Best way to attach framing to steel beam

Discussion in 'Building Construction' started by Bruce, Feb 27, 2005.

  1. Bruce

    Bruce Guest

    Hi All,

    I am finishing off a basement, and will be framing a wall under a steel
    beam. I am reluctant to drill holes in the bottom of the beam. What is the
    best way to attach the top plate of the framing to the beam? Thanks.
    Bruce, Feb 27, 2005
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  2. Bruce

    RicodJour Guest

    A few small holes spaced every few feet won't affect the strength of
    the beam, so you can drill and bolt or shoot pins into the steel. It
    might be easier all around to have the wall on one side of the beam and
    box out a soffit on the other side. That way your stud framing and
    drywall can run right up to the underside of the joists. You'll have
    to box the beam anyway unless the wall is as thick as the beam is wide
    or the other side is unfinished.

    RicodJour, Feb 27, 2005
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  3. Bruce

    Phil Scott Guest

    First wedge the new wall under the beam by cutting the studs
    1/8" long then pounding them in so they wedge the top plate up
    against the bottom of the beam... use an overdose of
    resiliant construction adhesive under the top plate.. that
    alone would probably come close to holding the wall in place.

    then you can shoot pins in every 2 or 3' like Rico
    suggested..that will not weaken the beam enough to be
    measured, With the wall wedged under the beam the finished
    project will probably have 5x the stenght of the original beam
    by itself anyway. If you were really worried or wanted to
    beef up the job to world class standards, substitute some of
    the wall studs for 4x4's.

    Phil Scott
    Phil Scott, Feb 27, 2005
  4. Bruce

    Nichevo Guest

    Whenever I have framed under a main beam It is usually specified by the
    engineer to have some sort of expansion/contraction mechanism. With
    steel we make a slip track(which also aids in beam itchulation), that
    way when the dead and live loads are finally added and temperature
    changes, the beam deflects its 300 or whatever, the wall does not bow,
    twist or crack. Keep in mind that this is in the commercial world,
    which is surely quite a bit different...
    I don't see any reason why Bruce couldn't hilti(or some other method of
    powder actuated fastening) some 20 guage track(C-Channel) to the beam
    and continue normal framing from there... The other method mentioned by
    RicodJour is also fine if you don't mind the additional cost/sight of a
    Nichevo, Feb 27, 2005
  5. Bruce

    Bobk207 Guest

    All the suggestions so far have been very good.
    With the new wall jammed up under the beam it won't be doing much any
    If the floor above has a bounce to it it won't after you're done. :)

    Make sure you use treated timber for the bottom plate.
    Don't want moisture or termites to ruin your job.

    Bobk207, Feb 27, 2005
  6. Bruce

    Bruce Guest

    Thanks guys. I was leaning towards glue and shooting .22 powered nails. I
    have actually already framed it, but haven't attached it yet. I just am a
    little leary about shooting nails or drilling holes into the bottom chord of
    the beam, although like Ricor says, probably won't hurt. Bruce
    Bruce, Mar 1, 2005
  7. Bruce

    Bobk207 Guest

    How wide is the beam flange?

    Shot pins are ~.2" dia, you're talking about a hole < 5% of the flange
    width every couple feet . Sounds like fly s...t to me.

    Bobk207, Mar 1, 2005
  8. I just am a little leary about shooting nails or drilling holes
    A few nails in the bottom of the beam mean nothing.
    The only reason you are worried is that you know nothing about it.


    Thanks guys. I was leaning towards glue and shooting .22 powered nails. I
    have actually already framed it, but haven't attached it yet. I just am a
    little leary about shooting nails or drilling holes into the bottom chord of
    the beam, although like Ricor says, probably won't hurt. Bruce
    JerryD\(upstateNY\), Mar 1, 2005
  9. Bruce

    Ralph Hertle Guest


    The original message didn't get through for some reason, and I've reposted it.

    beam. I am reluctant to drill holes in the bottom of the beam. What is
    the best way to attach the top plate of the framing to the beam? Thanks.

    The general structural principle is to not reduce the cross sectional area
    of the beam flanges in any way whatsoever.

    That means no drilled holes, no notching, and no coping. In the non-
    beam/column areas there may be qualified exceptions that are based upon the
    engineers calculations and designs.

    A hole drilled in either the tension or the compression flange may reduce
    the cross sectional area of that flange by a significant amount, say by 10
    percent. Do the arithmetic.

    That increases the beam deflection and stress in the local area, and it
    reduces the ultimate strength by similar amount based upon the section
    profile and the calculations.

    If you have a large enough beam and the calculations show that you still
    have an excess strength of safety factor, then why not buy a narrower beam.

    Save your money.

    Steel beams are expensive. Why waste your money or product value by
    drilling a hole in it?

    There are three accepted ways to attach members to a beam.

    One is to clamp to the beam, and many steel clamp products are commercially
    available. Clamps provide a way to attach other components.

    Two is to bolt "L" clips onto the web of the beam, and under specific
    conditions, and enabled by specific designs, drilled holes in the web will
    not reduce the strength of a beam by nearly as much as that would occur by
    drilling the flanges. Holes must be drilled only near the neutral axis of
    the beam, that is, as near the center longitudinal axis of the beam as
    possible. Beam clips at the end of the beam at the web are not in the area
    of the beam where there is maximum strain, and the beam does not suffer as
    much of a reduction of strength or deflection due to holes at that location.

    Again, calculations will govern. That is important.

    Two is to weld "L" clips onto the web of the beam. That does not reduce the
    amount of force-resisting material in the section of the beam. Tiny
    differences of metallurgy occur, but given correct welding practices and
    beam metallurgy, the welding method is the stronger when compared to bolts.

    Bolts are use for speed of assembly. Structural engineers should always be

    You have not provided enough information about your intended design.

    For your application I would say that you would be safe by leaving the beam
    in place as undrilled. Use wood blocking around the beam and enclose it
    with blocking attached to the joists above. Use plywood and GWB according
    to your plan. Steel clamps are possible, however, your added partition is
    not a primary load bearing element. Simply ignore the beam and encase it
    with wood and GWB as is required by your design.

    BTW, a house in NYC may be a ten to twenty storey heavy steel framed
    building. Do you have a parking garage in the basement of your building? A
    house in Kentucky could be a double wide with a some 28 to 20 ga. light
    steel framing elements here and there. What indeed are you talking about?

    On second thought, since the existing conditions were not of interest to
    you, and since the the specific designs and sizes of the elements involved
    were not of interest to you, I wish to recant on all of my above
    statements. You should discuss the matter with a professional civil or
    structural engineer.

    Ralph Hertle


    A 5% reduction of the cross sectional area of the top or bottom two flanges
    is 1/20 of the area. That, when the calculations are made, will allow a
    measurable increase in the deflection of the beam given a certain context
    of forces etc.

    The 5% reduction of material in the critical flange area is borrowed from
    the deflection resistance of the beam or from the safety factor regarding
    the resistance to beam failure.

    There are plenty of non-invasive ways to connect to the beam, two of which
    are the use of clamps and simple plywood encasing.

    Ralph Hertle, Mar 4, 2005
  10. Bruce

    RicodJour Guest

    Ralph, your reply to Bruce's post is misleading in so many ways I can
    scarcely believe you wrote this.
    If it is a general structural principle, than there should be no
    problem in citing a reference. Please do.
    He's attaching a plate, not bolting up an engine hoist. The holes from
    pins are what?, a little over an eighth of an inch. How small of a
    beam are you assuming he has up there?
    You're obviously not worried about shear, as the web is not affected,
    so it's Fbmax you're worried about. Would there be a problem in
    shooting pins 4' OC and keeping them away from the highest stress at

    Because the beam is already up there..?
    Actually, you're wrong. They're not expensive, they're economical.
    That's why they're there in the first place.

    Now you're assuming that shear wasn't the governing factor in the beam
    design. You're probably right, but it's still an assumption.

    And how does he get the connection from the welded bracket to the
    underside of the beam? If you want him to put the wall on the side of
    the beam, and not mess with the beam, just say that. That was my
    initial advice to him.
    Shot pins are used for speed of assembly, bolts are used primarily for
    ease of assembly when the memmbers are fabricated off site.
    Can't argue with that.

    No one, in NYC, or anywhere else, would call a ten story building a
    house. If the guy had a ten floor apartment/condo/building I tend to
    doubt he'd be doing the work himself.
    Wouldn't this have been a good point to _delete_ all that crap above
    before you posted it?!
    Thought you recanted all of that?

    You have mastered the art of obfuscation. I stand in awe.


    RicodJour, Mar 4, 2005
  11. Bruce

    3D Peruna Guest

    Especially since he apparently didn't read any of the posts from the
    engineers. Let's see...I would trust Ralph? Or an engineer? Ralph?
    Engineer? Hmmmmm....I dunno.
    3D Peruna, Mar 5, 2005
  12. I never knew the beam in a house was so stressed that four or five 1/8"
    holes drilled/shot into it, would cause the whole house to collapse. LOL !!!
    JerryD\(upstateNY\), Mar 6, 2005
  13. Bruce

    Ralph Hertle Guest

    RicodJour wrote:


    Misleading to you, perhaps. I was simply stating proper design principles
    and not the exceptions to them.

    Every college text ever written that deals with the subjects of Statics and
    Strength of Materials.

    I understand you from the conceptual and design idea standpoint, but in
    engineering that's only half the matter. Mathematical calculations
    determine whether there is sufficient deformation resisting material in the
    right places to do the job. Math is important.

    The most general principle concerning beams is that the cross sectional
    area should never be reduced. The original calculations were done to
    correctly size the beam, and that should not be interfered with. If the
    engineer can say that the beam was sufficiently larger than necessary to
    begin with he will specify how many holes may be made and where they may be

    An I-beam generally has two types of shear, and regarding shear
    calculations the weakest place in a beam are in the web near the end
    supports. Regarding longitudinal shear holes any where weaken the beam in
    terms of shear forces.

    Deflection in bending is the main problem. For every 1/8" hole that is
    drilled in an 8" steel beam and if the center of a 2 story building is the
    loading there will be a measurable amount of deflection.

    If you are talking shear forces the highest stress longitudinally may be
    any where in the beam web. Add to that the vertical shear forces at the end
    or middle supports and web stiffeners may be needed. The maximum sheer
    stress would more likely be in the web near the supports.

    Or are you speaking of stress due to the bending moment in the beam? That
    usually occurs between the beams for point uniform loading, however, if
    there is a point loading near a support where the maximum shear stresses
    are located the failure point may be near the support. It all depends on
    the loaded design and calculations.

    Of course.

    Of course, again.

    In terms of overall economy for a certain purpose, yes.

    Its context.

    Wood or masonry are cheaper supports. However, the convenience of having an
    open space beneath the floor above was probably deemed worth the extra
    money for the price of the steel.

    True. Bruce didn't provide enough information.

    You are stroking. The clip is bent.

    You are prevaricating, guessing what Bruce's intentions are.

    Why don't you ask him to produce a little text sketch for us and find the
    facts of the matter.

    Cheaper too.

    Go to New York City. I've lived there for many years. They do call
    apartment buildings of all sizes apartment houses.

    Bruce remained silent.

    clip to end]
    Ralph Hertle, Mar 7, 2005
  14. Bruce

    JTMcC Guest

    Tomorrow is Monday Ralph, time to think about sobering up.


    JTMcC, Mar 7, 2005
  15. Bruce

    RicodJour Guest

    You mean you want me to get in the car and drive twenty-five minutes?
    Why? No one, not even you, would call an apartment house a house.

    The point that you're either ignoring or ignorant of, is that the
    person that specified the beam in the basement of a house, didn't spec
    out the EXACT size (the beam wasn't fabricated to anything other than
    length). They either pulled the size from a chart, or did the
    calculations, then picked the closest _larger_ size beam.

    Such drivel as "economical in that context" is, well, drivel. What's
    the absolute economy for you? Not building the house in the first

    You oviously have no experience in design, or construction. I know
    you're the man when it comes to Microstation. Can we just leave it at

    RicodJour, Mar 7, 2005
  16. Bruce

    JTMcC Guest

    Wow, they're building houses with twenty floors in New York City!? And heavy
    steel frames!? Then let me ask you this Ralph, if the "house is twenty
    floors, and framed with heavy steel, and the beams are spec'd so tight and
    light that a series of 1/8" holes on 2' centers of the bottom flange will
    cause a failure, then what happens when the 220 lbs. Ironworker w/30 lbs of
    tools bebops out to the center of those beams to pull the chocker?? We would
    have multiple beam failures during erection.

    As for the Kentucky comment, I've been to Kentucky and they have a lot of
    beautiful countryside, a lot of beautiful women, and an abundance of very
    nice homes, your comment reeks of the old east coast arisocrat snobbery. One
    of those rednecks living in a double wide would most likely kick your butt
    within a week by the way.

    JTMcC, Mar 7, 2005
  17. Bruce

    JTMcC Guest

    You are assuming no beam deflection, or, that your wedged wall will assure
    no beam deflection. You couldn't get away with either assumption in
    commercial/industrial construction, as someone already said.
    In a house that might hold true (I don't know), but I'd be concerned with
    wall damage the first time their teenage daughter has a large group of her
    crazy dancing friends over, or the first time they move a gun safe into the
    house, or the first time their increadibly fat aunt comes to visit. In
    commercial construction you commonly see clips or slip track with 3/4" or so
    designed in.

    JTMcC, Mar 7, 2005
  18. Bruce

    Bobk207 Guest

    JTMcC Mar 6, 6:16 pm
    daughter has a large group of her crazy dancing friends over, or the
    first time they move a gun safe into the house, or the first time their
    increadibly fat aunt comes to visit. <<<<<

    Surely you're joking? The OP said it was a basement in a house not
    industrial / commercial space. The 2x4 framed wall is much stiffer
    than the exsiting steel beam when considering resisting any floor load
    above it.........that's why basements (cheaper ones) tend to have
    posts/columns right where you don't want them. Think of the wall as a
    bunch of really light posts all in a row.

    The house was probably designed for 10psf DL & 40 psf LL. Adding the
    wall can only improve the floor behavior.

    Run the calcs & be untroubled.

    Bobk207, Mar 8, 2005
  19. Bruce

    Phil Scott Guest


    Id wedge the wall under the beam, flush with the edge of the
    bottom flange so the sheet rock screwed to the studs can
    extend up to covah da beeeem.

    Screw the engineering, none of it is going anywhere. if the
    steel beam was sufficient before it will be 5x as sufficient
    with a wall jammed under it... and as you said a couple of
    1/8" pins wont weaken the beam, it becomes irrelevant with a
    bearing wall beneath the beam anyway.

    THEN I would all in a team of geologists to make sure that you
    dont put too much pressure on the earth in that spot and cause
    a bulge on the oposite side in China.

    Phil Scott
    Phil Scott, Mar 9, 2005
  20. Bruce

    Phil Scott Guest

    collapse. LOL !!!

    Oh ya.... one pin and the entire things sinks into the earth,
    all thats left is a little sheet rock dust for a minute or
    so... if for some reason there is no collapse, and a city
    inspector comes by and notices the pins, they arrest the owner
    and send him to gitmo for interrogation

    Flaunt the law at yer own risk
    Phil Scott, Mar 9, 2005
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