Point load on brickwork cracking

[John1967778]

Hi guys,

Are there any limits as to how close you should have openings to point loads on brickwork walls? I've looked through the Australian standards and can't seem to find any information in regards to how close openings in beickwork can be to the 45 degree spread of load from a point load.

I've got a case where large cracks and displacement has occurred besides a door opening to brickwork. Approximately 1meters away the wall is supporting an ibeam which is supporting upper story brickwork and a portion of the flooring and roof (double story house).

At this stage Im thinking the cracks could have been caused by either ground movement or a structural failure of the brickwork. I've attached some photos of the crack. Any thoughts would be much appreciated. Cheers

 

[John1967778]

Thanks for all of the responses everyone - much appreciated. The owner just informed me
that the house is over 15 years old and the crack only formed last week. This makes me think that the crack is probably more related to ground movement rather than brickwork failure due to the point load.

However, a large point load resting on a single skin of brickwork (110mm) thick so close to an opening just doesn't feel right to me and I'd like to check the capacity of the wall. Does anyone have any design document or references on checking brickwork under point loads?

Cheers guys

 

[haynewp]

It is a stepping crack above the wire. Here:

 

[haynewp]

I would be more likely to believe someone hit the door edge with a car, pushing the lower part of wall to the left. But I assume the door frame shows no such indication of impact. There appears to be very little vertical movement or rotation of the wall area below the main crack.

 

[civeng80]

50kN is about 5000kg i.e about 5 tonnes and its looks like a pretty substantial beam sitting on a flimsy 110mm pier on 110 brickwork next to an opening. Single brickwork crumbles very easily especially when not restrained. I would not be comfortable with the existing support for the roof beam in this case regardless of the cause of the crack.

 

[hokie66]

I agree with that, civeng80. It would be nice to have a better photo showing the beam bearing. It looks like the bottom flange edge is close to the side of the added pier brick. But it also looks thicker than the top flange, or is that a bearing plate? How far the beam bears into the wall is also important.

I don't consider unreinforced masonry to be a structural material, but am probably in the minority with that opinion.

 

[John1967778]

I've attached another photo guys. The beam passes over the pier and sits on directly on the single brick wall.

 

[hokie66]

That beam looks like a 250 PFC, based on 3 Australian brick courses = 257. And it seems to have something welded to the far side, which I assume is a shelf angle for brick on that side.

We don't know exactly how that pier is built. Just stack bond, except for the top course. But there does not appear to be any indication that the pier and the wall have separated, except at the top course where the pier bricks seem to go through.

I agree now with nonplussed and haynewp. The most likely culprit is impact from a vehicle.

 

[Mjkkb2]

Looks like settlement issue to me not related to the beam bearing.
The only issue is assuming the homeowner is correct, it is unlikely it would appear instantaneously.
The car hitting the wall is very plausible depending on the location of the crack with relation to the door/driveway.

 

[John1967778]

Thanks guys. One point I forgot to add, there is a gap between the bottom of the wall and the door opening, indicating that the bricks have essentially moved down and to the left. This is the side wall of the garage (cars run parallel with this wall). If a car had hit the wall, I don't think there would be a gap between the bottom of wall and door opening as the bricks would have been pushed too the right.

 

[jimstructures]

Douglas1992

Now we need a picture that backs up a little and shows the entire wall and maybe shows the crack propagation high-lighted.

It is hard for me to intuit what's happening when I only see fragments of a problem area. I do need to see the details, but I also need to see the whole picture of the problem area.

Thank you for your patience.

Jim

 

[hokie66]

The old expression "like pulling hen's teeth" comes to mind. It is a tedious operation.

 

[John1967778]

Haha thanks for all of the responses guys - much appreciated. Jim I've attached a picture below