The total porous span length: the total porous span length of beam bridges and plate bridge culverts is the total length of the porous standard span; the arch bridge culvert is the distance between the arch lines in the abutment on both sides; other bridges are the bridge deck system The driveway is long.
By the way, let me tell you the concept of standard span: standard span: for beam bridges, it refers to the center distance from pier to pier; for arch bridges, it generally refers to the clear span.
To put it simply, the total span length of multiple holes is the sum of the standard spans of each hole.