Truss failure - video

I like the videos we see of teams working together effectively (this Forging a large flange video is an excellent example), but I also like working alone: all errors will be solely my own. There's even a book on my Amazon wishlist called Working Alone: Tips & Techniques for Solo Building.

And then there's this guy. Failing trusses seem to a trend on YouTube (search for "truss failure"), and here we have an excellent example of the genre. It's so perfect, I don't even know if it's staged or not.

1:02 video:

https://www.youtube.com/watch?v=n5h8PARqh6g

Whew. Staged or not, glad that wasn't the case when mine [65 footers, about 11' rise] were set. With the lower chord 16' off the floor, no-one was propping them up either! Manufacturer design code required them being swung in by crane, 2 nailers walking opposing 2" x 12" plates; affixing 42 of them full span and 10 more halves...Yeah it cost plenty ---but I'll won't have to re-roof for 50 years. That'll make me around 107 years old; everyone already knows what to get me for THAT birthday!

The only trusses I ever worked with were steel so I used gin poles and a winch on my welding rig or had the larger ones set with a crane. But I've seen many wood worms stand trusses by themselves most have a telescopic aluminum pole with a rubber foot pad and a fork on the other end. As they raise the truss they will extend the pole then once erected drop the last bit to set the foot on the ground this will hold it in place long enough to do what ever needed to get the ends secured then the stay braces.
I still don't see why if he had to do it by himself without the pole I described, that he didn't pre install 2x4's on edge on top of the header leaving a gap between them to allow the truss to sit in once it was up. He could have cut a 45° bevel on one about an inch deep to guide the truss into the slot this would have still left about 2 1/2" of vertical to hold it in place the gap would need to be about 1/8" wider than the truss is thick but still tight enough to hold close to vertical. 2x6's would be better still.

I'm glad this fellow stepped out of the way in time to save his brains. One of the dangers of working alone (and in an unsafe manner) is that if you make a mistake, it can be costly. I wouldn't want my wife (or anyone) to find my lifeless body, especially due to a very avoidable catastrophe.

Unlike how this fellow is doing it, typically you start setting trusses at the gable end (assuming your building has a gable end, and not a hip roof). That first gable truss is diagonally braced plumb and fastened securely. Once that's done, a person working alone can attach a small block/pulley to the peak of that first truss and use a weight on a rope to assist in lifting and retaining the subsequent truss in place until you can get up there to secure it. From the camera angle, I see no diagonal bracing on his first truss, which looks downright scary.

Another problem with these guys are they are more in-tuned to making their so called indestructible videos than they are concentrating on the task at hand.

Perhaps 30 years ago I happened to be at a commercial building jobsite where my lumber company supplied the trusses. The walls were 12" blocks about 9-10 ft. high, span was around 30 ft. A strongback made up from 2X10s was attached the middle of the block gable end wall and was high enough to hold the attached end truss plumb. Lateral 2X4 bracing was nailed as the trusses were placed by a crane. All went well until a wind gust blew away the first truss from the strongback and they went down like dominos. If that was not bad enough, upside-down trusses make great wedges and they pushed out most of the masonry sidewall. No one was hurt but the trusses were condemned from re-use and the contractor took a huge $$ hit. Trusses are very fickle until plumb and all lateral and diagonal braces are secure.

Quote:

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Originally Posted by SRQSid

Perhaps 30 years ago I happened to be at a commercial building jobsite where my lumber company supplied the trusses. The walls were 12" blocks about 9-10 ft. high, span was around 30 ft. A strongback made up from 2X10s was attached the middle of the block gable end wall and was high enough to hold the attached end truss plumb. Lateral 2X4 bracing was nailed as the trusses were placed by a crane. All went well until a wind gust blew away the first truss from the strongback and they went down like dominos. If that was not bad enough, upside-down trusses make great wedges and they pushed out most of the masonry sidewall. No one was hurt but the trusses were condemned from re-use and the contractor took a huge $$ hit. Trusses are very fickle until plumb and all lateral and diagonal braces are secure.

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I like your statements. Many don't comprehend that a roof does more to support a wall than 'visible'. A lot of physics and mechanics at work. Fact when ridge-down, the weight alone buckled CMU walls is good proof. When I was screening contractors, they didn't know I was somewhat familiar with code and engineering directives, provided by a truss company. One clown "you don't need to buy them, I'll build them on-site" (really? without a flat 70' pad? one at a time? by the way, who's paying an 80' crane to standby 2 weeks while you are fabbing 50 trusses?). Another wanted to overlay the very faulty flat roof with scabbed rafters! (hello? we get snow here WHAT'S that roof load going to be? He didn't get the job either, didn't go inside to see 15 termite eaten posts.)
I'm in no way an expert at construction. But if logic and engineering don't add up, something's amiss. I talked to most every roofer in town; all had schemes of membranes, spray coatings, re-shingling, etc. Only a real construction contractor had an appropriate combination. I didn't tell a single one what I wanted or thought should be done.
That's their job.

Quote:

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Originally Posted by Toolmaker51

Whew. Staged or not, glad that wasn't the case when mine [65 footers, about 11' rise] were set. With the lower chord 16' off the floor, no-one was propping them up either! Manufacturer design code required them being swung in by crane, 2 nailers walking opposing 2" x 12" plates; affixing 42 of them full span and 10 more halves...Yeah it cost plenty ---but I'll won't have to re-roof for 50 years. That'll make me around 107 years old; everyone already knows what to get me for THAT birthday!

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A 53 year old girlfriend for the day with your misses permission of course

Quote:

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Originally Posted by Toolmaker51

I like your statements. Many don't comprehend that a roof does more to support a wall than 'visible'. A lot of physics and mechanics at work. Fact when ridge-down, the weight alone buckled CMU walls is good proof. When I was screening contractors, they didn't know I was somewhat familiar with code and engineering directives, provided by a truss company. One clown "you don't need to buy them, I'll build them on-site" (really? without a flat 70' pad? one at a time? by the way, who's paying an 80' crane to standby 2 weeks while you are fabbing 50 trusses?). Another wanted to overlay the very faulty flat roof with scabbed rafters! (hello? we get snow here WHAT'S that roof load going to be? He didn't get the job either, didn't go inside to see 15 termite eaten posts.)
I'm in no way an expert at construction. But if logic and engineering don't add up, something's amiss. I talked to most every roofer in town; all had schemes of membranes, spray coatings, re-shingling, etc. Only a real construction contractor had an appropriate combination. I didn't tell a single one what I wanted or thought should be done.
That's their job.

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Not being a wood worm I might have looked at it another way determine the width/ thickness of the existing walls and support posts then form a channel cap overlay with a beam then fabricate steel trusses the number of which would have corresponded with the number of posts per side wall IE 10, 12,or 15 ft centers New construction would most probably come in at 20, 24, or 30 ft centers the trusses would have been made out of angle iron and square tubing or simply completely out of sq tubing. a top of the trusses again depending on center distance 4" to 8" "C" or "Z" purling the roof itself would have been 4" thick inter locking sandwich panels flat steel sheet on the under side painted flat white the top side would be customers color choice, of commercial R or modified corrugated panels. 50 years? yea might need a repaint by then. the Completed roof would have been 10 to 30% lighter than any wood structure that could have possibly been half as durable or had anywhere near the insulation value
ANy badly termite damaged or aged posts could have been sprayed with an epoxy sealant then clad with metal to retain their saw mill new strength.
Cheaper than going with wood? probably not but many benefits of a roof system which is not dependent on the structure it is on top of that also adds to the strength and integrity of said structure would outweigh the difference in cost

Quote:

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Originally Posted by Frank S

A 53 year old girlfriend for the day with your misses permission of course

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I can only reply one way to that; channeling Professor Farnsworth. Here you go, 15 seconds well spent!
https://www.youtube.com/watch?v=QEkRs8NSOeg

A light weight and one of the strongest roof systems there is would be a space frame structure. The company I was with before retiring build among other things lots of steel structured buildings some of our space frame designs clear spanned 200 ft by 300 ft on 3 sides made up of a labyrinth of small pipes all bolted together no single connection carrying more than another once complete
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and to secure glass panels we used stainless steel spiders
the pic also shows how the system connected together
Attachment 20885
And for the lightest fastest structure to erect the award has to go to K span.
anything under 30 ft wide by 18 ft tall only needs a 3/8" thick by 6 inch wide curved steel rib placed between every 10 feet of roof panels 60 ft by 30 to 35 ft tall buildings needed 3/4" thick by 10 inches added every 30 ft along with the smaller ones. the panels were made on site in a mobile form rolling machine from coils
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One more thing from the dustbin of history: In 1961 the family lumber business built a modest store/showroom, about 20 X 30 or so. The trusses were built on-site using split rings which connected the sides of overlapping 2 X 4 truss chords and webs. Circular grooves were cut in both members and the ring rested half in each and secured by a center through bolt. The ring was split so it could adjust to the wood's changing size due to seasonal moisture level changes. This was constructed by employees when things were slow and has stood the test of time (55+years) and western Massachusetts snow loads.
This may be an option for modest DIY projects at difficult sites using engineered drawings.
Link: Split Ring Timber Connectors - Split Ring Connectors

The last shot looks a larger version of a Quonset Hut. Quick and easy construction made it popular and necessary during WW2. The name comes from their place of manufacture, Quonset Point, RI.

Quote:

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Originally Posted by SRQSid

The last shot looks a larger version of a Quonset Hut. Quick and easy construction made it popular and necessary during WW2. The name comes from their place of manufacture, Quonset Point, RI.

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Yes actually just the newer version except instead of taking corrugated sheets and curving them or using High edge rib standing seam heavy galvanized metal the K span is made from stupidly thin gauge metal that comes in 24 ft wide coils a 1000's of ft in length rolled to shape and curved in the same machine right on location
In another division of the company we had a 45 ft high cube container with a roll form machine to make the std commercial siding and roof sheeting on location it made 2 shapes of metal one above the other at the same time or separate When making both the upper an lower sheets simultaneously they were routed through 2 more double open ended containers placed in line with the forming machine in the middle container foam was injected between the sheets in the last container the now sandwich panels were cured and cut to length. Other construction companies mostly imported their sandwich panels from Izopoli in Turkey we Leased the equipment and made our own under license and partnership with Izopoli