We have many times repaired bracing for the undersides of couches and upholstered chairs. Often these good old pieces were built over a century ago. The techniques, tools, and materials by which springs support was achieved have changed over the decades. In most cases we can rework the underside of your antique spring-seat furniture to give it a long, new, refurbished life.
For some people there is a suspicion that the old wire springs are simply worn out. My experience is that this is rarely true. Typically it is the support for those springs that has given way. In most cases we can repair broken couch and chair frames back to new strength or better. And we can support those old spring seats to get them back to their original performance.
Restoration of furniture and refinishing is what we do here. Let us take a look before you toss that family heirloom.