Building construction formwork transverse back arris and formwork supporting system

The utility model relates to a building construction formwork transverse back ridge and a formwork supporting system, and belongs to the technical field of concrete pouring in the building industry. A split type structure formed by splicing a plurality of back ridge single components is adopted, the back ridge single components further comprise single connecting pieces used for connecting the adjacent back ridge single components together, each back ridge single component comprises an end plate A and an end plate B which are parallel to each other, and an upper layer connecting pipe and a lower layer connecting pipe which are parallel to each other are arranged between the end plate A and the end plate B; the single connecting pieces comprise shear-resistant connecting pieces and fastening connecting pieces, the upper ends and the lower ends of the adjacent end plates A and end plates B are connected together through the corresponding fastening connecting pieces, the adjacent end plates A and end plates B are