Wingwall question 3

[BFstr]

I have to decide about the angle for a wing wall. What impact the angle has in design?
I have seen 30 degrees, 45, 60 and sometimes even the wing wall is perfectly perpendicular to the head wall?

My case is a 10 foot head wall which I have no clue what angle do I use for wings?

Also anyone knows how I connect the wing to headwall?

I appreciate your direction and information. This is not a bridge abutment wing wall. It is only for purpose of holding soil behind so there is no road or bridge around.


Sincerely,
BFstr

 

[ishvaaag]

Since you are already designing some headwall you know more or less the maximum reinforcement you need. Usually wingwalls are made monolithic to the headwall; that may bring some rebar weight benefits with a proper structural model for calculations. The closer in alignment to the headwall the lesser the benefit; you may still have a joint between wingwalls and headwall and get some benefit from a common foundation. Now, wingwalls are made when something with the trapecial shape of a road with embankment to both sides needs be interrumpted at some point. Wingwalls in such cases are more than anything something to preserve the wanted behaviour at the abutments, specially when some bridge footing falls in the retained earth.

The variety of wingwall designs can be adscribed as well to aesthetics as much as to function, since it doesn't use to be considered a particularly expensive item in the related designs, and usually that is what I would propose to someone like you when all the engineering requirements are understood have been (or will be) met.

 

[msquared48]

If there is a slab at thew base of the headwall to catch soil for overturning, the wingwall serves as a catchment for the soil (obviously), and a stiffening of the edge of the slab so that it behaves more like a three sided slab.

The angle used is a function of the level of stability needed for overturning and sliding, plus aesthetics (blending with existing contours) as previously mentioned.

Thewre is no magic or one answer here.

Mike McCann
MMC Engineering

 

[cvg]

when you say "headwall", it usually means there is a culvert involved. if this is for a culvert there are hydraulic issues that should be considered besides just aesthethic, structural and cost. You need to ask your drainage engineer for some help with this one.

 

[BFstr]

Dear msquared48 (Structural) or Mr. McCann thanks for your comment but you mentioned that wings help to stability of wall. As I remember I designed headwall separtely and wingwall separetely, I didnot analyze the whole thing for overturning stability, well if I knew that I have to still didn't know how? Can you please explain it more. I love to learn thid



Thanks,

BFstr

 

[msquared48]

If you did not design the headwall and wingwall as a single unit, then they act separately as you designed. As I said, each solution is it's own.

Personally, I try to make them a single unit if possible though. You did nothing wrong here so long as it is stable structurally.

Mike McCann
MMC Engineering

 

[engrwiz]

One function of Wwll is as a retaining wall. The desired configuration of retained backfill will be critical in deciding the flared angle of the Wwll

Another function is to protect the backfill against scour and to provide gradual transitional flow("inlet contraction flow" and "outlet expansion flow").Here your hydraulics(e.g. flow rate and velocity) should have been critical in deciding the Wwll flare angle.