15 replies to this topic

[cantaloup]

You are filling in a few days for the project engineer who is on vacation. The project is a 16 story building. The 4th floor slab was poured on Friday. On Monday you get a call from the design engineer informing that the concrete strength of the newly poured slab achieves enough strength for the purpose of slab formwork & scaffolding removal. Which sequence below is correct?

A/ Removal of slab formwork & scaffolds and moving them up on 4th floor slab; building formworks for columns and shear walls on the 4th floor slab; shoring the 4th floor slab using jacks; pouring concrete for the columns and shear walls on the 4th slab; removal of formwork for columns and shearwalls; building scaffolds & formwork for the 5th floor slab to be poured.

B/ Building formworks for columns and shear walls on the 4th floor slab; removal of slab formwork & scaffolds and moving them up on 4th floor slab; pouring concrete for the columns and shear walls on the 4th slab; removal of formwork for columns and shearwalls; building scaffolds & formwork for the 5th floor slab to be poured; shoring the 4th floor slab using jacks.

C/ Removal of slab formwork & scaffolds and moving them up on 4th floor slab and shoring the 4th floor slab using jacks at the same time; building formworks for columns and shear walls on the 4th floor slab; pouring concrete for the columns and shear walls on the 4th slab; removal of formwork for columns and shearwalls; building scaffolds & formwork for the 5th floor slab to be poured.

D/ Building formworks for columns and shear walls on the 4th floor slab; pouring concrete for the columns and shear walls on the 4th slab; removal of formwork for columns and shearwalls; removal of slab formwork & scaffolds and moving them up on 4th floor slab and shoring the 4th floor slab using jacks at the same time; building scaffolds & formwork for the 5th floor slab to be poured.

[sgsmith2_PE]

And the answer is??? I'm not real sure, but I'd say C.

[EnvEngineer]

ACI 347 .2R-4 Give the following sequence

1 install shores and formwork cast concrete floor (completed friday)
2 Remove shores and formwork
3 remove reshores at lowest level
4 place reshores in new story

I would choose C as well,

Good question thanks

[Mike_NC]

I have the 7th Ed SP-4 with ACI 347 in the back. I am not finding the section where that sequence is discussed..

The order you listed makes complete sense, I just would like to have that page/section tabbed for quick reference during the exam...

THanks,

[EnvEngineer]

SP4 may not have ACI 347.2R-4 its section 3 Typical Phases of Construction, sorry no page numbers

[cantaloup]

Answer: This building is a concrete structure, which has concrete columns/shearwalls and slab. The answers A, B are incorrect because if you remove any scaffolding and slab formwork you must have jacks shoring that newly poured slab section immediately. C is incorrect because if you move the scaffold and slab form up, it would clog up the space for carpenters & iron workers building the formworks & rebars for columns and shearwalls to support the 5th floor slab, this means that columns and shear walls must be done (concrete poured, set and forms stripped) before moving scaffolds/slab formwork up. Even though the design engineer gives permission to remove the slab form work, you don't need to do it right away. D is correct.

[EnvEngineer]

this is one of those questions that is so complicated you really cannot get a good handle on it. D assumes that the formwork has been designed for addition live (workers and concrete pouring) and dead loads (set concrete) before full strenght has been achieved. Compared to haveing the whole works falling down "would clog up the space for carpenters & iron workers" is acceptable. But who ever makes up the question gets to define the rules.

What was the source of the question?

BTW, thanks for posting, it gave us a chance to investigate this type of question.

I need to coin a term for crappy question burn out at this point, there are alot of really poorly written questions and some that use unknown references that are just starting to piss me off, and they also cant seem to find the correct terminology in the NCEES references. I stopped wasting time on these if the question looks like crap I just look at the solution and try to figure why the did it that way.

If you have some good questions on formwork, cranes or temporary structure please post, there is not alot out there and we can use it as a learning experice

[sgsmith2_PE]

^......agreed!

[tymr]

X2

[sgsmith2_PE]

I never could find a direct answer for this question in SP-4 or in ACI-347. I looked in the sections mentioned above...maybe I'm missing something.

[EnvEngineer]

I am not sure how the ACI numbering system goes but within the appendix should be ACI 347-04 and that will not have the information discussed here, it is valuable stuff because it shows the equations you will need to calc the force of concrete on forms during pouring, I believe the equations in CERM 11 are old.

ACI 347.2R-4 is a seperate document for shoring and reshoring. It is not contained in SP-4

[sgsmith2_PE]

got ya. thanks for the clarification. I was thinking it was in the SP-4. No wonder I couldn't find it. I'll go see if i can find that manual....hell, at this point I've spent so much on manuals it doesnt even matter anymore.

[humner]

http://www.gamcoform.....I Reshore.pdf if this helps, I googled this

[sgsmith2_PE]

thanks humner. that might be the additional manual that gets me the one question I need to pass....lol

[abcoindia]

spam

[abcoindia]

spam