The transformation of raw structural steel into a high-performance open web joist is a marvel of modern industrial engineering. At COMSA Steel, our manufacturing process is not merely an assembly line; it is a synchronized system of metallurgy, structural design, and rigorous quality control. Understanding how a joist is made provides architects and contractors with the confidence that their structural “bones” are built to last.
The process begins with the procurement of high-strength steel, typically in the form of hot-rolled angles for the chords and either round bars or cold-formed angles for the web members. Before a single cut is made, the raw material undergoes chemical and physical testing. At COMSA Steel, we verify that the yield strength meets or exceeds ASTM standards (typically $50$ ksi or $345$ MPa), ensuring the material can handle the tension and compression forces it will encounter in the field.
Once the engineering specifications are finalized through BIM (Building Information Modeling) software, the data is sent to the fabrication floor. Automated saws and CNC (Computer Numerical Control) machinery cut the top and bottom chords to the exact required length, accounting for the “camber”—the slight upward curve engineered into the joist to compensate for future dead loads.
Simultaneously, the web members are bent or cut. In many joist designs, a continuous “zig-zag” round bar is used for the web, requiring specialized hydraulic bending equipment to maintain the precise geometry of the load-transfer triangles.
The heart of the manufacturing plant is the assembly jig. Here, the top and bottom chords are placed into a heavy-duty frame that holds them at the correct depth. The web members are then fitted between the chords.
Welding is the most critical phase of manufacturing. At COMSA Steel, our welders are certified to AWS (American Welding Society) standards. Every “panel point”—the junction where the web meets the chord—must be fused perfectly. These welds are responsible for transferring the shear forces across the joist; even a minor defect could compromise the structural integrity of the entire span.
After the structural assembly is complete, the joist undergoes a cleaning process to remove scale and oils. It then moves to the coating line. Most joists receive a standard “shop primer,” a dip-applied coating designed to protect the steel from atmospheric corrosion during transit and the construction phase. For projects in high-moisture or coastal environments, specialized coatings like high-performance epoxies or hot-dip galvanization are applied to ensure a multi-decade service life.
Before a joist leaves the COMSA Steel facility, it undergoes a final inspection. This includes:
By utilizing a controlled factory environment, COMSA Steel eliminates the variables and hazards of field-fabricated steel. The result is a product that is lighter than a solid beam but engineered with a level of precision that only a dedicated manufacturing facility can provide.
