Carl Oberg's Activities

Load Combinations Using Moving Loads

Carl Oberg — Fri, 15 Jan 2016 14:56:38 GMT

I have run into this problem several times now and have not found a good solution for it yet. I am modling a large structure in which I need to consider several loaded lanes of traffic traveling accross it. To generate the moving truck loads I am using STAAD's vehicle definition and load generation features. The structure I am analysing is approximately 96 feet long and i need to consider all possible load patterns for 4 lanes. From what I have found there is no way to include load generations within a load combination. To get around this I have taken load generated for each lane and put them into their own envelopes (i.e. all loads that get generated for the moving load in lane one get enveloped). In order to make the necessary AASHTO Load combinations I then have to export all results out of the prgram into Microsoft Excel where i can take the enveloped results and combine them with the results from any of the other static loads that have been applied. This is a very tedious and time consuming process in which there is great potential for human error. Is there any other way that these load generations can be combined with other load cases within the STAAD.pro program so that I do not have to export the data out and do it manually? Also, I am not able to use the STAAD.pro BEVA package for this as it is not approved for use by the DOT we are working for. Any input or suggestions on this would be much appreciated. Thanks.

Deck Spot Elevations

Carl Oberg — Fri, 16 Apr 2021 20:27:52 GMT

Good Afternoon! I have a unique bridge project I am working on where we are putting a park on top of our bridge. I am looking to see if there is an easy way to determine the top of deck elevation from the bridge model and various spots. Prior to porting my model over to OBM I had my bridge model created in ORD using corridors. This was nice because when I wanted to check the deck elevations with respect to the landscaping spot elevations given to determine soil depths, I could use the Civil Analysis --> Analyze Point tool, select the deck element in the corridor, and the tool would give me the deck elevation when i snapped to the 2D spot elevation location. This civil analysis tool does not work with the OBM bridge elements and I don't see any sort of similar OBM analysis tool available. I kind of thought having a tracking tool like this in OBM would have been a no brainer, but it appears I am wrong. I am currently debating extracting the top of deck surface from the deck solid and then trying to create a terrain from that, but im not sure how good the DTM will be giving it will be trying to create it from a B-spline curve surface. Is there any simpler way this can be done? I have a lot of spot elevations to check and i will most likely have to check several grading iterations in the future. Any help/suggestions would be very much appreciated. Thank you!

Moving Load Generation - Vehicle Not Displaying

Carl Oberg — Thu, 03 Dec 2020 22:59:27 GMT

So I seem to be having an issue when using the moving load generator. I have defined a custom vehicle with axle loads and spacings. I then created the load generation case and then assigned the vehicle with the appropriate starting location and step increment. The issue I am having is that for some reason, the start location of the vehicle does not display on the screen when I select the moving load for some reason, so i cannot verity its starting at the location I want it to. In the past (prior to Connect) the vehicle and wheel locations would show up in red on the model and the reference wheel would be boxed. Is there a view setting or something else that I may have toggled off that would prevent me from seeing the vehicle start location? Thank you!

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Thu, 03 Dec 2020 23:00:26 GMT

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Adding Nodes to 3D Lines for Graphical Import of Elements into a Terrain Model in ORD

Carl Oberg — Mon, 03 Feb 2020 20:55:35 GMT

Hello Eveyone,

I have done some research and digging related to this issue already and have not be able to find an answer or better solution for what I need to do. The issue I am having is that I need to create a terrain model from 3D contours and breaklines that I have receved from one of our subconsultants. The subconsultant is a landscape architect that is doing all their design in Rhino and AutoCAD. They are providing me with a 3D AutoCAD file with the 3D contours and breaklines which I am converting to Microstation to create the terrain. The problem I am having with this is that when importing these features, the triangulation is only to the node points on the elements and you do not have the ability to specify a point density interval (like you could with InRoads) on import. I am aware that there are stroking tolerance settings in ORD that can be adjusted, but those tolerances only work for linear features. Converting the 3D contours/breaklines to linear features is an option, but would be very time consuming. I would like to find a way to add additional node point at a maximum defined interval along an element if possible. I am aware of the facet curve command but that has its limitations, the main one being that if you try and facet at a fixed chord length it will drop off the remainder of the element if its lengths isn't evenly divisible by the defined chord length (i.e. if you line is 10.5' long and you facet at a fixed 1' chord length, the last 6" of the line will be removed). Has anyone else run into this problem and come up with another solution? I would really like to do this terrain modeling in ORD but due to not being able to control the point density interval at import, I have revereted to using InRoads for the time being. Any help/suggestions would be much appreciated.

Carl Oberg

Modeling a Very Wide Bridge

Carl Oberg — Fri, 21 Aug 2020 22:30:44 GMT

So I have been thinking about this for a while now and wanted to get others input an opinions on the best way to model a very wide bridge in OBM. I have a very simplified model of the bridge which I created with ORD but would like to migrate the model in ORD, if it possible to accurately model the geometry. The bridge I am working on is a 3-span continuous steel plate girder bridge that is 360' long and 608' wide. Given the extreme width of the bridge, I currently need to use 5 different alignments (all of which are parallel) with different profiles to set the deck geometry. To add another level of complexity, our Abutment 1 support follows the alignment of an on-ramp below which picks up a horizonal curve part way along its length.

For my model in ORD, I am not actually modeling the substructures, and for the girders, I am basically using a rectangle around the girder extents. To handle the horizontal curve at Abutment 1, I extend the corridor beyond the end limit and then use a clip boundary to trim the corridor back along the curve. For the deck geometry, I use 2 primary alignments, one at the left edge of the deck and one at the right edge of the deck. These two alignments corresponds to the two roadway alignments that cross the bridge. In between these I have 3 working alignments with profiles which I target with point controls when running the corridor.

I am having trouble figuring out how I can model this bridge in OBM accurately. I think I can handle the deck geometry the same way I am handling it currently in ORD by using point controls on the key deck points. My bigger question is how to handle the Abutment 1 support that has a horizontal curve partway along its length. I am not sure this is something OBM can handle, at least not yet. I am not sure if anyone else has run into similar situations or has an idea as to how I can model this? Thank you!

Copy Corridor From One ORD File to Another ORD File

Carl Oberg — Fri, 10 Jul 2020 16:38:08 GMT

I know there is a previous thread about this, but it doesn't seem like there has been any recent activity. I want to copy a corridor from one ORD file to another and still maintain all the civil features. Is there anyway this can be done? I do not want to do a 'save as' to create the new file. Thank you!

OpenRoads Geographic Coordinate System Reprojection - Vertical Not Transforming and Feature and Solid Failures

Carl Oberg — Wed, 08 Jul 2020 14:36:42 GMT

I am having several issues when trying to perform a geographic coordinate system transform on reference files in ORD. We are working on a very large project in Philadelphia which is the NAD83 coordinate system using the NAVD88 vertical datum. All of our project files are using this datum. With this project, there is an existing base slab running along the entire corridor as well as a very large twin cell box sewer, both of which were designed and built in the late 60's/early 70's, thus the geographic used for the record plans for the base slab and box sewer is NAD27 using the NGVD29 vertical datum.

We want to show the existing base slab and box sewer in our plans so I created two models in the older record plan datums (NAD27/NGVD29) one for the base slab and one for the box sewer. We decided to build the models this way since we thought it would be easier to create the models off the record plan coordinates/elevations and then just to a geographic reprojection when we reference the files to get everything in to the project datum (NAD83/NAVD88). Both models are created and dont have any issues. The issues I am having arise when I try to cut cross-sections.

For the cross-sections, I started a new file with the geographic coordinate system set to the project datum (NAD83/NAVD88). I then referenced in the project baselines along which I will cut the cross-sections. The project baselines file was set up in the project datum (NAD83/NAVD88). I then reference in the both the base slab and box sewer files with the orientation set to "Geographic - Reprojected". When the files come in, the x and y reproject correctly, however the z does not (i.e. the z vales of points are the same when reprojected as in the the original NAD27/NGVD29 datum.

The other issue I have is that the reprojection apparently causes errors from the referenced base slab and box sewer models. See the attached error messages. This error ONLY happens when these are referenced using the geographic reprojection. If I reference them in with "Coincident World" set, I do not get the errors. I think these errors are also casing problems when cutting the cross-sections because the named view limits doe not seem to want to pick up the elements in the corridor causing the errors. For example, when generate the cross-section named views, the boundaries on some sections cut partway through the thickness of the base slab.

Has anyone else experienced these issues and knows how to resolve them? Thank you!

Carl Oberg, PE

Issue with Stationing using Text Favorites

Carl Oberg — Wed, 23 Jan 2019 20:14:25 GMT

I am having a problem with a new text favorite I created for baseline stationing. For whatever reason, when annotating the baselines and using my newly created text favorite for stationing, i get the same station number at all major station marks which corresponds to the start station of the baseline. If I go back and use the Major Stations text favorite that is part of the delivered workspace, the stationing works fine. Not sure what the problem is. Any help/input would be much appreciated.

Stationing using my create test favorite:

Stationing using the delivered workspace text favorite:

Annotative Baseline Stationing and Annotations

Carl Oberg — Fri, 27 Oct 2017 13:55:00 GMT

Hello Everyone,

I have been searching online and in forums for an answer to this questions but cannot seem to find one. Is there any way to set up baseline stationing and annotation so that it is annotative? Currently, the workflow we use is to create multiple levels within our baseline file for the different baseline scales. I do not really like this approach because if the baseline geometry changes then you need to go through all the various baseline scale levels and update the stationing and annotations accordingly, which can be tedious and error prone. Right now I am trying to get my company to make the switch to start using InRoads SS4, mainly for is more dynamic capabilities when it comes to modifying/adjusting alignments/corridors/surfaces/etc. and what hoping that there may be a way with this newer version to also make annotations annotative. I know that for AutoCAD baselines are not only dynamic but all the stationing (labels, tick marks) and annotations (PT/PC callouts, bearings) are also dynamic and annotative so that if you change the geometry or annotation scale everything updates accordingly. I am hoping there may be a way to do something similar with SS4 but have not found any documentation on it yet. If this still is not possible, will this functionally be available in the Connect edition? Thank you.

Carl

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Fri, 27 Oct 2017 03:13:53 GMT

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STAAD.pro Global Statics Equilibrium Problem

Carl Oberg — Thu, 01 May 2014 17:28:01 GMT

Hello,

I am having some problems with a model I am trying to run for deflection purposes. The structure is a steel plate girder bridge with a composite concrete deck. I originally had the full structure modeled using beam elements for the girders and plate elements for the concrete deck. To make the connection between the girder and deck I used rigid master/slave body constraints. To verify the model was working properly I first ran it with only the 8" thick concrete deck weight applied. After the model was run I went to the post processing and looked at the statics equilibrium check and saw that the vertical load equilibrium was not being satisified for some reason and the sum of the reactions was about 15% less than the applied load. I went back and checked all my inputs and structure geometry to make sure there was not any error's or my part and from what I see everything looks ok.

In an effort to make trying to figure this issue out easier, I simplified the model to one girder with it's tributary deck width. Again, I ran the model with only the selfweight of the 8" concrete deck applied. As with the full model I got the same results where the sum of reactions was about 15% less than the total applied load. One thing I noticed with the model is that even though the applied selfweight load is in the -y direction, when the model is analyzed it results with a reaction force at one of the supports in the x-direction, which should not be the case. I have been through this model several times now and cannot figure out why this is happening. If anyone has had this problem before and know what may be causing, could you please let me know. I am attaching my simplified model in which am having the static equilibrium problem. Thanks.