Garage Beam Support 2

[rbg]

I have a wood framed garage that was in built in 1963. The layout of
the garage is 26 x 26 with a gable roof(12/4 pitch) and storage area
above the joists floored with 3/4 plywood. The garage finished ceiling is
1/2 sheetrock.

The garage was framed with 2" x 6" joists that span the entire 26 feet
(from one side of garage to the other) with no connection to the garage
door header or house structure other than bridging or cross
braces. Needless to say, the ceiling has dropped (or deflected) over 5
5/8 inches in the center.

Recently, I temporarily supporterd the ceiling/joists over their entire
span, and installed (2) 1 3/4 x 9 1/4 LVL beams sistered running
perpendicular to the joists along the centerline (approx. 13 ft from each
wall). Each joist was connected to the LVL with Strong tite Joist
hangers and the LVL beam was glued and bolted together along the
entire length.

These two LVL beams have a maximum load of 63lbs/ft over a 26 foot
span. I have temporarily supported the center of the beam (at 13 feet)
with a column to increase the load capacity of the beam to 539lbs/ft
(per allowable uniform load tables, 115%Snow, Georgia Pacific)

My question is this, I want to remove the center support column and
replace it with a single steel I-Beam (running perpendicular to the LVL,
parralel with the joists, just below the finished ceiling) down the
opposing centerline of the garage. What size steel beam do I need to
carry the load and span the 26 feet?

I have contacted several Structural Engineers in my area and none of
them are interested in calculating the requirements for a residential
homeowner. I am willing to pay someone for this, but I am quite
frustrated with the engineers in my area lack of interest in "small jobs".

Please provide some advice at your convenience.

Best regards,

RBG
Detroit, MI
USA

 

[JAE]

See my reponse in the other thread where you posted this question.

 

[Lina]

I will give some directions and just follow it steo by step.

1)Find the load on the joist lb/ft by multiplying the floor load lb/sf with the tributary area of the joist. If the joist are spaced @ 16" o.c. your tributary area will be 16".

2) Now you now the load in lb/ft along the joist, you must calculate the maximum span of the joist using any wood design book.

the design moment M= WL^/8 equation 1
W = lb/ft along the jost
L= the maximum span of the joist

The allowable moment M= Fbxs = Fbt x Cf xLdf x Cuf equation 2

Fb = design allowable stress

Cf , Ldf, Cuf = Modification factors

Set equation 1 = equation 2 and solve for L.

Knowing L is step one. Now you know where to place your steel beam.

Step 2 is to design your steel beem.

Allowable Stress Design (ASD) under beam section has several examples on how to select your beam.

Good Luck......

 

[LPPE]

Are the 2x6 ceiling joists connected to the roof rafters in any way? If so, why not strap the ceiling joists at midpoint to the ridge? Use a 2x6 at each ceiling joist up to the ridge. Look at the roof rafters and ceiling joists as a truss with a new king post now at the center. That oughta solve your deflection problem.

 

[JOHNPIERCE]

i DONT REALLY HOW TO USE THIS FORUM, BUT I HAVE A PROBLEM
WE ARE BUILDING A RACING CATAMARAN AND NEED TO MAKE A BEAM TO JOIN THE TWO HULLS TOGETHER, DOES ANYONE KNOW WHAT THE MAX LOAD THAT COULD BE APPLIED TO A 4 INCH 16SWG (1.6 MM WALL THICKNESS) T6 ALUMINIUM BEAM. THE LOAD TO BE APPLIED AT THE MID POINT OF 2 METRE SPAN. THANKYOU

 

[evelrod]

John Pierce---If you don't get a response here (it is somewhat off the thread subject) go back to the main STRUCTURAL ENGINEERS page and post your question as a new thread. You will find qualified engineers there to help you.


Rod

 

[pmkPE]

Lina:

You left out a very important factor in the moment equation stated above - you did not square the length! Providing such "engineering" vie email, or telephone can result in disasterous consequences. PLease be more careful in the future.

rbg:

In regards to finding a structural engineer in your area, you may wish to contact the MI Board of registration they probably have a list of engineers in your area that would consider accepting the design. You also may want to contact a company that inspects homes for resale in your area - they probably know of engineers that are called in to review residential structures that their (non-engineer) inspectors have discovered potential structural flaws; they could refer you to a licensed and hopefully competant engineer.

 

I have a 22' X 38' cabin which currently has a 4/12 pitch roof. The trusses 22' are gabled north to south. I have looked into changing the roof line with Boise Cascade I Joists & LVL Ridge Beams.

Roberts & Dybdahl, Inc. suggested material needs for changing the pitch to 9/12. Where a 16' section of the structure would be gabled in an east to west orientation, and the remaing 22' shall be tied in and gabled south.

A quantity of (2) 2-1B LVL ridge beams @ 1.75" thick were selected for the ridges. One spans 22 feet, the other 30', (22' + 8' tie in) respectively. BCI-40 I joists @ (1 1/2" x 11 7/8&quot 24" on center for rafters. Quantity of joists totals 48, plus conventional strick framing for valley ties.

I would like to know the type & lenght of ridge support(s)required to carry the load to the foundation. Likewise, I'd like to understand how to frame the (3) columns into existing stud walls at 7' high.

Thank you for you time and attention.

McIntyre85