Rebar-based support assemblies that can be fabricated without the need for on-site welding. The assemblies include a number of differing sized and shaped crimps used in place of welds to provide rebar assembly-to-rebar assembly connections. In some examples, a crimp for mechanically joining rebar for use in a support system for a physical structure includes a body with at least two recessed surfaces each configured for receiving a respective first and second piece of rebar; and a pair of spaced-apart arms at least partially enclosing an interior space of the body including the at least two recessed surfaces, a first tip and a second tip of the respective spaced-apart arms each defining a respective first and second opening to the interior space, in a first configuration.