Help with understanding construction method 1

[mjr6550]

I was asked to inspect the walls of a warehouse building and specify repairs. The method of construction is unusual (at least to me). It does not help that just about every wall is different. The building has a structural steel frame with I-beam columns at 20' o.c. Some walls are 8-inch block and some are 12-inch. As best as I could determine the walls are horizontally reinforced with truss wire and are not vertically reinforced (t least at the walls in question). The I-beams at some exterior walls and at an interior partition wall are partially embedded in the wall. The I-beam flanges provide lateral stability in one direction, but not the other. The block is also butted up to or very close to the webs. I am trying to understand if these walls are supposed to be shear walls (East Coast, low seismic area). How is this setup supposed to deal with drift?

In one section of the building I-beams supporting crane rails are located adjacent to the building columns and connected with melded brackets. There is diagonal bracing at one bay on each side between the columns for the crane rails.

One end wall has only one column at the center of the building and full height CMU wall. I assume that wall is vertically reinforced.

I would appreciate any comments.

 

[BAretired]

It would help if you had the structural drawings, but I assume you do not.

BA

 

[oldestguy]

What can be said for expansion due to temperature changes? Wind loading and provision for that in the steel only? For any "fix" I'd look at that and neglect effect of block walls for resistance.

 

[Yt.]

Masonry wall reinforcement doesn't improve wall resistance, but control the failure mode.
By seeing the pictures it seems that you have diferents walls heights and diferents lateral resisting systems, thus i'll assume some torsional behaviour. I don't believe that that roof behave as fully flexible at all.

Depending on how the steel panel are connected to masonry wall, they might be able to transfer some shear into the walls. But picture 4 depicts that steel column are resting on masonry when subjected to lateral load (So they are shear walls), that will explain why it's more crushed at top side rather than bottom. I-beam will act as fixed (elastic foundation will be more accurate) in wall plane, and fangles will resist out of plane action.

It seems that picture 5 shows some buckling at the left bottom side of the diagonal bracing. If you look the columns disposition of this picture left one is intended to provide out-of-plane stability and right one in-plane-stability.
i won't rest on picture 6 joint to share "in-plane" loads from the crane to wall, but it might help in out-of-plane. I think that that joint may be improved.

When repairing picture 4 check if there is some connection that ensure out-of-plane shearing loads between masonry and I-beam.

I'll try to check if reinforcement are necessary to out-of-plane stability on the expansion joint showed at picture 2. Perhaps it was meant to have a full height opening when designed.

Hope some of my ideas could help you!

 

[mjr6550]

I appreciate the replies. Ytyus, have you seen this construction before. I could not find much info. I see that column ties are made for this setup, but I don't think they were used here. If they are present, they do not do a good job keeping the walls straight. I did see the exterior of another building recently that appeared to be the same type construction. In that building the flanges of the columns were exposed and flush with the CMU. Apparently the CMU was anchored better to those columns.

 

[Yt.]

Not really, just once I saw something like this with brick masonry when i was consulting for a burned down house, sadly there wasn't someone able to build the hard fixing that project would needed, so we took other choices.

 

[Yt.]

I'm not used to design under low-seismic considerations but maybe an expansible material could do the work if the CMU doesn't get crushed.
Or some straps of metal could be handled to make a "continuous beam" if are placed outside the steel columns.

Giving a second thought on picture 2 the concrete beam could be used to gain weight over the CMU when acting as cantilever, then again i'm not used to low-seismic.