Abstract: A floor for a tank formed of a superstructure and a skin, wherein the superstructure is formed of a pair of spaced floor rails, one on the left and one on the right side of the tank, and a spaced series of normally disposed thereto V-trough struts or cross-members each of which slopes from the interior sidewall edges of the tank toward the center longitudinal axis, while at the same time their respective effective elevation is decreased from the back to the front of the tank, such that the skin attached over the superstructure slopes both inwardly toward the middle of the tank from each side and forwardly from the rear of the tank toward the front of the tank.