Week 11 Challenge
ANALYSIS AND DESIGN OF PIPE RACK STRUCTURES
Q1) Friction load determination
Given data :
A pipe carrying LNG rests on the shoe having vertical force of 125 kN. Friction load on the axis and friction force are required to be determined if there is TEFLON pad between shoe and pipe support.
Friction factor for steel to steel - 0.3
Friction factor for teflon to steel- 0.1
(A) When Steel pipe is resting on steel:
Friction force in longitudinal direction (`F_f`) = Coefficient of friction X Gravity Load
= 0.3 x 125 KN = 37.5 KN
Friction load in transverse direction = 10% of piping operation load
= 0.1x 125 = 12.5 KN
(B) When Steel pipe is resting on Teflon :
Friction force in longitudinal direction (`F_f`) = Coefficient of friction x Gravity Load
= 0.1x125 KN = 12.5 KN
Friction load in transverse direction = 10% of piping operation load
= 0.1x 125 = 12.5 KN
The results show forces pipe resting on steel be - 37.5 and 12.5 KN
Results for teflon be - 12.5 and 12.5 KN
Q2) Support types determination
FIGURE 1 - shows the spring support to move the pipe in vertical direction
FIGURE 2 - RIGID Support which allow small angular displacement and thermal movement.
FIGURE 3 - Stop support which restrained the movement of pipe in axial direction but allows the pipe movement in lateral direction
FIGURE 4 - Semi Anchor Support which restrict the pipes to move in axial as well as transverse direction.
FIGURE 5- GUYED support which restrained the lateral movement in two direction therefore also limits the rotational movemement of pipe but permit axial movement of pipe
FIGURE 6 -Anchor Support which does not permitt the pipe to move in any direction thus movement in all 6 degree of freedom is restricted.
Q3) DESIGN OF PIPE RACK
GIVEN DATA
COLUMN HEIGHT = 9 m
FIRST TIER HEIGHT = 6 m
SECOND TIER HEIGHT = 7.5 m
THIRD TIER HEIGHT = 9 m
RACK WIDTH = 7.5 m ( C/C of Column in width of pipe rack)
BAY SPAN = 6 m
NUMBER OF BAYS = 7
Top tier of pipe rack has 3 number of cable trays each 150 mm wide
Second tier of pipe rack has 4 pipes ,one of 24 " dia and one of 12 " dia, remaining two pipes are of dia 8".First tier of pipe rack has 6 pipes ,one of 18 " dia and remaining 5 pipes are of dia smaller than 8"
LOADS APPLIED :
Structural dead load - Excluding weight of pipe
Operating dead load - Weight of pipe, fluid in it and insulation. UDL of 1.9 KN/Sqm is asuumed for pipe of dia 8". Point load is considered at appropriate location for pipe larger than 8" dia pipes which will be reported by Piping Engineer.
Empty dead load - Weight of empty pipe without fluid in it but including insulation , it is assumed as 60% of operating load
Test dead load - In case test medium in pipe is not known, water with density of 1000Kg/CuM is considered as test medium so generally test load is same as operating dead load.
Cable tray load - UDL of 1 KN/m is assumed
Analysis is done and shows zero errors, zero warnings.
Pipe Rack as per given plan and Elevation has been modelled using STAAD PRO software and various members have been assigned the properties. Various Load due to piping in different situation such as empty pipe case when Siesmic effect is considered, operational pipe load when the pipe rack is commisioned i.e. fluid is being transported throuh it including insulation ( UDL @ 1.9 KN/Sqm for pipe upto 8" dia and Point load due to pipe of dia larger than 8" which will be prvided by piping engineer) , Test load will be considered with pipe load full of test fluid ( shall be considered water as test fluid if not known ), Cable tray load is considered @ 1 KN/Sqm on top tier of pipe rack.
Stadd file is attached below.