Ridge Beam Connection 2

[icedoc]

I'm planning to build a shed (12'x18') with a steel ridge beam supported at each end by wood columns. I've been searching for guidelines on how to properly connect the beam to the columns, but I cannot seem to find anything. Can anyone point me in the right direction? Thanks!

 

[BAretired]

You could use a steel angle welded or bolted to the beam flange and screwed or bolted to the wood column. The beam would bear on top of the column.

BA

 

[XR250]

Why are you using a steel ridge beam? For a hoist?

 

[icedoc]

That was basically my thought as well, but are there any specific details for fastening the plates to the column? (akin to a nailing schedule, for example?) My background is ME, so the detailed requirements of civil structures are relatively foreign to me.

Yes, the steel ridge beam will double as a trolley hoist. Nothing too crazy, I'm thinking ~500-1000lb capacity, which is dependent on beam availability and cost.

Here is what I had tentatively drawn up:

 

[BAretired]

That looks pretty good. You should probably add plate stiffeners in the beam to brace the top flange.

BA

 

[CBSE]

How much load is going into the column, how tall is it, and what size of column? Your column may. It have the capacity to handle what you are trying to do due to slenderness and combined loading issues from any eccentricity.

I agree with BA, the detail looks good.

 

[icedoc]

My worst case loading (DL + snow + 2.5x overloaded trolley at one end) puts about 5000lbf on the column. The column is 10'6" tall and has a 5.5" square cross section. I don't typically do calculations with wood, so I tried to be conservative with the properties in the tables I have, and it looked like I was right on the edge for buckling. This seemed acceptable to me given the design factor and unlikeliness of the load. Maybe you structural gurus can enlighten me if I have overlooked something here...

 

[dik]

can you just have a 3/16 plate welded across the flange, sticking down, and secured to the face of the wood column. Fastening can be glulam rivets or conventional bolts or lag screws.

Dik

 

[EIT231]

the racking is more of a concern when moving weight on trolly - consider using steel columns that can be more rigid or resistant to sway when you go to haul 1000# and rack your small shed - you don't need the beam to support the roof separate the items - easier to work with much less fabricating - basically make a 18-ft rigid frameand secure to gable ends to transfer loads to side walls - my $0.02

 

[XR250]

if it is a shed with wood stud walls, just use a stud pack to support it. Put jacks underneath and pad them out to the width of the beam then run a few kings up each side. The roof diaphragm and wall sheathing will make it all stable as long you have a fastened nailer on top. There really is no attachment required in this case as long as there is not significant uplift.

 

[txeng91]

Why use a steel beam here? 3-2x12 would surely work, if not use a glulam or lvl beam and strap it down to a stud pack at each end, would definitely be cheaper. If you don't have wood sizer software, check out span tables for 18' long member w/ 6' of roof at a 20 psf dead/ 20 psf live loading with 6' of trib (120 plf/120 plf).

Edit: I just saw you had a trolley on this. If you need the steel for the trolley I would use a 2-2x6 plate fastened to the top of the beam with 1/2" all thread rods or bolts through the flanges to support the rafters. at the column connections I would do what you are showing except with 2 bolts, keeping at least 4 x bolt diameter away from center of bolt to top of colunn.

 

[Lnewqban]

My worst case loading (DL + snow + 2.5x overloaded trolley at one end) puts about 5000lbf on the column. The column is 10'6" tall and has a 5.5" square cross section.

What will keep the column vertical and stable in all directions, eliminating the posibility of a moment load over the illustrated connection?

If used for automotive/engines repairs, consider protection from liquids (rain, oil, coolant, etc.), from accidental impact (vehicles, tool's carts, etc.) and from eventual bending/torquing loads (using the column as pivot point of vices, levers, etc.) for the low section of the wood column.

How is the load weight transferred to the ground?

"Engineering is achieving function while avoiding failure." - Henry Petroski

 

[icedoc]

Busy week, but I'm still here. Let me catch up and answer some questions...

can you just have a 3/16 plate welded across the flange, sticking down, and secured to the face of the wood column. Fastening can be glulam rivets or conventional bolts or lag screws.

Putting a plate on the face would be an easy way to add a top flange stiffener, but the plate and fasteners would protrude on the gable face, meaning my exterior sheathing wouldn't sit flush.

the racking is more of a concern when moving weight on trolly...

Valid concern. This shed is a home for my tractor and garden/yard tools- not a workshop, so I don't plan on lifting and moving a great deal of weight. I just want a helping hand to lift things if needed (with an emphasis on lifting, not transporting). Your concern kind of ties into what XR250 was saying...

if it is a shed with wood stud walls, just use a stud pack to support it... There really is no attachment required in this case as long as there is not significant uplift.

Agreed, but if there is any kind of axial force on the beam from trolley movement I would prefer not to have the beam floating on the columns.

In regards to the column design, there is much less nailing with a solid 6x6 versus a stud pack, and they are readily available in pressure-treated for added rot resistance.

...I would use a 2-2x6 plate fastened to the top of the beam...

Any reason you specify 2-ply nailer? I have included a single 2x6 nailer in my design, bolted at 24"OC.

...at the column connections I would do what you are showing except with 2 bolts, keeping at least 4 x bolt diameter away from center of bolt to top of colunn...

Good info, thanks!

What will keep the column vertical and stable in all directions, eliminating the posibility of a moment load over the illustrated connection?

This is really what sparked my original post. I was thinking of using a pinned connection to prevent creating a moment on the column, while still providing some axial retention; however, I then stumbled across some posts discussing how difficult it is to actually create a moment connection with timber. This led me here, since I could not find any published material on wood column connections.

How is the load weight transferred to the ground?

On one end, the column goes straight from the ridge beam to the sill plate, which is bolted to the thickened-edge slab. The slab has been well reinforced with 5/8" rebar. At the other end, the column runs into an LVL header that is supported by jack studs on each side.

 

[XR250]

Agreed, but if there is any kind of axial force on the beam from trolley movement I would prefer not to have the beam floating on the columns.

That is why called out the fastened nailer on top that would attach to the rafters. That would transfer the axial force into the roof diaphragm.

In regards to the column design, there is much less nailing with a solid 6x6 versus a stud pack, and they are readily available in pressure-treated for added rot resistance.

Either will work. They prefer 2x6's around here if buried in a wall as they do not twist when they dry.

I think this is getting over thunk. Just incorporate ridge into the structure like any other residential building and it ain't going anywhere. It is unlikely you are carrying more than an engine on that trolley anyway so maybe 500lbs - which will get lost in the noise. I have my shop setup similarly but my beam supports a floor instead of rafters.

 

[KootK]

@XR250: Double check those quotes. I see how this works now: Overthinking = KootK. Just for that, I'm going to intentionally inundate all future XR250 threads within much abstruse, impractical theory as I can muster.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[txeng91]

Any reason you specify 2-ply nailer? I have included a single 2x6 nailer in my design, bolted at 24"OC.

You can get away with a single nailer. I usually specify 2-2x because it provides continuity and you need the thickness for some simpson connectors.

If you are worried about axial thrust you should attach a continuous ridge board to the nailer at the ridge for the rafters to meet at. Then nail the plywood roof decking to the ridge board, that will give the beam a good attachment to the roof diaphragm which will carry any axial forces to sheathed walls at the exterior. On cranes you usually design for 10% of the maximum crane load for thrust, so you shouldn't have more than 100 lbs of thrust which is nothing.

 

[Ron]

Add a knee brace to each column/beam connection and you'll solve the racking issue. Your detail looks good. Your rafter connections can be used to brace the top flange.

 

[XR250]

KootK

Overthinking = KootK. Just for that, I'm going to intentionally inundate all future XR250 threads within much abstruse, impractical theory as I can muster.

I am so glad I fired you :>