PEMB manufacturers do usually add purlin bracing when using standing seam roofs to help with flexural capacity of the members.
You can find erection details for Nucor (one of the large PEMB manufacturers) online. While sizes aren't listed, it can be a good starting point look at how the system...
The IEBC (International Existing Building Code) says reroofing material 3 psf or less is acceptable for Alterations of existing buildings (generally without need for analysis). Your 6 psf is double that allowable. You should have it checked by your engineer.
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The snippet below is from a Crane Design Guide by CISC. The lateral side thrust is either 100% of one crane, or 50% of multiple. I've always limited it to 50% of two cranes; as you said, it's unlikely you'll be getting side thrust on a single column bay from that many cranes at one time. I think...
Are you concerned about the runway beam or the beams that support it? I would have no qualms with a roof beam having a simple end connection that's supporting an underhung crane. Were the moment connections provided for stiffness/provide a lateral load path?
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A prime example of why more information = better answers.
For crane systems, you should be looking at some kind of bearing connection at the end of the crane beams, whether they sit on a bracket off a building column or an independent column. Holes are a major stress concentration area; I don't...
Review the loads. Crane design assumes that the hoist, trolley, and crane load goes to one side (the hook is all the way on one side of the crane), and the bridge weight is evenly distributed. So for the example, the load per side is 57.2/2 + 40 + 10.6 = 79.2 kip. 79.2 kip/2 = 39.6 k/wheel. The...
For platforms that small, make sure whatever lateral load you use is enough to cover the guardrail lateral force too. Usually that's not an issue, but if my conversion is right the 1 kN is just enough to cover the guardrail requirements here in the states.
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A lot of the other engineers here have given good advice on how to handle the situation. In one of your other threads you said you work for a construction company. I feel like pointing out the liability the construction company would have, especially if they're doing the design acting as an EOR...
Note that Pre-Eng building will use multiple bays of roof bracing often depending on the building length. If the building is 200' long, there might be 3' bays with roof bracing, each taking 1/3 of the lateral load down to the eaves as bones described. The remainder of the load is taken through...
OP said he was designing a Special Truss Moment Frame. Those require a special segment in the middle of the truss where deformation occurs for seismic design. I've never personally designed one, but the reasoning is there.
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The 16.6 kips sounds way more reasonable for the tower you have. And going back to your earlier example, if you had a 50% solid area ratio, the wind load is 36.2 kip, even with the lower Cf.
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The coefficient is smaller but you'll still get a higher wind load since you're multiplying Cf * A. Note 1 in Table 29.5-3 says to use the solid area of the tower face projected on the plane, not the gross projected area. That should significantly reduce your wind load. The 113 kip wind load you...
PEMBs often use the purlins as struts to take the endwall wind to the horizontal roof trusses. If you're taking out some that align with endwall columns, you'll need to devise a way to get the load around the doghouse, or make sure the trusses (and the foundations) are sufficient for the extra...
I would definitely do an independent structure up through the roof. You're unlikely to get any information on the PEMB itself, and even if you did, it's extremely unlikely to work for the additional load from the doghouse above. Assuming you're in an area with any kind of snow load, you'll be...
I used to work for one of the major PEMB players, but work in the consulting world now. I will say that changing PEMB bracing from X-bracing to portal frames, with no other new loading consideration, is one of the least hesitant modifications to a PEMB I take on, especially if it's going into...
FYI, it's unlikely the eave member is used for anything except to transfer axial loads down the building and into the bracing. They likely weren't designed for any bending. That's how the big PEMB manufacturers design them, considering it to be fully supported vertically by the wall panel that...
You can take it to a Staples and have them bind it like a notebook. That's what I did with ASCE 7-10 for my SE. I have one that's the code and one that's the commentary since it's too thick to be bound on one spiral.
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Actually, when I worked at a design office for one of the major PEMB suppliers, I was the only engineer on a staff of 20 that had any experience outside the PEMB industry. It's extremely common for PEMB engineers to either be 1) straight out of school, with 0-4 years of experience or 2) have...
The sketches on p.2 show positive horizontal to the right (not inward/outward), so column 1C has a 3 kip load to the left under wind_left 1, which makes sense to me.
There should be endwall bracing between column B-C based off the reactions listed. Wind blows down on the plan (wind to the...
