Fifteen groups of piles support a continuous lattice girder, each set comprising four piles screwed into the river bed at an angle with an X-brace between each adjacent pair. The fitting of screw blades to iron piles, as opposed to the then accepted wooden pile, created a deeper and far more resilient base support.
A series of fifteen groups of piles form a continuous lattice girder, where each group comprises four piles driven into the river bed at an angle, connected by X-braces between adjacent pairs. The use of screw blades on iron piles instead of wood led to a more substantial and long-lasting foundation.