Integrating Revit Structure with Analytical Software

1. Integrating Revit Structure with Analytical Software Desirée Mackey Martin/Martin, Inc.

2. Overview Introduction Questions: When, How and Where to Start Discuss five software packages: do’s, don’ts and tips • RISA • RAM • Fastrak • ETABS • Robot Comparison of the above packages Open discussion

3. Objectives Wide view of software Unbiased comparison Focus on breadth of information Not focusing on details of the analysis software packages Have a little fun Discussion

4. Introduction – Revit Structure Revit Structure intended to: • Convey 3D geometry • Hold information • Produce construction documents Revit Structure not intended to: • Comprehensive structural analysis • Create/produce calculations • Intricate or complex design tasks

5. Introduction – Analytical Software Analytical software intended to: • Analyze and/or design structural elements • Accurately model/represent structural systems, loads, load paths • Produce data/calculations Analytical software notintended to: • Accurately convey all geometry, especially intricacies • Produce construction documents • Coordinate with other disciplines

6. Introduction – Revit Structure with Analytical Software Meant for entirely different purposes A big task to seamlessly integrate Frequent updates of both creates a moving target effect Thrown together in the name of efficiency

7. Exporting to/from Analytical Software: Questions to Consider Will an analytical software package be utilized in the design? Is there adequate interoperability? Was the Revit Structure model started/complete (enough) before needing an analytical model? Was the Revit Structure model created with the intent to send to an analytical software?

8. Exporting to/from Analytical Software: Questions to Consider Does the project require a comprehensive analysis? Does the project require a specific analytical software? Does the analytical software support model exchanges with Revit enough to make the process viable? If an analytical model is created prior to a Revit model, does that software support exporting into Revit?

9. Exporting to/from Analytical Software: Questions to Consider Does only part of the structure require analysis? If so, perhaps only part of the model should be exchanged? Is the person creating the Revit model adept enough at Revit enough to also create and maintain a viable analytical model? Is it more time/cost-effective to just have two separate people maintain two separate models? Will the export be one-time, or will the model be “round tripped”? Given the chosen analytical software, and its interoperability, does that affect the decision?

10. Which Direction? Most analytical software packages recommend starting in Revit, but not all Always clean-up, so which software is easier to manipulate? Is the modeler/engineer more comfortable in one or the other? Which model is required to start first? Many factors to consider

11. When to Start in Analytical Analysis is required prior to starting the Revit model (or receiving the Architectural model) The engineer is more efficient/comfortable in the analysis software Any specific required features, benefits, or limitations in either software that make starting in the analytical more appropriate/efficient

12. When to Start in Revit Revit is more readily used and understood Revit likely used on every project, not every project requires analytical software, and not the same software at that Revit seems to advance its analytical features often Important to make sure the geometry is properly represented Revit ultimately produces the construction documents

13. Preparing a Revit Structure Model for Export Pay attention to analytical lines Make sure analytical lines intersect properly Try to model on levels Consider how the levels are viewed in the analytical software Model level-to-levels, avoid unconnected heights

14. Preparing a Revit Structure Model for Export Consult the specifics of the intended software regarding how to handle mulit-span or multi-level elements Use the “approximate curve” option for curved beams if practical Consider only updating sizes if updating geometry is not required Floors, slabs, and roofs generally are not well updated, so consider only sending them one direction, one time

15. Preparing a Revit Structure Model for Export Only export what needs to be analyzed Create visibility filters, or use some other appropriate process to keep track/keep organized If needed, model “dummy” sizes (ridiculously large or ridiculously small) to help keep track of what has been designed The process is not perfect and there will be some amount of “clean up” regardless of analytical software

16. Software Researched RISA Technologies RAM Structural System CSC Fastrak CSiETABS Autodesk Structural Analysis – Robot Structural Analysis

17. Research Methods Documentation review Consultations with experts on each of the analytical software packages A few quick tests One basic model test

18. RISA Technologies RISA 3D – Three dimensional structural analysis for steel, concrete, masonry, cold-formed steel, aluminum and timber RISA Floor – Comprehensive analysis for floor systems Link available as a free download Active Autodesk partner and determined to advance with Revit

19. RISA – Notable elements that work Curved beams Beam Systems (members only) Continuous/cantilevered beams Braces (vertical only) Trusses (members only) Steel Joists Floor slabs Slab edges Walls Openings: by face or wall openings only Isolated footings Loads, Load cases, Load combinations

20. RISA – Notable elements that don’t work Openings: shaft and profile/boundary Foundation slabs Horizontal braces Rebar/hosted rebar Wall footings

21. RISA – Best Practices Only use start/end offsets to slope beams Use the z-direction offset to change beam elevations Outdated shapes/old structural shapes need to be mapped to current shapes in the mapping file Slab edge locations are precarious – may change in Revit 2013 Openings require opening framing to transfer properly

22. RISA – Best Practices RISAFloorrequires multi-story columns to be modeled floor-to-floor, and continuous/cantilevered beams need to have each segment modeled separately Check the merge tolerance settings and joint coordinates Be careful about changing node coordinates in RISA Reactions come back into Revit as separate parameters, RISA provides tag families Don’t bother with the Revit analytical checks, use the ones in RISA

23. RAM Structural System Complete analysis and design of steel and concrete 3D model, level based, and individual modules for different elements/materials Bentley software, but Bentley actually creates many add-ons for Autodesk software Link available as a free download

24. RAM – Notable elements that work Steel Joists Braces Trusses (members only) Beam systems (members only) Walls (bearing and structural combined only) Openings: by face or wall openings only Isolated footings Continuous/cantilevered beams (requires special setting) Many elements work but can be exchanged once only, cannot be updated, also will likely only transfer one way (either Revit to RAM or RAM to Revit)

25. RAM – Notable elements that don’t work Loads, Load Cases, Load Combinations Openings: shaft and profile/boundary Foundation slabs Walls set to shear Rebar/hosted rebar Curved beams

26. RAM – Best Practices Set the reference level for braces to the top level to which they frame Frame braces into beams and columns that are set to lateral Default mapping of shapes are set to out-of-the box families Loads just generally don’t work well “Member supports” in the structural settings >>Analytical Model Settings tab must be checked on to detect cantilevered members

27. RAM – Best Practices Multi-story columns in Revit are broken up at the levels in RAM Isolated footings have to be perfectly centred on columns for the information/sizing information to exchange properly Continuous beams need to be modelled as separate segments between supports to be imported properly into RAM If exporting from RAM to Revit, export to a Revit template, not to a blank project For slopped roofs, model flat, or at least all on one level before sending to RAM

28. CSC Fastrak Complete analysis and design of steel Originally a British software, now expanded into US codes “Seamless” communication with Revit Structure Link available as a free download

29. Fastrak – Notable elements that work Beam systems (members only) Curved beams (only if curve is approximated) Braces (vertical only) Steel Joists Trusses (Revit to Fastrak only, members only) Floor slabs (mapping setting required) Stiffeners/plates

30. Fastrak – Notable elements that don’t work Loads, Load Cases and Load Combinations Openings: shaft and profile/boundary Section/size properties – attribute sets Walls Rebar/hosted rebar Wall Footings

31. Fastrak – Best Practices Levels are required at the top of steel level Attributes have to be assigned to all the elements once imported into Fastrak Revit model has to be saved immediately after exporting to Fastrak  In Fastrak, slabs must be supported on all sides by a member If exporting from Fastrak to Revit, the structural usage will have to be adjusted once in Revit such that girders/beams/joists will have the correct line weights

32. Fastrak – Best Practices View filters and the “track changes” command to track changes If analytical lines are adjusted away from auto-detect, the same adjustment must be used at both ends of the member Foundations are created under EVERY column when transferring into Fastrak Revit and Fastrak models can be updated simultaneously, but any changes in one will override the other when exported Reactions exported only for a fully completed design model, and only if members are designated as “gravity only” design. A shared parameter must be added to use a Revit tag

33. CSiETABS Structural and earthquake design specialty Many modules Information is hard to find, and what is there is outdated. Company doesn’t seem to promote their interoperability with Revit Link available on a paid subscription

34. ETABS – Notable elements that work Curved beams (only if curve is approximated) Steel Joists (come through as beams) Walls Floor Slabs Isolated Footings Braces (vertical only) Openings: wall, shaft and by face Loads, load cases and load combinations (some limitations)

35. ETABS – Notable elements that don’t work Openings: shaft and profile/boundary Diaphragm designations Trusses Rebar/hosted rebar Wall Footings

36. ETABS – Best Practices Diaphragms will have to be defined once in ETABS Import/export dialog boxes appear during the import/export process If a parametric family has an unrecognized type, ETABS will create a corresponding shape Windows vista bugs End release updates are occasionally “buggy” Material updates not transferred from ETABS to Revit

37. ETABS – Best Practices Z-justification and start and end offset parameters don’t always translate properly Only openings completely inside a wall or floor will be transferred In-place families are imported into ETABS as frame members Elements can be deleted upon importing/exporting, but only if the entire model is exchanged Load combinations can be exchanged once, but cannot be later updated. They can, however, be deleted and replaced

38. Autodesk Structural Analysis – Autodesk 360 – Robot Structural Analysis Autodesk 360 structural analysis in the cloud, or local analysis using Robot Formerly Project Storm Large analytical updates with each of the last couple of releases Link native in Revit

39. Robot – Notable elements that work Curved beams Beam Systems (members only) Braces (vertical only) Trusses (members only) Steel Joists Floor slabs Slab edges Walls Isolated footings Wall footings Loads, Load cases, Load combinations Rebar/hosted rebar

40. Robot – Notable elements that don’t work Foundation Slabs Horizontal Braces Families/family types that don’t already exist in the Revit project Wall Footings

41. Robot – Best Practices Static analysis only if using 360 Differentiate the start and ends of members The same person will likely model both the Revit and Analytical model, so staff appropriately Multi-span members will be split into separate members once in Robot Use hosted area loads

42. Robot – Best Practices Send and update Revit/Robot models from Analyze tab within Revit Upon updating the Revit model, there is an option to keep updated elements selected Robot will analyze and exchange some connections: end plate and column flange connections Sloped planes/framing are supported Duplicate nodes will be created if analytical lines are not modeled properly

43. A little experimenting...

44. What to model...

45. The model...

46. The model...

47. Model Details Revit Structure 2012 – no 2013 links available yet Steel and concrete members Walls, beams, columns, foundations, braces Precise analytical model Loads, load cases and load combinations applied in Revit – a variety • Pigs modeled as point dead loads • Birds modeled as point and line live loads Followed as many “best practices” for as many of the software packages as possible

48. The model... • Differentiated ends of the analytical lines to help • Best I could do with the roof slab in Revit 2012 – aligns vertically with the members but not always in plan • Floors easier to align properly • Precise intersections

49. The model... • Intersections with many members were harder, especially with braces • Used snapping shortcuts • Definitely more time consuming to make both the geometry and the analytical correct • Occasionally deleted and redrew a member instead of trying to fix it

50. The model... • Made pigs dead loads • Made birds different live loads • Made custom load combination loosely based on IBC load combinations