Benji Michael Chit Khin's Activities

Verifying Fatigue Stresses in Leap Bridge Steel

Benji Michael Chit Khin — Thu, 24 Mar 2022 16:56:12 GMT

Hi I have a question regarding Fatigue stresses in Leap Bridge Steel.

I have several locations along the girder that fatigue is the controlling design.

Based on the calculations reported, it appears that Leap Steel is using non composite properties to calculate the fatigue stress rather than the composite properties which is causing a higher stress to be reported than it should. The girder itself is being reported as composite and has the composite values calculated correctly.

I saw a similar question was posted about this a few years ago and wondering if this has been resolved?

Thanks

Michael

Thermal force calculation with bearing pad for multi-column interior bent with varying column heights

Danny Villalpando — Tue, 06 Dec 2022 17:40:15 GMT

Hello, I have a couple questions regarding OpenBridge Designer (LEAP Bridge Concrete Substructure).

- How is the thermal force calculated for a multi-column bent with elastomeric bearing pads with varying column heights?

- Also, how is the out-of-plane stiffness calculated for a multi-column bent with varying column heights supporting girders on elastomeric bearing pads?

- Lastly, how is the out-of-plane stiffness calculated for a multi-column bent with different column and drilled shaft diameters to the point of fixity?

Thanks,

Danny V

Live Load Auto Generation in RCPIER

Benji Michael Chit Khin — Sat, 04 Mar 2023 11:18:05 GMT

Hi, can you explain what the difference in Truck Case A and Truck Case B is in RCPier? I've autogenerated Live Load and I've set the distribution to .5 to each bearing line for both cases, but it is still loading up only bearing line 1. I have tried zeroing out the distribution for Truck Case B to zero for both bearing lines and that seemed to have eliminated the loading to just one bearing line, but then I noticed that it wasn't applying the full number of lanes that can be on the bridge, which is 5. It only would apply 5 lanes when Truck Case B wasn't zeroed out, but I need the loading distributed to each bearing line equally.

Can you please help me with this?
Thanks

Leap Bridge Steel Live Load Vehicle Library Increment

Benji Michael Chit Khin — Mon, 24 Jan 2022 11:22:31 GMT

Hi,

I am looking at the output for the live load vehicle inputs and was wondering what the "Increment" column is for?

Also the actual default input for Double Truck doesn't have the 14' Increment that is shown in the output. See below.

Any help is appreciated.

Thanks

Leap Steel Live Load Reaction Report Different From Shear Diagram

Ran Ji — Thu, 22 Jul 2021 14:06:41 GMT

Hello,

I'm trying to get the live load reaction for a 3 span continuous span bridge and noticed the live load reaction values from the report is different from the static analysis diagram.

The support reaction report and lane loading details report show the same LL reaction 92.594 kip, while the shear diagram show a value of 61.4 kip. Is there any specific reason for this discrepancy?

LEAP Steel Service I HL-93 Reactions

Andrew — Wed, 09 Mar 2022 16:14:34 GMT

Hello all, I have had some issues with LEAP steel pulling reactions when using Line Girder or Grillage analysis.

These are the Service I HL-93 support reactions when running a Line Girder analysis.

I am wondering if this is a glitch in LEAP Steel, as the Service I deflections are substantially higher using Line Girder or Grillage analysis compared to FEM, and the live load reactions output in what looks like binary code.

See FEM results below for comparison.

Could this be a file related issue or a glitch in the program? Versions of LEAP below.

Thank you

Live Load Deflection Calc

Anthony Grkman — Wed, 09 Dec 2020 19:55:07 GMT

I am trying to make sure my bridge satisfies the LL defection criteria of AASHTO 2.5.2.6.2. My bridge is a curved steel girder bridge. According to AASHTO 2.5.2.6.2 - "For curved steel I-girder systems, the deflection of each girder should be determined individually based on its response as part of a system." In the ANALYSIS tab for HL-93 (Deflection per AASHTO) the graphic is showing different deflections for each of the 4 girders, which according to AASHTO 2.5.2.6.2 you would expect. However, in the DESIGN tab, for "Design Check", Deflection Check Report, for this LL the program is reporting equal LL defection for each of the 4 girders. The deflection being reported here matches the maximum LL deflection that was shown graphically in the ANALYSIS tab. This is causing the program to report a failure with excessive defection on the inside girder, since it has the smallest arc length. Shouldn't the LL Deflections in the DESIGN tab match the deflections in the ANALYSIS tab? Below are images from the Analysis output and the design output which shows the calculated deflections. Thank you.

Leap Bridge Steel Stiffened vs Unstiffened Webs

Benji Michael Chit Khin — Mon, 15 Nov 2021 16:02:24 GMT

I've noticed that the results in LBS are reporting the girder web stiffened in portions of the web that I would not want to be stiffened. I believe this is due to the program considering the connector plates for the crossframes as transverse stiffeners, which is not the design intent.

On the exterior beams it appears to considers the stiffened section correctly. I believe this is due to there being an additional stiffener on the opposite side of the web of the crossframe at the bearing. But it seems for the interior girder since it has two connector plates (one on each side of the web) it's thinking that the web is stiffened at each cross frame.

Is there a way to distinguish what is considered a bearing stiffener, transverse stiffener and connector plate?

I saw a previous question about this and the solution offered was to not select a material for the connector plate, but that did not change my results.

Here is what my exterior girder results show:

Here is what interior Girder results show:

Any help would be appreciated.

Thanks,

OBM to Leap Bridge Steel Interop

Charles Rodrigues — Mon, 20 Sep 2021 18:15:01 GMT

I'm trying to export a OBM model to Leap bridge Steel using the 'Send To' OBM's Interoperability. However, I keep on getting the following error: Database generation failed.

I have Leap Bridge Steel Installed and can be opened independently. I don't see any red-flags in my OBM model so far. I'm logged into my Bentley account. Any help would be appreciated.

Thank you

LBS Girders deleting when modifying member definition

Benji Michael Chit Khin — Mon, 08 Nov 2021 13:44:56 GMT

In LBS I'm having an issue with the girders not showing up after modifying the member definition. When I go back into the member definition dialog, it now says "Member has incomplete definition" and gives a lot of flags for each girders web, top flange and bottom flange that no elements defined between certain distances. The difference for instance says no elements from "0.000000 to 0.000081!". Before I modified the member definition everything showed as "valid definition" and "complete definition"

On other bridges that I've worked on, as long as I corrected all of the errors it would bring the girders back in. But in this case the program doesn't save the changes for those errors and if I go back into member definition the same errors reappear.

I'm working in 10.9 OBM and OBD. I have tried in the new version 10.10 and still have the same issues.

Has anyone else encountered this issue and can offer any guidance?
Thanks!

Multiple Units issue in Leap Steel Bridge

Benji Michael Chit Khin — Mon, 18 Oct 2021 15:21:03 GMT

The bridge I'm working on consists of a 3 span bridge with 2 units, a simple span followed by a 2 span continuous. The bridge was modeled using the BIM workflow. Once the model was complete I used the "Send to Leap Bridge Steel" button for the simple span. I was able to analyze and design that span with no issue.

I then went back to the model and set the second unit active and then clicked the "Send to Leap Bridge Steel" button. It said the data transfer was successful, but it did not import the girders. The only thing that was brought in was the deck and barriers. A few coworkers have had this happen to them when working with multiple units.

Has anyone had similar problems and can offer a solution?

Thanks,

Michael

LEAP Bridge RC-Pier

Benji Michael Chit Khin — Mon, 16 Dec 2019 12:51:08 GMT

Hi,

Our company has just downloaded the latest version of LEAPBridge Concrete (Version 19.01.00.11) and had a question related to the Pier View.

Has anyone noticed that the Pier view directions have flipped from what previous RC-Pier versions use?

We will always model everything as Upstation, but in this latest version if you select Upstation all of the inputs (Loads, Columns, etc) are backwards of previous versions. Girder 1 is now Girder 6, Column 1 is no column 4. If you select Downstation it appears that would be previous RC-Pier version Upstation setting.

Was this change supposed to be a part of the new version?

Thanks,

Benji

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Mon, 16 Dec 2019 06:25:37 GMT

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