Primary Member
The Powerhouse of Your Building: Unmatched PEB Frames & Trusses
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Introduction
The Powerhouse of Your Building: Unmatched PEB Frames & Trusses
Every Pre-Engineered Building (PEB) stands on the strength of its Primary Members. These are the structural backbone — the columns, rafters, and trusses that carry the entire load of the roof, walls, cranes, and external forces like wind and seismic activity.
At Arise PEB Construction, we manufacture PEB Primary Members in Odisha using high-grade structural steel and advanced fabrication technology. From built-up sections (I, H, and tubular) to readymade sections (ISMB, ISMC, ISA, NPB, WPB, channels, and angles), our primary members are engineered for precision, durability, and unmatched performance.
Whether you’re building a warehouse, factory, multi-storied steel building, or an EC poultry shed — the strength of your structure begins with the quality of its primary members. And that’s where we deliver.
What is a Primary Member?
Understanding Primary Members in PEB Structures
A Primary Member in a Pre-Engineered Building is the main load-bearing structural component that forms the framework of the building.
These members are designed to support:
Dead Loads: Weight of the structure itself (roof, walls, purlins)
Live Loads: Weight of people, equipment, and maintenance activities
Wind Loads: Forces exerted by wind on the building envelope
Seismic Loads: Forces generated during earthquakes
Crane Loads: Weight of EOT cranes and moving loads (if applicable)
Primary Members include:
Columns: Vertical members that transfer loads to the foundation
Rafters: Inclined members that support the roof
Trusses: Framed structures that span large distances
Beams: Horizontal members that support floors or roofs
Bracings: Members that provide lateral stability
At Arise PEB Construction, we design and fabricate primary members using both built-up sections (custom-fabricated for specific load and span requirements) and readymade sections (standard rolled steel sections available off-the-shelf).
Types of Primary Members We Offer
Built-Up Sections & Readymade Sections for Every PEB Application
We offer two broad categories of primary members:
Built-Up Sections – Custom-fabricated for specific load and span requirements
Readymade Sections – Standard rolled steel sections available off-the-shelf
PART A: Built-Up Sections
Built-up sections are custom-fabricated by welding together steel plates to create the desired cross-section. They are designed to meet specific load, span, and structural requirements.
A1. H Section (H-Beam)
An H Section (also called an H-beam) is similar to an I-section but with wider flanges and a thicker web. The flanges are parallel, giving it the shape of the letter “H”.
Key Features :
- Higher load-bearing capacity
- Better resistance to bending and buckling
- Wider flanges for easier bolting
- Ideal for heavy structures
Applications :
- Heavy-duty columns and rafters
- Multi-storied steel buildings
- Industrial sheds with EOT cranes
- Large-span warehouses
Specifications :
Depth : 200mm to 1500mm
Flange Width : 150mm to 500mm
Web Thickness : 8mm to 20mm
Flange Thickness : 10mm to 30mm
Material Grade : IS 2062 / ASTM A36 / A572
A2. I Section (I-Beam)
An I Section (also called an I-beam) is a steel section with a cross-section shaped like the letter “I”. It consists of two horizontal flanges connected by a vertical web.
Key Features :
- High bending resistance
- Efficient material distribution
- Cost-effective for standard spans
- Easy to fabricate and connect
Applications :
- Columns and rafters in standard PEB structures
- Floor beams in mezzanine floors
- Crane runway beams
- Bridge girders
Specifications :
Depth : 200mm to 1200mm
Flange Width : 100mm to 400mm
Web Thickness : 6mm to 16mm
- Flange Thickness : 8mm to 25mm
Material Grade : IS 2062 / ASTM A36 / A572
A3. Tubular (Hollow) Sections
Tubular Sections are hollow steel sections with either a circular (CHS) , square (SHS) , or rectangular (RHS) cross-section.
Key Features :
Excellent torsional resistance
Superior aesthetic appeal
High strength-to-weight ratio
Reduced wind resistance
Applications :
Architectural structures
Long-span trusses
Space frames
Towers and masts
Stadiums and exhibition centers
Specifications :
Outer Diameter (CHS) : 50mm to 600mm
Wall Thickness : 3mm to 25mm
Square/Rectangular Size : 50x50mm to 400x400mm
- Material Grade : IS 4923 / ASTM A500
PART B : Readymade Sections
Readymade sections are standard rolled steel sections that are readily available and used directly in PEB construction. They are ideal for secondary members, bracings, and lighter structural applications.
B1. ISMB (Indian Standard Medium Beam)
ISMB is a standard I-beam section used in structural steel construction.
Key Features :
Standard rolled section
Readily available
Cost-effective
Easy to fabricate and connect
Applications :
Secondary beams
Floor beams
Bracings
Lintels
Specifications :
Depth : 100mm to 600mm
Flange Width : 50mm to 210mm
Weight : 8.9 kg/m to 123 kg/m
Material Grade : IS 2062
B2. ISMC (Indian Standard Medium Channel)
ISMC is a standard channel section with a C-shaped cross-section.
Key Features :
Standard rolled section
Good bending resistance
Easy to bolt and weld
Readily available
Applications :
Purlins and girts
Bracings
Side runners
Edge beams
Specifications :
Depth : 75mm to 400mm
Flange Width : 40mm to 100mm
Weight : 6.8 kg/m to 49.4 kg/m
Material Grade : IS 2062
B3. ISA (Indian Standard Angle)
ISA is a standard angle section with an L-shaped cross-section.
Key Features :
Standard rolled section
High torsional resistance
Easy to bolt and weld
Versatile applications
Applications :
Bracings
Truss members
Connection plates
Support brackets
Specifications :
Size : 25x25mm to 200x200mm
Thickness : 3mm to 25mm
Weight : 1.1 kg/m to 74.7 kg/m
Material Grade : IS 2062
B4. NPB (Narrow Parallel Flange Beam)
NPB is a standard Narrow Parallel Flange Beam conforming to Indian Standard IS 12778:2004. It is a modern structural steel I-section with parallel flanges (unlike older ISMB sections where flanges are slightly tapered)
Key Features :
Parallel flanges for easy connection and bolting
Narrower flange width optimized for use as beams
Higher load-bearing capacity compared to ISMB
Manufactured in India by SAIL and other producers
Available in depths up to 750mm (SAIL NPB-750)
Applications :
Primary beams in PEB structures
Floor beams and mezzanine floors
Industrial platforms and equipment support structures
Crane runway beams
Multi-storied steel buildings
Specifications :
Depth : 100mm to 750mm
Flange Width : 55mm to 270mm
Weight : 8.9 kg/m to 202 kg/m
Material Grade : IS 2062 (E250, E300, E350, E410)
Standard : IS 12778:2004
B5. WPB (Wide Parallel Flange Beam)
WPB is a wide parallel flange beam section under Indian Standards as specified in IS 12778 (2004) for hot-rolled parallel flange steel sections.
Key Features :
Wider flanges than NPB
Higher load-bearing capacity
Excellent bending resistance
Ideal for heavy structures
Applications :
Heavy-duty columns
Rafters
Crane runway beams
Multi-storied buildings
Specifications :
Depth : 100mm to 1200mm
Flange Width : 100mm to 500mm
Weight : 13.4 kg/m to 443 kg/m
Material Grade : S235 / S275 / S355
B6. Channels
Channels are C-shaped or U-shaped steel sections used in various structural applications.
Key Features :
Standard rolled section
Good bending resistance
Easy to bolt and weld
Versatile applications
Applications :
Purlins and girts
Bracings
Side runners
Edge beams
Specifications :
Depth : 75mm to 400mm
Flange Width : 40mm to 100mm
Weight : 6.8 kg/m to 49.4 kg/m
Material Grade : IS 2062
B7. Angles
Angles are L-shaped steel sections used in various structural applications.
Key Features :
Standard rolled section
High torsional resistance
Easy to bolt and weld
Versatile applications
Applications :
Bracings
Truss members
Connection plates
Support brackets
Specifications :
Size : 25x25mm to 200x200mm
Thickness : 3mm to 25mm
Weight : 1.1 kg/m to 74.7 kg/m
Material Grade : IS 2062
Comparison: Built-Up Sections Vs. Readymade Sections
| Parameter | Built-Up Sections | Readymade Sections |
|---|---|---|
|
Customization |
Fully customizable |
Standard sizes only |
|
Load Capacity |
Optimized for specific loads |
Standard load capacities |
|
Cost |
Higher for complex shapes |
Cost-effective |
|
Availability |
Fabricated on order |
Readily available |
|
Lead Time |
4–6 weeks |
Immediate |
|
Applications |
Primary members (columns, rafters) |
Secondary members (purlins, bracings) |
|
Material Efficiency |
Optimized |
Standard |
Why Choose Pre-Engineered Buildings Over Traditional Civil Construction?
PEB vs. Traditional Civil Construction – Why PEB Wins
| Parameter | Pre-Engineered Buildings (PEB) | Traditional Civil Construction | |
|---|---|---|---|
|
Construction Time |
30–50% faster |
Slower due to on-site work and curing |
|
|
Cost |
20–30% more cost-effective |
Higher material and labor costs |
|
|
Quality Control |
Factory-controlled fabrication |
On-site work, variable quality |
|
|
Design Flexibility |
High – easily customizable |
Limited – changes are difficult |
|
|
Span Capability |
Clear spans up to 60m |
Limited spans, requires columns |
|
|
Seismic Resistance |
High – steel is ductile |
Moderate – concrete is rigid |
|
|
Expandability |
Easy to expand |
Difficult and expensive |
|
|
Waste Generation |
Minimal – precision fabrication |
High – material wastage on-site |
|
|
Sustainability |
Steel is recyclable |
Concrete is not recyclable
|
|
|
Maintenance Low |
Low |
Moderate to high |
|
Conclusion: Pre-Engineered Buildings offer superior speed, cost-efficiency, quality, and flexibility compared to traditional civil construction — making them the preferred choice for modern industrial and commercial projects in Odisha.
Pros and Cons Of Different Types Of Primary Members
I Section vs. H Section vs. Tubular Section vs. Readymade Sections – Pros & Cons
| Section Type | Pros | Cons |
|---|---|---|
|
H Section |
– Higher load-bearing capacity – Better resistance to bending and buckling – Wider flanges for easier bolting – Ideal for heavy structures |
– Higher material cost – Heavier than I sections – Requires more space for storage and transport |
|
I Section |
– High bending resistancet – Efficient material distributiont – Cost-effective for standard spanst – Easy to fabricate and connectt |
– Lower torsional resistancet – Not ideal for very heavy loadst – Limited aesthetic appeal |
|
Tubular Section |
– Excellent torsional resistancet – Superior aesthetic appealt – High strength-to-weight ratiot – Reduced wind resistance |
– Higher fabrication costt – Difficult to connectt – Requires specialized weldingt – Not easily repairable on-sitet |
|
ISMB / ISMC / ISA |
– Readily availablet – Cost-effectivet – Easy to fabricate and connectt – Standard sizes |
– Limited load capacityt – Standard sizes onlyt – Not optimized for specific loads |
|
NPB / WPB |
– High load-bearing capacityt – Parallel flanges for easy boltingt – Excellent bending resistancet – Ideal for heavy structures |
– Higher cost than ISMB/ISMCt – Limited availabilityt – Requires import or special order |
|
Channels & Angles |
– Readily availablet – Versatile applicationst – Easy to bolt and weldt – Cost-effective |
– Lower load capacityt – Not ideal for primary memberst – Limited torsional resistance |
Which One Should You Choose?
| Application | Recommended Section |
|---|---|
|
Standard industrial shed |
I Section / ISMB |
|
Heavy-duty factory with EOT crane |
H Section / NPB / WPB |
|
Multi-storied steel building |
H Section / NPB / WPB |
|
Architectural structure |
Tubular Section |
|
Long-span truss |
Tubular Section |
|
Warehouse with clear span |
I or H Section |
|
Secondary members (purlins, bracings) |
ISMC / ISA / Channels / Angles |
At Arise PEB Construction, our engineers help you select the right section based on your load, span, and budget requirements.
Our Manufacturing Process For Primary Members
Precision Fabrication – From Raw Steel to Finished Primary Members
Design & Engineering : 3D modeling and structural analysis using STAAD Pro and Tekla Structures.
Plasma Cutting : Precision cutting of flange and web plates using advanced plasma cutting machines.
H Beam Tack Welding : Flanges and web are tack-welded to form an H configuration.
Submerged Arc Welding (SAW) : High-quality welding for superior strength and penetration.
Straightening & Alignment : Ensuring dimensional accuracy and straightness.
Hand Tool Cleaning/Sand Blasting : Surface preparation for better paint adhesion.
Primer & Paint Coating : Corrosion-resistant coating for long-lasting protection.
Quality Inspection : Dimensional checks, weld inspection, and load testing.
Dispatch : Safe transportation to your site in Odisha.
Applications Of Our Primary Members
Where Our Primary Members Are Used
Our PEB primary members are used across a wide range of structures:
- Industrial Sheds : Columns and rafters for factories and manufacturing units
Warehouses : Large-span frames for storage and logistics
Multi-Storied Steel Buildings : Heavy-duty columns and beams for multi-level structures
EC Poultry Farms : Insulated shed frames for climate-controlled poultry farming
Cold Storage : Structural frames for temperature-controlled facilities
Mezzanine Floors : Beams and columns for elevated floors
Crane Runway Beams : Heavy-duty sections for EOT crane support
Residential Steel Buildings : Frames for steel-frame homes and apartments
Ready to Build Your PEB Structure with Strong Primary Members?
The strength of your building depends on the quality of its primary members. Partner with Arise PEB Construction — Odisha’s trusted PEB manufacturer — for precision-engineered frames, trusses, and sections that stand the test of time.
