Horizontal/Subsurface Infrastructure & Transportation

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  • 1.  retrofit pedestrian railing

    Posted 10-11-2018 01:36 PM
    Edited by Tirza Austin 10-11-2018 01:35 PM
    Greetings - An Alaska DOT & PF bridge constructed in the 70's has a galvanized steel pedestrian railing with vertical elements consisting of 1/2" pipes 7" o.c. Any ideas out there for a resilient but simple retrofit, i.e., snap over covers, to reduce space between rails to less than 6"?'

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    David Mearig P.E., M.ASCE
    Juneau AK
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  • 2.  RE: retrofit pedestrian railing

    Posted 10-12-2018 10:05 AM
    Edited by Tirza Austin 10-12-2018 10:04 AM
    Interesting concept for retrofit using a type of snap over cover to introduce a new rail - would they be at mid-point of the existing rail to reduce down the spacing to half the current spacing difference?  My only caution is that whatever the retrofit, do not trap water again the galvanization, especially at the coated welds, where moisture would cause accelerated corrosion.  That is my experience at Maryland DOT with galvanized W Beam Traffic Barrier.  I would recommend a perforated or slotted cover over the top and bottom rail if that is the system decided upon.
    --
    Mark Wolcott, P.E.
    iSee, LLC
    o-443-620-4733 (isee)
    c-443-877-0471


    ------Original Message------

    Greetings - An Alaska DOT & PF bridge constructed in the 70's has a galvanized steel pedestrian railing with vertical elements consisting of 1/2" pipes 7" o.c. Any ideas out there for a resilient but simple retrofit, i.e., snap over covers, to reduce space between rails to less than 6"?'

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    David Mearig P.E., M.ASCE
    Juneau AK
    ------------------------------


  • 3.  RE: retrofit pedestrian railing

    Posted 10-12-2018 10:05 AM
    Edited by Tirza Austin 10-12-2018 10:05 AM
    Maybe the folks at McNichols Co. could custom fabricate something for you. They make all kinds of gratings as well as handrail components.

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    Joseph Gilroy PE, PTOE
    Gonzalez Cos., Belleville IL


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  • 4.  RE: retrofit pedestrian railing

    Posted 10-12-2018 12:06 PM
    Edited by Tirza Austin 10-12-2018 12:05 PM
    Assuming these pipes are vertical balusters, i.e. numerous elements. Would attaching chain link fabric to the outside of the railing work?

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    David Kennicutt P.E., M.ASCE
    SR PROJECT MNGR
    Delta Engineers, Architects & L.S., P.C.
    Endwell NY
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  • 5.  RE: retrofit pedestrian railing

    Posted 10-12-2018 12:52 PM
    Edited by Tirza Austin 10-12-2018 12:51 PM
    If you add a middle picket to make them 3.5" o.c. you will exceed the IBC code for guardrails (4" max.).  The cheapest way would be to add chain link.  If there is more of an architectural concern, consider fastening a wire mesh or perforated metal panel to the pickets.  McNichols is a good resource.

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    Chad Morrison P.E., M.ASCE
    Professional Engineer
    Greenville RI
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  • 6.  RE: retrofit pedestrian railing
    Best Answer

    Posted 10-15-2018 07:54 AM
    Edited by David Mearig 10-15-2018 01:17 PM
    ​I don't recommend welding onto the existing.
    Build a separate frame that mounts to the first.
    Use an angle to weld the new members to and space the rails 7", just offset from the original railing.

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    Timothy Carre P.E.,CWI, M.ASCE
    Civil Engineer
    Harrisburg PA
    (717)783-6708
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  • 7.  RE: retrofit pedestrian railing

    Posted 10-15-2018 01:32 PM
    Edited by Tirza Austin 10-15-2018 01:32 PM
    Thanks, all, for your ideas. I neglected to mention that we get quite a bit of wet, heavy snow. Adding a chain link fence, perforated metal or other treatments that catch snow will create challenges for our winter operations. I like the idea of fabricating rail segments with vertical elements offset from the existing that can be mounted outboard of the existing railing.

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    David Mearig P.E., M.ASCE
    Juneau AK
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