Abstract: A vehicle body structure includes a perimeter frame including laterally spaced right and left side rails of tubular construction and front and rear bumper rails of tubular construction extending between the side rails. A structural tunnel extends longitudinally of the vehicle midway between the side rails and has front and rear ends. The structural tunnel includes an inverted U-shaped channel having vertically depending the first and second legs, and a close-out plate which extends horizontally between the legs. First and second front shear walls extend forwardly and diagonally from the first and second legs at the front of the tunnel to the respective right and left side rails of the perimeter frame. Similarly, first and second rear shear walls extend generally rearward and diagonally from the first and second legs at the rear end of the tunnel to the respective left and right side rails of the perimeter frame.