Roadcrossing

The pipeline model within the project 'Roadcross' is a crossing of a 36" potable water transport pipeline with a road. The road is 8 m width with a roadside of 1 m on each side of the road. The crossing is designed perpendicular to the road-axis and connected with two large radius bends R = 10*D and a angle of 60o.

Click to expand/collapsePipeline data

Pipe material

API 5L X52 steel

Yield stress

52.000 psi = 358 N/mm2

Outer diameter

914.4 mm (36")

Wall thickness

9.52 mm

Corrosion allowance

2 mm

Minimum manufacturing tolerance

5%

Maximum operating pressure

1.0 MPa

Transported matter

potable water

Deadweight of filled pipe structure

1.854 kN/m

 

Pipeline geometry and side elevation are shown in the figures below.

 

RoadcrossPipeProfileHor

Click to expand/collapseSoil data

Soil is assumed to consist of a silty sand with a sub-lager of non-consolidated clay. Road construction will be done after the pipeline was laid, resulting in expected soil settlements of the road-earth body with a maximum of 200 mm at the road-axis location. (consolidation of sub-layer of clay due to increased vertical soil pressure)

 

Main soil data are:

SOILNB

[N/mm2]:

soil overburden loading

RVT

[N/mm2]:

ultimate soil reaction, pipe moves vertically upward

RH

[N/mm2]:

ultimate soil reaction, pipe moves sideward

RVS

[N/mm2]:

ultimate soil reaction, pipe moves vertically downward

KLS

[N/mm3]:

vertical soil stiffness for pipe moving downward

KLT

[N/mm3]:

vertical soil stiffness for pipe moving upward

KLH

[N/mm3]:

horizontal soil stiffness

F

[N/mm2]:

ultimate soil friction

UF

[mm]:

ultimate displacement for linear soil friction

SETZ

[mm]:

vertical soil settlement curve

RoadcrossSoilVert

Relevant soil data have been determined along the pipeline axis based on the occurring overburden and the results are shown in the overall soil data diagrams below.

RoadcrossSoilData

Info KLT is usually (taken) equal to KLS, but may be specified separately, if different.

Click to expand/collapseLoad factors

This example is based on ultimate load design, meaning that load factors > 1 are applied on the various loading components in DF5 LOCASE.

The resulting stress is then evaluated on the yield stress of the pipe material.

If the allowable stress method should be applied, all load factors shall be set to 1 and the resulting stress evaluated on the allowable stress. Due to the non-linear behaviour of the pipe model (in this case due to the soil behaviour) the two methods give different answers.

Applied load factors are (according to NEN 3650-2:2012):

internal pressure

1.15

temperature

1.10

deadweight

1.10

soil settlements

1.10

traffic loads

1.35

elastic bends

1.10

wave/current loads

1.20

The Ple4Win project file containing this specific example can be found in the sample folder (Road Crossing.plex). However, this sample database is provided in case there are uncertainties about how the data should be entered and to verify the calculation results.


Last changed: 14/09/2016