Dear Engs,
Good day,
I have Just confused when i am doing a calculations of forces and moments that will affect my designed line with loops,
Pipe Data:
10″ X 0.365″, API 5L X52
Moment of Inertia: 160.8 in^4
Diff in temp (btw installation and operating) = 165 C = 329 F
Thermal Coefficient = 6.72 x 10^-6 in/in F
Modulus of elasticity = 28.23 x 10^6 PSI
Pipe All length = 920 m, straight line above ground with two anchors at the ends.
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I just calculate the forces on loops in three ways:
1- Kellog (Chart C-12)
Fx = 2395 lb
M = 38693.11 Lb.ft
2- Grinell
Fx = 120.45 lb (its so small, and i consider this force acting on the guide not on the anchor)
as we have 24 guides (supports) so the acting force on the anchor will be 120.45 X 24 = 2891 lb
Sb= 967 Psi ??
3- Cantilever Method:
by dividing pipe into segments and calculate expansion of every segment then:
F = 12 x E x I x Delta / L^3 = 7153.27 lb (this force is the whole force on the vertical leg of loop)
M = 6 x E x I x Delta / L^2 = 3576.63 lb.ft
NOTED that
Every method has a value of force and moment,, and the value of cantilever method is very very high comparing with Kellog and Grinell ???
So can any one understand this puzzle and help me, in any way….
sorry for my long POST !!
REGARDS
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