What other variables might affect the strength of a bridge?

Several variables can affect the strength of a bridge, including the materials used in its construction, such as steel, concrete, or composite materials, which have different structural properties. The design and geometry of the bridge, including its span length, load distribution, and support structures, also play a significant role. Environmental factors like temperature fluctuations, wind loads, and seismic activity can impact the bridge's integrity over time. Additionally, the quality of construction and maintenance practices can significantly influence the bridge's overall strength and durability.