Question

A 5000-ft long X-65 pipeline is laid down on seabed with two PLETS (One at each end). The pipe OD=7-in with 0.5-in wall thickness. The pipeline was laid at environmental temperature of 40 °F (As- laid temperature). When pipeline is put into operation, the oil flow was produced at 140 °F. If the thermal expansion coefficient of the pipe material is 6.5*10-/°F and its modulus of elasticity is 30,000 ksi, determine the compressive load applied by the pipeline on a PLET due to its thermal expansion. Assume no temperature change and no seabed friction along the pipeline span.

Answer 1

Answer: 199.1 kip

Step-by-step explanation:

Given that

Outer diameter is Do = 7 in

Inner diameter Di = ( Do - ( 2×0.5)) = 6 in

Length = 5000 ft = 60000 in

Now change in length of the pipe due to temperature difference

SL = L∝ΔT

= 60000 × 6.5×10^-6(140-40)

SL = 39 in

Also

sL = PL/AE

A = cross sectional area of pipe = π/4(Do^2 - Di^2)

so

P = SL×A×E / L

= (39 × π/4(7^2 - 6^2)×30000) / 60000

= 199.1 kip

compressive load applied by the pipeline on a PLET due to its thermal expansion is 199.1 kip