Six storey timber structures

[GalileoG]

I'm looking for any journals out there on design/considerations/economy of six storey timber buildings. Recently, British Columbia Building Code has allowed such buildings to be constructed but I have not been able to find any journals on this particular topic. I can't imagine what the hold-down requirements for something like that would be, or how one would deal with shrinkage issues.

Thanks,
Clansman

Clansman

If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.

 

[JAE]

Elastic drywall?

 

[BAretired]

Hello Clansman, it's good to hear from you again. I thought you had left us.

I have not designed a six storey timber building in over fifty years of practice, so I cannot comment on specific issues which might arise with modern technology, but I do remember a building I investigated briefly in the first year of my practice when employed by a consulting firm in Toronto, Ontario, Canada.

Even at the time (1955), it was a very old building. Actually, it was a storage building with live loads of 200 psf on every floor. The exterior walls were brick, varying in thickness from 30" at the bottom to 8" at the top, the latter supporting roof only.

The structure consisted of solid laminated wood floors on heavy timber beams on heavy timber columns with cast iron connectors. Shrinkage was very much in evidence as the sixth floor had settled more than six inches between the exterior walls and the first interior column.

Because the building was constructed of heavy timber, it had a pretty good fire rating. I do not feel nearly as confident in the materials of today. I do not doubt that strength, durability and stiffness can be achieved with modern timber materials, but I seriously question the advisability of building structures to a height of six storeys with the light wood materials available today. The risk of fire and the potential loss of life is simply too high.

BA

 

[dhengr]

Elastic drywall may not be necessary, but I wouldn’t run the drywall three stories high either, continuous without any joints. Hold-downs and the framing around them to get pretty large. Shrinkage and settlement is a problem and requires some special attention to details at each level.

 

[msquared48]

I would consider balloon framing the first and second, then the third and fourth floors, and using all TJI's and either Glulams or Paralams. Shrinkage should be manageable doing this as it will only be seen across the wall plates.

As for the drywall, hold the wall drywall 1/2" short of the bottom of the ceiling joists, and pull the 5/8" ceiling drywall up to the wall drywall. There should be room for some small vertical settlement without crushing the drywall.

As for the holddowns, you want to make sure you have enough wall and they stack. If not, fight for it. You will need to use a special roof to foundation system of continuous threaded rods. There are providers of these systems on the market, and I have used them for 5 story buildings with no problems.

I just hope that the floor does not have any gypcrete.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[csd72]

http://www.diva-portal.org/smash/get/diva2:206355/FULLTEXT01

http://www.brick.org.uk/_resources/Multi-Storey Timber Frame.pdf

 

[Cadair]

http://www.structuremag.org/Archives/2006-6/D-Fex-Hi-Rise-wood-frame-const-June-06.pdf

 

[GalileoG]

Thank you all for the excellent references. I will have much reading to do.

BARetired, glad to find you are still here posting! I had decided to take a little break from eng-tips as I found myself lurking here for many, many hours and almost burnt myself out by doing so.

Clansman

If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.

 

[boo1]

Post discusssing 4-5 stoory wood structure design issues was:

http://www.eng-tips.com/viewthread.cfm?qid=276910