Wait You first said that Troyanos book states that two arches at the Alconetar site are original spans m and m but now you write that his text and captions imply that the arch on the left is an original Roman arch and the other two are more recent In that case the bridge would not be a Roman segmental arch bridge at all wouldnt it    Did Troyano somewhere write that the wooden low spanrise ratio bridges of the Romans also constitute segmental arches despite their superstructure being out of wood not stone