How do pre-stressing tendons function in concrete structures?

Pre-stressing tendons function by producing compressive stress in concrete structures to effectively balance tensile stresses that occur when the structure is subjected to loads. This method is fundamental in pre-stressed concrete design, as concrete is strong in compression but weak in tension. By introducing tensile force through tendons that are intentionally stretched (pre-stressing), the resulting compressive stresses effectively counteract the tensile forces introduced by various loads, such as weight and environmental factors.

This action helps to enhance the strength and durability of the concrete element by reducing the likelihood of cracking and structural failure due to tensile forces. As the pre-stressing tendons are released after being tensioned, the concrete element experiences an equivalent compressive force, enhancing its load-bearing capacity and extending its service life. This design principle is pivotal in various applications, such as beams, bridges, and slabs, where improved performance under load is essential.