Multi-wythe brick wall support during lintel replacement

[BubbaJ]

Building was constructed in 1882, two-story 12" multi-wythe brick bearing walls. The wood lintels are severely deteriorated and need to be replaced. They are/were comprised of (8) 2x10s.

You can see from the photo that the wood lintel (what's left of it) is continuous under all the bearing points (cast iron columns or brick pilasters.) So a temporary pinch beam would have to span multiple supports and be blocked from the bearing point to the bottom or supported via external shoring posts so the wood could be replaced. The other thought I had was to use a shore post with a plated bracket on the top and cut a groove in the mortar joint to insert it. Shoring under each second story section of brick and somehow tying in the limestone window lintel. Temporary support would need to be located at the elevation of the window lintel as the brick work under the windows is also in poor condition.

If we shore, we'd have to shore both sides, which will be difficult due to the structure having a basement or design for an eccentric load. But there really isn't any good place to transfer load to at the current moment.

Similar conditions exist the 70' length of the building facade. Small sections would be replaced, hopping back and forth from one end to the other to allow brick to cure out.

Does anyone else have any clever shoring solutions?

Thank you.

 

[dik]

SRE has a posting of my historic brickwork paper you might want to review. This has a lot of information on historic brick and how not to repair it. As far as supporting the existing brick, it would be a matter of providing temporary support using C Sections through on the exterior and interior face bolted through the wall. This would allow you to carefully remove the existing wythes to replace the lintel; I'm not sure what your through wall/lintel detail is.

The existing masonry can carefully be replaced using mortar of a similar mix and colour as noted in the above paper. Do not use Portland cement... historic brickwork uses the entire wall construction to maintain its integrity.

Dik

 

[BubbaJ]

We frequently do restoration or renovation of historic structures, so I am aware if the delicate structural balance of the brick/mortar, but I am interested to read your work. I'm just not sure what "SRE" stands for?

I've used a pinch beam (as you are describing) on several occasions. I was looking for a secondary option due to the existing conditions. I've attached a detail of the existing lintel.

Thanks

 

[Ron]

SRE is slideruleera...the screen name/handle of a significant and knowledgeable contributor to this site. His experience and insight are invaluable. He knows more than most of us have ever learned!

 

[dik]

OP

http://www.SlideRuleEra.net

 

[dik]

OP

 

[JedClampett]

At several locations in the picture, it looks like there isn't much brick worth supporting.
I'm an amateur at this (a couple of jobs, probably more luck that they worked than anything), but I've sawed out a brick joint above the work zone and pushed in a temporary angle to shore the brick. but that was a single Wythe of brick backed by CMU and it was in good shape (we were cutting openings in the wall, not repairing it). But I was terrified all the same.
Maybe the BIA might have some suggestions. They have nice little pamphlets that I lean on heavily, but maybe giving them a call might get some ideas.

 

[hokie66]

Do you have a shot of the entire facade? That might help us in brainstorming how to approach it.

 

[dik]

The Parks group has more info than the BIA...

Dik

 

[OldBldgGuy]

I think you have to shore at the underside of the stone sills, since that seems to be the most consistent line you can use both vertically and horizontally, and everything below the sills ought to be rebuilt anyway. I've used shoring from 1 side because of the same constraints you have on this job, and you have to batter your shores to push back into the building. The existing structure is happy to fall toward you. Use angles (open up) under the sills, with plates welded to them that insert under the brick piers between the windows. Weld stubs to the angles (on a suitable angle for the batter) to either bolt to shoring posts with matching plates or sleeve into purpose-made HSS shores with screws welded onto the bottom ends of them; make angled timber cribs at grade to meet the shores at 90 degrees. The stubs take the torsion that the longer tabs for the brick require. Hydraulic jacks make sure things are tight before you remove the existing masonry below, then the whole upper level is held while you rebuild. I assume you can shore the floor joists with temporary walls inside as necessary. I rebuilt the bottom 10' of a 35' high ashlar stone wall with this method & it worked like a charm. (I'd post pictures, but my office burned down in 2015 & purged my files.) I've done quite a few of these in brick & it is usually easier in the sense that you have nice straight joints & uniform units, but be constantly aware that collapse is only one wrong move away...

 

[idecharlotte]

I generally use needle beams to shore masonry. You just have to space them a little closer for older masonry.

http://www.idecharlotte.com