Buoyancy Control
buoyancy
LTRO PROJECT
PIPELINE BUOYANCY ANALYSIS FOR 6" TRUNKLINE
Design Parameter
Pipe Properties-Pipe outside diameter, OD (in.)=6.625Density of
pipe, rp (lb/ft)=490.063=0.2836012731lb/in-Pipe wall thickness, tp
(in.)=0.562Density of Concrete Saddle, rc
(lb/ft)=149.828=0.0867lb/in-Pipe inside diameter, ID
(in.)=5.501Density mud soil, m
(lb/ft)=94.87=0.0549lb/in-Material=API 5L Gr.X42 SMLSDensity of
anti-corrosion coating, a (lb/ft)=56.229=0.0325399306lb/in-SMYS
(psi)=42,100Density water, w (lb/ft)=62.429=0.0361lb/in-Each
Standard Average Pipe Length (in)=472.44Design Safety Factor
SF=1.2-Anti-corrosion coating thickness, ta (in)=0.090Pipe depth of
cover (m)=2=78.74015748in
Buoyancy Calculation
a.Weight of Bared PipeCross Sectional Area (CSA) of Pipe wall,
Ap=
=10.70 in2
Weight of pipe per unit length, Wp=
=3.04 lb/in
b.Weight of Anti Corrosion CoatingCross Sectional Area (CSA) of
coating, Aa=
=1.90 in2 Weight of coating per unit length, Wa=
=0.06 lb/in
c.Pipeline Buoyancy in Open TrenchCross Sectional Area (CSA) of
line pipe+coating, At=
=36.37 in2
Weight of displaced water, Ws=(Archimedes' Principle of
Buoyancy)
=1.31 lb/in
Cross Sectional area of backfilled soil on top of pipe, Ad=OD x
Depth of Cover
=521.65 in2
Pipeline buoyancy per unit length, B=
=-1.78 lb/in
Pipeline buoyancy per joint pipe, Bp=-842.67 lb
Since the pipeline has ngative buoyancy force in the swampy
area, concrete set-on weight will not be used as the anti-buoyancy
force to prevent the pipeline from floating.
Calculation Page 1 of 1
