A common question in a slightly different form:
I am currently undertaking some arch bridges assessments for which I am using Archie-M (version 2.4.1). One of these bridges has a multi-span masonry arches widened with reinforced concrete arches. My query was – can we use Archie to assess a multi-span RC arches as well using appropriate RC material properties? If not suitable for reinforced concrete arch, can we use it assess plain concrete arches?
I will be grateful for your response.
Many bridges were extended in this way. They were designed assuming arching behaviour and assuming very low bending effects but modern requirements suggest elastic analysis. If you do that, the result is almost certain to be an indication of substantial overstress.
I have, in the past, somewhat facetiously, suggested cutting the reinforcement to turn it into an "arch". That is clearly unnecessary but I am sure the case can be made that if it would work as an un-reinforced arch, the reinforcement will not reduce the capacity.