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  1. bridgeDisciple

    Truss cost estimates

    I currently have a very light weight (less than pedestrian) modular steel bridge design. I'm trying to estimate its constructed cost, and could use your help/experience. The bridge module comes in at just under 100 plf (pounds/linear foot). Steel is currently going for about $666/ton =...
  2. bridgeDisciple

    Hiring a bridge engineer?

    (Electric Steel) Thanks. I'll check them out.
  3. bridgeDisciple

    Hiring a bridge engineer?

    (LittleInch 7 kissymoose) Interesting. When i first conceived of this and was considering feasibility without any knowledge of bridging at the time, i looked to construction cranes as my proof of feasibility. Trucked to site, assembled on site from sections, span farther than i need, and carry...
  4. bridgeDisciple

    Hiring a bridge engineer?

    (gte447) We expect a gridded system to be common. The formula is w(h+1) + h(w+1). So a site covering a 4x3 mile area with a 1-mile grid will take 31 miles of guideway. If its a 2-mile grid its only 21 miles of guideway. It needs clearance above existing cross-road cantilevered traffic lights...
  5. bridgeDisciple

    Hiring a bridge engineer?

    (gte447f and BridgeSmith) I'm sorry if i've been too vague. I was trying to be concise, not evasive. Hopefully my reply to LittleInch fills in some details. I do appreciate how doing a general/re-usable/re-locatable design, and for a modular bridge, and for a non-automotive one is a bigger...
  6. bridgeDisciple

    Hiring a bridge engineer?

    (LittleInch) UrbanMass came onto the scene about 18 months ago. I've not heard much from them since. We'll see if they show up at the annual trade show at the end of this month. Link The one think i note about the UrbanMass design is the "cantilevered" vehicle support. We were the first PRT...
  7. bridgeDisciple

    Hiring a bridge engineer?

    (LittleInch) We have reached out to multiple roller-coaster design companies. Most (Intamin is the exception) are allergic to public transit. Dealing with one theme park owner is so much simpler than dealing with a multi-jurisdictional public entity. Plus the sedate ride characteristics are...
  8. bridgeDisciple

    Hiring a bridge engineer?

    human909, I love it ! :-) Actually the drawing looks a lot like an Intamin P6. Link No, we're talking smaller. Link Just kidding. Something in between. Similar to this Link
  9. bridgeDisciple

    Hiring a bridge engineer?

    AZPete, I'm not sure i understand the vocabular well enough to answer accurately. I think "civil structure". Our bridge modules are to provide elevated guideways for lightweight people movers (on public lands).
  10. bridgeDisciple

    Hiring a bridge engineer?

    JoelTXCive, Good thought. Yes prefab pedestrian bridge manufacturers is the only place so far we have made progress. Their process generally assumes a specific site, which is a barrier to quoting. Also they basically re-parameterize previous designs and are less motivated to engage in a...
  11. bridgeDisciple

    Hiring a bridge engineer?

    to rb1957 Good point. Our market is the continental US.
  12. bridgeDisciple

    Hiring a bridge engineer?

    I have a startup company that needs bridge engineering design services. Its unusual in that we seek a modular bridge whose design is not site specific, and is robust enough to be deployable within a region. Thus we need a good design up-front, and then will need some follow-on work for each...
  13. bridgeDisciple

    Are HSS members in bridge trusses a good idea?

    @winelandv I assume the reason you've chosen side attachment of the web is because your web is angle and bolts, and you can tolerate the eccentric loading? I'm not sure i understand your warning. The pod loads will be applied through the bogie and wheels to the track rails. The rails...
  14. bridgeDisciple

    Are HSS members in bridge trusses a good idea?

    Now that i've told you how smart our selection of this box-eccentric design is, i think i should probably open my ears and learn. Where exactly were these cracks occurring, and why? How did you fix them?
  15. bridgeDisciple

    Are HSS members in bridge trusses a good idea?

    Here is another for you to picture - second half of (PRT Quick look [2 min] https://youtu.be/lfMzERCydBk). Our calculations (at least first pass) indicate cantilevered is better. First, who said anything about "decks"? Not needed, not present. Horizontal cross beams from the center box extend...
  16. bridgeDisciple

    CAST YOUR VOTE! The Great DIY Steel Joist Detailing Competition of 2022 - Win $250 USD

    I have been observing this very interesting contest from afar. This is a question, NOT a submission (i think the entry deadline has passed anyway, and i'm not offering sketches). A number of companies have arrived in the "lightweight steel frame" space - (prescientco.com...
  17. bridgeDisciple

    Are HSS members in bridge trusses a good idea?

    @jorton Excellent point! That may well be what tips me away from HSS. As i stated in my query, this design is highly cost sensitive (miles and miles of bridging). While temped by seeing examples like that attached (which uses HSS round for the bottom chords and web), i have to recognize i...
  18. bridgeDisciple

    Are HSS members in bridge trusses a good idea?

    I think you are talking about ASTM A1085. And those materials are now supplied. eg, https://www.atlastube.com/products/structural-steel/astm-a1085/ Yes AASHTO/AWS D1.5 excludes it. But then AASHTO LRFD BDS now includes A1085. So which is it - in or out ? AISC's Steel Bridge Design Book...
  19. bridgeDisciple

    Are HSS members in bridge trusses a good idea?

    Why is HSS weld inspection necessarily a problem? All welds are on the outside surfaces. Why isn't that equivalent to the situation where non-hollow shapes are used?
  20. bridgeDisciple

    Are HSS members in bridge trusses a good idea?

    I'm hoping for some shared wisdom here. I'm designing a bridging system for an autonomous transit network (ATN) - light-weight modern form of APM. It is roughly in the class of pedestrian bridge with light vehicle capability, and similar in form to pony truss bridges with outboard walkways...

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