Okay, releasing all the moments in the beams and adding a roller in Y up at the top (which doesn't actually exist, but is needed to run the analysis at all) brings my stress ratios down to around 7.83. Still no good, but better than with the beams fixed to the columns.
I don't think it's...
Okay, I tried setting the L torsion every 5', but I didn't get much of a difference. Perhaps it's because the beams are transferring moment to the columns as I modelled them as moment connections. I'm not sure they perfectly transfer the moment, but if I release the moments the whole thing is...
Well I didn't have calipers, but I did put a tape measure on the edge of the material and the thickness of the post looked like 1/16".
If I increase the thickness to 1/8", the stress ratio comes down to 4.85.
The beams on the upper shelves are okay. On the bottom shelf they're overstressed, but not to the absurdly high amount the columns are. I attached the design results for one of the columns. All the others are about the same.
I assumed a live load of one ton supersacks on 3.5 ft x 3.5 ft...
I'm analyzing some warehouse storage racks for a client to give them a load capacity. The problem is, my results keep showing that the capacity is far far FAR below what the rack company says they should be and far below what the client is putting on the shelves already. The rack manufacturer...
Yeah, that's how I feel too. They have this cleanroom area with big windows near the entrance and they like to walk VIP's past there to show off the employees working on their modern state of the art equipment, and I guess they prefer the look of ceiling tiles to historic trusses. Some people...
The reason for the analysis is they want to hang a drop ceiling from them. Not a large load, but they wanted verification that they were strong enough.
Thanks for the book suggestion! Figure 41 is almost the exact view of the actual truss, and the eye detail of the flat bars looks just like what's there. Based on that then, I'd say you're right that they're wrought iron.
I don't know about the shoes at the ends of the web members, but the shoe...
I'm trying to analyze a wood and steel bar roof truss built around 1870. Obviously A36 steel wasn't around then. I'm not even sure A9 steel existed. Does anyone have an idea of what kind of material properties you would use for this?
Ah okay, thanks for pointing out my mistake. My assumption of Ka=1 was wrong then. Ka of .33 helps a lot, but that only reduces my overturning moment to 3101 ft lbs, still greater than the resisting moment. Forget about any kind of factor of safety. How are these things not tipping all over the...
You're right, I didn't include that because I assumed it was cohesive soil and the Ka value would be one. I forgot about it in the bins of gravel case though and that would reduce the lateral pressure by a lot if the internal friction angle were around 45 deg.
Still not sure how these are...
I'm designing a retaining wall made of those 2'x2'x6' concrete bin blocks. The client needs it to be 8' tall. You can see in my attached calculation below, I'm coming up with an overturning moment that's way higher than the resisting moment. I've been told by the block supplier and the...
