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Loadfactor for internal pressure can be higher according to NEN3650
18-03-2010, 09:50 AM, (This post was last modified: 12-01-2013, 09:12 AM by shaswin.)
#1
Loadfactor for internal pressure can be higher according to NEN3650
Ple4Win assumes that a calculation of loadcase 2 (internal pressure) according to the NEN 3650 has always a loadfactor of 1,25 according to table 2 of NEN3650-2:2003.

This is however not always the case according to NEN3650. This loadfactor is higher for pipelines in a station. See chapter 8.5.2 of NEN3650-2:2003. The loadfactor is then 1,5/1,1. So the current assumption in Ple4Win is wrong in a case when a pipeline is in a station.

I did a request for this:
[796]: [# 25] Allow internal pressure loading factor to have a different value than 1.25 while using NEN3650

So there is a need for adding 2 extra columns in the PRESS table in function 4,2. Default values could be set to 1,25.
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19-03-2010, 03:58 PM,
#2
RE: Loadfactor for internal pressure can be higher conform NEN3650
You are right that Ple4Win has a fixed facctor 1.25 for the internal pressure only (BC2), while NEN 3650-2:2003 mentions some different factors. For instance 1.1 for the maximum incidental pressure (MIP) and 1.5/1.1 for pipelines in stations as you state.
The factor 1.25 has been chosen because it is the experience that the overwhelming majority of pipeline projects concerns pipelines outside stations. Nevertheless we deem it desirable to create the possibility to specify a factor different from 1.25.

The most suitable location is the input table LOCASE. By adding rows (and columns) to the table it becomes possible to specify sections of the pipeline to be situated at a station and other sections to be outside the station area.

This addition to Ple4Win is planned to be realised in one of the following versions.
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19-03-2010, 08:55 PM, (This post was last modified: 19-03-2010, 09:04 PM by shaswin.)
#3
RE: Loadfactor for internal pressure can be higher conform NEN3650
Yes, adding the BC2 loadfactor in LOCASE table is much better.

Multiple rows in the LOCASE would be great, so one could insert different loadfactors at a specific IDENT/AX-L/AX-LP. So a transition in loadfactor could be made at any point in the configuration:

1. transition between Rotterdam loadfactors and NEN3650 loadfactors;
2. transition between different materials (for example transition between steel and polyethylene);
3. transition between pipelines outside and inside a station;
4. transition maximum incidental pressure (MIP) and default internal pressure.
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10-07-2010, 09:06 PM, (This post was last modified: 10-07-2010, 09:11 PM by shaswin.)
#4
RE: Loadfactor for internal pressure can be higher conform NEN3650
According to NEN3650-2:2003 table 2 the loadfactors can be also 0 (variable load) or also 0,9 (permanent load) when the loading is reducing the stresses.

Quote from the Dutch code:
   

So this also a reason to add multiple rows in the LOCASE, so a reduced loadfactor can be applied locally.
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04-01-2013, 04:32 PM, (This post was last modified: 05-01-2013, 06:31 AM by shaswin.)
#5
RE: Loadfactor for internal pressure can be higher conform NEN3650
(19-03-2010, 08:55 PM)shaswin Wrote: Yes, adding the BC2 loadfactor in LOCASE table is much better.

Multiple rows in the LOCASE would be great, so one could insert different loadfactors at a specific IDENT/AX-L/AX-LP. So a transition in loadfactor could be made at any point in the configuration:

1. transition between Rotterdam loadfactors and NEN3650 loadfactors;
2. transition between different materials (for example transition between steel and polyethylene);
3. transition between pipelines outside and inside a station;
4. transition maximum incidental pressure (MIP) and default internal pressure.

When a transition is realised in the LOCASE (no fixed row) in the future, the displacement in axial direction at the transition node should have a jump (due to transition in different loadfactors).
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