×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Steel stair stringer

Steel stair stringer

Steel stair stringer

(OP)
I am doing a design of a steel stringer . there is two PFC supporting precast concrete treads. According to code requirement i used 4kpa live load on tread.so point load on stringer say 1.5KN. my question is do we need to consider a situation where all the treads are full of 4kpa . so in stringer each and every point which connects to tread having point loads . is that correct or which way need to think? if anyone post an idea that would be helpful.

RE: Steel stair stringer

Yes, you place the distributed load on the full horizontal projection of the stair.

RE: Steel stair stringer

Whats "PFC"?

RE: Steel stair stringer

Quote (MotorCity)

Whats "PFC"?

Parallel Flange Channel.

RE: Steel stair stringer

Re: PFCs - other than rolling and cooling distortions, are there any channels whose legs aren't parallel to each other? Isn't PFC a redundant term?

Thaidavid

RE: Steel stair stringer

I thought MC channels had straight flanges? I spec them regularly in the US. MC6x18's are real handy to attach shearwall straps to at the base of a metal stud wall.

RE: Steel stair stringer

Yes, that's correct.

Maybe I'm mistaken that MC's are not used often. I hardly use them but others can chime in or say otherwise.

RE: Steel stair stringer

I routinely use MC 10's and 12's for stair stringers.

RE: Steel stair stringer

Much of the world now uses parallel flange channels for the large ones, and tapered flange channels for the little ones.

RE: Steel stair stringer

Quote (hokie66)

Much of the world now uses parallel flange channels for the large ones, and tapered flange channels for the little ones.

Like much of the world uses the metric system...except the US smile

RE: Steel stair stringer

Quote (Ingenuity)

Like much of the world uses the metric system...except the US
The rest of the world's loss. Who wouldn't want to use a unit of slugs?! I'm just glad we don't have to do a lot of mass calculations because lbm and lbf starts opening up problems.

Edit: Oh yeah, I meant to also say something relative to OP's question. In the US, we need to design the entire horizontal projection with 100 psf [4.8 kPa]. Each tread also has to be designed for a single point load of some magnitude (can't think of it right now; I'm thinking either 300 lbs [1.33 kN] or 1000 lbs [4.45 kN]). That point load is applied at center for bending check and at the end for shear check.

Juston Fluckey, SE, PE, AWS CWI
Engineering Consultant

RE: Steel stair stringer

The concentrated design load is 300 lbs. All the treads need to be assumed to have 100 psf on them to account for the stair to be full of people using it due to evacuation or whatever else might cause people to pile into the stairway all at once.

Nearly all men can stand adversity, but if you want to test a man's character, give him power. Abraham Lincoln

RE: Steel stair stringer

(OP)
Thanks for all your comments and ideas.

Further I need to clarify something. I need to design a base plate for newel post in this stair . as per the attached sketch i use 4 bolts for the connection. is it require this newel post exactly be in middle or any arrangement as per my sketch is ok?

RE: Steel stair stringer

(OP)
Also I am using a 75mm pocket in foundation to put this base plate . and use non shrinking grout below the base plate and on top of the base plate to hide the base plate. further is there any issue if we put another layer of concrete to cover the non shrinking grout on top of the base plate?

RE: Steel stair stringer

Not sure of UK or European requirements but there are no requirements for newel post locations in IBC. They merely need to be able to support the design loads. And keep openings in the Guard to 4 inches or less. The Architect might not like the look if it's unsymmetrical.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources