What is the primary function of moveable bearings in bridge design?

The primary function of moveable bearings in bridge design is to allow for movement. This movement accommodates thermal expansion and contraction, as well as other dynamic forces that occur due to traffic loads, wind, and seismic activity. By enabling parts of the bridge to shift relative to each other, moveable bearings help to prevent stress concentrations that could lead to structural damage. This is vital for maintaining the overall integrity and longevity of the bridge.

In contrast, options like vertical stability, fixed support, and aesthetic appeal are not the main roles of moveable bearings. While vertical stability is important for the overall design of a bridge, it is primarily managed by other structural elements. Fixed supports are designed to resist movement, which is contrary to the function of moveable bearings. Aesthetic appeal might be a consideration in bridge design but does not relate to the primary mechanical function of moveable bearings.