A frame and support assembly for a vehicle lacking a conventional, separate B-pillar includes first and second frame members and a plurality of support assemblies. Each support assembly includes a plurality of bulkheads, a pair of outriggers, and a cross member. The bulkheads are incorporated into first and second side sill assemblies. The outriggers extend between the side sill assemblies and the first and second frame members. The cross members extend between the first and second first frame members. The strength of the bulkheads, outriggers, and cross members is selected such that the cross member is stiffer than the outriggers, and the outriggers are stiffer than the bulkheads so that the support assemblies progressively crush during a side impact.