What material is primarily used for structural support in modern large buildings?

Steel is primarily used for structural support in modern large buildings due to its high strength-to-weight ratio, durability, and versatility. This material allows for taller and more expansive structures than could be achieved with traditional materials like wood and brick. Steel can handle significant loads and is capable of spanning large distances without the need for numerous supporting columns, which contributes to open floor plans and creative architectural designs.

Additionally, steel is resistant to various elements such as fire and pests, enhancing the overall safety and longevity of a building. Its ability to be prefabricated also expedites the construction process, making it the preferred choice for architects and engineers when designing high-rise buildings and other large structures. Concrete is often used in conjunction with steel, particularly in foundations and for structural elements, but steel remains the primary material for framework and support in these types of construction.