What is the primary purpose of thermal expansion joints in structures?

The primary purpose of thermal expansion joints in structures is to accommodate movement caused by temperature changes to prevent cracking. As materials heat up, they expand, and when they cool down, they contract. This cycle of expansion and contraction can lead to significant stress on the materials, especially in structures like bridges or buildings where large spans of material are involved.

Thermal expansion joints are specifically designed to absorb this movement, allowing sections of a structure to move independently without causing damage. By providing a designated space for this movement, these joints help maintain the integrity of the structure, thereby minimizing the risk of cracking, bending, or distortion that could occur if the materials were rigidly fixed together. This function is particularly critical in environments where temperature fluctuations are significant, ensuring long-term durability and safety of the structural elements.