new concrete column on existing wall

[n3jc]

Hi, I have never done something like this so i have a question...

I want to add new concrete colums 30 x 30 cm on existing concrete wall (width = 30 cm).
Im wondering whats important and how it can be done?
Drilling holes first (whats max depth that can be done in existing concrete walls), cleaning holes, adding special glue, putting in dowels/rebars for columns,....

Also is it OK to model this column supported that way:
displacement in all directions + rotations in all directions are restrained (not possible)?

see attached file. tnx for answers.

 

[KootK]

Wall thickness? Column size perpendicular and parallel to the wall?

Normally:

- Bearing stress at the interface is important.

- Consider the joint pinned if possible and restrict dowels to a couple of centrally located drill and epoxy vertical bars.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[n3jc]

Wall thicknes is 30 cm and its long 15 meters... colums cross section is b/h = 30/30 cm

About bearing stress - you mean something like this:
Rd = 300 kN (compressive force in column)
A = 30 cm x 30 cm = 900 cm2 (contact area)
stress = 300 kN/ 900 cm2 = 0,33 kN/cm2 < fcd (1,67 kN/cm2 for concrete C25/30).

So there is not a chance to consider fixed supports instead of pinned. Because pinned supports cant bear moments...

tnx for answer.

 

[n3jc]

I was thinking... what about removing part of concrete from the top of the wall and then connect new reinforcement bars/dowels with existing wall reinforcement? can this be considered as fixed supports? t

 

[KootK]

Based on your relative sizes, you may be able to achieve fixty. Depends on the rebar in the wall. Probably easier to call it a pin though if you have the choice.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[KootK]

Latest idea would work but surely easier to locate existgbars and drill and epoxy near them.




I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[n3jc]

thank you!
have a good day.

 

[MotorCity]

Be careful if you have any lateral load on the column or wall, you will be creating an unstable hinge if you model the bottom of column as pinned.