i've been working for some time on category roman bridges but you certainly provide new infos here this is what a webpage says about the alconetar bridge destroyed in the th century arches left moved in i hope they did not change the arch structure then here the most authoritative photo el puente de alcon tar sobre el tajo en garrovillas c ceres cerca de alc ntara estaba en la v a de la plata debi de ser tambi n monumental fue destruido por los rabes en el siglo xiii y nunca despu s reconstruido hoy d a es un puente sin r o al construir el pantano de alc ntara hubiera quedado sepultado por las aguas en el a o se trasladaron sus restos a un nuevo emplazamiento apenas quedan tres arcos de los que tuvo se aprecia su solidez en sus fuertes machones as for the pons fabricius there are some roman bridges and even more medieval ones whose arches are designed somewhere between semi circular and segmental this is only natural as a demanding structure the segmental arch bridge could not have been invented in a day but must have been reasonably the result of a lengthy development process this means there are certainly transitory forms between the two types what we need in every single case is the span rise ratio of the bridge to make qualified judgements on its segmental or semi circle character