Applies To Product(s): AutoPIPE, Version(s): 2004, XM, & V8i Environment: N/A Area: Modeling Subarea: Original Author: Bentley Technical Support Group Problem: What are some typical modeling approaches for different types of piping? Answer: #1: Coated PIPE (ex. concrete encased steel pipe) - Fin: Similar approach may be used here to come up with an equivalent modulus for the modeling pipe with Fins: . Answer: See link here #2. Corroded PIpe or Spot corrosion?: Question: Does AutoPIPE offer a function or upgrade that will analyze corroded pipe with the following user information: a. Corrosion network sizes b. Longitudinal and rotational positions c. Minimum wall thickness at pit depths Answer: See link here #3. Corrugated Straight pipe Answer: See link here #4 Jacketed Piping Answer: See Link here #5 Large Bore Piping: Question: Are there any problems analyzing big diameter pipe systems? It was indicated that some issues with regards to Caesar's analysis of big diameter pipe analysis? Answer: This is a long standing issue with the Piping codes and this question comes up often. Basically the piping codes only supports SIF calculations for D/t 100, AutoPIPE can be used to provide the correct forces, moments, and displacements in the piping system by applying these user-defined SIF and flexibility factors. Care should be taken with such systems as they are susceptible to ovaling and denting and that should be considered while lifting or supporting the pipes. Modeling, an equivalent pipe section with same section modulus for this large pipe with stiffeners could be calculated. Then adjust the density of pipe to get the equivalent weight of stiffened pipe when selecting a non-standard material (NS) #7. Rigid Pipe Element with "ZERO" Mass (Pipe & Water S.G.=0) Answer: Select a range of pipe, press Insert> Rigid options over Range> uncheck "Include Weight" and user choice to consider "Include Thermal Expansion". #8. Pipe Lining: Question: what is the best way to model material on the ID of pipes. Answer : The cladding mentioned in the pipe properties grid is referring to application on the outer most diameter of insulation. On the pipe properties dialog, enter as lining thickness. Please note that lining is an added weight only and would not contribute the pipe stiffness. If this lining increases the stiffness, then a modified pipe modulus may be entered by computing an equivalent modulus that would give that same EI Ee*Is=Es*Is+Ec*Ic This will give correct bending stiffness by using Ee instead of Es in AutoPIPE. Axial stiffness will be approximate. s=steel, c=CRA. Is=steel moment of inertia. #9. How to model NFPA pipe? Does AutoPIPE have Fire Protection Requirement capabilities? Answer: NFPA (National Fire Protection Association) codes provide specific details about design, construction, operation, and maintenance of piping systems for fire protection. To answer these questions, at this point AutoPIPE does not have a specific NFPA piping code. However, NFPA codes typically refers to the appropriate ASME design code which AutoPIPE may already have. Please review your NFPA code for stress analysis requirements. If AutoPIPE was found to contain the correct Piping Code specified by NFPA, then model the piping system in AutoPIPE as required. #10. Can you analyze tubing, i.e. small dia [ex. 1/2" (13mm)]? Answer: Yes, AutoPIPE has been used in development of tubing systems by our many users. From the AutoPIPE online help: Standard Pipe Cross Sections - ANSI/ASME Library. This library of pipe cross sections pertains to the ANSI/ASME codes B36.10M and B36.19M (1985). They are contained in the file AUTOPIPE.LIB. Pipe sizes from 1/8 (.405") OD with 0.049" wall thk, up to 36" sch 40 wall thk. Copper Tubing Type L (ASTM B88 Refrigeration piping), pipe sizes from 1/4 (.375") OD with 0.030" wall thk up to 3" (3.125") OD with 0.090" wall thk #11. My pipe size and material is not available in AutoPIPE libraries. What options do I have? Answer: A. Pipe size options: AutoPIPE can model almost any size pipe used in most typical piping system built today. for a complete list of pipe sizes available in AutoPIPE, please see the following AutoPIPE help section: Help > Contents> Contents Tab> Reference Information> Libraries> Standard Pipe Cross Sections 1. If you need to specify a pipe that is not currently in the library, perform the following: open the pipe properties dialog screen in a model, place cursor in the "Nominal Diameter" field and press F1 keyboard key. This will display the help for this field, there are instructions on how to enter in your Non-Standard (NS) pipe size. 2. If you like the pipe size added to a customize library file, please log a service ticket requesting information about creating a Component Library file. B. Pipe Material options: Select this link for options to add a new material into a Library file #12. How can I model a pipe that is continuously supported over all its length atop the ground, along a steel beam, in an open trench or gutter using AutoPIPE? Answer: See link here #13: How to model multiple pipe connections to a single header: Answer: See Link here See Also Bentley AutoPIPE External Links Bentley Technical Support KnowledgeBase Bentley LEARN Server Comments or Corrections? Bentley's Technical Support Group requests that you please submit any comments you have on this Wiki article to the "Comments" area below. THANK YOU! You may find some interesting scenarios on our Pipe Stress Wiki: https://communities.bentley.com/products/pipe_stress_analysis/w/pipe_stress_analysis__wiki/8058.model-different-types-of-piping-in-autopipe.aspx The example scenarios have information on how to calculate the equivalent modulus for say pipe enclosed in concrete or pipe with lining that increases stiffness of the pipe. Similar approach may be used here to come up with an equivalent modulus for the pipe.
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