Elevator Foundation 2

[Gus14]

I resorted to using the elevator wall to support the floor beams. Floor beams frame into the corners of the wall on each floor. The wall will end on the ground floor, then 4 corner columns will come up and continue till the 2nd-floor roof. The accumulated dead+live floor loads are written on each side.

For the wall footing design, should I consider the load center at the center of the wall or should I model the loads as 4 columns and ignore the wall?

 

[dik]

I'm a little slow this AM, but your sketch makes little sense to me.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Gus14]

I do have a habit of overcomplicating things. I made better sketches in the following links of something close to my plans. The main question really is whether the reactions of the beams will spread evenly across the wall-length or not? Meaning should I consider the wall as a long column with loads at the center of it?

https://files.engineering.com/getfi...bad5-4e1b-954a-ed0821e3382f&file=sketch_1.pdf

https://files.engineering.com/getfi...0922-4945-95c2-e83f0f4f1d12&file=sketch_2.pdf

 

[dik]

If those column loads are going into the ends of the walls, there should be no difficulty in transferring the loads... make sure you have enough dowels to accommodate any change in concrete strength and confinement. There should be no other issues.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[BulbTheBuilder]

The wall ends on the ground floor so I want to assume you've slabs sitting directly on the wall as a flat slab. Does the wall carry other loads aside that of the forces transferred by the columns? If yes, then you'd need to include the wall to also account other forces in the design of the wall's foundation.

For the loading, do you've a symmetrical structure? and are forces/stress equal on both ends? If that's the scenario then yes, you can load it at the center. Same can be done if there's a slab or any rigid diaphragm restraint it in the horizontal plane.

 

[Gus14]

Thank you dik, and NicOkai for replying. I agree with you dik because I remember seeing a provision for masonry walls where the point load spreads at 60-degree angle so it makes sense to me that the point load will be Eventually spread when it reaches the foundation.

For the loading, do you have a symmetrical structure? and forces/stress equal on both ends? If that's the scenario then yes, you can load it at the center

The structure is unsymmetrical and loads at the wall ends are not equal. I think this will control the wall design but will eventually spread across the wall length. Is this what you mean?

 

[ProgrammingPE]

You are permitted to spread out concentrated loads in walls using a 2 vertical to 1 horizontal slope per ACI 318-14, Section 11.8.2.2, so you should be able to treat the reaction at the base of the wall as a distributed load.

Since your reactions at the ends of each wall are not equal, your soil reaction will be trapezoidal instead of uniform. You can determine the magnitude of the trapezoidal reaction just like you would for a footing with a moment where you determine the uniform pressure due to the axial load and the triangular pressure due to the moment and add them together. You can then design the footing for the pressure at the more heavily loaded end of the wall.

Structural Engineering Software:

http://www.structuralcentral.com

Structural Engineering Videos:

http://www.youtube.com/channel/UCOj2mXXf3ZbZtgxTc6BtkGg

 

[BulbTheBuilder]

[/I resorted to using the elevator wall to support the floor beams]

Unfortunately, I missed the pictures and misread the post the first time.

If you ignore the wall you indirectly ignore the load from the floor beams as well which wouldn't be the right approach. I don't know the software you're using but from software like RISA and MIDAS gen you can attached a beam-column to concrete at any point along the wall as shown in my image (attached). Columns can be offset from the ends of the wall as in my attachment. The stresses from the column will be distributed in your concrete wall as concrete are really stiff and rigid (plane-stress scenario). The load will definitely be transferred into the foundation but with a concrete wall(an effective stiffness member) and strip foundation(distributing load along strip helping with bearing) foundation will experience 'better' performance'.
I hope this helps

I don't know why it shows "Civil/Engineering" by my username. How do I change it to structural :'(

 

[HTURKAK]

Structural engineers are also literally 'CIVIL ENGINEER '.... So, do not take serious...he he ..

 

[BulbTheBuilder]

Thanks HTURKAK!