Shear in Retaining Wall 1

[preynolds]

I have limited experience with cantilever retaining walls and was wondering what the general procedure regarding shear at the base of the stem is? CRSI uses a bent bar over the theroretical 45 degree crack of the shear but 3 different text books I have do not show any shear reinforcing throughout their explanation. Any help and references would be greatly appreciated.

 

[Qshake]

Shear in the cantilever wall is rarely a problem due to either the bulk of the wall or reinforcing required for moment as well as standard details.

In many cases standard details require a keyway in the footing of such walls which provides plenty of shear resistance. Moreover this is aided by consideration of "shear friction" at the interface of the wall and footing including, of course, the rebar. The rebar can be quite a bit on the fillface and additional rebar is detailed on the frontface for temperature.

 

[JAE]

Qshake is correct.... the shear at the base of a cantilever retaining wall is rarely a controlling issue in their design.

Simply check the phiVc value of the wall itself; and then check the shear friction between the stem and the footing (ACI chapter 11).

 

[ishvaaag]

Yet in any case I had the experience of making a collection of retaining walls, even thick ones -over 1 m thick for over 10 m tall walls- and the hypotheses asked for shear reinforcement; the wall being to this purpose a slab didn't help since the code ordered diminished concrete shear contribution. The thing went to what would be one of your DOTs here and they didn't blink an eye when they were shown that the calculations so asked. So it is clear that as always, most surely most of the safety radicates at the first step in any structural calculation, i.e., evaluation of the loads being applied. For such a generic task it was probably some just a bit conservative assumption required for the backfills what pushed the slabs to the need of reinforcement in shear... something by the way not restricted anyway to the walls, I have a very close similar experience whilst reinforcing some not precisely thin slab for vehicle traffic with some civil engineer! So simply, follow the code, and if what results looks incorrect, revise and/or look further opinion.

 

[bengineer]

ishvaaag..... Your use of the english language, as demonstrated in your reply above, is comparable to a pro bowler on a bocce ball court. I don't mean to be rude, but I can't understand a word. Next time you reply try the "KISS" method.

 

[ishvaaag]

English is not my first language, bengineer, hence you can't expect my being as proficient as a native contributor.
If you are kind enough explain please what the "kiss" method is, I didn't understood this word in this context.

 

[Ingenuity]

ishvaaag,

"KISS" is an ancroym for "KEEP IT SIMPLE STUPI...". It is used in a friendly way...

I know that you are a frequent and valued contributor to all structural forums, and occasionally i also have to read your responses several times to understand your point/contribution.

I would offer this friendly advice, as english is a second language for you: try and use shorter sentences, and also use more paragraphs. Try and seperate each point/comment in a seperate paragraph. This is particularly so for responses that are lengthy.

We shall all value your continued contributions so much more if we are able to understand them with your original intent.

HTH

 

[DaveVikingPE]

It looks like ishvaag is sharing his experience fighting with local transportation departments reagarding large retaining walls.

In fairness to ishvaaag, I have read posts by people who are Americans - their mother tongue being English - whose written language skills could use some work; if they wrote as well as ishvaaag it would be a world of improvement. As far as "having" to re-read posts several times to "understand" them goes, I'm sure that this is the case with many posts related to highly technical questions - even in the case of a poster from England, where they speak the King's English.

I thought bengineer's response was, despite his caveat, rude, thoughtless, offensive, unfair and unnecessary, amounting to a worthless, childish flame. Eng-Tips is a great service to the international engineering community. Since it's an English language site there will be unavoidable language difficulties. The answer is patience not punishment. I work with many folks whose first language is Chinese. They are brilliant engineers but have a lot of difficulty with English. If I need an answer from one of them, I don't get it by yelling at them, complaining that I can't understand them or making the excuse to my supervisor that I couldn't get a strait answer out of so-and-so. If you're not getting the "right" answer, ask the person to clarify and include a bit more detail in your question. Isvaaag is a valuable contributor. His remarks comparing Spanish building codes and practices related to the UBC, etc. make him an amazing resource. His attention to detail is especially welcome by this engineer. And in truth, his responses are not hard to understand. He answers the technical question at-hand and understanding that leaves only about a 5% effort required to understand how he's saying it. Ishvaaag pays more attention to spelling than a lot of native-English speakers, too! I've seen posts in these forums that are downright incoherent due to creative spelling (I'm not the best speller nor the most careful typist but I do care enough to try) and I haven't seen flames attacking them like bengineer's did to ishvaaag.

 

[ishvaaag]

Thanks, Dave, and...bengineer, I do some things, many, in a hurry, this is no thing I revise for a great presentation.

I am trying to convey as quickly as feasible my view on the question, far more to produce the more understandable writing in my reach.

In fact I think that what I stated above, in spite of many imperfections was simple: that in spite of my being in accord with shear rarely require reinforcement in walls, I have meet this myself in the context of tall wall designs, as -also seemingly looking rare- I have found the same case occur in 60 cm thick or so bridge-slabs.