Wood beam pocketed into existing masonry wall 1

[Lion06]

I have a situation where this was an option. It is not the option that we are going to use, but was wondering if anyone had any suggestions anyway (in case it comes up again). There is an existing stone masonry wall that needs to have two girders (5 1/2 x 11 7/8 PSL) supported on it. The girders are perpendicular to each other and are both very near to the end of the wall. Because of edge distances, a plate with epoxy anchors for each wasn't a realistic option.
We considered chipping away a section of the corner of the wall and bearing the beams on the wall and grouting around the beams to fill in the chipped away section. Obviously, this creates problems for decay of the wood. I was wondering if there is a typical detail floating around out there to address this. Has anyone wrapped the end of the beam in light gauge metal, or a roofing material to protect it? Any other details? I assume the beams would also have to be fire-cut to ensure they don't destroy the wall if a fire caused the beam to collapse.

 

[samdamon]

EIT- Its ok in my opinion to bear a PSL on masonry, without using a sheet metal jacket, if you use pressure treated material. Fire cuts are a good idea. Another issue to think about is how the new members are tied into the wall laterally. Normally you would want some method of tying new and old together. Regards

 

[civilperson]

A pair of plates with through bolts connecting the plates is a detail that can be used with most masonry situations as you described. Flexible and cost effective for a myriad of connection types. Installs quickly with a hammer drill and long bit.

 

[valleyboy]

It is common practice in the UK to wrap the ends of joists bearing in pockets with DPC material to prevent the onset of timber decay - particularly where the timber bears onto solid masonry walls where moisture penetration is likely to occur.

 

[McSEpllc]

A thing to consider is the impact of the girder load on the wall. A face-mounted connection induces eccentricity that can cause excessive tensile forces in stone masonry walls. Keep in mind that even when the beam has full bearing on the wall ASCE-5 (masonry code) requires designing for a minimum of a 10% of the wythe eccentricity. When bearing stress on the masonry is excessive (I get that some times with old soft brick masonry), I usually spec to cut a pocket and to install a reinforced concrete "pillow beam" that is capable to spread the load over a large enough area. In any case wood in contact with masonry needs to be treated, preferably by bearing an untreated beam (so it has no strength loss) on a treated sill plate on grout as a leveler. Untreated beams in beam pockets should have a minimum 1/2" clearance to masonry. For beams on basement walls I personally like to specify to seal the end of the beam with epoxy paint and to fill the cavity with polyurethane foam.

Eric McDonald, PE
McDonald Structural Engineering, PLLC

 

[tdsull]

We commonly wrap LVL ledgers with ice and water sheild prior to being bolted to existing masonry walls.