steel bridge - increase dimensions by 5

[yxgao]

If you increase the dimensions of a bridge by 5, how much is its strength increases? How much is its weight increased?
Any help is appreciated.
Thanks

[Doc Al]

Assume that the components of the bridge can withstand a certain amount of stress: Force per unit area. Thus the "strength" of the bridge (maximum force the bridge components can support) is proportional to the cross-sectional area.

If all dimensions of the bridge are multiplied by 5, what happens to the cross-sectional area of each component? And what happens to the volume, and thus the weight?