BUILT-UP SECTIONS are structural elements made by joining steel plates together to form a single structural unit. These sections are commonly used in construction due to their strength and versatility. The steel plates used in built-up sections conform to ASTM A 572M Grade 345 type (or equivalent), ensuring they meet specific quality and strength standards. This grade of steel has a minimum yield strength of 34.5 kN/cm2 (50 ksi), indicating its ability to withstand significant loads without permanent deformation.

The construction of built-up sections involves welding flanges to a web. Flanges are the horizontal elements of the section, while the web is the vertical element that connects the flanges. The welding process used is a continuous single side fillet weld, which is a type of weld where the filler material is deposited in a triangular shape along the junction of the flange and web. This welding process is typically performed using an automatic submerged arc welding process, which provides a high-quality, uniform weld along the entire length of the joint. This ensures the structural integrity of the built-up section, making it suitable for use in various applications requiring strength and durability.