Built Up Beams

Built-Up Beams are made of structural metal units such as plates and angles which are riveted, bolted, or welded together. Built-up beams are versatile structural elements widely used in construction. Combining two or more construction materials results in enhanced strength and durability. Built-up beams, also recognized as framed structures, consist of individual angle irons, channels, I-beams, and similar basic metal sections. These components are interconnected into a unified entity through batten plates or lattices. Primarily employed as structural elements under compression, built-up beams serve as columns or chord members in trusses. Their application becomes crucial in situations where the risk of buckling requires an augmentation in the cross-sectional radius of gyration of a specific member, implying a reduction in the member’s flexibility. In such instances, the cross-sectional constituents of a built-up beam can be adequately spaced to prevent buckling, subsequently linking them through single or double-diagonal crossbars or batten plates to ensure structural integrity.

The primary purpose of creating built-up beams is to increase the load-carrying capacity and stiffness of the beam while utilizing the beneficial properties of different materials. This approach allows engineers to take advantage of the strengths of each material while minimizing their weaknesses.

For example, in steel-concrete composite beams, a steel beam (usually an I-section or an H-section) is connected to a concrete slab. The steel beam provides high tensile strength and stiffness, while the concrete slab contributes to compressive strength and can help distribute loads more evenly. This combination results in a beam that can handle higher loads and spans than a single material beam of similar dimensions. 

Built-up beams can also be created using different types of wood beams or by combining various types of materials, depending on the specific requirements of the project and the available materials.