Pre-tensioning is a technique used in construction and engineering to enhance the strength of concrete structures. It involves placing steel tendons or cables under tension before the concrete is poured. This tensioning helps the concrete resist tensile forces, making it more durable and capable of handling heavy loads. Once the concrete hardens, the tension is released, allowing the tendons to compress the concrete. This process is commonly used in prestressed concrete applications, such as bridges and high-rise buildings, where structural integrity and longevity are crucial. Pre-tensioning ultimately leads to safer and more efficient designs.