Physics – 2.2.1 Thermal expansion of solids, liquids and gases | e-Consult

One significant consequence of thermal expansion is the development of stress within materials when their temperature changes. If a material is constrained from expanding or contracting (e.g., by being fixed at both ends), the expansion or contraction creates internal forces. If these forces exceed the material's strength, it can lead to deformation, cracking, or even failure. This is particularly problematic in large structures like bridges, pipelines, and railway tracks.

Engineers mitigate this problem by incorporating expansion joints or expansion loops into the design. These features allow the material to expand or contract without causing excessive stress. Expansion joints are gaps built into structures, while expansion loops are curved sections of piping or rails that allow for movement.

Example: Railway Tracks. As mentioned earlier, railway tracks have expansion gaps between sections of rail. These gaps allow the rails to expand in hot weather without buckling. Without these gaps, the immense pressure from expansion could cause the rails to bend and potentially derail a train. The gaps are carefully calculated based on the expected temperature range and the material properties of the rails.