×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

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!

*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

Did the Architect Specify the right BEAM Size?

Did the Architect Specify the right BEAM Size?

Did the Architect Specify the right BEAM Size?

(OP)
I am a Computer Guy not an Engineer. I hired an Architect and Contractor to renovate my 1930s Bungalow adding a 2nd floor.

I need advice(I am willing to hire an Engineer to come on-site to Consult, I know each situation is different and it's difficult to advise withoout seeing) on whether the Beam installed in place of a load bearing wall between my Kitchen and Den is structurally sound.

Above the kitchen and Den are 2 Bedrooms and it appears all roof load is carried by outside walls. The Beam is made of 3 2"x10" spanning 10'4" supported by 4x4 on each end. The joist above are 14"(16" OC) Engineered lumber spanning 28' and joined over the Beam(each side is about 14'. This has been in place for almost 3 yrs; however where the beam meets the wall(this is an outside wall)I can see just a little cracking at the seams of the sheetrock, nothing major but enough to make me wonder. There are no other signs of problems. The question is does the Beam size etc appear OK? Should I be concerned? Should the fact that it has been 3 yrs give me comfort? PLEASE HELP!

RE: Did the Architect Specify the right BEAM Size?

I have practical experience with moving beams and supporting walls in basements although I am not a structrual engineer. This beam of 3 - 2x10s with a span of 10'-4" is fine. I have seen this in many basements to support load bearing walls. The mistake most contractors make is not place the foot of the load bearing column on a proper footer. Check your to see if the footing looks solid. It shoud be on a 10" thick concrete pad. If it is sitting on the basement slab you won't know what is under it, but if there is no cracking of the concrete where the 4x4 foot is setting it should be ok. If the footing looks ok the next reason for the cracking of the sheet rock is shrinkage of the 2x10 lumber. Green Douglas Fir will shrink form 9 1/2" to between 9 1/4" to 9". This is enough to cause cracking of the sheet rock. As long as your floor remains level I would just spackel the crack.  

RE: Did the Architect Specify the right BEAM Size?

falinatl,

I am a structural engineer, and although Bobnj may have seen this beam work in similar situations, I checked this beam as if you have carpet upstairs (a very light Dead load) and this beam is overstressed per the code by a factor of 1.9.  This would be reason for a little bit of cracking on your sheetrock.  I would recomend that you hire a registered professional to assess the situation with exact loads, but it looks to me as if a small Glu Lam beam would be more sufficient.

akastud

RE: Did the Architect Specify the right BEAM Size?

I'm an SE also - I got about 1.8 unity (80% overstressed) based on 15 psf dead load and 40 psf residential live load using Douglas Fir No. 2 and 14' tributary width on the beam.

falintati - you might want to go hire an engineer to check this out.   

The 40 psf live load is intended to cover all your furniture weight and other non-connected items that load the floor in addition to humans.  Normally you don't get the floor loaded up that much (14' x 10.33' x 40 psf = 5,784 lbs.) so according to the 1.8 unity you've got a SAFE capacity of 15.5 psf live load (= 2,214 lbs on the beam)

SAFE capacity means that your beam is delivering a code required safety factor when it just gets loaded with the 15.5 psf.

FALL DOWN capacity is perhaps 60% to 80% or more higher than the safe level so the beam would theoretically fail at about 35 psf which is about 5,000 lbs of weight on the beam.

All these weights are in addition to the self weight of the beam and floor system.

But still...go get an engineer as you may have to show your builder that what he did doesn't meet code.

RE: Did the Architect Specify the right BEAM Size?

(OP)
Thank you all for your help. I have since realized that there appears the Beam is made of 4(not 3) 2"x10" spanning 10'4". How does this effect the situation?

RE: Did the Architect Specify the right BEAM Size?

(OP)
Thank you all for your help. I have since realized that it appears the Beam is made of 4(not 3) 2"x10" spanning 10'4". How does this effect the situation?

RE: Did the Architect Specify the right BEAM Size?

As far as code goes, I estimate that you are still about 35% overstressed.

RE: Did the Architect Specify the right BEAM Size?

4 - 2x10's will simply give you 4/3 more capacity than 3 - 2x10's.  Also, your deflection would be 3/4 of the deflection of 3 - 2x10's.

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! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close