There are several way to prevent scour, which is the worst enemy of stone arch bridges with shallow foundations as is common.
The amount of weight a stone arch bridge can handle is related to a variety of factors including span, arch thickness, condition and more.
While a distorted arch in a stone bridge is not always a problem, it often points to an underlying serious trouble elsewhere within the structure.
The length of time a stone arch bridge lasts is directly related the workmanship and foundations, with various treatments extending the bridge’s life.
The spandrel walls hold the fill of a stone arch bridge, and need to be correctly engineered to do so without gradually bulging and failing.
Partially collapsed arches are repairable, though such repairs tend to be involved. Of course, the cause of the collapse needs to be remedied as well.
A stone arch bridge, while an enduring structure in its own right, does need to see some basic maintenance to ensure maximum longevity and usefulness.