Rotation and Deflection of Lintels

[Abuh001]

Hi

1.) Euro-code seems to lack detail regarding issues such as deflection and rotation limits, now for a lintel supporting a brick wall what deflection limits are recommended. I normally used L/360 however I have heard other engineers suggest much more stringent requirements like L/500 or L/600. This does however greatly increase the beam sizes for many a project, how do other engineers deal with this?

2.) I have found little info regarding rotation limits, the SCI guide P-385 does state a maximum rotation of 3 degrees at ULS and a maximum rotation of 2 degrees at SLS, does this seem ok?

Thanks

 

[MotorCity]

Use L/600 to minimize cracks in the brick. I have never seen a rotation limit imposed for a lintel, just a deflection limit.

 

[MikeE55]

I use L/600 or 0.3" max.

 

[KootK]

Same limits for me. I've worried about the rotation but consider the tight vertical deflection limits to be a suitable way to limit it indirectly. Loose angle brick lintels exhibit complex behavior in a lot of ways with the brick arching and interesting end restraint conditions. These things are often beneficial and make accurate prediction difficult. It's almost a design by past experience thing at this point for me.

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.

 

[Abuh001]

Thanks for all your responses, really appreciate it

Also if I may ask,what do you make of this research

https://www.researchgate.net/publication/240757112_Deflection_Criteria_for_Masonry_Beams

 

[XR250]

Do you guys use tighter limits for retrofits versus new construction? I typically use super high limits for existing construction as the brick/mortar cannot creep as easily as green mortar to match the lintel deflection. Then again, my guess is not much load ever get transferred to the lintel in retrofits as the brick seems to form a deep beam by itself.

 

[masonrygeek]

Here is another source of information on steel lintels supporting brick veneer:

http://www.gobrick.com/Portals/25/docs/Technical Notes/TN31B.pdf.

It's a little dated in that it doesn't reference current codes, but it is still generally correct. BTW, TMS 402 removed the maximum deflection of 0.3 inches and just has the requirement for L/600. The only time the 0.3" value comes up now is when brick veneer is supported on wood construction. There has been some info on rotation of the angle, but is not required in the code. As KootK mentioned there are a lot of things that keep the rotation to a minimum in normal walls.

 

[Abuh001]

Hmmm...so I spoke to another engineer who says he keeps the deflection limit at L/360 for new brickwork construction as the bricks are "wet" and less likely to crack, would be interested in your opinions with regards to this. Thanks