Office Live Load - when to NOT include partitions

[mattkh]

Hey All,

I am working on a typical office building with loads based on ASCE 7-10. Regarding the live loads for the upper stories, I was wondering what some of your opinions are. For the typical offices I am designing for 50+15psf, but I am wondering what to do for the corridors. Should I be designing for 80+15psf to include the partition? Or should I be using 80psf without the partition? ASCE 7-10 Section 4.3.2 does have the EXCEPTION provision which states that live loads that EXCEED 80 psf do not need to include the partition. I'm wondering what others do regarding this.

 

[EngineeringEric]

If it is corridor loading then there are no partitions. So I would design based on 65psf and 80psf. but i usually increase that office load and partitions of 20 psf so i am more like 75psf everywhere and a check to make sure corridor can handle 80psf. it has minimal effect on the whole structure but makes analysis and hand checks easier.

If you knew where all partitions are going then you would not include any 15psf and would include their real DL and effect. So in the corridor you know where all these corridors are going, no where.

 

[jdgengineer]

I personally design for 80 PSF without partition loads. I've been in an AISC seminar when this came up. The speaker was a high profile engineer ( I think Rafael Sabelli but could be wrong). The speaker acknowledged this section and mentioned some people design for 80.01 PSF to "exceed" 80 psf. I believe he mentioned he uses 85 PSF to exceed it a little but but not quite as hockey as the ".01" psf. To me I think it's splitting hairs, and just use the 80 PSF.

 

[MotorCity]

Use 80 psf and you are covered for any future renovations/wall re-configurations regardless of where corridors or partitions are located. The difference in slab thickness, framing members, etc. won't even be noticeable if you are on the fence between using 65 psf and 80 psf. (Also, it is very unlikely that your client will consult a structural engineer if they decide to move non load bearing partitions around in the future.)

 

[calvinandhobbes10]

I prefer to use actual loads, although I find that vibration usually controls steel office floors, which is probably why folks are saying 80/65/50/80.01---this decision doesn't drive floor design.

I use:
65psf typical (use reduction on ALL 65 as permitted by Code), 80psf corridors (also fully reducible). With the 15psf partition, I do NOT review the initial tenants' fitout plans to distinguish between hallways and offices, this is excessive and not warranted by Code. Tenant space = 65. Common core space = 80. IThis is because offices require keycards to get in, same as hotels and dorm halls. Private corridors use same load rating as the occupancy served.

Also, consider your superimposed DL. 25psf, as many engineers use, is too high for standard office space. 10psf is realistic, 15psf max (2 finish 2 ceiling 2 lights 4 mech).

You'll find that 15 psf partition allowance covers a LOT of partitions, and doesn't warrant additional fluff. Do the math...how many 9' tall 7 psf GWB partitions does it take to yield 15 psf. It's like 6' square cubicles.

 

[dik]

I consider partitions and show them on the drawings as permanent partitions and make allowance for these. I do not carry a 'lump' value for partition design. There is an exclusion in the Canadian code, exempting Permanent Partitions. I also have a note in my General Notes that partitons are permanent and that any revision must be reviewed by an engineer.

The actual weight of the partition per foot, is compared to the design live load, and the difference is considered as the added partition load. If a partition weight 40#/ft and is 6" wide, and if the design LL for the floor is 50 psf then the partition load at max would be 40 - 50/2 = 15 psf. If the minimum spacing of partitions is 3', then the max partition load is 5 psf.

The important part is that the partitions be considered as permanent.

From my Drawing Notes:

PARTITIONS SHALL BE FIXED AND PARTITION LOADING IS PREDICATED ON ACTUAL PARTITION LAYOUT SHOWN. ENGINEERING REVIEW REQUIRED TO MODIFY PARTITION LAYOUT

Dik