weight machine inside house

"Steve Freides" <steve.RemoveThis@fridayscomputer.com> wrote in message
news:3u495tFv94ntU1@individual.net...
> "Spammers_Should_Be_Shot" <NoSpam.RemoveThis@MyEmail.com> wrote in message
> news:Y56ff.1712$vq1.1227@tornado.rdc-kc.rr.com...
> >
> > "John" <y_tu_momma_tambien.RemoveThis@hotmail.com> wrote in message
> > news:_94ff.118006$zb5.80445@bgtnsc04-news.ops.worldnet.att.net...
> >> "Spammers_Should_Be_Shot" <NoSpam.RemoveThis@MyEmail.com> wrote in message
> >> news:SNYef.450$js5.404@tornado.rdc-kc.rr.com...
> >> >
> >> > "David" <forgotwhy.RemoveThis@yahoo.com.au> wrote in message
> >> > news:D8Xef.19669$Hj2.6270@news-server.bigpond.net.au...
> >> > >
> >> > > "spodosaurus" <spodosaurus.RemoveThis@_yahoo_.com> wrote in message
> >> > > news:437c3b67@quokka.wn.com.au...
> >> > > > jeremy_ho.RemoveThis@my-deja.com wrote:
> >> > > >> I am considering a weight training machine
> >> > > >
> >> > > > Which "machine"?
> >> > > >
> >> > > >> to work out at home, it has
> >> > > >> a pull up bar located at 82", I would like to place it inside
> >> > > >> the
> >> > > >> house (ceiling : 8 ft / 96") , instead of the garage for
> >> > > >> various
> >> > > >> reasons. I was wondering if a ceiling height of 8' would
> >> > > >> hinder
> >> the
> >> > > >> pull up exercise. I figure my shoulders do not reach up past
> >> > > >> the
> >> > > >> handle bar, and from the shoulder to top of my head should
> >> > > >> leave me
> >> > > >> about 2-3" from the ceiling.
> >> > > >>
> >> > > >
> >> > > > When you develop the strength to pull the bar to your chest,
> >> > > > the
> > tops
> >> of
> >> > > > your shoulders will be above the bar. Any momentum also
> >> > > > involved
> >> > increases
> >> > > > the experience of pain as your head impacts the ceiling.
> >> > > >
> >> > > >> Next question is the foundation of the home, it is crawl space
> >> > > >> foundation type, the various weight machines I am looking at
> >> > > >> varies
> >> > > >> from 250-350 lbs, would I need to add any reinfocements in the
> > crawl
> >> > > >> space or generally this kind of weight, plus mine (160 lbs),
> >> > > >> so
> >> figure
> >> > > >> about 500 lbs loaded on around a 3'' x 5' area.
> >> > > >
> >> > > > Sorry, I haven't a clue on this one.
> >> > >
> >> > > Ari, I believe this person is a f------d. How does he expect
> >> > > anyone to
> >> be
> >> > > able to figure out what his structural load is
> >> >
> >> > 55 psf (pounds per square foot) = equates to 40 psf Top-live(1), 10
> >> > psf
> >> > Top-dead(2), and 5 psf Bottom-dead(2). All building codes require
> >> > that
> >> the
> >> > stiffness factor be at least L/360 (though it's common to use L/480
> >> > to
> >> > minimize deflection or "bouncy" floor). The OP need not worry
> >> > about
> >> weight
> >> > causing structural failure. The only real concern would be
> >> > cosmetic
> > (i.e.
> >> > cracks in a finished ceiling below, cracks in grout lines of a tile
> > floor,
> >> > dents/scruffs in a wood floor, etc.) As a general rule of thumb,
> >> > you
> >> almost
> >> > never need to worry about a load until it's 750+lbs. in a 1 s.f.
> >> > area
> >> (think
> >> > a FAT guy standing on one leg). Anything less than that will be
> >> > fine.
> >> Now
> >> > if the OP is deadlifting (and dropping) 1500+lb lifts, I'd suggest
> >> > he
> >> > consult a local Structural Engineer to further address his rooms
> >> structural
> >> > capabilities.
> >>
> >> Agreed. One other problem would be if he dropped a wheel on an area
> >> of the
> >> floor that was not supported by a joist. OSB is the common material
> >> of
> >> choice for subfloor and a 45# plate on edge, dropped from knee
> >> height,
> > could
> >> easily damage it if it landed between joists. The force would be
> >> greater
> >> than 45 psi. If he doesn't get careless with the weights, he should
> >> be
> > fine.
> >>
> >
> > Granted that would result in a "point load" however the floor would
> > still be
> > fine (other than possible cosmetic damage). The subfloor (OSB or T&G
> > plywood are the most common) is usually 3/4" (sometimes the floor may
> > consist of 2 layers - but 3/4" is a minimum). The subfloor will take
> > the
> > load and disperse it to a larger area than just the impact area. In
> > any
> > case, dropping a plate will not pose a problem. Try this test at
> > home,
> > stand on one leg, jump up and down, does your foot go through the
> > floor?
> > The area of one of your feet is <1 s.f. and your weight is more than a
> > 45#
> > plate. If your foot doesn't go through the floor than why would a
> > plate?
> > Because it's made of steel?
> >
> > I'll give another example: A typical Friday night at my house. I
> > have a
> > queen "soft sided" waterbed (~800lbs.). On the bed let's say there's
> > 600
> > lbs. (if I weigh 180lbs. that leaves 420lbs. for 3 fit females - and
> > if
> > they're thin, maybe there's enough left over to allow a midget to join
> > in).
> > Also, any weight being supported by the swing wouldn't count. So we
> > have a
> > live load total of 800+600=1400lbs. The bed area is ~5'x7'=35s.f.
> > Keep in
> > mind that the total load is being distributed over an area much
> > greater than
> > 35s.f. (i.e. adjacent joists are carrying a portion of the weight as
> > distributed by the subfloor). For "worst case scenario let's say the
> > weight
> > WAS all compacted into the 35s.f. At a designed load of 40lbs. per
> > s.f.
> > that would be 35s.f. x 40psf = 1400 lbs. So it would support the
> > weight
> > fine. Also keep in mind that the floor is designed to carry the live
> > load
> > with acceptable deflection (usually less than 1/2" of
> > deflection/bend).
> > Exceeding the load doesn't necessarily mean immediate structural
> > failure
> > (i.e. the bed and party goers end up in the basement). As the load
> > goes up
> > the floor "flexes" more, up until the point of failure (the actual
> > point of
> > failure depends upon a lot of factors but let's just say it's quite a
> > bit
> > more).
> >
> > Now to look further at my situation, my floor joists are spanning 13'
> > and
> > are 16" o.c. (so the bed is bearing on 4 joist spans). So the floor
> > area
> > the bed is located in is designed for a minimal deflection in an area
> > of
> > 13'x5.33'. 13x5.33 = ~69s.f. x 40psf (live load) = 2760 total lbs. in
> > that
> > area. So in the above "Friday Night" example the 1400lbs. load (bed
> > and
> > occupants) would still leave us with 1360lbs. of load before
> > deflection
> > became unacceptable. So if the remaining load (1360lbs.) is
> > spectators
> > (each 272lbs.) I could have 5 of them standing at the foot of the bed.
> > (BTW, the average 272lb. person is going to utilize ~6s.f.). So,
> > (rounding
> > off the numbers) the area is 69s.f. (of which the bed is 37s.f. and
> > the
> > spectators are 30s.f.). And the floor is designed to carry this
> > weight. To
> > actually induce structural failure we'd have to start stacking
> > spectators
> > vertically.
> >
> > Now, here's an example of a structural failure that's not too
> > uncommon.
> > Decks. Decks are not always designed to carry as heavy a live load
> > and
> > being exposed to the elements can lead to degradation of the
> > structural
> > members. Also, in areas with seismic movement or frost lines,
> > footings can
> > "heave" which can cause problems. Another big factor leading to deck
> > failure is shoddy construction, either materials or methods, or both.
> > Put an 8 person hot tub on the deck, which can weigh 3500lbs.
> > (tub+water+people) all in an area of 7'x7' and you can start to see
> > how it
> > can fail. Decks can also fail due to too many people on them at once.
> > If a
> > fraternity house packs 50 people onto a 150s.f. deck you're asking for
> > trouble.
>
> If you drop a squat onto the pins, would the load be in the four points
> of contact under the rack legs, and not distributed as in the other
> examples you gave?
>

The load would be concentrated to the points where the rack rest on the
floor (not just the 4 corners, they are distributing the weight to the racks
cross members). Just like in the "bed" example the weight is distributed to
the bed legs (9 in the case of my bed). But the subfloor takes that weight
and distributes it over a much wider area. Let's take the example of a
person jumping and compare it to dropping a DL. If a 400lb. man jumps up
and lands on 2 feet everything would be fine (agreed?) So a 400lb. bar
dropped is different how? Now let's consider an 800lb. DL. There are 2
contact points with the floor (each roughly the same size as a persons
foot). So it'd be roughly equal to an 800lb. man jumping (or 2 400lb. men
jumping). The biggest difference between a man jumping and a bar being
dropped is the impact point spacing. A bar will hit the floor with wider
impact spacing, thus distributing the load over an even greater area ( and
therefore, more joists to carry the load).

Of course, at some point the subfloor will fail, but unless someone's
dropping 750+ lbs. it's not worth worrying about. Over 750lbs. and it might
be fine, but best to consult an engineer or architect to look at your actual
structural issues.

Spammers_Should_Be_Shot wrote:

> I'll give another example: A typical Friday night at my house. I have a
> queen "soft sided" waterbed (~800lbs.). On the bed let's say there's 600
> lbs. (if I weigh 180lbs. that leaves 420lbs. for 3 fit females - and if
> they're thin, maybe there's enough left over to allow a midget to join in).
> Also, any weight being supported by the swing wouldn't count. So we have a
> live load total of 800+600=1400lbs. The bed area is ~5'x7'=35s.f. Keep in
> mind that the total load is being distributed over an area much greater than
> 35s.f. (i.e. adjacent joists are carrying a portion of the weight as
> distributed by the subfloor). For "worst case scenario let's say the weight
> WAS all compacted into the 35s.f. At a designed load of 40lbs. per s.f.
> that would be 35s.f. x 40psf = 1400 lbs. So it would support the weight
> fine.

<golf clap>

It's always nice to see a finely honed engineering mind applied to real
problems.

Dally