Applies To Product(s): AutoPIPE, Version(s): 2004, XM, & V8i Environment: N/A Area: Modeling Subarea: Original Author: Bentley Technical Support Group Dec 2014, AutoPIPE V8i 09.06.01.10 Overview The mass and flexibility of structural supports can have a profound impact on the piping stress analysis. In many instances, if the support structure deflects only a fraction of an inch, it can affect piping moments to the extent where hangers can be eliminated, and/or piping loads on equipment nozzles and supports can be significantly altered. In addition, consideration of structural support flexibilities changes the natural frequencies of the piping system. Modeling pipe/structure interaction as part of piping stress analysis Despite the fact that structural support flexibilities can have a significant impact on piping loads and stresses, most piping engineers do not consider these flexibilities in their piping stress, analysis. Typically, structural supports are modeled as simple supports such as rigid guides, vertical stops, line stops, etc. with no consideration given to the flexibility of the support itself. Although AutoPIPE allows engineers to input a stiffness as part of the support element, the piping engineer often does not have convenient access to structural support details needed to calculate support stiffness'. As a result, the support is typically treated as rigid. As an alternative to using simple supports, AutoPIPE enables engineers to easily build the support structure into the piping model in order to consider pipe/structure interaction. The structural modeling is done within the piping model itself and takes advantage of AutoPIPE's graphical user interface, Using AutoPIPE's ability to graphically copy & paste between separate jobs or within the same job, users can now create libraries of common support structures and paste them into their new model in seconds . We will explain later AutoPIPE's unique abilities in defining the relationship between piping and structural steel. AutoPIPE users are riot burdened with going back and forth between separate programs or batch files to model support structures. Currently, AutoPIPE supports the American Institute of Steel Construction cross, sections as well as a material properties library for common structural steel materials. Once a cross section has been interactively selected, the user immediately sees the cross sectional properties with moments of inertia from the AutoPIPE structural database as well as the steel material properties. Nonstandard cross sections or cross sectional properties for International steel shapes can be entered as nonstandard or saved in the AutoPIPE database. AutoPIPE's structural steel analysis provides beta angle options, moment releases for pinned joints, and rigid end length options. Users see the structural model graphically as it is being built. Once the support structure has been created, users can define the connection between piping and structural steel using one of AutoPIPE's 2 point supports such as a guide or a vertical stop. A user can, for example, define the support connection between node B10 on his piping system and node 21 on his support frame by connecting them with a guide from B10 to 21. From there, the user can place gaps in any direction in the event that the pipe would lift off or move, and can also input friction. The flexibility of the support structure, including friction loads, will then be considered as part of the piping analysis. In addition to piping analysis results, users can also review beam deflections, beam forces and moments. Comments, Questions, and Answers about modeling Beam / Frames In AutoPIPE Item #1: How to insert a beam into an AutoPIPE model questions related to: a. Beam Properties dialog b. Insert Beam dialog Item #2: How to model piping held by 2 rigid beam structural supports members Item #3: How to model a vertically pipe supported by a Pipe clamp and spring supports as shown below: Item #4: How to model a U-bolt in AutoPIPE : Item #5: How to Model Equipment Supported by Steel and Springs? Item #6: How to model a Trunnion welded structural pipe support in AutoPIPE? Item #7: Modeling the same beam 3 different ways in AutoPIPE Item #8: How to model a support that moves with the tank/vessel? 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!
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