darkjmf1
Structural
- Dec 17, 2012
- 49
Section "6.2.8 Design of column bases with base plates" of Eurocode 3, Part 1-8, shows how to obtain the "Design moment resistance Mj,Rd of column bases" in Table 6.7, but there is something in these formulae I cannot understand:
Mj,Rd is obtained as the minimum value of two formulae (for every possible combination of tension/compression at both sides of the column).
This formulae depend on the value of the eccentricity of the load defined as e=MEd/NEd.
Let's say that I calculate the value of Mj,Rd from two given values of MEd and NEd (e=MEd/NEd is an input data). It is supposed that the obtained Mj,Rd is the maximum moment that the base plate could resist for the given NEd.
But if I calculate again using as input data the previously obtained Mj,Rd and NEd, I get a new Mj,Rd(2), which is smaller than the original one (as long as the new eccentricity e(2)=Mj,Rd/Ned is bigger than the original e=MEd/NEd).
In conclusion, Mj,Rd depends on the input data. Isn't it a bit strange provided that it is a resistance?
What am I misunderstanding?
Can anyone explain it to me or point me to any document which clarifies this issue, please?
Mj,Rd is obtained as the minimum value of two formulae (for every possible combination of tension/compression at both sides of the column).
This formulae depend on the value of the eccentricity of the load defined as e=MEd/NEd.
Let's say that I calculate the value of Mj,Rd from two given values of MEd and NEd (e=MEd/NEd is an input data). It is supposed that the obtained Mj,Rd is the maximum moment that the base plate could resist for the given NEd.
But if I calculate again using as input data the previously obtained Mj,Rd and NEd, I get a new Mj,Rd(2), which is smaller than the original one (as long as the new eccentricity e(2)=Mj,Rd/Ned is bigger than the original e=MEd/NEd).
In conclusion, Mj,Rd depends on the input data. Isn't it a bit strange provided that it is a resistance?
What am I misunderstanding?
Can anyone explain it to me or point me to any document which clarifies this issue, please?
