Michael Duncanson's Activities

STAAD.Pro 2023 vs Previous Versions

Michael Duncanson — Tue, 12 Sep 2023 20:25:26 GMT

Is STAAD.Pro 2023 == STAAD.Pro CONNECT V23? Or put another way....is the new STAAD.Pro 2023 a step away from the "CONNECT" framework? If it was a step away from CONNECT framework, what is STAAD.Pro 2023 working towards? iTwin?

Sorry, but I swear there have been so many systems in the past 5-8 years being thrown around (v8i, CONNECT, iTwin, etc), I am getting confused.

OpenBuilding Designer - Why Item Sets removed from AECOSim?

Michael Duncanson — Thu, 08 Jun 2023 16:48:51 GMT

Item Sets in AECOSim were highly useful in creating sets of elements and being able to make the rest of the items in 3D views to be transparent, or isolate the item set, or show different Item Sets as different colors for showing 3D graphical representation of changes.

Item Sets were removed in OpenBuilding Designer....closest i can see that USED to be Item Sets are now Named Groups but with limited functionality. Displayset is just a way to isolate.

Did "Item Sets" get moved/renamed somehwere that I just can't find it?

SBeam vs STAAD CONNECT

Michael Duncanson — Tue, 16 May 2023 15:52:13 GMT

What are the benefits of using RAM SBeam over STAAD?

If I already have STAAD, I am wondering if having SBeam would be useful as well.

"Lateral Only Bracing" and P-Delta

Michael Duncanson — Fri, 30 Dec 2022 03:44:56 GMT

Related help topic: Braces Carry Lateral Loads Only

I get that we can use INACTIVE command for primary load case definitions to remove bracing for gravity-only load cases to ensure the column takes the gravity load and not bracing. However, I don't seem to understand how this is accounted for in load combinations, especially when P-Delta needs to be considered.

LOAD COMBINATION command (using superposition summation method) doesn't do P-Delta, BUT the command also does not need primary load cases to be analyzed first...so the INACTIVE method only works for a single load case and therefore is only useful in gravity-only load combinations (a small fraction of total load combinations needing to be considered).

If using combinations utilizing REPEAT LOAD command...great we can consider P-Delta but that means the bracing needs to be active for all iterations and will therefore take on gravity load.

How do others deal with this dilemma? I was looking at an AISC presentation from 6 years ago regarding load path (https://youtu.be/-_1h4muNI7k (1h03m08s)) and a great example comes up regarding this exact issue where knee braces have a huge load due to gravity load in the analysis which was initially intended to be lateral-only bracing.

STAAD .db3 Database - Name vs StaadName?

Michael Duncanson — Fri, 02 Dec 2022 14:57:42 GMT

What is the difference between "Name" and "StaadName" in the .db3 file? If I have a shop mark (say H250W is an H250x250x9x14 japanese section), which one would I update?

Also, in more general I do not see any type of technical literature as to how these databases are set up, or definitions of the variables that are in the table. Is there something like this available?

STAAD CE: Seismic Load Definition & Accidental Torsion Factors

Michael Duncanson — Fri, 28 Jan 2022 14:35:54 GMT

Hopefully this is an easy one, but I can't find a relevant wiki about it. I am going to be using the seismic definitions for IBC/ASCE, however we have a site-specific ground acceleration that allows us to use 80% of the mapped design spectra as a lower-bound. For the most part, except at a small range, this lower-bound governs. I set the seismic load definition as normal (Ss, S1, Fa, Fv, etc.) as I don't want to apply the 80% factor in the input portion; instead, I apply a factor of 0.8 in the IBC LOAD definition, as shown below.

For rigid diaphrams, I will be activating the multiplying factor for accidental torsion moment to the definition as well. Does the Accidental Torsion get affected by the general factor in the first part?

So let's say:

F - The seismic force calculated by STAAD without factors

Eh - Seismic force applied = a*F

At - Accidental Torsion

Is:

At = b*Eh = a*b*F

At = b*F

STAAD CE - IBC LOAD export to POINT LOAD ???

Michael Duncanson — Wed, 23 Feb 2022 14:59:42 GMT

Say I have the following Load Cases to define an IBC Seismic Definition on a structure which is a large process platform that is concentrically braced:

**SEISMIC(+X DIR)****************************************
LOAD 101 LOADTYPE Seismic-H  TITLE EX
*POSITIVE EX IN COMBINATIONS = FORCES APPLIED TO STRUCTURE TOWARDS +X
*
IBC LOAD X 1.0
*
PERFORM ANALYSIS
CHANGE
*
**SEISMIC(+Z DIR)****************************************
LOAD 102 LOADTYPE Seismic-H  TITLE EZ
*POSITIVE EZ IN COMBINATIONS = FORCES APPLIED TO STRUCTURE TOWARDS +Z
*
IBC LOAD Z 1.0
*
PERFORM ANALYSIS
CHANGE

After I perform the analysis, I see that when going back to the analytical modelling workflow - under LOAD 101 and 102 I see point loads assigned to each node. Am I able to extract from STAAD these loads as POINT LOADS, so that I am able to split up the structure to do a separate analysis without having the weight/seismic load distribution disturbed?

STAAD CE Update 7 - Adding Custom Section Database does not work

Michael Duncanson — Thu, 09 Sep 2021 19:40:10 GMT

Trying to follow this: M. To add a custom section database, but I cannot for the life of me see the custom section database in STAAD, even though it shows up in the Section Database without errors.

To be sure it isn't my custom file, I made a copy of the AISC_15.db3 and renamed it to AISC_15_test.db3 and placed it in another personal folder. I opened the db3 file in SQLite, and just updated the DBInfo section as described in the help section to make it a unique file.

I go into STAAD's Section Database and go through the steps to add the new custom database. It accepts it no problem, and asks me to restart STAAD once I close the window.

Restarting STAAD and reopening the Section Database, I see the new custom AISC_15_test.db3 "TEST", but when I try to use the database in STAAD, I cannot use the custom database.

If I had to take a guess....the "Custom.ini" OR SectionDatabaseInfo.xml file(s) are not being written to for adding the custom database.

Is the help file missing a step in getting these custom databases to show up in the Main STAAD window?

Various Questions with Straight-Line Approximation of Curved Beams

Michael Duncanson — Wed, 04 Aug 2021 22:34:17 GMT

Looking for some help regarding understanding the 'right' way to do a straight-line approximation of a curved member, and limitations that need to be accounted for. My questions are near the end and highlighted if you wish to skip it, but understanding the whole picture you might want to read everything.

A colleague of mine has modelled a 'curved' parabolic beam using nodes and straight-line members to approximate the curved shape. They created the curve in the XZ plane (horizontal plane) and loaded it radially in the horizontal plane as well using UDLs in the member's local 'Z' direction. We would have expected to get an accurate representation of the shear force diagram when using tight node spacing, however there were always these large jumps in the SFD:

My interpretation is due to the change in angle between the adjacent straight-line elements is causing these effects, but I cannot count for this magnitude of effect given we used very tight spacing (~70mm over ~8.67m). As noted in other topics regarding 'curved' members - STAAD has a limitation of not being able to calculate intermediate shear/bending moment diagrams for curved members, but always recommended of modelling with straight-line members for approximation. As we have done straight-line members for approximating the curve, I would expect the model is not subject to these same limitations but looks like we are.

I did an experiment and took to heart the limitation as being the case for any curve beam (either approximated by straight lines between nodes, or exact using STAAD's curve member specification). If STAAD (or any analysis program for that matter) cannot calculate intermediate axial/shear/bending for curved members, then the limitation would also be to the load application. So I converted this UDL application to Member Concentrated Load command with 'd1' & 'd2' = 0 to apply the concentrated loads at the starting node of each member to more easily deal with applying the loads radially. This gave a much cleaner SFD:

These diagrams are very close to the SFD and BMD for the approximation of applying loads directly to the nodes, which confirms the jumps in the above SFD can be ignored:

An additional issue we saw was that when changing the section size the shear/bending moments were magnified (the thicker the concrete section, the more shear/bending moment and less axial force). Note that there are no self-weight loads active and only fixed loads are applied, so changing the section size should have no impact on the SFD or BMD. For instance, a PRIS 1000x500 section has a max shear of ~15.4 kN, but a PRIS 1000x1000 section has a max shear of 57.4kN.

My questions for this post are:

Why does this issue arise when applying radial UDLs to a straight-line approximation of a curved member? We are using straight line members as recommended by other topics / help pages, and I would expect a more cleaner SFD regardless of using a UDL load. Depending on if we take the starting node or ending node side of the straight-line members for the true shear force will give drastically different results. There is also overlap in the SFD, so where Shear = 0 cannot be readily determined.
Do the limitations of curved members in STAAD also apply to straight-line approximations of these curved members? My experiment seems to suggest this, and straight-line approximations of curved members should not have intermediate loads applied.
Why does increasing section size cause magnification of the SFD and BMD? If everything stays the same (geometry, material, loading), then changing the section size and its stiffness should not change axial/shear/bending magnitude.

I have attached a STAAD file that has 6 versions of the curved beam in the same file to see the results simultaneously, using the key diagram below:

communities.bentley.com/.../2D-Concrete-Arch-Beam_5F00_forum.STD

Any assistance would be great! Looking forward to the discussion. I will note that this is not a STAAD-specific issue, but more an analysis/understanding issue; I copied the same model into Space Gass and the same results come up.

STAAD Next Update Query? (currently v22 Update 6)

Michael Duncanson — Thu, 17 Jun 2021 17:17:08 GMT

I know it's not really known exactly 'when' STAAD updates get sent out to the masses (i.e. it's ready when it's ready), however I missed the Update 6 notification from April....

I just want to know (ballpark) if the next update after 'Update 6' is going to be released in the next month or so (say Q3 release)...or is it way off in the distance (say last quarter / next year release)? I just am trying to avoid internally having staff in multiple global offices to update from #5 to #6 only to see in a matter of weeks the next iteration come in....obviously a "me problem", but thought I would ask so I can make a better judgement call.

New Staad Version 22.05.00.131 giving different results

Mario Cuervo — Tue, 10 Nov 2020 20:09:47 GMT

I upgraded to the latest version 22.05.00.131 from 22.04.00.40 and the changes on the way it designs the horizontal bracings is very different, and now all my horizontal bracings are failing, what happened to the program? what has changed?

Right now I had to change from member truss to member release and the section from previous version was a WT6x17.5 and now WT6x32.5 and barely passing.

Adding a little more to this issue, the axial forces in member truss as an example is 120 kips and for member release is 26 kips, this is very odd. It is only affecting my horizontal and vertical bracings when assigned as member truss.

[STAAD v22.04] Structural Wizard Plate Generator - Polygon with Holes always says "boundaries not on the same plane" when they are

Michael Duncanson — Sat, 19 Sep 2020 18:39:43 GMT

I'm just trying to get a STAAD file going for an FEA of a bi-axially bending base plate. I can get the Structure Wizard to get me the general plate into the XZ plane just fine.

However, everytime I add a circular hole, it's always telling me "Input Error: Boundary points are not in same plane!". I don't know how many times I can enter ZERO (0) into the "Y" coordinate to "make" it on the same plane, but STAAD's interface just won't accept it. Seems something with the internal check if things are in-plane or not. I even double checked the "Y" coordinate of the Boundary points are set with "Y" = 0 ( I pressed the enter key very firmly too ).

I tried generating the plate & holes in the XY plane (the default plane for this Structure Wizard), but it still will not accept the hole.

Any help?

polygon:

X	Y	Z	Div.	Bias
-115	0	175
-75	0	175	3	1
75	0	175	10	1
115	0	175	3	1
115	0	97	6	1
75	0	97	3	1
-75	0	97	10	1
-115	0	97	3	1
-115	0	175	6	1

hole:

Region Type:		Circle
Origin:	X	Y	Z
	-75	0	135
Radius of Circle:			13
Division Along Periphery:			16

STAAD CONNECT v22.01.00.39 - AISC 360-10 Truss Design Check - Incorrect Labeling of Axial Force

Michael Duncanson — Mon, 12 Aug 2019 15:09:03 GMT

Hello!

I have had a colleague come to me with a problem with the latest STAAD CE (v22.01.00.39). They created a simple truss model, and when checking the compression chord (Beam 3) on the outside of the truss, the loading diagram and beam end results are correct (compression), however for the code check for AISC 360-16 STAAD assigns the load as "tension".

(CONNECT v22, AISC 360-16)

(CONNECT v22, AISC 360-10)

This was checked back to STAAD SS6 v20.07.11.90 and compared to the previous version of CONNECT (v21), and the code check was showing the correct "compression" indicator (see below). Can a fix be provided by Bentley to correct this error? Please verify that this does not happen in the other design codes as well.

(SS6 v20.07.11.90, AISC 360-10)

STAAD File Attached: /cfs-file/__key/communityserver-discussions-components-files/5932/Truss-Example.STD

Thanks,

Michael Duncanson

SP 16.13330.2017 implementation?

Michael Duncanson — Mon, 20 Jan 2020 15:03:03 GMT

Just a curiosity question on whether the Russian СП (SP) 16.13330.2017 design code will be implemented into STAAD CE? I saw a bunch of updates for SP 16.13330.2011 being put into the analytical design check for v22.03.00.28, so thought to check!

Also, I noticed in the revision notes for v22.03.00.28 that the Russian code publication number is incorrect. It should be SP ##.13330.xxxx.

Explanation of different "Section Databases" in STAAD (v22.02)?

Michael Duncanson — Thu, 17 Oct 2019 15:21:36 GMT

I've tried looking in help files and older technical reference manuals, but I cannot seem to find any explanations on the different section database names and what they include. Take for example below:

It is quite clear that AISC_14.1 and AISC_15 databases respectively correspond to AISC 14th and 15th edition shapes, however it is unclear what years AISCSECTIONS, AISCSECTIONSRCECO, and AISCSECTIONS_ALL_EDITIONS correspond to.

Is AISCSECTIONS use 15th edition shapes or a much older database?
Does the AISCSECTIONS_ALL_EDITIONS database include the most recent 15th edition and all versions prior (including historical)?
Is there a page that goes into explanation of each of these databases?

This is the same with Canadian sections. There are two databases: CANADIANSECTIONS and CANADIANSECTIONS_OLD. Is the first database the based off the current CSA S16-14 / CISC Handbook of Steel Construction 11th edition, or is it still from S16-09 / CISC Handbook 10th edition?

Any clarification on the matter would be helpful.

Thanks!