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Author Topic: Effective widths of stairways  (Read 3347 times)

ronniethomas

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Effective widths of stairways
« on: April 02, 2012, 10:27:36 pm »

Hello,

I am conducting some research with various stair sizes, and am trying to correlate my data from real world observations to the model.  I have one staircase that I am looking at that has a measured total width of 47.5in and a measured width between the railings of 43in.  I am using the default settings in my model, and have set up landings that hold my occupants with exit doors on either end.  I am running three occupants up the stair and two down. 

The problem I have is that when I set the stair measurement to 43in, the occupants get stuck.  Using the default shoulder width of 17.95xxx in, it seems as though there shouldn't be a problem, but in steering mode they get stuck.

Does the model account for an effective width of the occupants, so to speak? 

Thank you,

Ronnie
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Charlie Thornton

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Re: Effective widths of stairways
« Reply #1 on: April 03, 2012, 08:36:14 am »

The only meaningful context in which Pathfinder uses effective width is in the calculation of the doorway flow rate for SFPE-mode simulations. In steering mode, the only thing that would come close to effective width is occupants' tendency to avoid walls. However, they'll brush against a door jam it that's what it takes to get through a door.

How are the occupants getting stuck? Is it a problem where the occupants cannot counterflow through the narrow space? Situations where an occupant needs to take a step back to allow another occupant to pass are problematic in Pathfinder because we don't currently have the code we would need to make that happen (the hard part is not deciding who gets priority, it's more in figuring out where the yielding occupant should go).

On the other hand, if it's a matter an occupant just getting bizarrely stuck, please post your model or send it to support@thunderheadeng.com and we'll try to figure out what the bug is and get a fix.

Also, do you have small-scale observational data that measures walking speed up and down as a function of stairway variables? I'd love to see it.
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ronniethomas

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Re: Effective widths of stairways
« Reply #2 on: April 03, 2012, 08:43:25 am »

Hello,

The occupants are getting stuck mid-stair.  It seems to be a problem where they cannot counterflow through the narrow space.  Yes, it seems like one does not want to yield to the other.  I will send you the file today, it’s quite simple.  I will also send the observational data.  Feel free to use it as you wish.  We are trying to get PathFinder to mimic the actions of our actual data, and that was quite simple. 

Thank you,

Ronnie
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