Your course of action depends on whether there is an historical (hysterical) preservationist/architect involved with the project, or if you are the prime consultant. You cannot "retain the original structure as much as possible" without affecting the appearance or gain back any strength of the original material. Covering or reinforcing the original structure with steel completely voids the purpose of leaving the original material or preserving historical significance. And by the way, these types of structures never check out with current loads and codes, so you must consider if your design is safe with whatever you end up doing. The best way to approach this is to shore and replace the material, use same material and details "as much as possible" but make the structure satisfy current loads and codes. You will always be fighting cost and difficult construction conditions - let the fun begin. 😁
As a design engineer with 30 years of experience here are my comments. Don't attach anything to rotted wood. It won't work. Remove all bad wood members and replace.
I probably didn’t make it clear in the video but the two steels bolted to the timber beam will have its own bearing effectively rendering the timber beam useless. With the steels capable of supporting all the load.
So how is this repair on a like for like basis if this is a listed building? Surely the correct solution is to replace the beam baulk with a similar sectional sized beam. Who wants to see steel remedial work like this? Why cant the original Purlin also be replaced with a new timber member, even if increasing the sectional size it would be better and less complicated design specification. In my humble opinion these proposals don't fit with the ethos of a like for like repair and certainly don't look good.
Generally heritage hierarchy prefers original material to be left in place; ie. Conservation is conserving the original elements. Therefore the approaches proposed here generally are non destructive and allow the original elements to be kept in place.
Love the videos! On the timber beam remedial detail - if the timber beam fails, will this not bring down the pfc sections as well, or are these fixed to the wall as well which supports the existing beam and runs parallel with the joists?
