Technical Paper | calcstress

This section consists of technical papers implying documents on which our studies about basis of some piping stress engineering methods are formed. The presented knowledge gives users an opinion about philosophy of formulas, criteria, assumptions and limitations on which some common engineering methods or codes are based on. Informed engineers who are familiar with the basis and limitation of those methods make use of them effectively. Nothing has been invented by us but in some cases users may recognise clearly our interpretation which may be different from theirs. We will be grateful if users send us their opinion. In the future, a mechanism will be devised to communicate effectively with users. What is important to us is shedding a light on dark side of some common methods and start documenting and sharing opinions and experiences in this field. Using all parts of this site, you agree to the disclaimers which are mentioned in Terms and Conditions.

The technical papers, in this part, cover the following subjects:

Concept of discontinuity stress (Local Stress).
Common applied models which have been developed for local stress calculation in support locations including Ring Model (basis of local stress calculation in saddle supports) and bare pipes and Choking Model (basis of local stress calculation in welded attachment such as structural profile or pipe).
Developed local stresses which are studied in WRC-107 as well as the method limitations and assumptions.
A method to combine local and general stresses as well as safety factor calculation at discontinuity area

The technical papers, in this part, cover the following subjects:

Introduction to FRP pipes unique behaviors and characteristics.
Interpretation to Common applied methods, codes and standards which have been developed for FRP pipes stress analysis including: ISO 14692, BS 7159, UKOOA, ASME B31.3.
Description on the codes and standards applications, assumptions and restrictions.
Definition of criteria required for design and stress analysis of FRP pipes.
Special considerations in designing of AG and UG FRP pipes.
Improper supporting of FRP pipes and possible solutions

The technical papers, in this part, cover the following subjects:

Introduction to buried pipe behaviour
Developed stress calculations in a restrained and unrestrained AG and UG piping system
Elongation calculations in an unrestrained AG and UG piping system
Pipe-soil interaction including: internal and external pressure effects, surface loads effects, buoyancy effects and soil resistance,…
Introduction to Hydrostatic thrust
Criteria for designing buried pipes and pipelines

The technical papers, in this part, cover the following subject:

Concept of flexibility analysis in vessel-piping connection, the displacement imposed to the piping by vessel and the effects of piping loads on vessel.
Introduction to common applied methods, codes and standards for stress analysis of vessel nozzles including: API 650, WRC 107, BS5500,…
Interpretation on API 650 requirements for storage tanks in order to analysis the local nozzle stresses and allowable loads.
Calculation of radial and rotational movement of tank nozzle based on chocking model.
Calculation the stiffness and allowable loads of tank nozzle.

The technical papers, in this part, cover the following subject:

Introduction to the application of flexible joints including: bellow expansion joints, slip joints-flexible hoses.
Basic elements of flexible joints and the related design codes and standards
Methods of modeling flexible joints by using design catalogs or calculation sheets.
Calculation operational movements of expansion joints and their limitations.
Effects of pressure thrust on designing of expansion joints.
Improper installation of expansion joints and possible solutions

The technical papers, in this part, cover the following subject:

Common characteristics related to piping interface with rotating equipment.
Introduction to common applied methods, codes and standards for determination of allowable piping loads on rotating equipment including: API 610, 617, NEMA SM23.
Determination of movements in nozzle connection points.
Proper supporting for pipes connected to a rotating equipment in order to minimize the sustained and operational loads
Problems associated with pulsating flow and pulsation pressure in reciprocating compressors and pumps.