Thanks Enable! Sorry for the really late reply!! I hadn't posted a thread in a long time and my email address needed to be updated. Therefore, I never received a notification. It is always useful to get second opinions for the uncommon situations that we encounter from time to time. I will...
A contractor has been successfully using lap-spliced snap ties in certain wall forming applications. I questioned the practice recently because it seemed there would be significant yielding from the eccentricity on the small diameter rods. They sent their modified products for testing and the...
BA,
I agree that if you used a stepped bulkhead as you describe that the concrete pressure would bear normal to the riser and tread with the lateral and vertical forces. You would have axial load on the bulkhead from these forces.
I share your same concern about the zero friction value between...
From what I have seen, we need full liquid head applied normal to the inclined form to account for the full weight of the concrete above. If you reduce the lateral pressure to a value less than that figured from the full depth, then we would not see the full load of the concrete on the form...
BA,
So if we have a 40' Column on a 20 degree incline and 1050 psf lateral load, what would you say the maximum normal load is to the form at the lowest point? I come up with 1630 psf. What do you think? I think we're almost done here!!
I would like to make one more point. I have attached a sketch of an external frame. If the force on the bulkhead is normal only and does not apply an axial load, as I am arguing, then the inclined member of an external bulkhead support frame could actually experience an axial tension force from...
BA,
I like the sketch that you included in your last post - it added a new perspective to the solution.
From your sketch, are you saying that there is an axial load on your inclined form because of the load or because of the tie? This is the most important question. You show a tie component in...
BA,
I agree that the ties would exert an axial load on the form - that is not the problem. A load applied normal to the surface will in turn create axial load through the horizontal ties because the ties have a positive connection to the form. However, my ties will actually be installed normal...
I have attached the file that I mentioned in my previous post.
The model only considers the self weight of the element. The lateral form pressure would be a separate component to be added and would be resisted by the form...
doka1,
Does MK Hurd's book touch on the subject of inclined forms? I do not have this book but I would purchase it.
I have talked to 2 other formwork companies about this subject. One sees my point but has still designed as BA is recommending. The other designs as I'm suggesting; no axial load...
BA. The 10 kip block is used to compare to the vertical load of concrete. I still feel that I need to treat the lateral load separately. If we only considered pressure as a function of depth and unit weight then I could never reduce the pressure due to any amount of initial set - right?
Let's...
I would like to attempt to prove my point with one last sketch (see attachment). The 10 kip block is on a frictionless surface. A column support keeps the block from sliding downhill. The normal force is a small portion of the block weight (3.42 k). The biggest component of the block weight...
BA,
One minor correction on the area equation should read: A=.5*H^2*tan20.
Besides that, I would agree with your final equation for the axial load.
Go on....
Grahammachin - The concrete will be placed with a pipe from within the form. The pier form is plenty wide to fit crew members inside to work the concrete from bottom up.
BA - I can't figure out your last 2 equations. Do you have a reference that you can provide? I am still confused as to how we...
