Seperate Modeling of Two building and taking their effect on each other

[TLycan]

We are Designing a two separate building one R.C and the other is steel. What I mean by separate they are not structurally or architecturally connected. the R.C is 4 floors and the steel is the same. I want to make the R.C building Supports the steel building laterally. and of coarse there is an engineer how is modeling and design the R.C while another is working on the steel.

the Question is how can I take the effect of each building on the other since I am working on separate model.

the other question suppose the steel building was a light steel structure does it make a difference.

thanks in-advance

 

[Ron]

Use dummy joints and springs to represent the reaction you expect from either building on the other.

 

[DETstru]

Going to need some more information but I'll try to respond.

Are the buildings the same plan dimensions and adjacent?
Are you resisting both seismic and wind loads?

I ask because if the buildings are next to each other and the same size the lateral loads due to wind will be the same in the parallel direction but larger in the perpendicular direction. Seismic loads will be larger in both.​

Are you resisting all directions of lateral loads with the concrete structure?

If the buildings are next to each other you will have one hell of a torsion going into your lateral system in the concrete building.​

If all of the above are resolved you will just design the steel for gravity design, diaphragm forces, and collectors to transfer the lateral load to the concrete building. Of course you have to work out the connections to the concrete building.

The concrete building is trickier.
In the parallel direction you basically just add nodal loads based on the seismic load from the steel building. Wind load is unchanged.
In the perpendicular direction you have to take into account how you are connecting the two buildings. If you are connecting at only a few points you have to consider the tensile and compressive forces in the cantilevered diaphragm along with the shear in those connections. It'll be very tricky. I can't say much more without knowing the layout, elevations, and grid.

 

[KootK]

Two additional points:

1)Connections for the light steel building may be more difficult to accomplish.

2) Be wary of fire rating requirements between the two buildings that might hinder your attempts to structurally connect 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.

 

[TLycan]

Dear All thank you for your prompt response.
Ron,
Your answer is what I was thinking of. But to deliver it in more details I was going to do the following:

1-find the horizontal stiffness of R.c and steel building.
2-model them as springs in the corresponding model (i.e R.C spring in steel model & vise versa)

but I found that this is not enough because of the following:
suppose that my steel columns are supported on R.C beam or even r.c columns, under gravity load, Not speaking about lateral loading now,
the R.C column will deflect laterally . how can I take this effect on the steel structure. by the way taking the deflection value of the r.c column and adding it a displacement load in the steel model is not right

Ahermiz1016
I think your proposal will be appropriate if, in certain direction, the beam column connection will be pined i.e the steel structure is completely leaning on the the r.c. building. otherwise their stuffiness have to be taken into consideration


attached is a PDF of some of the building I have in this project