Advantages & Disadvantages of Steel Construction

Advantages of Steel Construction

1. Industrial Efficiency

Steel sections are produced in factories where they are often cut and prepped for assembly. The joining of these components is executed on-site using rivets, bolts, or welding. Sometimes, parts of the structure are pre-assembled in factories, promoting prefabrication. This approach minimizes manual errors, boosts construction speed, and reduces total costs.

2. Speedy Construction

The industrial nature of steel construction allows for quick progress, making the structures cost-effective. The ability to use these structures earlier reduces labor costs and overheads while enabling the benefits of early use of the buildings.

3. High Strength and Light Weight

Steel's high strength-to-weight ratio means smaller dead loads. Since dead loads constitute a substantial part of total loads on a structure, their reduction leads to smaller supporting members. This aspect is crucial for long-span bridges, tall buildings, and structures with weak foundations.

4. Uniformity and Durability

Steel is a homogeneous and uniform material, aligning well with the basic assumptions of most design and analysis formulas. With proper maintenance like painting, steel's properties remain stable over time, unlike concrete in reinforced concrete structures, making steel structures more durable.

5. Elasticity

Steel follows Hooke's Law up to relatively high stresses, meaning stress and strain remain proportional. This property ensures that steel sections do not crack before reaching ultimate load, making the calculation of moments of inertia straightforward, unlike in reinforced concrete structures.

6. Ductility and Failure Warning

Steel's ductility allows it to withstand significant deformation under high tensile stress without failing. Mild steel can exhibit elongation of 25-30% post-fracture, providing visible warnings of impending failure under overloads. This characteristic allows for removing extra loads to prevent collapse or provides time for evacuation.

Under normal loads, high-stress concentrations at various points are mitigated by steel’s ductile nature, preventing premature failures by redistributing stress.

7. Ease of Expansion

Adding to existing steel structures is straightforward. New connections can efficiently integrate new bays or entire wings with existing buildings, and steel bridges often accommodate widening effortlessly.

8. Reusability

After disassembly, steel sections can be reused, promoting sustainability.

9. Residual Value

Even if not reusable in its current form, steel retains a scrap value, adding an economic benefit.

10. Water and Air-Tight Construction

Steel structures are impervious, making them ideal for reservoirs, oil pipes, gas pipes, and more.

11. Long-Span Structures

Steel is used in high-rise buildings, long-span bridges, and tall transmission towers. Industrial buildings with spans up to 90 meters can be designed using plate girders or trusses, with bridge spans reaching up to 300 meters.

12. Temporary Structures

Steel is preferred for temporary constructions, such as army structures during wars, due to its ease of assembly and disassembly.

Disadvantages of Steel Construction

1. High Maintenance and Corrosion

Steel is prone to corrosion when exposed to air and water, necessitating periodic painting, which adds extra cost and requires special care. Weathering steels can mitigate this issue, but poor maintenance leads to significant loss of material thickness, compromising structural integrity over time.

2. Fireproofing Costs

Although incombustible, steel loses strength at high temperatures. Around 400°C, creep (plastic deformation under constant load over time) causes large deflections and potential collapse. Steel’s excellent heat conductivity can also spread fire, necessitating extra fireproofing expenses.

3. Buckling Risks

Steel sections, often thin and slender, are susceptible to buckling under compression. This risk necessitates additional material for stiffening, making columns less economical compared to reinforced concrete.

4. High Initial Costs and Availability

In some countries, steel is costly and less readily available compared to other materials, discouraging its use in construction.

5. Aesthetic Concerns

While steel can be aesthetically pleasing in specific architectural designs, many residential and office buildings require additional cladding to enhance their appearance, increasing costs.