concrete12
Structural
- Apr 26, 2023
- 3
Hi All,
I’m trying to understand how moments in an insitu RC column transfers to the column below.
For example, on L5, the column above is loading the column below eccentrically (200mm). The load from the column above is N* = 5000kN, so the column below takes a moment of 5000kN * 0.2m = 1000kNm as well as an axial compression force of 6000kN (assuming the load increases by 1000kN each floor). Column below L5 can be designed for this combined compression and moment.
Assuming that all columns are fixed, and the column below L4 is concentric to the column below L5 and it takes an axial compression force of 7000kN. However, I’m trying to see how the moments in the column below L5 will transfer to the moments in the column below L4. Will the column below L4 also take a moment of 1000kNm, or, can you resolve the moment from the column below L5 into a push/pull and combine us with the 7000kN force that acts uniformly over the column cross section so that the resultant force is eccentric to the column below L4 (but the eccentricity is less than 200mm) and design that column for combined bending and axial force?
For simplicity in this example, let’s assume all columns are 1000x1000. Also, for simplicity, I haven’t taken into consideration any additional moments from the slabs/beams.
I’m trying to understand how moments in an insitu RC column transfers to the column below.
For example, on L5, the column above is loading the column below eccentrically (200mm). The load from the column above is N* = 5000kN, so the column below takes a moment of 5000kN * 0.2m = 1000kNm as well as an axial compression force of 6000kN (assuming the load increases by 1000kN each floor). Column below L5 can be designed for this combined compression and moment.
Assuming that all columns are fixed, and the column below L4 is concentric to the column below L5 and it takes an axial compression force of 7000kN. However, I’m trying to see how the moments in the column below L5 will transfer to the moments in the column below L4. Will the column below L4 also take a moment of 1000kNm, or, can you resolve the moment from the column below L5 into a push/pull and combine us with the 7000kN force that acts uniformly over the column cross section so that the resultant force is eccentric to the column below L4 (but the eccentricity is less than 200mm) and design that column for combined bending and axial force?
For simplicity in this example, let’s assume all columns are 1000x1000. Also, for simplicity, I haven’t taken into consideration any additional moments from the slabs/beams.