Posted by: rajagopal
Sustained - Hot Sustained - 06/13/07 07:34 AM
Hi everyone. I would like to post a question. I built the following load cases
1) W+P1+T1(OPE)
2) W+P1 (SUS)
3) T1 (OPE)
4) L1-L2 (EXP)
5) L1-L3 (SUS)
The load case five L1-L3 is my hot sustained case. The system i analysed was a piperack line of NPS 8 inch. There was lift at many places. When i checked the stresses in hot sustained it was under allowable but around 90%. I checked the displacement in hot sustained (which is usually not reqd) for my reference. The disp was around 1000 mm with negative sign. Then i modelled a pipe of same size (8 inch - STD), schedule, material as simply supported beam. The stress in sustained case was above the allowable with support span 20M. I checked the displacement at the middle i.e at 10M it was -290mm. My question is why the stress in hot sustained case is below allowable even when the displacement was -1000mm and above allowable with displacement -290mm when the allowable is same (Sh) in both cases.Please clarify.
Thanks in advance.
1) W+P1+T1(OPE)
2) W+P1 (SUS)
3) T1 (OPE)
4) L1-L2 (EXP)
5) L1-L3 (SUS)
The load case five L1-L3 is my hot sustained case. The system i analysed was a piperack line of NPS 8 inch. There was lift at many places. When i checked the stresses in hot sustained it was under allowable but around 90%. I checked the displacement in hot sustained (which is usually not reqd) for my reference. The disp was around 1000 mm with negative sign. Then i modelled a pipe of same size (8 inch - STD), schedule, material as simply supported beam. The stress in sustained case was above the allowable with support span 20M. I checked the displacement at the middle i.e at 10M it was -290mm. My question is why the stress in hot sustained case is below allowable even when the displacement was -1000mm and above allowable with displacement -290mm when the allowable is same (Sh) in both cases.Please clarify.
Thanks in advance.