What to learn for a bright future in the industry (Bridges) 1

[Bridge_Man]

Hi,

It seems multiple states are moving forward with the BIM and 3D modeling for construction and plans and I want to be able to save my spot amongst those who can deliver such things in addition to the obvious technical abilities. I want to get your thoughts on what should I be focusing on for a bright future in the industry.

Abilities:
1- I have 4 years of experience in the bridge engineering industry
2- going for my PE soon
3- I have decent technical capabilities and codes interpretation capabilities
4- I have decent knowledge in advanced 3-D modeling (SAP2000 and MIDAS)
5- I have very basic knowledge in seismic engineering (I hate that) but my state is not big on seismic. and I can't (don't know how) deal with it on an advanced level or in modeling.
6- I have OK MicroStation capabilities. and this is where I would like to largen my horizon, I would very much like to be able to use both MicroStation and Inroads with a high level of experience. I sincerely believe that those two tools distinguish so many engineers from others. not just drafting by laying out the work, and I believe 3D modeling for construction is very close in our industry.

What are your thoughts. this is an open discussion, no wrong answers here.

Thank You !

 

[PEinc]

It seem to me that BIM would be more useful on a structure (like a building) that is more complicated than a bridge. Just because you can BIM a structure, it doesn't mean it will be worth the expense. Sometimes it is better to KISS.

http://www.PeirceEngineering.com

 

[Bridge_Man]

PEinc. You are correct, I agree. but many states are moving in that direction in a few years. that is why I want to be ahead of time. I think FDOT and NY are examples of those states (not yet, but sometime in the future).

Thanks for your insight

 

[STrctPono]

I agree with PEinc that buildings are more spatially and geometrically complicated than bridges and have more coordination needed across disciplines. Once the hydraulics are set and the bridge length and width are determined, the Structural typically has free reign to design as they please. There may be some electrical lines or waterlines or other utilities crossing the bridge but not in a way that would (IMO) require a BIM model.

With that being said, I remember we were working with TYLin on a job out in my State some years back and they had just finished construction of the San Fran - Oakland Bay Bridge East Span project and one of the Engineers showed us a 3D model that their office had created for the Pier Cap elements. It was so complicated and congested with reinforcing that they spent time to create this model to make sure that all the steel could fit in the element. I can't remember the exact number but he told us that the cost to model it in 3D was something like $500,000. This is obviously not the norm but does occasionally happen. I also worked on a recent job where we were designing 2 identical utility bridges that doubled as pedestrian bridges. These bridges carried major high voltage power lines across it and had a very complicated tie in with the lines at the bridge approaches. For that, the Civil actually created a 3D model of the bridge with the utility lines just to make sure they could make the horizontal and vertical bends in the lines to meet the bridge elevations. Other than that, we had one other 360ft long simple span bridge on a horizontal curve that utilized a general 3D model to present to the State.

Being able to visualize an object in 3D in your head and replicate that image in 2D drawings can be difficult and is an art. This is something that not every Engineer can do. We don't have the luxury of seeing and displaying everything in 3D like some other Engineering disciplines do.

Each State may be different but my State DOT is nowhere near transitioning to a 3D BIM modeling approach to bridges as the norm. 3D might seem alluring to young Engineers and may be useful in very complicated bridge projects but it unnecessarily overcomplicates simple projects.

 

[Bridge_Man]

Strctpono, thank you for your insight and detailed answer.

 

[BridgeSmith]

There are FEA packages tailored to bridge design, such as CSI Bridge, and some others that have bridge-specific modules, such as Lusas. Bentley (the makers of Microstation) recently acquired the LEAP structural analysis package and integrated it into their software line as OpenBridge Designer.

We've had the Lusas package for several years, but it's way more than what we need and way too much money for the small amount and limited extent that we use it, so we're going to be trying out OpenBridge.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[Settingsun]

USA may lag a bit, but 2D drafting is on the way out elsewhere. Eg STrctPono said the civil engineer created a bridge model; next step is that the bridge engineer is expected to provide it for complex cases; then a routine expectation. Then it's just easier. Every young modeller I know says it's quicker than traditional CAD (even bridges), and most senior drafters also come around IME.

The thing is, though, that you'll become too senior to be a modeller. It will still be useful knowledge, but I expect you'll find that BIM review software will become your tool. Another path to look towards is BIM management. When BIM does hit your industry, it will be sudden and many people will be behind. I can't see the $500k example given earlier as anything other than cost of coming up to speed.

One thing to consider is that the asset managers are starting to want the models. The design phase isn't always the driver of CAD vs BIM.

 

[Guest090822]

As one of the states experimenting with 3D “planless” contracts, I’m seeing pushback from contractors. The big fish contracting companies are lobbying for 3D planless contracts because they have the staff and money to do the work. However, smaller companies are complaining to state lawmakers that this in unfair. I think planless contracting isn’t going away, but won’t be taking over any time soon.

 

[bridgebuster]

Bridge_Man, NYSDOT let a project in January using a limited amount of 2D plans, & 3D models. The contract documents can be found here:

Link

Perhaps it will give you an idea of what it's all about. I never looked at the models; couldn't get them to run on my laptop.

Some of the younger people in my office have been trained in BIM. IMHO, some 3D drawing is helpful but we've been able to build complex structures without it; maybe I'm too old school.

 

[BridgeSmith]

IMHO, some 3D drawing is helpful but we've been able to build complex structures without it; maybe I'm too old school.

As we saw a few years ago with that pedestrian bridge in Miami, relying too much on models and FEA can have disastrous results. There's good reasons for working through, and thinking through, complex structures without (or at least in addition to) computer models and analysis.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[r13]

3D modeling is very useful tool for interdisciplinary collaboration and clearance check for powerplant type projects. Without fully integrated structural design function/capability, I certainly doubt its usefulness in the simple form project, but for presentation purpose. We might have to wait a few generations for AI to take over the design function from human being.

 

[gwynn]

Turning aside from the discussion of 3D modeling for a moment, one of the things I would suggest to anyone planning a career designing bridges is to spend some time working on the construction engineering side of things. This is probably the best way to understand how design decisions impact constructability and associated costs.

STrctPono
I have seen 3D modeling used in bridge design a few times, but these have been few and far between. The one that comes to mind was modeling the rebar cage, rebar support frame and cable stay tubes in the knuckle of a cable stayed bridge due to congestion. And on that one it wasn't the engineers spending the time doing the 3D modeling, it was drafters.

BridgeSmith
Just curious, if you don't mind, but what have you been using Lusas for? The only place I see Lusas used is for Bebo arches.

 

[BridgeSmith]

BridgeSmith
Just curious, if you don't mind, but what have you been using Lusas for? The only place I see Lusas used is for Bebo arches.

So far, I've only used it for a full retaining integral concrete abutment. Others have used it for similar analysis.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[Settingsun]

I don’t know the lay of the engineering land in North America, but I’d still bet on BIM coming into bridges in a big way based on this discussion. The objections here are nothing that wasn’t said in Australia a few years ago yet my current company and former company both use Revit as their main bridge drafting software now. Their reasons for getting started were different and a few years apart, but it was necessary for some projects and then it didn’t make sense to retain expertise across the whole drafting team in both AutoCAD and Revit. To be clear, the deliverables are still mainly 2D drawings in PDF format and Revit handles this just fine. Also to be clear, I’m not a drafter/modeller myself as it’s common in Australia for consultancies to have ‘pure’ engineers and ‘pure’ drafters, so my knowledge on the subject comes from talking to the drafters.

I’ve given specific responses to some of the objections below. They were all overcome for various reasons and I think might help Bridge_Man’s effort to predict the future.

It seem to me that BIM would be more useful on a structure (like a building) that is more complicated than a bridge. Just because you can BIM a structure, it doesn't mean it will be worth the expense.

The only expense is learning the new software, which Autodesk is trying to minimise – or is required to be learned for other reasons anyway. Simple structures are simple to model in 3D once you’re familiar with the software, to the point that quick mock-ups at proposal stage (no pay) are becoming more common as sales tools. I imagine that the first CAD projects cost more than hand drafting because of the difference in skill level in the workforce for the two methods, but hand drafting still lost.

Being able to visualize an object in 3D in your head and replicate that image in 2D drawings can be difficult and is an art. This is something that not every Engineer can do. We don't have the luxury of seeing and displaying everything in 3D like some other Engineering disciplines do.

Not sure if this is an objection or a sales pitch TBH. The other side of the coin is that builders sometimes have trouble visualising the 3D structure from the 2D drawings, or using the 2D drawing just takes more effort on their part. Having the model alongside the drawings overcomes this. Contractors who know we work in Revit are increasingly requesting the models, even with our disclaimers that the 2D drawings are the design and using the model is at their risk.

I think planless contracting isn’t going away, but won’t be taking over any time soon.

Agree but, as stated above, planless contracting isn’t the only way BIM is used. I’ve never done it in 6 years of primarily working on Revit projects.

some 3D drawing is helpful but we've been able to build complex structures without it; maybe I'm too old school.

They’ve been built with BIM too, so that’s not a differentiator. There have been some almighty balls-ups that BIM clash detection would have avoided, and these stick in memories.

As we saw a few years ago with that pedestrian bridge in Miami, relying too much on models and FEA can have disastrous results. There's good reasons for working through, and thinking through, complex structures without (or at least in addition to) computer models and analysis.

I don’t agree with your assessment of the problems with that bridge. If you were to read the report of the inquest into the Westgate bridge collapse in 1970 (Australia), you could easily change a few names (and structural details) and think you were reading about the Miami collapse. The problems were on the capacity side of the calculations, not the analysis side but, more fundamentally, relatively novel structure types that didn’t get the attention they needed from senior engineers. Also designers of very high standing whose reputation quelled the doubts people felt when the design didn’t seem right, and when things started going wrong on site. Nothing is new; bridges collapsed before computers.


The impetus for BIM could come from any of several directions, such as:
- Government mandate like in the UK. Maybe less likely in USA, but then a metric mandate was tried once upon a time (I understand).

- Client whim. One company here got started when one of their key clients (D&C road contractor) thought it was odd that they produced 3D road designs but there were gaps at the bridge locations. They started with doing it as an extra to tick the box—without extra fee of course—so then successfully tried to use the model to produce design drawings and won back the profit margin on future jobs.

- The bridge is part of a building development where the rest of the project is using BIM. Might never happen for a government agency but I do know one privately-delivered bridge that fell into this category.

- Consultancy that wants an overseas job has to use BIM for that and then goes from there.

- A consultancy’s overseas head office mandates it, or uses its expertise to support the US branch as a marketing differentiator.

- Asset manager wants it.

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https://www.sofistik.com/products/bim-cad/bridge-infrastructure-modeler

- For the reasons above, everyone else is doing it. This might be when the government agencies decide it’s the way to go.

 

[BridgeSmith]

I don’t agree with your assessment of the problems with that bridge. If you were to read the report of the inquest into the Westgate bridge collapse in 1970 (Australia), you could easily change a few names (and structural details) and think you were reading about the Miami collapse. The problems were on the capacity side of the calculations, not the analysis side but, more fundamentally, relatively novel structure types that didn’t get the attention they needed from senior engineers. Also designers of very high standing whose reputation quelled the doubts people felt when the design didn’t seem right, and when things started going wrong on site. Nothing is new; bridges collapsed before computers.

I'm not familiar with the Australian bridge, but I've read numerous reports and studied alot of analysis from the Miami bridge. The design and check were primarily accomplished using 2 different 'black box' FEA programs, neither of which were asked to model and analyze the area that failed. Then, when the large cracks appeared, they again relied on an analysis model that didn't match up with the reality of what was happening.

Of course, it appears what ultimately cost those people their lives, was ego. The prudent thing to do, even if you think it's going to be fine, is to divert traffic away from the bridge, but they were so proud that they were able to get it in place without major disruption to traffic, that they weren't willing to look bad by doing so after it was in place.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[BridgeSmith]

This might be when the government agencies decide it’s the way to go.

Don't count on it. Government agencies in the US are notoriously slow to innovate. Also, most bridges, while sometimes complex in the internal stresses in the components, are generally geometrically fairly simple. Interference checking, for instance, is rarely much of an issue. There is usually not much interdisciplinary coordination required - bridges are almost exclusively structural, with little, if any, other systems (mechanical, etc.) for the structure to interact with. The Miami pedestrian bridge is one of those exceptions, though, and the utility ducts running through the anchorage zone were a contributing factor in the collapse.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[Settingsun]

BridgeSmith, do consultants do much bridge design for you or is it mostly in-house? And for your in-house work, is there much automation in the drafting? Simple isn't necessarily an argument against BIM, it can actually work in its favour (easier to automate drawings for simple/repetitive structures).

 

[r13]

I believe cost is the main barrier. Also, ease in handling complicate details.

 

[BridgeSmith]

steve49, we do most of the design and detailing in-house, but some goes out to consultants. Not really any automation in the drafting, beyond what Microstation does. We reuse designs and details when we have bridges that are similar enough.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[STrctPono]

Bridge Man,

A few additional skill sets that I find useful in my daily endeavors of bridge design. Not sure if any apply to you but they are important in my office:

An ability to run a soil structure interaction analysis. We do a lot of fully integral abutment bridge designs and being able to translate the p-y curves into either bilinear or linear soil springs along the height of the shafts/piles is an important step in the design process. We typically run this with varying level of scour heights and in collaboration with a response spectrum analysis (which you mentioned is not important for you).

Multi-staged post tensioning analysis for bridge girders. In the design of a spliced post-tensioned girder.

Designing a GRS backfill.

Figuring out girder seat heights. Easy, but something that many new Engineers need to be taught.

Externally bonded FRP design for bridge retrofits.

A real working knowledge of concrete mix designs. This is a HUGE one for me and something that many Engineers don't even bother to concern themselves with. This skill set has earned us many jobs.

The ability to understand constructability constraints and limitations and how this will affect your design choices. Gwynn mentioned this and I think they are spot on. More so than buildings, bridges are typically limited by crane access and the designer has to have a realistic understanding of the most efficient bridge type to use. Many young Engineers think that designing the rebar down to the gnats eye is going to save the project money (which is incorrect). We have Value Engineered many jobs that have already been designed because the original designer made some bad initial assumptions that lead them down the incorrect design path and unnecessarily blew the construction budget up higher than it needed to be by choosing the wrong superstructure type or by being overly conservative with their foundation work.

With bridges come retaining walls. Familiarize yourself with how to design every single type of wall imaginable. Cantilever, gravity, buttress, counterfort, soil nail, active tie back, CMU, Keystone, Mechanically stabilized earth, Precast T-Walls... Having a variety of weapons in your design arsenal for walls is more important than many people realize for bridge Engineers.