Re: Replacing Herringbone Struts
Well, you're right, if obstructed, they can't be replaced. They are called cross-bracing or x-bridging. Nowadays we use solid blocking, or metal x-bridging. The whole purpose is to prevent deep joists from twisting under load. So, if your joists are less than 2x10's they are of almost no value. If your joists are 2x10's or 12's, you can get the same benefit by attaching strips of furring to the bottom of the joists in the center of each span. That way, no single joist can twist alone.
Remove not the ancient landmark, which your fathers have set.