Agricultural building - loads
Agricultural building - loads
(OP)
Hi - I have a question about the live load for a pole barn hay loft.
I can't find anywhere in the IBC that specifies what the live load should be for a loft of this type... I was going to use 40 psf, but I was wondering if anyone had some input as to what they would typically use.
Thanks for your help!
I can't find anywhere in the IBC that specifies what the live load should be for a loft of this type... I was going to use 40 psf, but I was wondering if anyone had some input as to what they would typically use.
Thanks for your help!






RE: Agricultural building - loads
Hope this helps.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Agricultural building - loads
RE: Agricultural building - loads
So using Mike's dimensions (H x W x L = 1.5 x 1.5 x 2.5), the bale would be 5.625 CF. If it weighed 80#, the PCF would be 14.2. That would match the upper end of the Penn State Document that Splitrings listed (14 PCF).
I did some google searches and it seems like the size of a bale is not uniform, but I could just determine the volume of my loft storage area and then use 14 PCF to get the total weight the loft would hold at any given time.
Thanks!
RE: Agricultural building - loads
It has been a long time since I have been around a baler, but I know density and or size are adjustable on most balers. On a recent project I did, I simply used the volume of storage times the bale density.
RE: Agricultural building - loads
One variable is how high the hay would be stacked... I assumed a maximum height based on the available head room, but maybe that's too high. Does around 5 ft sound reasonable? I've never worked with hay bales, but I would think a guy of average strength could lift an 80# bale that high.
RE: Agricultural building - loads
RE: Agricultural building - loads
RE: Agricultural building - loads
RE: Agricultural building - loads
Mike
RE: Agricultural building - loads
Specifically I was looking at the analysis procedure outlined in Chapter 5 of the National Frame Builders Association (NFBA) design manual. I have also downloaded the DAFI program from the NFBA website (h
My question is about calculating the horizontal shear stiffness of the roof diaphragm. The roof of the barn will be sheathed with 1/2" CDX plywood and finished with composition shingles. The NFBA design manual outlines how to calculate the stiffness of a metal clad diaphragm using tabulated diaphragm assembly test data. I have not been able to find any similar data for plywood diaphragms.
Has anyone done an analysis on a post-frame building with a plywood roof diaphragm? If so, did you account for the diaphragm action, and what did you assume for the diaphragm stiffness?
Thanks!
CEmonkee
RE: Agricultural building - loads
RE: Agricultural building - loads
RE: Agricultural building - loads
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Agricultural building - loads
Thanks!
CEmonkee
RE: Agricultural building - loads
At the loft section:
1. Add horizontal 2X12's from the loft columns to the exterior posts at each stall to better transmit the seismic load from the hay loft to all the posts. You can add them just above the hay loft 2X12's.
2. Since this is intended to be a pole structure, I would recommend the exterior posts be embedded in 24" round, concrete filled, augered holes. As for the loft area poles, the spread footings are a nono if you intend these poles to carry lateral too. The soil has to be undisturbed. If you need more bearing for the vertical load, either go deeper with the hole, or increase the diameter, or both. The deeper you drill, the greater the allowable bearing value at the emd of the pier.
The truss sections seem fine, but I would still use the 24" concrete filled augered holes.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Agricultural building - loads
Good idea on adding the 2x12's for better seismic load transfer.
The foundations shown on the interior posts are actually 8" thick 18" diameter pads. I think I probably will need to increase the diameter for bearing considerations (the loft load will be fairly large).
For the outside poles, what about using concrete pads with collars (see attached .jpg)?
RE: Agricultural building - loads
Just fill the bottom of the hole with 6" of gravel for a water break, and put the treated post directly on the gravel, filling the rest of the hole with concrete. Do not backfill with earth. The depth of the hole for lateral will start at the top of the gravel, so you will need to dig the hole 6" deeper than shown by the calculations.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Agricultural building - loads
Thanks again.
RE: Agricultural building - loads
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Agricultural building - loads