Steel Frame Construction refers to a structural system where the primary columns and beams are made of steel This creates a strong, stable framework composed of a regular grid of steel beams and columns forming the building’s main structure. Due to its high stability, relatively light weight, and superior resistance, steel frame construction is widely utilized across various building types including industrial buildings, warehouses, halls, garages, and multi-story residential and office buildings.
In earthquake-prone regions such as Kerman, Tehran, Qom, and Mashhad, the flexibility and durability of steel frame structures provide exceptional resistance against lateral forces and seismic activity. Steel’s ability to absorb energy from impacts and vibrations enhances structural stability while its lighter weight compared to concrete reduces foundation loads. Therefore, steel frame buildings are an excellent choice for renovation and reconstruction projects in Kerman and Sirjan.
Types of Steel Frame Construction
There are two primary methods for steel frame construction:
1. Bolted Steel Frame Construction
In this method, beams and columns are prefabricated in factories and transported to the construction site. They are then assembled using bolts and nuts. This approach is faster because it eliminates on-site cutting and welding, and factory-controlled conditions ensure higher quality.
2. Welded Steel Frame Construction
Steel components are cut and welded on-site. This method requires skilled welders and rigorous quality control, including non-destructive testing. Welded frames allow more complex designs but are harder to disassemble compared to bolted frames.
| Criterion |
Bolted Method |
Welded Method |
| Execution Speed |
High (due to prefabrication) |
Moderate (on-site cutting/welding) |
| Quality Control |
High (factory-controlled) |
Moderate (site-dependent) |
| Execution Cost |
Higher (production and transport) |
Lower (reduced transport costs) |
Important Considerations for Bolted Steel Frames
- Quality of Parts: High dimensional accuracy and consistent quality are essential. Dimensional standards must be verified before shipping.
- Connection Organization: Precise bolt hole placement and proper alignment of columns using leveling tools are critical.
- Pre-Assembly: If feasible, partial assembly in workshops helps identify errors early.
- Safety: Proper use of cranes and safety protocols during installation prevent accidents and damage.
Key Aspects of Welded Steel Frame Construction
- Selection of welding wire and electrodes matching steel grade (e.g., ST37, ST52) is vital.
- Pre-heating and post-heating reduce residual stresses in thick or cold steel components.
- Welds must be inspected visually and with ultrasonic or X-ray methods to ensure quality.
- Skilled welders trained in structural welding and equipped with safety gear are required.
Steel Materials in Steel Frame Construction
Common materials include:
- Structural steel sections: I-beams (IPE, HEB), angles, channels, Z-profiles, plates, and box profiles (rectangular or square hollow sections).
- Reinforcing bars for concrete foundations and steel-concrete connections.
- Steel grades: Typically ST37 (yield strength ~230–240 MPa) and ST52 (~345–355 MPa).
- Steel elasticity modulus ~205,000 MPa; Poisson’s ratio ~0.3.
Steel Frame Construction Using Box Sections
Box profiles are frequently used in residential and villa projects due to their lightweight and aesthetic appeal. Their hollow shape reduces weight and eases installation. However, they have lower compression and torsion resistance than flanged beams, requiring appropriate sizing and thickness. Galvanized or painted finishes protect against corrosion.
Factors Affecting Steel Frame Construction Costs
Steel frame costs depend on:
- Building area and number of floors (steel quantity required).
- Steel section types and thickness.
- Current steel market prices, influenced by currency exchange and global trends.
- Labor and welding expenses.
- Transport and project complexity.
Generally, bolted steel frames cost more upfront due to prefabrication but save time. Currency fluctuations especially impact imported steel and equipment prices. Overall, steel frames can cost approximately 60–70% more than concrete frames.
Price Estimation for Steel Frame Construction
Estimate costs by:
- Calculating steel weight per square meter (typically 40 to 70 kg including beams and rebar).
- Multiplying weight by current steel price per kilogram.
- Adding labor, transport, bolts, plates, concrete, and installation expenses.
- Summing the detailed quantities and unit prices from project plans for accuracy.
Steps in Steel Frame Building Construction
- Foundation Construction: Excavation and concrete foundations, embedding base plates and anchor bolts, with verification post-curing (14–28 days).
- Steel Column Installation: Setting prefabricated columns, tightening anchor bolts, and aligning with plumb lines. Temporary braces provide stability.
- Beam and Horizontal Member Installation: Using cranes for placing beams; bolted frames are fastened with bolts, welded frames are aligned and welded.
- Roof Selection: Options include composite concrete slabs, joist-block, sandwich panels, or steel joist with lightweight concrete, based on load and cost.
- Brace Installation: Diagonal braces resist lateral forces (wind, earthquake), preventing displacement and buckling.
- Finishing Work: Interior/exterior walls, insulation, electrical and mechanical installations, plastering, and painting. Walls are typically non-load-bearing partitions.
Important Notes for Steel Frame Construction
- Maintain quality control and engineering supervision at every phase.
- Use temporary bracing to avoid instability during construction.
- Proper scheduling between foundation curing and steel erection.
- Optimize steel usage to reduce material and transport costs.
Advantages of Steel Frame Construction
- High strength and durability for long spans and heavy loads.
- Lightweight reduces foundation size and costs.
- Superior impact and seismic energy absorption compared to concrete.
- Consistent factory-produced quality.
- Fast construction through prefabrication.
- Easy to strengthen or modify.
- Design flexibility for complex architectural forms.
Challenges and Solutions in Steel Frame Construction
- Higher initial cost versus concrete frames, mitigated by efficient design.
- Fire sensitivity requires protective coatings.
- Susceptibility to corrosion necessitates galvanizing and maintenance.
- Risk of local buckling under compression, addressed by proper design.
- High thermal and acoustic conductivity demands effective insulation.
