Supporting H-Beam using bolted plates on wooden posts

admin

Hello,I have a build where an 8" H-Beam (4" flange, 1/4" material) is spanning a 20' distance.  I want to mortise the wooden posts and sit the beam into the mortises, weld angle to the flanges and bolt to the posts just to keep things from moving.  However, others are saying to just bolt a piece of plate to the post and weld the beam to that.  My fear is the shear strength of the bolts holding up the beam and additional weight of the 2x8s, roofing, etc.  The build is a free-standing patio cover that will be supported on the opposite end using multiple posts along the 20' span.  The framing will be 2x8 24" OC with furring strips and Tuftex panels on top.  Posts are 6x6 anchored in concrete below the frost line.Thoughts or suggestions?Thanks,Wic
Reply:With the proper size bolts, they are the least of your problems. Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Thanks for the table.What type of screws are the typical galvanized lag screws at the big box stores?  Would they be sufficient if I used 4, 1/2" x 4" screws per plate?Also, your comments of "With the proper size bolts, they are the least of your problems. "  Are you implying other issues I am unaware of?  For example, the posts not being able to carry the load?  I plan on putting angled supports from the posts back to the framing materials to prevent racking.Thanks!
Reply:[QUOTE=wicrules;4018891 they are the least of your problems. "  Are you implying other issues I am unaware of?  For example, the posts not being able to carry the load?Thanks![/QUOTE]In a few years the wooden posts will be rotting out at the ground level unless kept very dry, and that may only add a few more years. A better choice would have been to use 4x4x3/8 steel tubing, with a good protective coating. If you want the wood look, then just clad the outside of it with 1x6 wood.
Reply:Not sure I understand why you want to mortise the H-beam into the 6”x6” post? Why not set the H-beam on top of the post, weld some flatbar on the bottom flange to sandwich the post, and through bolt through the post. Here is the last one I did on a 8'x40' roof over the back deck on the house to the garage. 10-degree angle on the roof, been up there 14-years. Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:OH, OK.  I plan on making concrete footing below the frost line and using the stand-off connectors for the posts.  That helps to keep them from rotting.  Plus, we are required to use a solid exterior wood stain by the HOA, so they will have some protection from that.Thanks for all of the inputs.
Reply:This build has to match an existing structure on the property.  It was much smaller and didn't require the load carrying capacity this one does.  On that build, they sandwiched the 6x6s with two 2x6 crosspieces and rested the joists on that.  Plus, the 6x6s continue up and have a copper cap on them.  Trying to match that look with the H-Beam resting on the top of the posts would be difficult.Thanks for the suggestion though.
Reply:Here's a picture of the existing structure that has to be matched.And the patio that is being covered.  Only part of the patio will be covered.Last edited by wicrules; 04-08-2014 at 02:08 PM.
Reply:Just to be safe, what do you think about taking some 4”x4” angle iron. Weld a gusset to it. Place the angle iron bracket under the H-beam, and through bolt through the 6”x6” post. Weld the angle iron bracket to the H-beam?Don’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:I had thought about having a "shelf" like you talk about to make it easier to put the beam in place.  I was thinking lag screws, but through bolting would be stronger.  Any suggestions on what size bolts for this?
Reply:I would go with 1/2” bolts. Don't use malleable washers. I have broken them before. Use a plate washer, or better yet use a bracket on both sides of the post, and through bolt through the brackets. You want to sandwich the post, and squeeze the sh!t out of it!  Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:How thick do you think the plate and angle should be?
Reply:Hey CEP - what's the standard engineering fee for a retired welder these days?   (yeah, I've nothing of substance to add - lol)Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Originally Posted by wicrulesHow thick do you think the plate and angle should be?
Reply:Originally Posted by CEPAll I know is what I've seen, and done. On the job it was a lot easier. 99.9% of the time we had an engineer on site. The other .1% of the time, there was at least 50 in the main office you could run something by.
Reply:Awesome!  Thanks for all of the help and information!
Reply:Originally Posted by MinnesotaDaveHave to admit, that would be pretty darn handy
Reply:This is probable overkill, the top plate would provide better bearing than the bolts when the post dries and shrinks. I only drew one but I think two bolts on each side of the web would be minimum Sorry the grain is going the wrong way I am new to 3D drawing.
Reply:That helps to keep them from rotting.
Reply:Originally Posted by jedreylingThat helps to keep them from rotting.
Reply:So, this is what I came up with last night..... Attached ImagesLast edited by wicrules; 04-09-2014 at 09:25 AM.
Reply:That's how I would do it! Don’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Originally Posted by CEPThat's how I would do it!
Reply:when the beam is welded to the plate, I don't really see the need for the additional angle below it, unless you're not going to weld the beam on beforehand.
Reply:Originally Posted by kingnerowhen the beam is welded to the plate, I don't really see the need for the additional angle below it, unless you're not going to weld the beam on beforehand.Originally Posted by walkerweldYes, good use of the materials by recessing the large plate into the post.  Keeping the bottom of the plate into precise contact with the accurately cut bottom kerf in that relief will go a long way toward controlling any shear concerns.
Reply:Originally Posted by CEPI really like that part! Extra work, but well worth it in my opinion. In the past I've taken a Skilsaw, set the depth of the blade, made cuts every 1/4” or so. Take a wood chisel knock everything out. Have even taken a chainsaw to remove what the Skilsaw cut for depth.
Reply:Originally Posted by M J DThe chainsaw, the only woodworking tool a weldor should use.
Reply:Chainsaw. I got ona them ! Wanna get dizzy ?Bubble gumTooth pixDuct tapeBlack glueGBMF hammerScrew gun --bad battery (see above)