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7/25/2019 Revit Link - ETabs & Robot

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Integrating Revit Structure with Analysis

Softwares. (Best Practice)

When Revit Structure first came out in the mid-2000s it was pitched as a

design and documentation tool. But, even at this early stage of its

development, Autodes recogni!ed the importance of lining to structural

analysis software"s.

When it comes to analytical software there are numerous options in which

software to use, and how e#actly to utili!e that software with a Revit model.$his article will cover when Revit models should %e e#ported to analytical

pacages, how %est to prepare a Revit model for use in analysis software and

will %e a comprehensive overview of the famous two analytical software

options, Ro%ot and &$ABS. We will compare the different software pacages

and loo at %enefits, draw%acs, similarities and differences among them. $his

session will %e a %alanced loo at these software pacages from the perspective

of the end user.

Overview

Autodes supports lining through the open Revit A'(, which ena%les third-

party structural analysis software developers to create worflows %oth to and

from Revit. $he process relies on Revit"s analytical model, which is

automatically created alongside the physical model.

)nce the analytical model has %een %rought across the analysis application

can %e used to perform all types of structural analysis including nonlinear,

dynamic and seismic. *ost analysis applications also perform code checs and


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any changes to mem%er si!es can then %e fed %ac in to Revit Structure so the

whole design stays in sync. (t can %e a highly iterative process so the worflow

is incredi%ly important.

Revit Structure also has a +visuali!ation framewor", which allows users to

view analysis results inside Revit itself. $his could %e things lie moments,

forces or displacement diagrams and can help engineers uantify si!es of

structural components.

How to prepare a Revit Structure Model for Analysis

$here are specific %est practices for each software pacage, %ut the following

are good things to eep in mind when creating a Revit model that is intended

to %e e#ported to analytical software

Pay attention to analytical lines

Make sure analytical lines intersect properly

Try to model on levels, not arbitrary distances away, i.e.

perhaps create a T.O. Steel level, or many levels for varying framing

levels. However, keep in mind that sloped levels, such as roofs, may

reuire speci!c attention and considerations

Model between levels, avoid unconnected heights

"onsult the speci!cs of the intended software regarding how to

handle multi#span or multi#level elements

$se the %appro&imate curve' option for curved beams


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"onsider only updating si(es if updating geometry is not

reuired

)loors, slabs and roofs generally are not well updated, soconsider only sending them one direction, one time

Only e&port what needs to be analy(ed, mark everything else

as %not for analysis', create visibility !lters, or use some other

appropriate process

$nderstand that the process is not perfect and some amount of

%clean up' will be reuired regardless of what analytical software is

used.

Revit to Analytical or Analytical to Revit?

*ost, %ut not all, analytical software companies suggest starting the model in

Revit. owever there are certainly via%le reasons to %egin a model in analysis

software

*nalysis was reuired prior to starting the +evit model

receiving the *rchitectural model-

The engineer is far more ecient/comfortable in the analysis

software

*ny speci!c feature, bene!t, or limitation to the interface of

the analytical software and +evit Structure such that it is more

ecient to begin the model in the analysis software.


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While there are e#ceptions, my opinion is that the models should generally

%egin in Revit Structure. As time goes on engineers are %ecoming more and

more comforta%le with Revit and Revit"s analytical features advance every

year, maing this worflow more reasona%le. Also, Revit is consistently the /

modeling software utili!ed, and preferred analytical software may change

often. But furthermore, as engineers, our delivera%le is 1usually a set of 2

documents. Revit is the software used to create the geometry that ultimately is

used to create the 2 drawings. $herefore, ( %elieve it is important that the

geometry is correct. Although there are other reasons that support starting in

Revit, ( %elieve this reason alone is enough to suggest %eginning in Revit.

Analysis Software Overview

$wo widely used analysis programs will %e discussed. $hese article will cover

more specific %est practices of each. $he following elements were supported

for e#changing %etween each software and Revit Structure.

1.0 ETABS

3omputers 4 Structures, (nc. speciali!es in software programs for structural

and earthuae engineering. &$ABS was specifically developed for multi-story

structures. 3Si has several other design software pacages such as SA'2000,

'&R5)R*-/, SA5&, and more. )ne item of note is that the 63Si#Revit7 lin

is not free, as is the case with the other software pacages, and the latest %est

practice documentation is intended for Revit versions.

ETABS Ele!ents"#roperties supported for e$c%an&e

0rids once only- 1 2evels


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3eams 1 "urved beams only if curve is appro&imated-

Steel 4oists come through as beams- 1 "olumns

5alls 1 )loor Slabs

6solated )ootings 1 3races vertical only-

Openings7 wall, shaft and by face

2oads, load cases and load combinations some limitations-

+eactions 1 Material Properties limited, once only-

Section/si(e properties 1 8nd !&ity/releases

ETABS Ele!ents"#roperties unsupported for e$c%an&e

Openings7 pro!le/boundary

9iaphragms

Hori(ontal 3races

Trusses come through as unrecogni(ed frame sections-

3eam Systems come through as unrecogni(ed frame sections-

5all )ootings

Phasing

+ebar/hosted +ebar


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ETABS Best #ractices

9iaphragms will have to be de!ned once in 8T*3S

6mport/e&port dialog bo&es appear providing mapping editing

opportunities during the import/e&port process. 6f a parametric

family has an unrecogni(ed type, 8T*3S will create a corresponding

shape

Software setup7 users must run as administrator 8T*3S,8T*3S6O and +evit.e&e-. 6f +evit is not run as administrator then

there is a possibility that "S6&+evit will not be able to open .log !le.

6n this case "S6&+evit will not be able to write any warning in the log

!le and all warning messages will be displayed on the screen time to

time. 9irectly sending data to 8T*3S may not work if +evit is not run

as admin.

8nd release updates are occasionally buggy

:#;usti!cation and start and end ooor will be

transferred


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6n#place families are imported into 8T*3S as frame members

8lements can be deleted upon importing/e&porting, but only if

the entire model is e&changed

2oad combinations can be e&changed once, but cannot be later

updated. They can, however, be deleted and replaced

'.0 Ro(ot

Ro%ot Structural Analysis 'rofessional software is Autodes analytical

software provides engineers with advanced B(*-integrated analysis and

design tools to understand the %ehavior of any structure type and verify code

compliance. Ro%ot Structural Analysis 'rofessional structural software helps

engineers more uicly perform simulation, sla%s8walls meshing, analysis,

and code-%ased design for any type of structure.

Ro(ot Ele!ents"#roperties supported for e$c%an&e

0rids 1 2evels

3eams 1 "urved beams

3eam Systems members only- 1 "olumns

3races vertical only- 1 Trusses members only-

Steel 4oists 1 )loor slabs

Slab edges 1 5alls


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6solated footings 1 5all footings

Pier/Pile caps 1 2oads, 2oad cases, 2oad combinations

+eactions 1 Material Properties

Section/si(e properties 1 Section rotation

8nd !&ity/releases 1 +ebar/hosted rebar

Ro(ot Ele!ents"#roperties unsupported for e$c%an&e

Openings 1 )oundation slabs turn into >oors-

Hori(ontal braces 1 Phasing

9rilled pier foundations 1 Structural $sage

Ro(ot Best #ractices

Static analysis only. *nalysis is limited by the capabilities of

+obot Structural *nalysis and some analyses may reuire the

enhanced capabilities of +obot Structural *nalysis Professional

"onsider di


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Multi#span members will be split into separate members once

in +obot

$se hosted area loads whenever possible

Send and update +evit/+obot models from *naly(e tab within

+evit

$pon updating the +evit model, there is an option to keep

updated elements selected

+obot will analy(e and e&change some connections7 end plateand column >ange connections

Sloped planes/framing are supported, so only one level and

then element o


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9ining Revit Structure to analysis can help engineers thin a%out the

specifics of the design much earlier on, ena%ling them to try out different

options long %efore things get too e#pensive to fi#.

$his article provided a large amount of information on famous analytical

programs with hopes of clarifying the %enefits and limitations when

integrating the use of these products with Revit Structure *odels. Although

the analytical software themselves are different, and intended for different

types of analysis, this article also compared and contrasted each of them in

relation to their a%ility to interface with Revit. $his article hopes to have not

only offer the information to help mae the decision of which analytical

software is most appropriate, %ut also to provide enough information to now

what to e#pect when %eginning to use the software in con:unction with Revit

Structure.

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