Dr. Robert Forward of Hughes Research developed the concept of dynamic support to build large structures. A linear magnetic accelerator acting upon a stream of mass provides a force-counterforce arrangement, along Newton’s motion law. This applies whether adding or subtracting velocity to the mass flow, the direction of the reaction force flipping positive or negative.
This provides for a circumvention of materials strength requirements. A structure can be built in which support is supplied along distributed points, by adding or subtracting momentum of a high velocity matter flow by electromagnetic manipulation. Obviously, electrical energy can be stored or extracted from the kinetic energy of a ferromagnetic mass flow. This exchange inherently involves the application of force to accomplish the transformation of one for another.
I'm not sure about a building that becomes structurally unsound if the power goes out, however.