Steel vs. wood beams
d_...@my-deja.com
I-beam rather than a build-up wood beam to carry the joists for the
first floor. This seems like a great idea to me - only two steel
columns in the whole basement, and I would suspect the steel beam will
never sag.
Is this too good to be true? Are they any disadvantages with a steel
beam? What does this mean in terms of the builder's costs vs. a wood
beam?
TIA,
-Dave
Sent via Deja.com http://www.deja.com/
Before you buy.
ken
construction.
ken
The advantage of larger spans in your basement will probably out-weight
the disadvantages, mentioned in my first post.
Steel beams will sag if not sized properly. You or your builder should
run the sizes by a structural engineer.
Another consideration is the expansion of steel versus wood. Room for
movement should be provided in your foundation, and for any
wood joists or flooring that is to be carried by the steel.
Look here for more benefits using steel:
http://www.steel.org/facts/power/roofs2.htm
Joe Barta
>The builder who will be building our new house like to use a steel
>I-beam rather than a build-up wood beam to carry the joists for the
>first floor. This seems like a great idea to me - only two steel
>columns in the whole basement, and I would suspect the steel beam will
>never sag.
>
>Is this too good to be true? Are they any disadvantages with a steel
>beam? What does this mean in terms of the builder's costs vs. a wood
>beam?
What you describe is very common in modern residential construction. In
my experience it would be UNcommon to see wood beams in the basement to
hold up the first floor joists. I have no idea what the cost difference
is, or what the specific advantages are. I suspect though that after
everything is factored in, steel is cheaper.
- Joe Barta
Matthew Whiting
>
> The builder who will be building our new house like to use a steel
> I-beam rather than a build-up wood beam to carry the joists for the
> first floor. This seems like a great idea to me - only two steel
> columns in the whole basement, and I would suspect the steel beam will
> never sag.
>
> Is this too good to be true? Are they any disadvantages with a steel
> beam? What does this mean in terms of the builder's costs vs. a wood
> beam?
Probably the main disadvantage is fire resistance. A wood beam, even a
built-up one, will hold a substantial load through a fairly long period
of esposure to fire. A steel beam will heat up fairly quickly and sag
with little warning once it gets to the softening temperature.
Most commercial construction now requires a fire resistance coating be
sprayed onto steel columns and beams, but I've never seen that done for
residential construction.
Matt
Jd2OO1
a fire, it would take a lot more heat for a lot more time to get a heavy I-beam
that hot. I suspect that by the time the I-beam fails due to heat, the rest of
the house will allready be distroyed.
Disclamer: I have no real knowlege or training about this.
Ecnerwal
Your idle, unknowing, untrained speculation is dead wrong. Would you
like a prize?
Heavy wood members exposed to fire char on the outside, but the inside
continues to bear the load for quite some time. Exposed steel gets hot
(rather quickly) and bends. There is a buttload of heat when a building
burns. Even concrete covered steel fails faster in a fire than heavy
wood framing. This has been seen in the real world when buildings with
additions of "modern" materials burn - the wood framed part falls down
after the steel framed part.
Joe Barta
>I would think that although light gage steel studs might lose there strenght in
>a fire, it would take a lot more heat for a lot more time to get a heavy I-beam
>that hot. I suspect that by the time the I-beam fails due to heat, the rest of
>the house will allready be distroyed.
>Disclamer: I have no real knowlege or training about this.
It's a fairly well known that given a wood beam and a steel beam of
equal strength, in a fire the wood beam will take significantly longer
to burn through sufficiently and collapse. The steel will soften and
bend much more quickly. Of course, under both circumstances the building
is going to recieve significant damage. The idea though is that the one
with steel beams will collapse much sooner than the the one with steel.
If you are a fireman crawling around looking for a someone trapped in
the fire, then this becomes a real issue.
- Joe Barta
Matthew Whiting
Joe, you are right on. Since the post above was in reply to one of my
posts, I'll only add the comment that it is amazing how many people who
admittedly "have no real knowledge or training" will post false
"information." Then again, the content of the post itself pretty much
precluded the need for the disclaimer! :-)
Matt
Jd2OO1
d_...@my-deja.com
Consider this, however: if the only steel in the structure is the
first-floor beam, how big of an issue is this really? Presumably, it
would be rather unlikely for a fire to begin in the basement, so the
beam would not get hot for quite some time if the fire started on the
first or second floor. I would think that the fire would have to burn
down through the first floor deck before the beam started to get hot.
And in an unfinished basement there is very little combustible material
down there. I would guess the house would already be nearly destroyed
before the fire got down to the basement and the beam got hot enough to
deform?
Frank Ruff
requiring fewer lolly columns. The steel costs more, but
the elimination of lolly columns partially offsets the extra
cost. Depending on the weight (strength) of the beam,
it still could sag slightly. One minor drawback it that you
can't nail to a steel beam. Overall, steel is usually better.
d_...@my-deja.com wrote in article <7t29jj$qt9$1...@nnrp1.deja.com>...
> The builder who will be building our new house like to use a steel
> I-beam rather than a build-up wood beam to carry the joists for the
> first floor. This seems like a great idea to me - only two steel
> columns in the whole basement, and I would suspect the steel beam will
> never sag.
>
> Is this too good to be true? Are they any disadvantages with a steel
> beam? What does this mean in terms of the builder's costs vs. a wood
> beam?
>
> TIA,
Joe Barta
All things considered, it is a minor issue yes. Although in a larger
custome home, quite a bit of steel can be used throughout.
In my mind a bigger concern is all the OSB used in the average house.
Especially one with OSB studs. Anyone ever burn OSB? The stuff burns
VERY fast and VERY hot (due probably to all the glue in the boards). I'd
hate to be anywhere near an OSB house in flames.
- Joe Barta
Stan Huntting
news:<7tag5a$mmo$2...@plonk.apk.net>...
> In my mind a bigger concern is all the OSB used in the average house.
> Especially one with OSB studs. Anyone ever burn OSB? The stuff burns
> VERY fast and VERY hot (due probably to all the glue in the boards).
Food (fuel?) for thought. How about other engineered wood products, like
gluelam and microlam beams? Are they also fast burners or does the mass of
wood in a gluelam give it the fire resistant character of "heavy" beams?
Stan
Joe Barta
I've just noticed this undesirable property in ordinary 7/16 and 3/4
OSB. Heavy microlams seem to burn slower than ordinary dimensional
lumber.
Mind you, none of this is scientific. It's just my observations of many
winters of throwing scrap wood in a burn barrel.
- Joe Barta
RB Jones
there for a few years the amount of stuff tha will accumulate in the
basement will be very large.
I just put on a 600 sq foot addition with a flat roof deck combination
and uses 2 steel I-beams so I could use 2x8's instead of 2x10's. This
was critical in the indoor height as well as the outdoor height of the
deck. They were very heavy but we installed them ourselves. And as for
the poster who said you cannot nail to them, I guess he doesn't own a
hilti gun or similar ... too bad.
The I-beam is OK, not to worry.
Bob Jones
AlTrussGuy
LVL, Glue Lam, Steel question (from the steel capitol of the south) Who
tells you what size steel, the builder who has a beam from another job?
Just install LVL in basement 2 Columns and stairwell walls used for
bearing, 70 feet by 30 foot basement.
Wood has steel beat hands down, First floor and fire is goofie, beam is
holding floor , walls, roof loads.
The first thing a beam must do is carry it's own weight, the stell will
sag under it's own weight if not sized for the span.
Advantages to steel my brother in law has a hunk in his back yard I can
unload on you , and stand behind for 1 year,
Disadvantages, CUTTING, WELDING, HANDELING (back hoe knocks down
basement walls), WEIGHT, STEEL SNAPS UNDERLOAD , (Wood sags) Steel is as
good as the poorest weakest weld. condensation (wet dripping) attaching wood
to steel (Joist, hangers) expansion rate, wood moves steel doesn't (as fast)
floor squeeks. alittle time I'm sure there are more other than fire.
BUILDER COST DEPENDS ON WHERE THE STEEL COMES FROM. His labor cost is more
to install steel period.
YOU WANT 2 COLUMNS, tell me about your house and I'll size the LVL..........
I joist must be sized also, based on span, load, deflection, and spacing.
I'll asnwer these question for you too......
d_...@my-deja.com wrote in message <7t29jj$qt9$1...@nnrp1.deja.com>...
Walter D. Graves
beam is correct. We are not talking commercial construction here. We are
talking residential. The timber members (exterior load bearing walls,
interior load bearing walls, and partition walls) are either formed with 2x4
studs or metal studs. Either will fail before the I beam. It is true that
heavy timbers char and retain much of their structural strength after a fire
(or at least enough to sustain some load). However, 2x lumber is not heavy
timber and will burn sufficiently to render them useless before the I beam
is toast.
Walt Graves, PE
Ecnerwal wrote in message <37F6C1...@SOuthernVERmont.NET>...
>Jd2OO1 wrote:
>>
>> I would think that although light gage steel studs might lose there
strenght in
>> a fire, it would take a lot more heat for a lot more time to get a heavy
I-beam
>> that hot. I suspect that by the time the I-beam fails due to heat, the
rest of
>> the house will allready be distroyed.
>> Disclamer: I have no real knowlege or training about this.
>
Walter D. Graves
AlTrussGuy wrote in message <7td38d$es0$1...@nntp4.atl.mindspring.net>...
>Built up beam, is this 3 - 2 X 12's spruce, pine, doug fir?
>
>LVL, Glue Lam, Steel question (from the steel capitol of the south) Who
>tells you what size steel, the builder who has a beam from another job?
> Just install LVL in basement 2 Columns and stairwell walls used for
>bearing, 70 feet by 30 foot basement.
> Wood has steel beat hands down,
Not necessarily. If it did we would not use steel for anything.
>First floor and fire is goofie, beam is
>holding floor , walls, roof loads.
> The first thing a beam must do is carry it's own weight, the stell will
>sag under it's own weight if not sized for the span.
So will any other material
> Advantages to steel my brother in law has a hunk in his back yard I can
>unload on you , and stand behind for 1 year,
> Disadvantages, CUTTING, WELDING, HANDELING (back hoe knocks down
>basement walls), WEIGHT, STEEL SNAPS UNDERLOAD
Not true. Steel deforms and is a very ductile material. It will undergo
significant strain before failure.
> , (Wood sags)
Yes. It also will deform permanently under continous load (develop a
memory) and when unloaded will not return to its original state. Steel will
return to its original state provided you have not exceeded the yield point.
A properly designed steel beam will be operating below its yeild point if
either Allowable Stress Design or Load Resistance Factored Design is used to
size the beam.
>Steel is as
>good as the poorest weakest weld.
And timber is as good as its weakest connection. Timber also is subject to
weakened areas due to rot, knots, splits, checks, termites, etc
>condensation (wet dripping) attaching wood
>to steel (Joist, hangers) expansion rate, wood moves steel doesn't (as
fast)
If you did it right, you attached a nailer to the steel and the wood to the
nailer. This will almost eliminate squeaks.
>floor squeeks. alittle time I'm sure there are more other than fire.
>BUILDER COST DEPENDS ON WHERE THE STEEL COMES FROM. His labor cost is more
>to install steel period.
>
>YOU WANT 2 COLUMNS, tell me about your house and I'll size the
LVL..........
>I joist must be sized also, based on span, load, deflection, and spacing.
Unless you are an engineer and licensed to practice in his state, you may be
making a very bad move. How familiar are you with the theory behind the
charts? How do you know when the charts are applicable or not? Unless you
are familiar with the theory and constraints of the design guides or model
building codes, you really are not qualified for using them to design with.
Otherwise you could easily be applying a formula or using a chart that is
not valid for the situation.
>I'll asnwer these question for you too......
Walt Graves, PE
AlTrussGuy
Walter D. Graves wrote in message ...
>This demands correction.
>
>AlTrussGuy wrote in message <7td38d$es0$1...@nntp4.atl.mindspring.net>...
>>Built up beam, is this 3 - 2 X 12's spruce, pine, doug fir?
>>
>>LVL, Glue Lam, Steel question (from the steel capitol of the south)
>
Mr. Graves, Wood products can and do replace steel in Residential
aplications. The products have the consistancey, that framing lumber lack,
these products must be sizes.
>
>> The first thing a beam must do is carry it's own weight, the steel
will
>>sag under it's own weight if not sized for the span.
>
>So will any other material
Mr. Graves you attack a statement that said. a beam must carry , it doesn't
say steel beam, our wood, states beam (any beam)
>
>> Disadvantages, CUTTING, WELDING, HANDELING (back hoe knocks down
>>basement walls), WEIGHT, STEEL SNAPS UNDERLOAD
>
>Not true. Steel deforms and is a very ductile material. It will undergo
>significant strain before failure.
Mr. Gray explain shear , as it applies to over loaded beams, please
steel being ductile has what to do with my statement?
>
>> , (Wood sags)
The nature of wood fiber is IMHO much more likly to move, give, change
shape, show signs of overloaded long before steel , The steel will handle
much more ? so when steel being more brittle does give up , wouldn't it
follow that these reactions would be more damaging.
>
>Yes. It also will deform permanently under continous load (develop a
>memory) and when unloaded will not return to its original state. Steel
will
>return to its original state provided you have not exceeded the yield
point.
>A properly designed steel beam will be operating below its yeild point if
>either Allowable Stress Design or Load Resistance Factored Design is used
to
>size the beam.
So will the wood under the same conditions. Residential loading does not
require, steel for many, many, application. Stress design, uniform load,
point loads, side loading, top loading, cantilevers, Mr. Graves your attack
on wood products seems un called for these product work and are being used
every day.
>
>
>>Steel is as
>>good as the poorest weakest weld.
>
>And timber is as good as its weakest connection. Timber also is subject to
>weakened areas due to rot, knots, splits, checks, termites, etc
Steel rust, bust, bends, corrodes, and flakes. please roll out your purfect
construction material. excuse me, steel will remain prestine under the
conditions which cause problems with wood.
>
>>condensation (wet dripping) attaching wood
No responce to condesation dripping from steel and the problems associated
which mixed medi............
>>to steel (Joist, hangers) expansion rate, wood moves steel doesn't (as
>fast)
>
>If you did it right, you attached a nailer to the steel and the wood to the
>nailer. This will almost eliminate squeaks.
Mr. Graves please explain this attachment, is the wood bolted to the flange
for a drop girder. should the wood be attached to the web on each side, so
the joist can be cut to fit, and the top flange be scabbed over to support
decking. The bait to almost eliminate squeaks will be passed,
>
>>floor squeeks. alittle time I'm sure there are more other than fire.
>>BUILDER COST DEPENDS ON WHERE THE STEEL COMES FROM. His labor cost is more
>>to install steel period.
No comment, I will assume that this statement is correct in your eyes then.
>>
>>YOU WANT 2 COLUMNS, tell me about your house and I'll size the
>LVL..........
>>I joist must be sized also, based on span, load, deflection, and spacing.
>
>Unless you are an engineer and licensed to practice in his state, you may
be making a very bad move.
That is true, the product selection question should be handled through
education,
How familiar are you with the theory behind the
>charts?
I am very familiar with the theory behind the charts.
How do you know when the charts are applicable or not? Unless you
>are familiar with the theory and constraints of the design guides or model
>building codes, you really are not qualified for using them to design with.
>Otherwise you could easily be applying a formula or using a chart that is
>not valid for the situation.
YOU ARE ABSOLUTLY CORRECT, which is why I said, " tell me about your house",
while I offer to help sovle a product selection question, you as a PE have
made severial confussing statements. The home owner would not hire a PE to
size the products, the PE will not expose himself to select new materials.
The construction industry continues to old tried and true methods. The
manufacturies carry product insurance for years until new PE's can replace
the old ones.
lg...@my-deja.com
This discussion is becoming incoherent and
acrimonious.
The point here is that wood and steel have
their place in construction and either will serve
perfectly well when all the conditions of service
are properly accounted for.
This could mean that either material will be
eliminated if the requirements begin to reach the
limits of performance for the material in
question.
I some cases a particular materials
disadvantage can be compensated for. For
example: Steel can be brought up to the required
fire resistance by coating or covering it with
fire resistance materials. In residential
construction, fire is not generally considered to
be a hazard since there is usually not enough
fuel in the proper place to bring the steel to
the yield point. You may find some hard nosed
building inspectors though.
In many cases either wood or steel will provide
a practical solution to the same problem.
If that is true, then considerations other than
material performance become important.
Cost, ease of use, shipping and handling,
interfacing to the rest of the building,
aesthetics and perhaps many other things will
become the deciding factors.
All building materials have their advantages
and disadvantages and these must be balanced
against the structural, service and maintainance
requirements.
With reguard to the original question asked by
d_a_p. If the builder has used steel before and
feels it will adequately serve then it most
likely will. If you feel uncomfortable with his
recommendation, get him to show you his reasons
and the design details that he used to make his
recommendation. I.e. the load tables that he
used to select the beam size, the load he
determined the beam would have to support etc.
If he can't do this then you are right to
question his reasoning.
Good luck.
Walter D. Graves
AlTrussGuy wrote in message <7ti83k$fg1$1...@nntp9.atl.mindspring.net>...
>
>Walter D. Graves wrote in message ...
>>This demands correction.
>>
>>AlTrussGuy wrote in message <7td38d$es0$1...@nntp4.atl.mindspring.net>...
>>>Built up beam, is this 3 - 2 X 12's spruce, pine, doug fir?
>>>
>>>LVL, Glue Lam, Steel question (from the steel capitol of the south)
>>
>>Not necessarily. If it did we would not use steel for anything.
>
>Mr. Graves, Wood products can and do replace steel in Residential
>aplications. The products have the consistancey, that framing lumber lack,
>these products must be sizes.
>>
>
>>> The first thing a beam must do is carry it's own weight, the steel
>will
>>>sag under it's own weight if not sized for the span.
>>
>>So will any other material
>Mr. Graves you attack a statement that said. a beam must carry , it doesn't
>say steel beam, our wood, states beam (any beam)
The statement says and I quote "the steel will sag under it's own weight if
not sized for the span". My statement is correct. So will any material if
not properly sized for the load.
>>
>
>>> Disadvantages, CUTTING, WELDING, HANDELING (back hoe knocks down
>>>basement walls), WEIGHT, STEEL SNAPS UNDERLOAD
>>
>>Not true. Steel deforms and is a very ductile material. It will undergo
>>significant strain before failure.
>Mr. Gray explain shear , as it applies to over loaded beams, please
>steel being ductile has what to do with my statement?
Steel does not "snap" under load. It strains significantly even before
going into a plastic state. From there it starts plastic deformation
(permanent) along with strain hardening. ASTM A36 steel (a very common
steel for I beams) has a yield strength of 36ksi. Minimum elongation at
yield is 20%. That is pretty doggone ductile. A brittle material
(non-ductile) would fail suddenly with little to no indication of overload.
Steel will yield significantly before this happens. My name is Mr. Graves,
however, since you asked for some information on shear, I will provide.
Since shear is not a normal failure mode for steel I beams (it is more
common in timber member), I fail to see what shear has to do with this
thread. A timber member overloaded in shear will tend to fail rapidly. In
actuality, timber fails by cascading splits down the center of the beam
starting at the high shear point, which reduces moment carrying capacity to
vitually nothing and down it comes. It is very sudden if a shear failure
occurs. The reason for this failure mechanism is timber is not an
isoptropic material. The strength along the grain is much less then accross
the grain. However, using simple strength of materials concepts it can be
shown that the maximum shear will be at the center of the beam and will go
both against and with the grain in equal magnitude (a small element at the
center of the beam must be in rotational equilibrium, this mandates the
shear along the grain to equal the shear across the grain). Thus, shear
impacts timbers weakest feature (splitting along the grain). After a split
occurs, the strength is significantly reduced and a second split rapidly
develops. Typically the split will start at the high shear point and result
in a failure at the nearest knot, connection, or notch. Steel on the other
hand is isoptropic. Shear failures are hard to produce in steel (web
crippling or web buckling usually occur first. In fires, steel beams do not
nornally fail in shear. They fail due to a bending moment. Columns fail
due to buckling (which is a bending phenomenon associated with pdelta
effects after a minute deflection or destablization). Steel is shear is far
superior to timber performance. In bending it is at least equal. It has a
far superior strength to weight ratio.
I would like to know what your structural engineering credentials are. I am
a registered Professional Engineer, I majored in structural engineering
summa cum laude from the Ohio State Univeristy. I have designed several
structures, both timber and steel and am well versed on both the AISC codes
(steel) and NDS codes (timber). Of course, like any good civil engineer, I
also am well versed in ACI codes and pavement design.
>>
>>> , (Wood sags)
>The nature of wood fiber is IMHO much more likly to move, give, change
>shape, show signs of overloaded long before steel , The steel will handle
>much more ? so when steel being more brittle does give up , wouldn't it
>follow that these reactions would be more damaging.
Not true. Steel beams will show signs and has, depending on the grade of
steel selected, more elongation before catostrophic failure. This includes
tension members. In tension timber will provide almost no warning before
failure. Steel will elongate quite a bit, but you may still not see it in
time (example is the Hyatt Regency walkway disaster). However, we are
talking beams. That steel will handle much more per unit weight is a fact.
It has an extremely high strength to weight ratio. However, it used to cost
so much more than timber that one used timber primarily for economics, not
structural reasons. Steel is not a brittle material. Cast iron is, but not
steel. Wood is forgiving, but that is not because it is a superior
material, quite the contrary, it is because we have to use a large factor of
safety when working with it due to its non-homogeneous nature (knots,
splits, checks, etc).
>>
>>Yes. It also will deform permanently under continous load (develop a
>>memory) and when unloaded will not return to its original state. Steel
>will
>>return to its original state provided you have not exceeded the yield
>point.
>>A properly designed steel beam will be operating below its yeild point if
>>either Allowable Stress Design or Load Resistance Factored Design is used
>to
>>size the beam.
>
>So will the wood under the same conditions.
Not true. Timber develops a memory if subjected to a sustained load. It is
an unusual creep strain whose mechanism is not yet fully understood, but has
been computed and added to the design guidance. Try reading the NDS.
>Residential loading does not
>require, steel for many, many, application.
True. Almost most residential construction in the US and Canada uses
timber. If I built a house today it would use mostly timber. I might have
a steel member here or there, but timber is still economically more
attractive (barely) and you don't have to be an iron worker to work with it.
>Stress design, uniform load,
>point loads, side loading, top loading, cantilevers, Mr. Graves your attack
>on wood products seems un called for these product work and are being used
>every day.
Of course, and so is steel. I don't attack timber. I design with it as
well. I do counter attributing advantages and disadvantages to steel that
are not accurate. Steel is a good material and so is timber. Steel's major
drawback in residential construction is still cost (with the exception of
light gage metal studs which are now very close to wood studs in cost
including installation). As an engineer, my selection of material is based
on structural requirements (sustaining the loads), architectural
considerations (will it fit and how will it look), economics (what is the
most bang for the buck), and life safety code (what kind of fire rating do I
need). Thus in some applications I use timber, some use steel, and some use
concrete. However, steel is a very versatile material and is not brittle.
It is more difficult for the average homeowner to deal with when it comes to
installation and modifications. Most homeowners can swing a hammer, but
very few can use a welder.
>>
>>
>>>Steel is as
>>>good as the poorest weakest weld.
>>
>>And timber is as good as its weakest connection. Timber also is subject
to
>>weakened areas due to rot, knots, splits, checks, termites, etc
>Steel rust, bust, bends, corrodes, and flakes.
rust--yes but not when used within the building envelope. At least not in
any significant amount.
busts--not if designed properly
bends--not if designed properly
corrodes--corrosion on steel is rust so answer is the same
flakes--flaking is rust so answer is the same
>please roll out your purfect
>construction material.
There is none. All have good points and bad. You will note that I did not
disagree with some of the drawbacks you attributed to steel. I do take
exception to calling it a brittle material. Structural steels are not
brittle. Or saying that connections make steel a bad material. In any
material, connections are almost always your weakest link and the MOST
common location for a failure.
>excuse me, steel will remain prestine under the
>conditions which cause problems with wood.
Maybe in heaven steel will remain prestine, but not here. It is pretty much
safe from termites, but steel will often outlive timber in hostile
environments with the noted exception of salt air. The salt will
dramatically increase the corrosion rate.
>>
>>>condensation (wet dripping) attaching wood
>No responce to condesation dripping from steel and the problems associated
>which mixed medi............
Condensation will not be a problem unless the member is used as a portion of
the building envelope. Even then, proper vapor barriers and insulation
prevent this problem. Attaching wood to steel is not a problem. I have
done it in several times.
>
>>>to steel (Joist, hangers) expansion rate, wood moves steel doesn't (as
>>fast)
>>
>>If you did it right, you attached a nailer to the steel and the wood to
the
>>nailer. This will almost eliminate squeaks.
>Mr. Graves please explain this attachment, is the wood bolted to the flange
>for a drop girder. should the wood be attached to the web on each side, so
>the joist can be cut to fit, and the top flange be scabbed over to support
>decking. The bait to almost eliminate squeaks will be passed,
The nailer is attached to the flange using a Hilti drill or powder actuated
fasteners. (Yes, you can blow a fastener into ASTM A36 steel. I have seen
it done many many times.) You may need to go out and watch some structural
steel go up some time. Take close notes on how non structural members are
tied in. You will learn a great deal. Fastening timber to steel is not
difficult. However, Joe homeowner does not own the equipment for it. Some
carpenters do. Most iron workers do.
>>
>>>floor squeeks. alittle time I'm sure there are more other than fire.
>>>BUILDER COST DEPENDS ON WHERE THE STEEL COMES FROM. His labor cost is
more
>>>to install steel period.
>
>No comment, I will assume that this statement is correct in your eyes then.
Yes.
>>>
>>>YOU WANT 2 COLUMNS, tell me about your house and I'll size the
>>LVL..........
>>>I joist must be sized also, based on span, load, deflection, and spacing.
>>
>>Unless you are an engineer and licensed to practice in his state, you may
>be making a very bad move.
>That is true, the product selection question should be handled through
>education,
>
> How familiar are you with the theory behind the
>>charts?
>I am very familiar with the theory behind the charts.
>
> How do you know when the charts are applicable or not? Unless you
>>are familiar with the theory and constraints of the design guides or model
>>building codes, you really are not qualified for using them to design
with.
>>Otherwise you could easily be applying a formula or using a chart that is
>>not valid for the situation.
>
>YOU ARE ABSOLUTLY CORRECT, which is why I said, " tell me about your
house",
>while I offer to help sovle a product selection question, you as a PE have
>made severial confussing statements. The home owner would not hire a PE to
>size the products, the PE will not expose himself to select new materials.
Says who? I am a PE and I use new materials. I research them first, but I
do use them when they make sense.
>The construction industry continues to old tried and true methods.
This is primarily driven by the labor market. A new material generally
requires different skills to install and these skills may not be available
in the market. As the labor market changes so do materials. Engineers are
not opposed to new materials, however, emerging new materials usually are
not economically attractive. Try convincing an owner he/she should spend an
extra 10-20% to use this new product when an existing product can meet there
need. A very difficult sale. If you are designing a turn key project, then
you will lose the bid.
>The
>manufacturies carry product insurance for years until new PE's can replace
>the old ones.
Are we talking steel, timber, and concrete? These are not new. Moving back
and forth between steel and timber is not new. Nor is the current moving
back and forth between steel and concrete in commercial construction new.
It is simply driven by economics. Insurance really has nothing to do with
these moves. An example of emerging construction materials is the
introduction of plastics into the construction as structural members.
Introductions of plastics as structural members is occuring slowly. Again,
this is not necessarily due to insurance. My insurance company does not
review my design work nor do they forbid me to use "new" technology. I have
concerns on plastics mostly based on engineering principles (effects of UV,
flame spread, toxic gasses when burning), that make me leary of using it
until I feel confortable as an engineer that I will not put someone in harms
way. I don't even consider my "insurance" or "liability" in that decision.
I could not sleep at night if I knowingly put someone in harms way. They
trust me to design a safe structure for them and I have made a commitment to
do just that. My decisions are based on protecting the interests of my
client, especially when it comes to life safety.
Walter D. Graves
really would not cost that much to get the written opinion of a structural
engineer. The piece of mind may be worth it.
Walt Graves, PE
lg...@my-deja.com wrote in message <7tirm9$5l9$1...@nnrp1.deja.com>...
AlTrussGuy
Matthew Whiting
Lots of good information deleted.
You mentioned that steel will rust at an insignificant amount within a
building. I looked at a house last year that I was considering buying
(before I decided to build in the sprint). It had steel support beams
in the basement and they were rusted very badly, enough that they were
flaking. The basement was finished and showed no signs of dampness such
as a musty smell in the carpet or stains, etc. I'll probably use steel
in my new home as I have some 24' spans that I want to clear without
using posts. Timber would have to be pretty large. Is there any
significant benefit to sandblasting the beams and painting them before
installation? I'm thinking about a coat of Rustoleum as much for
aesthetic reasons as anything else, but wondering if rust protection is
another reason to do this. I would have to do it myself as I doubt the
contractor is going to want to do it given that code does not require
it. Any drawbacks to a coat of paint? I don't plan to weld anything to
it...
Matt
Carbon Unit
Open-web steel joists are used mostly in commercial
construction, but I think anyone using steel i-beams
should also consider these. The commercial guys
like them for their long span abilities and how you
can thread your mechanicals and plumbing thru the
webs --something you can't do with plain i-beams.
Depths run from 8" on up depending on your span.
I'm using 18" deep joists for a 30' clear span and 40"
spacing that will hold my 50psf live load requirement
and a 4.5" thick concrete and steel floor (dead load).
Of course, with wood floors and/or a lower live load
requirement you could span more and reduce the
required depth of the joist or increase the spacing.
I'm gonna leave them exposed. I like that "loft-ty", industrial,
structural look. (No ducting to look at because I have radiant
heat flooring.) My first floor garage must qualify as type 1
construction so I've chosen a suspended ceiling for fire protection.
Your engineer can specify the camber (a slight curve) of the joist, so
that after your dead loads are applied (typically the concrete
slab over deck) the joists deflect just enough to negate the camber
so your floors are flat. --tom
Vulcraft is a popular manufacturer of open web steel joists and
the deck that goes with it. (205) 845-2460.
d_...@my-deja.com wrote:
> The builder who will be building our new house like to use a steel
> I-beam rather than a build-up wood beam to carry the joists for the
> first floor. This seems like a great idea to me - only two steel
> columns in the whole basement, and I would suspect the steel beam will
> never sag.
>
> Is this too good to be true? Are they any disadvantages with a steel
> beam? What does this mean in terms of the builder's costs vs. a wood
> beam?
>
> TIA,
>
> -Dave
>
CharlieDIY
>I'm thinking about a coat of Rustoleum as much for
>aesthetic reasons as anything else, but wondering if rust protection is
>another reason to do this. I would have to do it myself as I doubt the
>contractor is going to want to do it given that code does not require
>it. Any drawbacks to a coat of paint? I don't plan to weld anything to
>it...
>
Don't know how much good Rustoleum will actually do over the years, but I'd
guess most contractors wil be glad to coat the beam if you pay for the paint
and the hours. If you don't, they won't. Code should have zip to do with it,
but they're not gonna give you a freebie.
Charlie Self
Word Worker
AlTrussGuy
Prior to using the standard, it worked last time sizing for steel,
Please take a look at the Engineered Wood Products which are currently on
the market.
The most recent aplication I used LVL, (Laminated Vineered Lumber) 3, 1
3/4 inch by 18" x 36 feet long, are supporting a I joist floor system
along with the walls and the roof loads. The LVL is support with one column.
Matthew Whiting wrote in message <37FE735C...@epix.net>...
>"Walter D. Graves" wrote:
>
>Lots of good information deleted.
>
>You mentioned that steel will rust at an insignificant amount within a
>building. I looked at a house last year that I was considering buying
>(before I decided to build in the sprint). It had steel support beams
>in the basement and they were rusted very badly, enough that they were
>flaking. The basement was finished and showed no signs of dampness such
>as a musty smell in the carpet or stains, etc. I'll probably use steel
>in my new home as I have some 24' spans that I want to clear without
>using posts. Timber would have to be pretty large. Is there any
>significant benefit to sandblasting the beams and painting them before
>installation? I'm thinking about a coat of Rustoleum as much for
>aesthetic reasons as anything else, but wondering if rust protection is
>another reason to do this. I would have to do it myself as I doubt the
>contractor is going to want to do it given that code does not require
>it. Any drawbacks to a coat of paint? I don't plan to weld anything to
>it...
>
>Matt
AlTrussGuy
anything I can think of.
If the rust is showing on the outside, What does the inside look like.
The wall thickness has been compromised so badly that the paint may become a
structural column.
Columns do not have to be steel tubes, with flanges on each end
CharlieDIY wrote in message
<19991008194239...@ng-fp1.aol.com>...
>Matthew Whiting writes:
>
>>I'm thinking about a coat of Rustoleum as much for
>>aesthetic reasons as anything else, but wondering if rust protection is
>>another reason to do this. I would have to do it myself as I doubt the
>>contractor is going to want to do it given that code does not require
>>it. Any drawbacks to a coat of paint? I don't plan to weld anything to
>>it...
>>
>
>
AlTrussGuy
>>>> The first thing a beam must do is carry it's own weight, the steel
>>will
>>>>sag under it's own weight if not sized for the span.
>
>>Residential loading does not
>>require, steel for many, many, application.
>
>True. Almost most residential construction in the US and Canada uses
>timber. If I built a house today it would use mostly timber. I might have
>a steel member here or there, but timber is still economically more
>attractive (barely) and you don't have to be an iron worker to work with
it.
The above statement from your post is the answer that the original post was
seeking, all other information, though informative has nothing to todo with
the posting,
>
I said,
>>>>BUILDER COST DEPENDS ON WHERE THE STEEL COMES FROM. His labor cost is
>more
>>>>to install steel period.
>>
>>No comment, I will assume that this statement is correct in your eyes
then.
Your responce
>Yes.
To Dave the beginning,,,,
PE's pump themselves and others up, My degree from Alabama or Graves
from Ohio State, I give a shit. Engineered Wood Products where not in the
Books that Mr.. graves studied in Ohio.
Mr.. Graves who switched My wood products to Timbers, you did, Who
quoted Ken ,"steel will sag" stating that I said it . Mr. Graves you truly
scare me, lord your degree to some one who cares........
I'll stand toe to toe with you line for line but not here, take your
pompous attitude which changes post to fit your argument an put em where
the sun doesn't shine.
DO NOT MISS QUOTE ME IT IS BELOW YOU EDUCATION, and mine too.
PS read over you r statement you have agreed with me, Thank You very Much.
Dave get the products sized by some one steel isn't an automatic better than
because its steel.
Mr.. Graves, carpenters with, powder actuated fasteners, Hilti drills,
torches, welders, and a crane to fasten steel are not CARPENTERS. EWP's,
are cut with a saw, nailed with a nail and installed 1 (one) piece at he
time by carpenters.
Walter D. Graves
section for a beam. I beams (W section to be more specific) or bar joists
are much more common.
AlTrussGuy wrote in message <7tm1jg$a7n$1...@nntp1.atl.mindspring.net>...
Walter D. Graves
something I use a lot as well. Have not seen them rust much at all in the
building envelope.
Carbon Unit wrote in message <37FE76F9...@brinet.com>...
Walter D. Graves
the steel primed at the steel yard. However, I have seen many occasions
where the steel supplier does not remove all of the mill scale prior to
priming. If you get unprimed steel, you will need to blast it regardless of
whether it is flaking of not. This will remove mill scale and ensure
adhesion of the primer. You would then prime it with a rust inhibitor and
then put on a finish coat or two. If fire proofing is needed you would also
apply that. Rust is a corrosion cell. In order for it to form you need the
following: a. a conductor, b. an electrolyte, c. a potential difference.
Steel is a conductor and minor irregularities within the steel provide to
potential difference. If disimilar metals are involved, the potential
difference is larger and the potential for a corrosion cell is larger.
However, the last element--an electolyte requires moisture. Where was this
house at? Was it near the coast? At any rate, the moisture would have to be
present to develop the electrolyte for the corrosion cell.
Walt Graves
Matthew Whiting wrote in message <37FE735C...@epix.net>...
>"Walter D. Graves" wrote:
>
>Lots of good information deleted.
>
>You mentioned that steel will rust at an insignificant amount within a
>building. I looked at a house last year that I was considering buying
>(before I decided to build in the sprint). It had steel support beams
>in the basement and they were rusted very badly, enough that they were
>flaking. The basement was finished and showed no signs of dampness such
>as a musty smell in the carpet or stains, etc. I'll probably use steel
>in my new home as I have some 24' spans that I want to clear without
>using posts. Timber would have to be pretty large. Is there any
>significant benefit to sandblasting the beams and painting them before
>installation? I'm thinking about a coat of Rustoleum as much for
>aesthetic reasons as anything else, but wondering if rust protection is
>another reason to do this. I would have to do it myself as I doubt the
>contractor is going to want to do it given that code does not require
>it. Any drawbacks to a coat of paint? I don't plan to weld anything to
>it...
>
>Matt
Walter D. Graves
becoming incoherent.
AlTrussGuy wrote in message <7tm4qd$tfr$1...@nntp1.atl.mindspring.net>...
>Snipped from your post,
Your post:
>
>>>>> The first thing a beam must do is carry it's own weight, the steel
>>>will
>>>>>sag under it's own weight if not sized for the span.
>
NOTE: My response to this is cut out. I stated "so will any material"
Your post:
>>>Residential loading does not
>>>require, steel for many, many, application.
My post:
>>
>>True. Almost most residential construction in the US and Canada uses
>>timber. If I built a house today it would use mostly timber. I might
have
>>a steel member here or there, but timber is still economically more
>>attractive (barely) and you don't have to be an iron worker to work with
>it.
Your post:
>The above statement from your post is the answer that the original post was
>seeking, all other information, though informative has nothing to todo with
>the posting,
My response:
The poster wanted to know if a steel beam was OK. Of course it is OK. So
is an engineered wood product. So is a reinforced concrete beam. It is all
in whether you want to pay for it and what features are critical to you.
Your post:
>>
>I said,
>>>>>BUILDER COST DEPENDS ON WHERE THE STEEL COMES FROM. His labor cost is
>>more
>>>>>to install steel period.
>>>
Your post:
>>>No comment, I will assume that this statement is correct in your eyes
>then.
My post:
>>Yes.
Your post:
>To Dave the beginning,,,,
> PE's pump themselves and others up, My degree from Alabama or Graves
>from Ohio State, I give a shit. Engineered Wood Products where not in the
>Books that Mr.. graves studied in Ohio.
My response:
This is a very unsubstantiated and insuating remark. It implies that I do
not care. That is not a true statement. Additionally you have not
substantiated your comments on Ohio State. For your information, Ohio State
does teach engineered wood products. Additionally, I am current on
engineered wood products and use them when they are the best solution to the
problem I am trying to solve.
Your Post:
> Mr.. Graves who switched My wood products to Timbers, you did, Who
>quoted Ken ,"steel will sag" stating that I said it . Mr. Graves you truly
>scare me, lord your degree to some one who cares........
My response:
Timber is wood and that is the term commonly used to refer to wood amongst
structural engineers. We use timber, steel, and concrete. I snipped the
quote directly out of your post. If his line was mixed in with your line,
then you need to work on your posting skills to separate your work from
others. I don't Lord my degree. My degree along with my registration and
my experience qualify my statements. I am curious as to what your degree is
in and your registration status. A professional engineer generally must
have an engineering degree from an ABET certified school, passed an 8 hour
Fundamentals of Engineering Exam, passed another 8 hour Principles and
Practices of Engineering Exam, completed 4 to 5 years of engineering work as
an intern under another registered engineer, and be recommended by 5 other
registered engineers. The requirements vary from state to state, but almost
all have similar requirements. The Principles and Practices Exam generally
has a pass rate of around 30 to 40%. They are not easy tests and determine
the depth of your engineering knowledge.
Your post:
>
>I'll stand toe to toe with you line for line but not here, take your
>pompous attitude which changes post to fit your argument an put em where
>the sun doesn't shine.
My response:
My my, but you do get emotional.
Your post:
>DO NOT MISS QUOTE ME IT IS BELOW YOU EDUCATION, and mine too.
>PS read over you r statement you have agreed with me, Thank You very Much.
My response:
You were not misquoted unless you mixed someone elses stuff in your posting
line. The only direct quote I used was snipped out our your posting line.
The only comments I disagreed with were that steel will fail suddenly
(snap). That is not true for structural steel.
Your post:
>Dave get the products sized by some one steel isn't an automatic better
than
>because its steel.
My response:
True. Steel is just another building material and option for the engineer
to use.
Your post:
>Mr.. Graves, carpenters with, powder actuated fasteners, Hilti drills,
>torches, welders, and a crane to fasten steel are not CARPENTERS. EWP's,
>are cut with a saw, nailed with a nail and installed 1 (one) piece at he
>time by carpenters.
My response:
And your point? My comment was that the difficulty with steel is that the
average carpenter or homeowner can't work with it. They don't have the
skills or equipment. There are a few multi-talented carpenters out there
that do have the tools and equipment, but they are rare. That is one of the
big advantages of engineered wood products or timber construction in
residential work. You asked how the attachment would be made and I told
you. I did not say your average carpenter would do it. Some can, but they
are not the majority. That is why it will cost a few extra dollars for a
steel beam. But if you want a steel beam or if the contractor wants to use
one over a engineered wood product (or timber member) then that is fine. It
must be properly sized just like any other structural member would have to
be (regardless of the material the member is made of).
>
>
AlTrussGuy
d_...@my-daja.com posted
The builder who will be building our new house like to use a steel I-beam
rather than a build-up wood beam to carry the joist for the first floor.
This seems like a great idea to me - only two steel columns in thw whole
basement, and I would suspect the steel beam will never sag.
Is this too good to be true? Are they any disadvantages with a steel beam?
What does this mean in terms of the builder's cost vs. a wood beam?
And my point is, that 8 days later you have posted the same information that
I gave him early on. after taking me to task, and covering information that
was far afield from the original post.
10/9/99 11:27 AM
Mr. Graves said,
Matthew Whiting
>
> Yes, you should put a protective coating on steel. Many times you can get
> the steel primed at the steel yard. However, I have seen many occasions
> where the steel supplier does not remove all of the mill scale prior to
> priming. If you get unprimed steel, you will need to blast it regardless of
> whether it is flaking of not. This will remove mill scale and ensure
> adhesion of the primer. You would then prime it with a rust inhibitor and
> then put on a finish coat or two. If fire proofing is needed you would also
> apply that. Rust is a corrosion cell. In order for it to form you need the
> following: a. a conductor, b. an electrolyte, c. a potential difference.
> Steel is a conductor and minor irregularities within the steel provide to
> potential difference. If disimilar metals are involved, the potential
> difference is larger and the potential for a corrosion cell is larger.
> However, the last element--an electolyte requires moisture. Where was this
> house at? Was it near the coast? At any rate, the moisture would have to be
> present to develop the electrolyte for the corrosion cell.
The house is in northcentral PA, just up the road from where I live. It
is certainly humid here during the spring and summer, but not bad during
fall and winter. I've never seen a painted steel beam in a house in
this neck of the woods. Always seemed odd to me, but it appears to be a
common practice. I'm going to have mine painted if I have to rent a
sand blaster and spray outfit and do it myself.
Matt
Matthew Whiting
> Timber is wood and that is the term commonly used to refer to wood amongst
> structural engineers. We use timber, steel, and concrete. I snipped the
> quote directly out of your post. If his line was mixed in with your line,
> then you need to work on your posting skills to separate your work from
> others. I don't Lord my degree. My degree along with my registration and
> my experience qualify my statements. I am curious as to what your degree is
> in and your registration status. A professional engineer generally must
> have an engineering degree from an ABET certified school, passed an 8 hour
> Fundamentals of Engineering Exam, passed another 8 hour Principles and
> Practices of Engineering Exam, completed 4 to 5 years of engineering work as
> an intern under another registered engineer, and be recommended by 5 other
> registered engineers. The requirements vary from state to state, but almost
> all have similar requirements. The Principles and Practices Exam generally
> has a pass rate of around 30 to 40%. They are not easy tests and determine
> the depth of your engineering knowledge.
Yes, and this pass rate is on a test that typically requires only a 70%
score to pass! I took my FE and PE test back-to-back (a Thursday and
Friday) as I'd not been encouraged to take the FE while an undergraduate
(lousy advisor). By noon on Friday, I no longer cared if I passed or
failed ... I just wanted to get it over. Luckily, I passed both tests
with a comfortable margin.
Matt
Walter D. Graves
both back to back. I tood the FE two years after graduating and the PE
three years after the FE. Neither was any fun, but I did leave the PE
feeling somewhat like a zombie. I can't even think of what I would feel
like after taking both tests back to back. For those not familiar with the
tests, the FE covers several branches of engineering are really tests a
candidates breadth of knowledge in areas within and out of their field. It
is multiple choice. The PE (Principles and Practices of Engineering) is a
test within an engineers field and tests the depth of knowledge within their
particular branch. It is a combination of essay and multiple choice. Noon
would have just finished the essay portion (which most would agree is the
hardest area). To take both tests back to back is tough because you not
only need to be prepared for an intense exam to test how much you know about
your job, but you also need to be able to pass an exam to test how much you
know about other engineering fields.
Walt Graves, PE
Matthew Whiting wrote in message <37FFDDF4...@epix.net>...
Bob Morrison
total of 20 hour!. And in most cases this test is taken after you already
have passed the FE and PE exams.
--
Bob Morrison
R L Morrison Engineering Co
Structural and Civil Engineering
Poulsbo WA
Matthew Whiting
>
> I hear you. Not the easiest test in the world. I imagine it would be worst
> both back to back. I tood the FE two years after graduating and the PE
> three years after the FE. Neither was any fun, but I did leave the PE
> feeling somewhat like a zombie. I can't even think of what I would feel
> like after taking both tests back to back. For those not familiar with the
> tests, the FE covers several branches of engineering are really tests a
> candidates breadth of knowledge in areas within and out of their field. It
> is multiple choice. The PE (Principles and Practices of Engineering) is a
> test within an engineers field and tests the depth of knowledge within their
> particular branch. It is a combination of essay and multiple choice. Noon
> would have just finished the essay portion (which most would agree is the
> hardest area). To take both tests back to back is tough because you not
> only need to be prepared for an intense exam to test how much you know about
> your job, but you also need to be able to pass an exam to test how much you
> know about other engineering fields.
I don't recall exactly, and it has been several years since I took the
test ('93 I believe), but I was thinking that the essays were in the PM
for the PE.
The morning of the FE was something like 170 multiple choice questions
such that you had slightly over a minute per question. I think the
afternoon was something like 70 or 100 multiple choice questions which
were a little more difficult but for which you had around three minutes
each.
I think the morning of the PE was four "essay" problems with each
problem having 10 questions to be answered. I also recall that you had
a set of 12 problems from which to select the four you wished to
submit. I think the afternoon of the PE test once again presented a 12
problem set from which you selected four to complete. My recollection
is that these were more elaborate problems and essentially asked you to
complete a somewhat involved analysis or design problem.
I took the test in NY state and in the EE discipline ... which explains
why I keep asking you questions about structural stuff!
Matt
Matthew Whiting
>
> You should try the Structural Engineers Exam. In Washington State it is a
> total of 20 hour!. And in most cases this test is taken after you already
> have passed the FE and PE exams.
That's OK, 16 hours over the course of two days was enough for me!
Besides, I'm making much better money as an engineering manager than as
a P.E.! I got the P.E. mainly for the challenge of it as I've always
worked for a corporation and thus the P.E. was not required nor provided
me any benefit (my employer is not a utility or other company that pays
a salary permium for registered professional engineers ... sigh!).
Actually, if you check the NY state web site you will see that I've let
my license move into the "inactive" status to avoid paying the $90/year
fee.
Matt
Walter D. Graves
sets were in the afternoon. However, they are constantly changing the
format and presentation of the test.
Matthew Whiting wrote in message <38010628...@epix.net>...
Walter D. Graves
does not have a separate branch for structural engineering. Washington,
California, and a few other states have a separate branch and require these
two tests. I plan to move to Washington in about three years (Seattle or
Everett area). I grew up there for 16 years. I am planning to take the
structural series in about two years. Where is Poulsbo? Is it in Eastern
Washington or Western Washington?
Bob Morrison wrote in message ...
>You should try the Structural Engineers Exam. In Washington State it is a
>total of 20 hour!. And in most cases this test is taken after you already
>have passed the FE and PE exams.
>
RWatson767
> Steel vs. wood beams
FWIW. I am building a 20' x 20' shop and storage building. Using 2 x 12 steel
studs for both studs and rafters. I purchased the steel for about 40% of the
cost of wood. It is taking some learning to get it done but I expect the next
job, if there was going to be one, would go twice as fast.
I am using 2 X 12 to get enough insulation in for the climate. I am usng the
prescriptive method from www.steel.org . The city said OK and there are enough
directions in the books to get it done. #8 screws throughout. I can feel the
structure getting more solid with each screw and metal piece.
Like your disertation. Read it all.
Take care
Bob AZ