Week 11 Challenge
Q1. Friction load determination
A pipe carrying LNG rests on the shoe having vertical force of 125 kN. Calculate the Friction load on the axis. Also find the friction force, if TEFLON pad is used between shoe and pipe support.
Ans:
Aim and Introduction :A pipe carrying LNG rests on the shoe having vertical force of 125KN.Friction load on the axis and friction force are required to be determined if there is TEFLON pad between shoe and pipe support.
Procedure:
Friction factor /Coefficient and friction load on piping :-
Materials Friction Factor
Steel to Steel 0.3
Teflon to steel 0.1
i)When a steel pipe is resting on steel
Friction force in the longitudinal direction (Ff)=Coefficient of friction X Gravity load
= 0.3*125KN =37.5KN
Friction force in the transverse direction (Ff)=10% of piping operation load
= 0.1*125KN =12.5KN
ii)When a steel pipe is resting on TEFLON
Friction force in the longitudinal direction (Ff)=Coefficient of friction X Gravity load
= 0.1*125KN =12.5KN
Friction force in the transverse direction (Ff)=10% of piping operation load
= 0.1*125KN =12.5KN
Result:
Friction load in the longitudinal direction and transverse direction are 37.5KN $ 12.5KN respectively when pipe is resting on steel and friction load in the longitudinal direction and transverse direction are 12.5KN $ 12.5KN respectively when pipe is resting on Teflon.
Q2. Support Types
Identify the type of support as Spring, Guyed, Stop or Semi Anchor (Guyed + Rest + Stop ) or Rigid Strut from following images.
Figure 1:
Spring support which permit the pipe to move 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:Guid support which restrained the lateral movement in two direction therefore also limits the rotational movement of pipe but permit axial movement of pipe.
Figure 6 :
Anchor support which does not permit the pipe to move in any direction thus movement in all 6 degree of freedom is restricted.
3. Design of a pipe rack
Design a typical pipe rack bent in oil plant. The pipe rack configuration shall be as shown in Figure 1 and the plan layout as shown in Figure 2.
Figure 1
Figure 2
Ans :
Modelling procedure
- As soon as the STAAD software is opened the analytical model is selected and then the units that are used for load and distance measurement are selected and then the file is saved at the appropriate location.
- Next the nodes are created with structure node option that appears at the right side of the screen.In that the co-ordinates are entered in the format of X,Y,Z system. Where the X is along the horizontal direction and Y direction is along vertical direction and Z is also along the horizontal direction.
- Theen these three nodes are connected each other with the help of the add beam option which helps to create the beams and columns and rafter.The beams are connectes as per the requirement.These beams can also be repeated with the help of the transitional repeat option
- Thus the structure that is required is modelled.The extra beams that are not required are deleted.
- Go to properties and add section and assign property.
Go to support and create support and assign support
Loading add load definition and add load case details and assign loads to members
- Uniform operating dead load =1.9KN/sqm
- Pipe load =1.9*7.5 =14.28KN/m
- 60% of pipe load =8.5Kn/m
- Point load =15KN
- 60% of point load =9KN
Go to load combination and add envelope and add combinations and loads.
Go to design parameter and add parameters
Run analysis and check results
RESULTS:
From the project carried out it can be concluded that the concept of the modelling of a pipe rack structure and the applications of the loads and defining of the load combination of the structure as per the given data with the use of the STAAD software.