Economic Comparison Between Hot-Rolled H-Beams and Welded H-Beams in Bridge Engineering

In bridge engineering, the choice of structural steel directly impacts project costs, construction timelines, and long-term durability. Hot-rolled H-beams and welded H-beams are two common options for bridge load-bearing components, but their economic performance differs significantly—making a targeted comparison critical for engineers and project managers.​

Key Differences in Production & Performance for Bridge Use​

Hot-rolled H-beams are manufactured by heating steel billets and rolling them into the iconic “H” shape in one continuous process. This method creates a uniform, dense structure with consistent mechanical properties (e.g., tensile strength, bending resistance) ideal for bridge main girders and support frames. They require minimal post-production processing, as their standard sizes (e.g., HEA, HEB series) often match bridge design specifications.​
Welded H-beams, by contrast, are fabricated by cutting steel plates into flanges and webs, then welding these parts together. This customization allows for non-standard sizes—critical for bridges with unique span lengths or load requirements—but introduces potential variability in weld quality, which demands strict quality control to avoid structural weak points.​

Economic Contrast: Cost, Time, and Maintenance​

1. Initial Material & Processing Costs​
Hot-rolled H-beams typically have lower upfront costs for standard bridge designs. Mass production reduces per-unit pricing, and their ready-to-use form eliminates welding labor and equipment expenses. For small-to-medium span bridges (e.g., 20–50 meters) using standard H-beam sizes, hot-rolled options can cut material costs by 15–25% compared to welded alternatives.​
Welded H-beams are more costly for standard designs due to labor-intensive fabrication. However, their customization becomes economical for large-span or irregularly shaped bridges (e.g., curved overpasses). When a bridge requires non-standard flange widths or web thicknesses, welded H-beams avoid the need for expensive hot-rolling die modifications—offsetting higher fabrication costs in complex projects.​
2. Construction Timeline​
Hot-rolled H-beams speed up construction, as they arrive on-site pre-formed and ready for installation. This reduces on-site labor time by 30–40% compared to welded H-beams, which require on-site or off-site welding, inspection, and surface treatment. For time-sensitive bridge projects (e.g., replacing aging infrastructure), the faster turnaround of hot-rolled beams lowers indirect costs like site rental and labor overhead.​
Welded H-beams extend timelines due to fabrication and quality checks (e.g., ultrasonic weld testing). Delays may increase if weld defects require rework, adding unplanned costs to tight budgets.​
3. Long-Term Maintenance​
Hot-rolled H-beams’ uniform structure resists corrosion and fatigue better than welded H-beams, as weld joints are common points for rust accumulation and stress cracking. Over a bridge’s 50–100-year lifespan, hot-rolled beams may reduce maintenance costs (e.g., repainting, joint repairs) by 20–30%.​
Welded H-beams require more frequent inspections of welds, especially in high-stress areas (e.g., bridge piers). While anti-corrosion coatings can mitigate risks, they add to long-term maintenance expenses.​

Choosing the Right Beam for Bridge Engineering​

For standard, small-to-medium span bridges, hot-rolled H-beams offer the best balance of cost, speed, and low maintenance. For large-span, custom-designed bridges where standard sizes won’t suffice, welded H-beams become the economical choice despite higher upfront costs.​
Ultimately, the decision hinges on bridge design, span length, and budget priorities—with both options delivering reliable performance when selected to match project needs.