Pipe Strength Against Surface Load

Read about START-PROF pipe stress analysis software

 

Input data can be copied using the toolbar icon and  inserted into any other Start-Elements analysis by using the toolbar icon in that file.

Pipe strength against the surface load is calculated using the method described here.

Input Data

Property

Description

External diameter, Da

External pipe diameter, D

Pipe wall thickness, S

Nominal wall thickness

Mill tolerance

Mill tolerance at the time of production. More...

Corrosion and wear allowance

Corrosion and wear allowance (working mill tolerance) for wall thickness. More...

External casing diameter, Dc

External insulation casing diameter. If insulation is absent, set as 0

Casing thickness, SC

Insulation casing thickness

Weld bending quality factor

Set based on standards. Can be calculated automatically by pressing . More...

Ambient temperature

Average wall (metal) temperature at the time when pipe segments become a single joined structure. More...

Operation temperature

Operation temperature in operation state. More...

Depth, Z

Depth (distance from soil surface to pipe axis)

Insulation weight

Insulation uniform weight. More...

Product weight

Product uniform weight. More...

Backfill soil number

Trench soil number, can be selected from the soil database (see appendix 1 below)

Base soil number

Base (undisturbed) soil number, can be selected from the soil database.

Steel grade

Pipe material from the materials database

Operation pressure, P

Operation pressure in operation state. Set for all standards except SNIP 2.05.06-85. More...

Working pressure, Pwork

Working pressure (based on standards). Set when analyzing with SNIP 2.05.06-85. More...

Insulation type

Insulation type: armopenobeton, polymer, polyurethane, other

Theory

The additional vertical load for each point of the pipe insulation casing perimeter from the concentrated force, applied on the ground surface can be obtained from Bousinnesq equation

The additional vertical load for each point of the pipe insulation casing perimeter from the infinite length uniform load across the pipe, applied on the ground surface can be obtained using the equation

START-PROF apply two concentrated loads P at the distance L and one uniform load q, and calculate the sum of soil pressure on each point of the pipe finite element model surface around the upper half of the pipe. Also the pressure from the soil weight and pipe internal pressure are applied to the finite element model. After that the nonlinear finite element analysis is done the same way as mentioned above.

Two options of concentrated forces application are considered. The first option is the application of the two forces at the distance L/2 from the pipe axis. And the second option is when first force is right above the pipe axis. The worst pipe and insulation stresses are calculated and taken into account.

See also Polyurethane (PUR) Insulation Stress Analysis

Output

Operating Stress - ring bending stress in the pipe wall

Allowable Stress - allowable stress according the selected code

Ovalization

Dmax, Dmin - maximum and minimum diameter of ovalized cross section of the pipe, Dн - pipe outer diameter

Deflection - ring deflection

Menu Access

Pipe. Buried> Pipe Strength against Surface Load