Fixed Ladder - Stringer Extension Design (Walk-through)

[FHErfurt98]

I am looking for design requirements for fixed, wall-mounted ladders, specifically the stringer extension that forms the walk-through at the top of the ladder.
OSHA and ANSI provide design requirements but do not specifically call out lateral loading at the top of the stringer end/walk-through. One could apply the IBC point loading for guard railing of 250 pounds. However, this loading would render any flat bar stringer extension unsuitable.
Any comments?

 

[JStephen]

I have seen ladders with the step-through portion made from angle specifically for this reason. (I would take the design load as what could reasonably be applied by a climber of the rated capacity rather than the guardrail load).

More often, it is possible to either support those bars by tying them into the platform guardrail or by a ladder cage.

 

[racookpe1978]

For practical reasons, you MUST attach the verticals (the bars or supports your hands are "following/sliding upwards as you climb the ladder) smoothly up to the hand rails of the higher stage. At a power plant two weeks ago, a person (me!) climbing the ladder up to the deck entrance could slide their hands up to a gap so that the person (me!) could fall backwards away from the deck.

You're looking for a blame-free design-by-rulebook or design-by-code answer: The right answer is the "how much weight (waht force) is going to be passed through that memeber when a design-sized person gets in that position. So provide a sketch of the problem. Even a 240 lb load can be resisted in tension by a 1/2 x 1/4 bar adequately welded on both ends, even when that 230 lbs is multiplied by a reasonable safety factor, so I do not understand your concern.

 

[FHErfurt98]

JStephen and racookpe1978, Thank you for your replies. I will make reasonable loading assumptions for ultimate and deflection design of the stringer.