Concerns about Corner Bar Detail 1

[wvu4646]

thread507-223809

Please see the attached standard detail for corners and intersections. Depending on the location the corners will be exposed to lateral on either the inside face, outside face, or both. This is not a typical detail that I have seen before. The Engineer provided a new detail that is standard to what I have seen, but has requested to keep the old detail in one of the structures in which the detailing was complete as not it impact the job schedule. Any Insight would be helpful.

 

[ron9876]

If the horizontal bars on the inside face will be in tension then I think there is a problem since the embed is no doubt less that the required embed depth.

 

[csd72]

wvu4646,

I can see the source of your concern as this does not appear to be a very well thought out detail.

As ron has said, the bars on the inside corner will tend to pop out the cover under bowstring effect if they are in tension.

Also there are a lot of bars in this corner, which could lead to poorly compacted concrete and thereforefore (counterintuitively) more cracking.

I have never specified diagonal trimmer bars in this situation.

 

[JedClampett]

Seriously, have these guys done water bearing structures before? I see details that look poorly thought out. This is likely to fail. They got a textbook on opening corners, found the diagonal bar detail (of minimal value), but didn't develop the hooks sufficiently. Their wall intersection detail is weird, too. They show additional bars, I guess, but they don't say to space them inbetween the main wall steel. And they need to maeasure the development length from the wall face, not the hook.
This ruined my morning.

 

[dik]

I commented on this detail in another thread... inside corner bars should go to the far side to be hooked. You might consider replacing the corner bars with 180degree bent 'hairpins' for both the corner as well as the intersecting walls. I don't often see inclined corner bars. Can get pretty congested...

Dik

 

[BAretired]

May suggestions are:

Corner Bar Detail:

1. Don't hook bars on outside face. Use only L dwls.
2. Move hook from inside face to outside face to develop bars.
3. Extend diagonal bars to outside face.
4. Omit L dwls on inside face.

Wall Intersection Detail:

1. Remove hook from bars each side of wall.
2. Reverse direction of L dwls so they lap across wall.

BA

 

[wvu4646]

Dik,

Thanks for the comment on my other thread. I wanted to see what some others had to say about it. The other side of this is that the diagonal bar cannot be bent as shown in the detail. The way the bar can be bent would extend the bar to the outside face (as suggested by BA). We are also in the process of installing the steel in the field. The standard detail was updated, but we were directed to use the one I attached for the BAF Structure. This structure was designed by a different Engineer than the Engineer of Record for the project. I am not confident that the Engineer confirmed with the Design Engineer before directing us to use the old detail.

 

[Splitrings]

Check out thread507-228698. It covers this topic

 

[dik]

BA has the right idea... I usually use corner dwls as he noted or 'hairpins' so that the contractor doesn't have to fight with long bars hanging from the joint... also allows the use of a straight bar between parallel walls that doesn't have to be a precise length, the slop can be taken out by the corner dowels.

The bars should extend to the opposite face (more or less). If a high tension load, then too close to the face may cause the concrete to spall...

Dik

 

[wvu4646]

Thanks Plitrings. I referenced that thread when I started this thread. That thread was no longer available to post, and I thought this detail was unique.

 

[Brad805]

Assuming this is a watertight structure, I suggest they stick to the details recommended in "Concrete Watertight Structures." You might also want to give them a stack of those bars and see how well it all fits.

Brad

 

[hokie66]

wvu4646,
The thread referenced by Splitrings is a different one, and much more applicable, than the one you posted. The works by Nilsson should be required reading for anyone designing corners subject to opening forces.

 

[wvu4646]

Hokie66,

You are correct. That is the thread I was reading prior to starting this one. I must have added the wrong thread as I meant to add the one that Splitrings referenced. Thanks for the correct reference.