Beam Size
Beam Size
(OP)
I am working with a four car garage 35'X 20'The building was built in 1919. The roof is flat with 1" pine sheeting and rolled roofing. (Approx.7.5 psf) There is a wall between each garage. The owner wants to open the garage up into one space. The 2X6 Roof joists (24"oc) run parallel (the 35'length) to the building and overlap on top of each garage seperating wall. When I remove these load bearing walls and install a beam to replace them, What size wood beam do I need? Steel beam?
RE: Beam Size
Also, by adding the beams, you are directing much of the roof loading to each end where there would be a concentrated load on the supporting walls. These may need to be beefed up with additional studs.
There would also be some concern on the footings at those concentrated load locations, although a continuous spread footing may be adequate to support the new concentrated load. You may experience some new settlement of the wall footing in these locations.
RE: Beam Size
As told by jae if u could specify the loads on roof at site(as per local code) it would be much simpler to determine the beam size.
Also specify is the structure a wooden or of any other material.
If wooden then the post supporting steel beam need to be steel post thus some connections required at beam post junction aswellas there might be some existing footing provided for the wall. But as now we would be dealing with concenterated load a seperate isolated footing would be needed(i,e some modifications to existing footing can be done but seems not feasible as it is more than 80yrs old so it would be wise to ignore strength of existing footing)
As far steel beam is concerened W8X18 should be OK for a roof load of 37psf(as per UBC)
PL elaborate the conditions at ur location so that any remedy can be suggested.
RE: Beam Size
RE: Beam Size
Not to make your issue worse, but in S. CA. you've also got the seismic considerations. By removing these walls, you are altering the way the garage resists the lateral forces (assuming the walls are sheathed and behave as lateral shearwalls.
The beam you install can be a microLam wood beam. Using an estimate of 15 psf for the dead load (assuming light roofing) and a roof live load of 20 psf (per code), you would have a total load of 35 psf on the roof.
With beams at 8.75' o.c. (35' divided by 4 car spaces) you would have a load on your beam of 8.75 x 35 = 306.25 plf.
A triple 1 3/4" x 11 7/8" microlam should work. (total width = 3 x 1.75 = 5.25"). A steel beam, probably an 8" wide flange, would also be very feasible. The steel beam could rest on built-up wood studs, designed for the new load.
I would, though, have an engineer look at the actual dead loads and lateral stability of the garage before doing any of this work. If the roof deck is not adequate to carry the lateral seismic to the side walls, and if the two side walls cannot resist the lateral, you would have an unstable garage.
RE: Beam Size
can u let me know what connection/hardware u would prefer for resting steel beam over lumber studs?
RE: Beam Size
Normally, steel beams on wood are limited in size due to the constraints on wood bearing.
RE: Beam Size
What size wood beam or steel beam should I use?
RE: Beam Size
Evaluation of the loads is the most important task in the design of any structure.
So indicate
Span=26 ft?
dead and live loads acting on the beam, then we can do something.
RE: Beam Size
RE: Beam Size
mom@arrakis.es
if you draw one schematic structure I may advise afterwards
RE: Beam Size
What size beam should I use.
RE: Beam Size
Please comment on my beam and rafter selections. Do I need to go heavier timber?
Thanks, Russ
RE: Beam Size
RE: Beam Size
RE: Beam Size
Russ
RE: Beam Size
RE: Beam Size
To the engineers that reponded I think you need to reconsider the advice you give and consider the implications (legal liability, professional liability, etc) and your responsibilty in providing fully informed advice.
sc
RE: Beam Size