Abstract: A structural support device in the form of a push pier capable of use in high load-bearing capacity applications involving significant lateral load conditions, the push pier having a lead section with a ground penetrating friction collar, and one or more extension members that are machine fabricated with an integrally formed hardened alloy steel coupling section that is adapted to mate with the push pier lead section or another similarly constructed extension shaft. The hardened coupling section is formed of heat-treated and hardened alloy steel which is quenched and tempered to a yield and tensile strength substantially exceeding that of the main tubular shaft section to which it is connected, and inertia friction welded thereto.