I think the lateral deflection you're trying to hold at 8m is unreasonable. That's L/800 of the column height. The beams that support the rails are generally only designed for L/800 vertical deflection and usually L/400 lateral deflection. But that's for the beam itself, generally the column...
Just FYI, PEMB manufacturers, or at least the major manufacturer I worked at, would not use the full length of the purlin to determine trib area. They would use the frame spacing x purlin spacing to determine tributary area on purlins. Wall panel pressure is girt span*panel width.
i.e. 100 ft...
I am the former engineer. I reviewed and sealed drawings in 5 states. That time working there has vastly helped me now that I'm back in the consulting world.
As an FYI for #3, the PEMB engineers assume all the anchor bolts work in shear. They also only provide a standard hole for the anchors (not oversized), hence why they don't spec or call out plate washers.
Source: former engineer for one of the largest PEMB manufacturers in the states.
The column reinforcing plates will interfere with the building girts if they extend past the outside flange. Those inside of the girts are generally flush with the outside of the column flange.
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...
