I}{A}} ).

Tolerances:

• As per Clause 7.2, dimensional and mass tolerances follow IS 1852:1985.

Usage Tips:

• Choose section based on required moment capacity (Z), weight, and dimensions.
• Heavier sections (marked *) are for wagon industry, made by roll adjustments.
• Verify flange slope (usually 9°6' or 91.5°) as it affects section properties.

flowchart LR
    A[Select Channel Type] --> B{Sloping or Parallel Flange}
    B -->|Sloping| C[Refer Table 4.1]
    B -->|Parallel| D[Refer Table 4.2]
    C --> E[Check Dimensions & Properties]
    D --> E
    E --> F[Calculate Section Modulus & Moment of Inertia]
    F --> G[Design Structural Element]

For detailed design, always

IS 808: Symbols and Definitions Summary

1. Symbols for Sectional Properties (Clause 4.2.2)

2. Symbols for Dimensions (Clause 4.1.1)

3. Abbreviated Reference Symbols for IS Sections (Clause 5.2, Table 5.1.4)

Key Formulas

• Section modulus:
  [ Z_x = \frac{I_x}{e_x}, \quad Z_y = \frac{I_y}{e_y} ]

• **Radius of gyr

IS 808 Key Data: Nominal Dimensions & Mass

1. Nominal Dimensions & Mass (Clause 7.1)

• Beam, column, channel, equal & unequal angles conform to Sections 2, 3, 4, 5, 6 respectively.

2. Junior & Light Weight Beams (Clause 2.2)

• Refer Table 2.2 for nominal dimensions, mass (kg/m), sectional area (cm²), and sectional properties.

3. Medium Flange Beams (Clause 2.1, Table 2.1)

4. Equal Leg Angles (Clause 5.2, Table 5.2)

IS 808: Sectional Properties Key Formulas & Tables

1. Symbols for Sectional Properties (Clause 4.2.2)

2. Key Formulas

• Radius of gyration:

[ r_x = \sqrt{\frac{I_x}{a}}, \quad r_y = \sqrt{\frac{I_y}{a}} ]

• Section modulus:

[ Z_x = \frac{I_x}{e_x}, \quad Z_y = \frac{I_y}{e_y} ]

• Moment of inertia about principal axes:

[ I_u = \frac{I_x + I_y}{2} + \frac{I_x - I_y}{2} \cos 2\alpha + I_{xy} \sin 2\alpha ]

[ I_v = \frac{I_x + I_y}{2} - \frac{I_x - I_y}{2} \cos 2\alpha - I_{xy} \sin 2\alpha ]

3. Tables of Sectional Properties (Selected)

IS 808: Ordering and Availability Key Points

1. Section Types & Designations

• Columns & Heavy Weight Beams: Designations like SC 100, SC 120, HB 150, HB 200, etc.
• Parallel Flange Channels: MCP 75, MCP 100, MCP 125, etc.
• Equal Leg Angles: e.g., 2 50×50×7, 2 60×60×10.

2. Key Tables for Ordering

3. Ordering Notes

• Heavier sections (* marked) are produced by roll spreading; specify mass when ordering.
• Flange slope and radii (R1, R2) are standardized.
• For railway electrification, SC 150* (BFB Section) is common.

4. Typical Section Properties Format

Example: SC 150 Column Section (from Table 3.1)

Steel Economy & Usage Notes from IS 808

1. Steel Economy Program:

• Rationalized standard sections for beams, channels, and angles.
• Series includes junior, light, medium, wide flange, and heavy weight beams.
• Revised in 1964 for efficiency and economy.

2. Sectional Properties:

• Tables provide mass (kg/m), area (cm²), and key dimensions (mm).
• Includes moments of inertia (Ix, Iy), radius of gyration (rx, ry), and section modulus (Zx, Zy).
• Flange slope angle and corner radii specified for fabrication accuracy.

3. Important Formulas:

• Section Modulus:
  [ Z = \frac{I}{y_{\max}} ] where (I) = moment of inertia, (y_{\max}) = distance to extreme fiber.

• Radius of Gyration:
  [ r = \sqrt{\frac{I}{A}} ] where (A) = cross-sectional area.

4. Usage Tips:

• Heavier sections (marked *) are made by roll spreading; specify mass while ordering.
• HB sections can be used as columns.
• BFB sections (e.g., SC 150*) are specialized for railway electrification.

Key Tables Summary (Excerpt)