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OSHA Handrail (top rail) 200lb exac

OSHA Handrail (top rail) 200lb exac

OSHA Handrail (top rail) 200lb exac

(OP)
OSHA Handrail (top rail) 200lb exact location.

Hi! Good day Engineers.

I am design a OSHA stairs with handrail. I'm confused about 200lb concentrated live load, downward or outward direction.


For example top rail length is 25ft. I am planning to distribute the 200lb over the total length of top rail. And it becomes 8lb/ft acting in the top rail total length.

Can anyone give me advice.

Thank you.

RE: OSHA Handrail (top rail) 200lb exac

Don't distribute the concentrated load. it is a point load, keep it as a point load. I forget, doesn't both OSHAs also have a 50plf requirement? (sorry can't find my copy from home)

Basically, everything needs to be able to transfer 200# minimum. the post. the rail to post. the rail. and then the rail needs to be able to transfer it.

If there is a 50plf requirement then if your posts are at 4ft o.c. they need to resist 200# or 4ftx50plf = 200# but if posts are 12.5ft apart the middle post will need to resist 12.5ft x 50 plf!!! Oh and deflection limits are a thing with OSHA design.

Call up one of the structural firms you work with and run it by them, or better hire a structural engineer. We can always use the work :)

RE: OSHA Handrail (top rail) 200lb exac

(OP)
I'm sorry, I confused.

No OSHA requires 200lb only.

The distance between posts are 3.28f (1m)

You mean, in every post I should apply 200lb at the top rail. For example the stairs has 9posts. 9 of 200lb should be applied at top rail and post?

RE: OSHA Handrail (top rail) 200lb exac

What if the load is right at an end post? That one post must resist the entire load.

The code says that the load could be anywhere in any direction. Find the worst case and design for it. This is a basic and simple tenet of structural engineering.

RE: OSHA Handrail (top rail) 200lb exac

(OP)
Hi, Sir.

I'm just confused about the exact location of 200lb concentrated live load.

I though it should be located at every top of post.

RE: OSHA Handrail (top rail) 200lb exac

You need to check the post for the load being right at the top of post. And you need to check the rail as if the load was mid way between posts.

RE: OSHA Handrail (top rail) 200lb exac

(OP)
And I need to check for vertical and horizontal load Sir?

RE: OSHA Handrail (top rail) 200lb exac

(OP)
Dear Engineers,

For example, the length of posts are 3.28ft and it has midrail.

Should I seperate the design of post with 200lb at the top and 150lb at the middle. Or I should design the the post with those loads acting at the same time?

I think that was the worse case.

Thank you.

RE: OSHA Handrail (top rail) 200lb exac

The 200 lbs is a single load that can occur at any point along the top rail. The rail must be able to resist that load when applied at any point, but if the post spacing is the same everywhere, the critical location will be at the midspan of the end spacing (between the 1st and 2nd posts). It can also occur at a post, and the post must be able to resist the 200 lbs and the moment it produces at the base.

If you're still not clear on this after my reply and the previous replies, you need to consult a structural engineer to design the railing.

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

RE: OSHA Handrail (top rail) 200lb exac

The 200lbs can be applied to the post and for the rail, I apply the 200lbs to mid span and use PL/6 to accommodate the end span... for interior spans the Mp = PL/8. I also use the plastic section modulus Z. I don't think any additional loading is concurrent.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: OSHA Handrail (top rail) 200lb exac

I agree that the load need not be applied concurrently in both directions. The lateral load will always govern the design of the items from my experience.

RE: OSHA Handrail (top rail) 200lb exac

Quote (use PL/6 to accommodate the end span.)


The actual number is about 5.8...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: OSHA Handrail (top rail) 200lb exac

BridgeSmith nailed it with: "The 200 lbs is a single load that can occur at any point along the top rail." This answers the OP's question directly. The load may be horizontal or vertical - you have to check both. It can be anywhere so you have to find the worst case.

RE: OSHA Handrail (top rail) 200lb exac

Cassidy,

You shall learn how to simplify a structure, and always look for the loading case that produces the most critical reactions in the simplified structure.

RE: OSHA Handrail (top rail) 200lb exac

Slightly improved... and Mp = P x L / 5.8



Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: OSHA Handrail (top rail) 200lb exac

You just couldn't get out of the hall (hole) of plastic design !:) Now the OP is confused again.

RE: OSHA Handrail (top rail) 200lb exac

(OP)
Yes, I understand Engineers. Thank you.

If it has mid rails, it should resist the 150lb.

If I will design the post, should I design it with 200lb and 150lb acting at the same time?

RE: OSHA Handrail (top rail) 200lb exac

(OP)
The codes says, the stair landing live load should be at least five times the normal load or min of 1000lb.

The code give an example of 300lb worker (tools included)

The structure I'm design has stairs outside and the landings are cantilever. The landings dimension are 4.6ft x 9.8ft.

I used 330lb, then the normal live is 7.32 psf. And it will becomes 36.6 psf.

It is alright? Because it is overhang landings with no support at the ends. The design is already alright with the live load.

But I'm thinking that it's 5*330lb or 5 persons. 4.6ft x 9.8ft landing is big space, I'm thinking what if 7 to 10 persons standing in the landings.

Any suggestions, recommendations are really appreciated.

Thank you.

RE: OSHA Handrail (top rail) 200lb exac

Did code mention you need to do load combination in handrail design? Follow the code.

RE: OSHA Handrail (top rail) 200lb exac

I sense you are designing industry structures. If so, follow industry guidelines for specific requirement.

RE: OSHA Handrail (top rail) 200lb exac

Quote (Now the OP is confused again)


I suspect he's smarter than that... just pointing the way forward... to produce a safe, easy, and economical design...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: OSHA Handrail (top rail) 200lb exac

Where I practice, all commercial, industrial and multi tenant residential stairs are designed for 100 psf live load. Which on a 5x10 platform would equal 5000lbs total.

What is the application of the stair? Does it fall under Oshawa the local building code? If it's an egress stair, I believe it would need to comply with both.

RE: OSHA Handrail (top rail) 200lb exac

It it's egress, I'd design for 100spf. If it's not an egress stair, and only provides access to a small platform or piece of machinery for maintenance (some sort of typically unoccupied area), I'd use 40 psf as a "catwalk for maintenance access."

And I always combine handrail loads with floor loads for this kind of structure. For somebody to apply the load on the handrail, they must naturally be standing on the platform. Unless they're falling from a higher one, but I don't think that's quite a condition the code contemplates.

RE: OSHA Handrail (top rail) 200lb exac

I remember, in the old time, there is a concentrate load requirement. For industry settings, it can govern, if required.

RE: OSHA Handrail (top rail) 200lb exac

For maintenance catwalks it's a minimum 300# point load, higher if you know the future use sufficiently and know that some piece of equipment will load it more.

RE: OSHA Handrail (top rail) 200lb exac

(OP)
Hi Engineers

It is OSHA stairs, for industrial and warehouse.



That 100psf is for IBC stairway, but the code says,

(It should be noted that factory, industrial and storage
occupancies in areas that are not accessible to the public and
that serve an occupant load not greater than 50 are excluded
from the uniform live load for guards. Refer to ASCE/SEI 7,
Section 4.5.1.)

RE: OSHA Handrail (top rail) 200lb exac

(OP)
For OSHA stairs

Five times the normal live load or minimum of 1000lb.

The code give an example.

(For example, a 3-ft-wide stair with nine treads is used to
access an equipment platform by one worker weighing 300
lb (including tools). The total live load is 300 lb over approx-
imately 27 ft2
. The uniform load is then (300 lb)/(27 ft2
) =
11.2 psf. Per OSHA, this is the normal live load. The stair
should be designed for five times this value or 56 psf.)

But if you check the load that the 1 tread will carry it is only 168 lb.

RE: OSHA Handrail (top rail) 200lb exac

(OP)
I'm designing a stairway for industrial and warehouse.

The stairs are outside the structure. And it's like overhang stairway.

RE: OSHA Handrail (top rail) 200lb exac

Quote (OSHA)

1910.25(b)(6)

Each stair can support at least five times the normal anticipated live load, but never less than a concentrated load of 1,000 pounds (454 kg) applied at any point;

I hope this provision clears your concern.

RE: OSHA Handrail (top rail) 200lb exac

(OP)
r13

Yes Sir I already read that. Meaning each stair tread should resist at least 1000lb concentrated load.

But I only thinking about the example given by the code.

RE: OSHA Handrail (top rail) 200lb exac

(OP)
For examle each stair tread has dimension of 2.79ft x .82ft. Using the 1000lbs min.

Each tread should resist 437.1 psf?

Which quite large compared with IBC 100psf. That 100psf is for public use.

RE: OSHA Handrail (top rail) 200lb exac

The thread shall be able to support 5*100= 500 psf uniform load, or a 1000 lbs concentrate load. Does this make sense?

RE: OSHA Handrail (top rail) 200lb exac

(OP)
Sir, the 100psf is live load for IBC, for public use. I think 100psf should be greater than the live load for industrial stairs (OSHA)

RE: OSHA Handrail (top rail) 200lb exac

(OP)
Sir jayrod12 and Sir phamENG

100psf is for IBC right?

Or even industrial stairs (OSHA) you used 100psf for stair tread, landings?

RE: OSHA Handrail (top rail) 200lb exac

Note the key sentence in this provision is "Fixed stairways shall be designed and constructed to carry a load of five times the normal live load anticipated but never of less strength than to carry safely a moving concentrated load of 1,000 pounds".

For the stair way, as a whole, to achieve the objective to have a strength to carry 5 times of the normal live load anticipated, or a minimum 1000 lbs concentrated load placed anywhere in the stair system, each components (thread, landing, stringer...) must have the same capacity. The IBC specified live load shall be considered the normal live load anticipated, thus, for each component, as well as the entire stair way, a 500 psf live load is to be applied, and compared with the 1000 lbs minimum concentrated load applied anywhere on the components, and the stair system. However, this contradict the example by a mile, where is the example provided, and how the "normal live load" is defined? I agree that we need ti dig little deeper into it.

RE: OSHA Handrail (top rail) 200lb exac

Quote:

Design of stringers, treads, and their connections are left to the structural engineer. Regarding structural design criteria, 2018 IBC Table 1607.1 (30) requires stairs to resist a minimum live load of 300 pounds (concentrated load) or 100 pounds per square foot (psf), or 40 psf for one one-and two-family dwellings.

IBC specifies 300 lbs concentrated live load is less than the OSHA 1000 lbs minimum requirement, so OSHA governs. Then the IBC specifies 100 psf uniform live load, thus per OSHA, 500 psf governs. Hope this helps.

RE: OSHA Handrail (top rail) 200lb exac

First - please don't call me "Sir phamENG" - I'm flattered, but there hasn't been a knight in my family for over 300 years.

You still haven't clarified the use of this stair. Is it leading from an exit route used for life safety planning? If so, then your "normal live load" needs to be 100psf. If not, then you can use something lower, like 40psf or 50psf.

Based on the clarification statement issued by OSHA that you posted above, the 5x sounds like a safety factor. It specifically says it is for ultimate design and should not be used with AISC's ASD specification (the letter is a bit dated). I would still use the AISC design equations, but be sure to ignore Ω and Φ. Instead, compare your 5xNormal Live Load directly to the result of Mn, Vn, etc. It's very important that you understand the codes, how and why they are written the way they are, and what all of the adjustments, factors, etc. mean. If you don't, get with a senior engineer to go over them and help you through this. Swapping out the wrong thing can mess everything up really easily.

The 1000 lbs is applied everywhere, but not all at once. You need to put it in the middle of the tread (not spread over the tread) to check bending in the tread. You need to put it on one stringer, in once place at a time, and develop and enveloped bending moment diagram and shear diagram (and torsion, depending on your design). But you don't have to put them all over the stair all at once. It's to test individual components and ensure their strength and resiliency (uniform loads work well for the overall structure, but don't always capture the little stuff sufficiently).

The guard exemption in ASCE 7 doesn't get you out of the OSHA requirements. ASCE 7 has the 50plf requirement AND the 200# requirement, whereas OSHA only has the 200# point load requirement.

Where is this project located? Looks like you're in the Philippines. I know you guys use several American building codes, but do you all use our OSHA standards, too? Or are you designing a US project?

Hope this helps.


RE: OSHA Handrail (top rail) 200lb exac

(OP)
Good day, Engineers.

I really appreciate your comments and advice, thank you.

I need some clarification. For example the thread has dimension of 0.850m x 0.250m.

Let say the live load is 500psf or 23.94kPa.

1 thread should resist 518.58 kg. Is it alright. I think it's too heavy.

RE: OSHA Handrail (top rail) 200lb exac

(OP)
phamENG

The use of stairs is to provide a way or to access different floor levels.

The structure is 6-storey. It is pre-treatment, meaniny every floor has operating equipment.

Is it still 100psf normal load, and become 500psf?

RE: OSHA Handrail (top rail) 200lb exac

Cassidy G,

Yes, it sounds high, but that's the rule of the game. An OSHA Q&A is linked FYI, Link.

RE: OSHA Handrail (top rail) 200lb exac

(OP)
r13

Yes, Engineer. I already read that. When the time I changed the live load for threads, some of structural members are failed (pipes)

I used Staad.Pro to design the whole stair system stringers, threads, railings and landings.

I already understand the live loads for railings but not for threads and landings.

For example, 1 staircase has 15 threads. Each thread has dimension of 0.850mx0.250m. I apply 500psf (23.94 kPa) to each thread. It's like 518.58kg x 15 threads.

I understand that not all of the threads should carry live load at the same time.

So, I check it one by one. 1st thread only has live load, pass. 2nd thread only, pass. And so on. It pass/safe if the live load is applied only in 1 thread.

But I'm thinking what if 2 or more threads has live load in actual. Let say 3rd and last thread has live load in acutal. Therefore, I apply the live load in all threads at the same time to check if it is ok. Now some of structural members are failed.

Any advice. Thank you and God bless, Sir.

RE: OSHA Handrail (top rail) 200lb exac

(OP)
I used software because my boss told me.

RE: OSHA Handrail (top rail) 200lb exac

Cassidy G,

One of the article mentioned an OSHA response which may help:

“Each stair can support at least five times the normal anticipated live load, but never less than a concentrated load of 1,000 pounds (454 kg) applied at any point.”

The 1,000-pound point load is meant to account for a 300-pound person potentially running down the stairs. The impact of their footfall in that scenario will be higher than if they were simply standing on a tread. OSHA further clarifies the criterion by providing an interpretation for this loading with the following response:

The design of fixed stairways and their components must be based on their ultimate strength [yield stress (FY) or ultimate stress (FU)] and not on the allowable stresses as given in the Allowable Stress Design method of the American Institute of Steel Construction, Ninth Edition.”

RE: OSHA Handrail (top rail) 200lb exac

Cassidy G,

The plates one steps on are treads not threads. Just FYI.

Jim

RE: OSHA Handrail (top rail) 200lb exac

(OP)
r13

Yes, Sir. I understand this “Each stair can support at least five times the normal anticipated live load, but never less than a concentrated load of 1,000 pounds (454 kg) applied at any point.”

I'm just thinking where I should apply the live load. Just like what I have said, I'm designing the whole staircase in software (Staad.Pro). I already check one by one. Live load placed at first tread (pass/safe). Live load placed at 2nd tread (pass/safe) and so on. The design of whole staircase is pass and safe if live load will apply one by one, like a person walking/running up and down the stairs.

But I'm thinking that not all the time one person will only use the stairs. What if 2 or more.

Let say the stairs has 15 treads. Person A used the stairs going up and when he/she stands exactly at 10th tread, person B used also the stairs. The treads can carry the 1000lbs but not the stringers. With person A and B, it's like stringers should resist 2*1000lbs.

I'm sorry, I'm not just asking for treads this time. I'm also asking for stringers since I already check the treads one by one.

Thank you, Sir.

RE: OSHA Handrail (top rail) 200lb exac

(OP)
jimstructures

Yes, wrong spelling.

Thank you.

RE: OSHA Handrail (top rail) 200lb exac

I've came to a realization after the OSHA's response:

1. Design the individual tread for a concentrate load 300*5 = 1500# > 1000#. 300# concentrate load is typically required by the building code.
2. Apply 100*5 = 500# everywhere on the stair to design all other components.

I think you shall treat the above loads as factored )ultimate) loads (LF = 5), and use LRFD design method.

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