Wood truss moving bearing

[youngblood30]

I have a 40’ wood metal plated truss that is cantilevered on one end to span a rear porch. Plan is to remove bearing on cantilevered side and move it out to the end about 8’. Im having a local truss company run the design on the original truss bearing conditions and also for the proposed with bearings on the end (no cantilever). Some of the members have CSI failures and some joints failures.

The existing trusses were designed in the 90’s and luckily they had the shop drawings available. There are adjacent existing trusses that handle the full/same span(without cantilever) but the geometry of the truss is slightly different. The Plan is to reinforce chords/webs that failed based on the tension/compression values and plywood gusset the joints that need to be addressed.

Are there any standards or references for situations like this? I know the truss companies have a lot of testing data on their plates and fairly robust software but I haven’t been able to find anything detailed on plywood gussets or typical practices for reinforcing/repairs. Thanks in advance!

 

[XR250]

Might be easier in install a dropped or flush beam.

 

[youngblood30]

Might be easier in install a dropped or flush beam.

Thank you for your response X. Yes that was my original thought but they definitely don’t want a dropped beam and the span due to the space would be large.

 

[RFreund]

I usually see plywood/OSB gussets and adding members/bracing as needed. Here is an old article.

 

[youngblood30]

I usually see plywood/OSB gussets and adding members/bracing as needed. Here is an old article.

Thank you for the reference. Seems to be slim pickings.

 

[RontheRedneck]

If a situation like that were brought to me, I'd refer it to Aline. The engineers there would design the repair and return it to us. They do repairs every day, so they know exactly what to do.

If you're planning to do the repair design on your own, I don't have any info that would be of any help.

 

[XR250]

If a situation like that were brought to me, I'd refer it to Aline. The engineers there would design the repair and return it to us. They do repairs every day, so they know exactly what to do.

If you're planning to do the repair design on your own, I don't have any info that would be of any help.

I have never been able to get the truss engineers to provide repair details for me.

 

[Eng16080]

Is it possible to support the current bearing point with a beam located within the truss space (above the bottom chord) and some type of hanger connection?

 

[youngblood30]

I have never been able to get the truss engineers to provide repair details for me.

That is exactly the issue. We were lucky to even have a local designer run it in mitek just to get the forces. Without that I told them no go.

 

[youngblood30]

Is it possible to support the current bearing point with a beam located within the truss space (above the bottom chord) and some type of hanger connection?

Yes that was an option I was looking at but it would be about 30’ span and would have to go through a girder. Constructibility issues making that even fit too

 

[SWComposites]

Can you sister in some new trusses that are designed for the new span?

 

[bones206]

I recall Medeek and EngineeringEric had a pretty in-depth thread on plywood gussets. But it's another one of those things where you have to go down the rabbit hole.

 

[RontheRedneck]

That is exactly the issue. We were lucky to even have a local designer run it in mitek just to get the forces. Without that I told them no go.

That's odd.

We will always try to help an existing customer. If we built a truss and someone is modifying it, we'll help them - Even if they're not a customer.

Alpine will do a repair for a truss we built, even if it's several years later. I don't know Mitek's policy.

 

[Zidan Yang]

Please provide the detailed original truss calculation files, and I can assist you with the repair. I have a team with 14 years of experience in truss design and repairs.

 

[TRAK.Structural]

I've done some of this type of work in the past and pieced together an approach that I am comfortable with. I've found that the nailing of the gussets is often the limiting factor. Here are some resources I have used.