Mat Foundation with column stiffeners

[lejam]

How do you integrate column stiffiners to a mat foundation? Do you make it thicker or with more top bars or do you put separate tie beams above it?

 

[PicoStruc]

Are you talking about Concrete columns or steel columns ?

If it is concrete columns, Explain what do you mean by column stiffiners ? Shear reinforcement ?

 

[hokie66]

Like PicoStruc, "column stiffener" is an unfamiliar term to me. Perhaps a sketch would help.

 

[lejam]

Let us say you have mat foundation 3 meters below ground. The columns would be too long and become slender. To hold against sway or make it non-sway and turn in into short columns, designer put ground beams between columns making it stiffer. Is this not a normal procedure? How do you integrate the ground beams to the mat foundation then?

 

[hokie66]

3 metres is not a long column. So your foundation is down 3 metres, then what? If you have a floor at the ground level, I don't see an issue. If there is a problem with columns being slender, make them larger. Again, perhaps a sketch would help, as I don't think this is a "normal procedure".

 

[lejam]

Dearhokie66.. from mat foundation to ground floor, there is 3 meters.. from ground floor to second floor, there is 4 meters. The total column height is 7 meters from mat foundation to ground floor ceiling. Are you saying the ground floor slabs divide the effective column length to 3 and 4 meters respectively? Just saw this elsewhere.

 

[hokie66]

Yes. Why not? If you want ground beams, place them with the ground floor slab.

 

[lejam]

dear hokie66, is the term "ground beam" and "tie beam" the same? If not, how do they differ based on the context of our discussions above.

 

[hokie66]

I am not sure if there is a universal definition, but to me a ground beam or a grade beam is a flexural element, while a tie beam is an axial element.

 

[lejam]

Ground beam is supposed to hold the columns against sway and tie up can't do that (but only avoid differential movements of separate footings? But are they not similar in design? So they should do the same either can do.

 

[Enhineyero]

Lejam - all beams connecting to a column prevents the column to buckle with respect to the beams longitudinal axis. ground beams may be used to carry the ground floor (if the engineer does not want the soil to carry the slab), to resist seismic loads, carry brick walls. etc.

Tie beams for me serves as beam that connects two or more footings to stabilize the connected footings and prevent overturning. ground beams can act as a tie beam if your footing is resting on the same level with the ground floor

 

[aminugusau]

what are the recent types of foundation construction on peat soil

 

[lejam]

If there are ground floor slabs without ground beams. Are the ground floor slabs enough to hold the columns against sway (let's say the columns are 2 meters from foundation to ground level and 4 meters from ground level to second floor?