A lower frame midrail structure for an automotive vehicle is formed from a pair of tubular members manufactured through a hydroforming process. The two tubular members are welded together in a longitudinally extending portion to provide support for the mounting structure of a bumper assembly. The joinder of the two tubular members creates a lower frame midrail cross-section that has a generally vertical internal web to strengthen and stiffen the midrail structure. The two tubular members laterally diverge from one another in a divergent zone in which the laterally spaced tubular members provide a stable interior and exterior support for a shock tower support member to be welded to the top of the tubular members. The hydroforming process can form openings in the sidewalls of the tubular members to permit passage of cross frame members to enhance the welding of the cross frame members to the midrail structure.
