Image Number 4 for United States Patent #8118355.
Outer side sill member includes an upper wall section slanting upward in a horizontal, outer-to-inner direction, and a lower wall section slanting downward in the horizontal, outer-to-inner direction. At least one of upper and lower wall sections of the outer side sill member has a channel-shaped bead extending along the side sill, so that the side sill has a polygonal closed sectional shape extending in the front-rear direction of the vehicle. The bead has a bottom portion having a width greater than a vertical dimension in a direction orthogonal to the surface of the bottom portion. Each of bulkheads, partitioning the interior of the side sill, is fixedly joined to the outer side sill member with its recessed edge portion substantially fittingly engaging with the bottom portion of the depressed wall portion of the outer side sill member.