Home Ownership (misc.consumers.house)

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
 
Posts: n/a
Default Wall Removal Question?

I am planning on removing a 13 foot (plaster) wall on the 1st floor of
my 2 story house that I am going to assume is load bearing.

When I look in the basement directly under the current wall, there is a
double 13 foot 2X12 with one end sitting on the foundation wall and the
other end on a metal i-beam that spans the length of the house. Not
sure of the wood type, but late 1940's construction.

Directly above the wall I am planning on removing is the center of the
floor of a 13X20 bedroom. (also: the joists above the removal wall are
perpindicular to the wall.)

My first plan was to replace the current wall with a double 13 foot
2x12 header. (possibly triple?)

My Question is.

1. Does this sound adequate.

2. What would be the equivelent LVL beam(s) (ie: microllam) to use
instead of using wood? I would like the reduce the depth of the header
so it will not be as notciable.

And yeah, I know, I should consult an engineer. Just looking for
opinions here.

  #2   Report Post  
BobK207
 
Posts: n/a
Default

.. My Question is.

1. Does this sound adequate.

No, my SWAG (no calcs) would be a 4 x14 but someone's got the run the
numbers

2. What would be the equivalent LVL beam(s) (ie: microllam) to use
instead of using wood? I would like the reduce the depth of the header
so it will not be as notciable. .

Reducing the depth is asking for trouble unless you go to steel.

If you really wan to make the header "disappear" completely you could:

Shore in the basement & the first floor on either side of the exsisting
wall.
remove the wall
cut second floor joists back to allow for a steel beam ~the depth of
the cut joists.
Install hangers & the beam.
close the ceiling,
remove the shoring.

no visible header, but a lot of work

cheers
Bob

  #3   Report Post  
BobK207
 
Posts: n/a
Default

on second reading of the OP, your double or triple 2x12 would work;
that's what's holding up first floor currently. I wasn't exactly clear
on that.

How does the first floor feel?

my suggest to hide the header still stands
cheers
Bob

  #4   Report Post  
 
Posts: n/a
Default

I've removed 2 walls in my life but nothing that complicated. I'm 51%
sure you're ok with doing what you describe, one problem is if you're
wrong and your house caves in your insurance may not cover it. For
example you're counting on the builder following logic, are the floor
joists for room above actually able to cover the span without the wall
you wanna yank ? Lotta questions.

  #5   Report Post  
barry7
 
Posts: n/a
Default


schreef in bericht
ups.com...
I've removed 2 walls in my life but nothing that complicated. I'm 51%
sure you're ok with doing what you describe, one problem is if you're
wrong and your house caves in your insurance may not cover it. For
example you're counting on the builder following logic, are the floor
joists for room above actually able to cover the span without the wall
you wanna yank ? Lotta questions.

Yep, maybe the floor above the wall isn't continous.




  #6   Report Post  
 
Posts: n/a
Default

That's why I figured I might as well overdo it.

I've now decided to go with a Steel I-beam (looks like it will be the
same or cheaper than lumber - but will make a much smaller header.)
Question now is, should I go with a 4" 6" or 8" IBeam? What iBeam size
would be equivalent to Three 2X12 at 13 feet??

Keep in mind, the only thing holding up the wall I plan on removing is
Two 2X12's

  #10   Report Post  
Brian Whatcott
 
Posts: n/a
Default

On Sun, 20 Mar 2005 13:22:34 GMT, Rob Munach
wrote:

Brian Whatcott wrote:

On 18 Mar 2005 08:36:10 -0800, wrote:


That's why I figured I might as well overdo it.

I've now decided to go with a Steel I-beam (looks like it will be the
same or cheaper than lumber - but will make a much smaller header.)
Question now is, should I go with a 4" 6" or 8" IBeam? What iBeam size
would be equivalent to Three 2X12 at 13 feet??

Keep in mind, the only thing holding up the wall I plan on removing is
Two 2X12's



A specimen load for a 6X12 in wood beam at 13 feet is 200lb per foot
uniform loading, for which the max deflection is 0.1 inch This has a
safety rating of X2 to failure for reasonable assumptions:
Youngs 1.5E6 psi limit stress 1.2 kips

A steel I beam: W8X15 deflects 0.09 inches for this load,
a W8X13 deflects 0.11 inches.
Youngs 29E6 yield stress 36 ksi

Respectfully

Brian Whatcott Altus, OK

Brian,
You may want to re-check your calcs.

6x12 (assuming 5 1/2 x 11 1/4 - which is larger than the (3)2x12
specified) S = 116

For 200 plf over 13', M = 4225 ft-lb

M/S = 437 psi which is a little under 1/2 of what is typically used for
the design stress (which already has a huge factor of safety).

Regards,



Rob, the calcs aren't mine, they are the result of Archon's Beams
program which also checks against code.

I made explicit my inputs, as to Youngs, limit stress and dimensions
for both the wood beam and the steel beam.
You note that you used commercial "finished" dimensions rather than
gross rough-sawn, and that's a not unreasonable basis for the
difference in your wood beam calcs, I certainly agree.

Respectfully

Brian Whatcott Altus, OK


  #11   Report Post  
Rob Munach
 
Posts: n/a
Default

Brian Whatcott wrote:

On Sun, 20 Mar 2005 13:22:34 GMT, Rob Munach
wrote:


Brian Whatcott wrote:


On 18 Mar 2005 08:36:10 -0800, wrote:



That's why I figured I might as well overdo it.

I've now decided to go with a Steel I-beam (looks like it will be the
same or cheaper than lumber - but will make a much smaller header.)
Question now is, should I go with a 4" 6" or 8" IBeam? What iBeam size
would be equivalent to Three 2X12 at 13 feet??

Keep in mind, the only thing holding up the wall I plan on removing is
Two 2X12's


A specimen load for a 6X12 in wood beam at 13 feet is 200lb per foot
uniform loading, for which the max deflection is 0.1 inch This has a
safety rating of X2 to failure for reasonable assumptions:
Youngs 1.5E6 psi limit stress 1.2 kips

A steel I beam: W8X15 deflects 0.09 inches for this load,
a W8X13 deflects 0.11 inches.
Youngs 29E6 yield stress 36 ksi

Respectfully

Brian Whatcott Altus, OK


Brian,
You may want to re-check your calcs.

6x12 (assuming 5 1/2 x 11 1/4 - which is larger than the (3)2x12
specified) S = 116

For 200 plf over 13', M = 4225 ft-lb

M/S = 437 psi which is a little under 1/2 of what is typically used for
the design stress (which already has a huge factor of safety).

Regards,




Rob, the calcs aren't mine, they are the result of Archon's Beams
program which also checks against code.

I made explicit my inputs, as to Youngs, limit stress and dimensions
for both the wood beam and the steel beam.
You note that you used commercial "finished" dimensions rather than
gross rough-sawn, and that's a not unreasonable basis for the
difference in your wood beam calcs, I certainly agree.

Respectfully

Brian Whatcott Altus, OK

Actually, Brian, 5 1/2x11 1/4 is the finshed dimensions of a 6x12. You
may want to do the calc by hand to verify the results from the program.
I imagine you have an input wrong. Your deflections, however, seem to be
correct for the steel beam. For 0.1" deflection and an E of 1.5, the
moment of inertia of your wood section is 856 in^4 which is the moment
of inertia of a true 6x12 (6"x12") The section modulus of this beam is
144in^3. For a 4225ft-lb moment, the bending stress is 352 psi!

Regards,

--
Rob Munach, PE
Excel Engineering
PO Box 1264
Carrboro, NC 27510
  #12   Report Post  
Brian Whatcott
 
Posts: n/a
Default

On Mon, 21 Mar 2005 10:44:00 GMT, Rob Munach
wrote:

A specimen load for a 6X12 in wood beam at 13 feet is 200lb per foot
uniform loading, for which the max deflection is 0.1 inch This has a
safety rating of X2 to failure for reasonable assumptions:
Youngs 1.5E6 psi limit stress 1.2 kips

A steel I beam: W8X15 deflects 0.09 inches for this load,
a W8X13 deflects 0.11 inches.
Youngs 29E6 yield stress 36 ksi

Respectfully

Brian Whatcott Altus, OK

Brian,
You may want to re-check your calcs.

6x12 (assuming 5 1/2 x 11 1/4 - which is larger than the (3)2x12
specified) S = 116


I made explicit my inputs, as to Youngs, limit stress and dimensions
for both the wood beam and the steel beam.
You note that you used commercial "finished" dimensions rather than
gross rough-sawn, and that's a not unreasonable basis for the
difference in your wood beam calcs, I certainly agree.

Respectfully

Brian Whatcott Altus, OK


Actually, Brian, 5 1/2x11 1/4 is the finshed dimensions of a 6x12.



Let me say this again, slowly:

a finished (planed) 6X12 may measure about 5 3/4 X 11 3/4, I believe
depending on its moisture content.
A finished composition of 3 off 2 X 12 may measure about 5 1/4 X 11
3/4,I believe. These figures may or may not represent your
experience, probably not. Still, I could care less, because it is
not material to my response.

If I say that a rough sawn 6 X 12 inch measures 6 X 12 inch, (duh)
and provide the Code approved results for such a beam, given the
Youngs and stress limit I specify, then I have provided an engineering
calculation which is explicitly correct.

If you wish to say that your planed, finished beams are 5 1/2 X 11
1/4 that's just fine by me too. And your figures may be accurate for
these dimensions. Or not. I haven't checked.

Wouldn't it be better to ask the questioner what are the ACTUAL
dimensions of the beam he has in mind, rather than playing "I'm
smarter than you"?
[People don't usually win these games with me, Rob!]
:-)

Sincerely

Brian Whatcott Altus, OK
  #13   Report Post  
Bob Morrison
 
Posts: n/a
Default

In a previous post Brian Whatcott says...
If I say that a rough sawn 6 X 12 inch measures 6 X 12 inch, (duh)
and provide the Code approved results for such a beam, given the
Youngs and stress limit I specify, then I have provided an engineering
calculation which is explicitly correct.


Brian:

The calculation may be correct, but the answer is wrong. What is the
point of doing a calculation on a product that one cannot readily
purchase? That is not an "engineering" solution, but simply a
mathematical exercise.

What Rob is trying to tell you is that if you are going to make a
recommendation then base your recommendation on real lumbers sizes with
real lumber material properties. It does no one any good to specify
some material that cannot be purchased.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA
  #14   Report Post  
Brian Whatcott
 
Posts: n/a
Default

On Mon, 21 Mar 2005 15:39:10 GMT, Bob Morrison
wrote:

In a previous post Brian Whatcott says...
If I say that a rough sawn 6 X 12 inch measures 6 X 12 inch, (duh)
and provide the Code approved results for such a beam, given the
Youngs and stress limit I specify, then I have provided an engineering
calculation which is explicitly correct.


Brian:

The calculation may be correct, but the answer is wrong. What is the
point of doing a calculation on a product that one cannot readily
purchase? That is not an "engineering" solution, but simply a
mathematical exercise.

What Rob is trying to tell you is that if you are going to make a
recommendation then base your recommendation on real lumbers sizes with
real lumber material properties. It does no one any good to specify
some material that cannot be purchased.


Ah, now we are getting to the nub, I see.

Can you purchase a 13 ft beam in the US?
Can you purchase a (metric) 13 ft beam elsewhere?

Can you ask a mill to resaw used timber?
Can you have beams rough-cut to specified dimensions?
Does the allowance for timber "finished four sides"
allow a wastage off the rough-cut (nominal) dimensions?

We are (presumably) not talking about dashing down to
Lowes with a bill of materials, but talking engineering stress.

The answers to these questions may help one
be better prepared NOT necessarily to suppose a weak
hypothetical wood beam, and speculate that it is Southern yellow
pine finished four sides, rather than rough cut Douglas Fir on nominal
dimension, and so to avoid converting it to a steel beam that is
lighter than a conservative conversion would provide.

If a home-owner asks for advice, it is far, FAR better to err on the
conservative side, wouldn't you say? To put it another way:
whose advice would YOU take, if you were not in the field:
mine or Rob's?

Still, I will keep batting this one around with you, by all means, at
least until the ad hominem approach supervenes.

This can be educational, after all.

Have a happy day!

Brian Whatcott, Altus, OK
  #15   Report Post  
Bob Morrison
 
Posts: n/a
Default

In a previous post Brian Whatcott says...

If a home-owner asks for advice, it is far, FAR better to err on the
conservative side, wouldn't you say? To put it another way:
whose advice would YOU take, if you were not in the field:
mine or Rob's?


Brian:

You can specify any product you want, including odd sized material. If
it suits your fancy call out 3-3/4" x 10-7/8" teak beam, but if you give
the homeowner advice about a product he cannot readily buy then you
begin to look foolish and the homeowner will begin to question whether
or not your advice was accurate.

Since "I" know this was not your intent, it is not really a problem for
me. But, if the person to whom you are giving advice is not an
engineer, then giving misleading or inadequate information can be a
problem. This is one of those issues where knowing the materials and
their specifications is important. It gives the homeowner a sense of
confidence that the engineer knows what he/she is talking about.

BTW, there are much better programs than "Archon" for computing stresses
in wood members. I'm partial to "Beamchek" which I use daily and is an
excellent tool for doing simple beam calculations in wood or steel. One
simply selects the material type (Douglas-Fir/Larch, Southern Pine,
steel, etc) and the software will input the appropriate "E" and "Fb"
values. Members will be then selected by the engineer from "standard"
manufactured sizes. This provides economical design. As in any good
software you can set your deflection limit to a more strict value than
the building code requires, thus giving you stiffer beams.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA


  #16   Report Post  
Brian Whatcott
 
Posts: n/a
Default

On Tue, 22 Mar 2005 02:18:45 GMT, Bob Morrison
wrote:

In a previous post Brian Whatcott says...

If a home-owner asks for advice, it is far, FAR better to err on the
conservative side, wouldn't you say? To put it another way:
whose advice would YOU take, if you were not in the field:
mine or Rob's?


Brian:

You can specify any product you want, including odd sized material. If
it suits your fancy call out 3-3/4" x 10-7/8" teak beam, but if you give
the homeowner advice about a product he cannot readily buy then you
begin to look foolish and the homeowner will begin to question whether
or not your advice was accurate.///


Perhaps it would be better to read the thread Bob.
I specified some standard steel I beam sections, as did Rob.
The ones he suggested to a naive home-owner were weaker
than the ones I mentioned. Not a lot weaker. Just low-ball.

Did you think the questioner was going to buy wood beams then?

Oh well!

Brian Whatcott Altus, OK
  #17   Report Post  
Chuck
 
Posts: n/a
Default


"Bob Morrison" wrote in message
k.net...
In a previous post Brian Whatcott says...

If a home-owner asks for advice, it is far, FAR better to err on the
conservative side, wouldn't you say? To put it another way:
whose advice would YOU take, if you were not in the field:
mine or Rob's?


Brian:

You can specify any product you want, including odd sized material. If
it suits your fancy call out 3-3/4" x 10-7/8" teak beam, but if you give
the homeowner advice about a product he cannot readily buy then you
begin to look foolish and the homeowner will begin to question whether
or not your advice was accurate.

Since "I" know this was not your intent, it is not really a problem for
me. But, if the person to whom you are giving advice is not an
engineer, then giving misleading or inadequate information can be a
problem. This is one of those issues where knowing the materials and
their specifications is important. It gives the homeowner a sense of
confidence that the engineer knows what he/she is talking about.

BTW, there are much better programs than "Archon" for computing stresses
in wood members. I'm partial to "Beamchek" which I use daily and is an
excellent tool for doing simple beam calculations in wood or steel. One
simply selects the material type (Douglas-Fir/Larch, Southern Pine,
steel, etc) and the software will input the appropriate "E" and "Fb"
values. Members will be then selected by the engineer from "standard"
manufactured sizes. This provides economical design. As in any good
software you can set your deflection limit to a more strict value than
the building code requires, thus giving you stiffer beams.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA


Great response there Bob.

Chuck...
__________________________________________________ ______
Charles I. Dinsmore, PE SE RA ~


  #18   Report Post  
Rob Munach
 
Posts: n/a
Default

Brian Whatcott wrote:
On Mon, 21 Mar 2005 10:44:00 GMT, Rob Munach
wrote:


A specimen load for a 6X12 in wood beam at 13 feet is 200lb per foot
uniform loading, for which the max deflection is 0.1 inch This has a
safety rating of X2 to failure for reasonable assumptions:
Youngs 1.5E6 psi limit stress 1.2 kips

A steel I beam: W8X15 deflects 0.09 inches for this load,
a W8X13 deflects 0.11 inches.
Youngs 29E6 yield stress 36 ksi

Respectfully

Brian Whatcott Altus, OK

Brian,
You may want to re-check your calcs.

6x12 (assuming 5 1/2 x 11 1/4 - which is larger than the (3)2x12
specified) S = 116



I made explicit my inputs, as to Youngs, limit stress and dimensions
for both the wood beam and the steel beam.
You note that you used commercial "finished" dimensions rather than
gross rough-sawn, and that's a not unreasonable basis for the
difference in your wood beam calcs, I certainly agree.

Respectfully

Brian Whatcott Altus, OK



Actually, Brian, 5 1/2x11 1/4 is the finshed dimensions of a 6x12.




Let me say this again, slowly:

a finished (planed) 6X12 may measure about 5 3/4 X 11 3/4, I believe
depending on its moisture content.
A finished composition of 3 off 2 X 12 may measure about 5 1/4 X 11
3/4,I believe. These figures may or may not represent your
experience, probably not. Still, I could care less, because it is
not material to my response.

If I say that a rough sawn 6 X 12 inch measures 6 X 12 inch, (duh)
and provide the Code approved results for such a beam, given the
Youngs and stress limit I specify, then I have provided an engineering
calculation which is explicitly correct.

If you wish to say that your planed, finished beams are 5 1/2 X 11
1/4 that's just fine by me too. And your figures may be accurate for
these dimensions. Or not. I haven't checked.

Wouldn't it be better to ask the questioner what are the ACTUAL
dimensions of the beam he has in mind, rather than playing "I'm
smarter than you"?
[People don't usually win these games with me, Rob!]
:-)

Sincerely

Brian Whatcott Altus, OK

Brian,

Please re-read my post and do these calcs by hand! Your stress results
for the wood beam are off by at least a factor of two. Here is my
previous post:

"Actually, Brian, 5 1/2x11 1/4 is the finshed dimensions of a 6x12. You
may want to do the calc by hand to verify the results from the program.
I imagine you have an input wrong. Your deflections, however, seem to be
correct for the steel beam. For 0.1" deflection and an E of 1.5, the
moment of inertia of your wood section is 856 in4 which is the moment of
inertia of a true 6x12 (6"x12") The section modulus of this beam is
144in3. For a 4225ft-lb moment, the bending stress is 352 psi!"


Based on the deflections you gave, the section properties compute to a
"true" 6x12, but your bending stress doesn't even copme close to this
section. You have an error!



--
Rob Munach, PE
Excel Engineering
PO Box 1264
Carrboro, NC 27510
  #19   Report Post  
Brian Whatcott
 
Posts: n/a
Default

On Tue, 22 Mar 2005 11:51:26 GMT, Rob Munach
wrote:

Brian Whatcott wrote:
On Mon, 21 Mar 2005 10:44:00 GMT, Rob Munach
wrote:


A specimen load for a 6X12 in wood beam at 13 feet is 200lb per foot
uniform loading, for which the max deflection is 0.1 inch This has a
safety rating of X2 to failure for reasonable assumptions:
Youngs 1.5E6 psi limit stress 1.2 kips

A steel I beam: W8X15 deflects 0.09 inches for this load,
a W8X13 deflects 0.11 inches.
Youngs 29E6 yield stress 36 ksi

Respectfully

Brian Whatcott Altus, OK

Brian,


You may want to re-check your calcs.

6x12 (assuming 5 1/2 x 11 1/4 - which is larger than the (3)2x12
specified) S = 116



I made explicit my inputs, as to Youngs, limit stress and dimensions
for both the wood beam and the steel beam.
You note that you used commercial "finished" dimensions rather than
gross rough-sawn, and that's a not unreasonable basis for the
difference in your wood beam calcs, I certainly agree.

Respectfully

Brian Whatcott Altus, OK



Actually, Brian, 5 1/2x11 1/4 is the finshed dimensions of a 6x12.




Let me say this again, slowly:

a finished (planed) 6X12 may measure about 5 3/4 X 11 3/4, I believe
depending on its moisture content.
A finished composition of 3 off 2 X 12 may measure about 5 1/4 X 11
3/4,I believe. These figures may or may not represent your
experience, probably not. Still, I could care less, because it is
not material to my response.

If I say that a rough sawn 6 X 12 inch measures 6 X 12 inch, (duh)
and provide the Code approved results for such a beam, given the
Youngs and stress limit I specify, then I have provided an engineering
calculation which is explicitly correct.

If you wish to say that your planed, finished beams are 5 1/2 X 11
1/4 that's just fine by me too. And your figures may be accurate for
these dimensions. Or not. I haven't checked.

Wouldn't it be better to ask the questioner what are the ACTUAL
dimensions of the beam he has in mind, rather than playing "I'm
smarter than you"?
[People don't usually win these games with me, Rob!]
:-)

Sincerely

Brian Whatcott Altus, OK

Brian,

/// For 0.1" deflection and an E of 1.5, the
moment of inertia of your wood section is 856 in4 which is the moment of
inertia of a true 6x12 (6"x12") The section modulus of this beam is
144in3. For a 4225ft-lb moment, the bending stress is 352 psi!"

Based on the deflections you gave, the section properties compute to a
"true" 6x12, but your bending stress doesn't even copme close to this
section. You have an error!


Forgive me for seeming to be picky with this illustrious band of
professionals who presumably make a living at getting structures
right, but here are the section properties I used (notice I ran them
two ways, for a cross-check) I lifted then straight out of Archon
Beam.

I did not use a LIMIT load, but as specified I used a specimen load of
200 lb/ft.

What is the conceptual problem with you fellows? Civils can't ALL be
wrong, not all the time! :-)

TRAPEZOID, Bending about CG
d(in) = 12.00
b(in) = 6.000
b1(in) = 6.000
A(in^2) = 72.00
Ix(in^4) = 864.0
Sx(in^3) = 144.0
Rx(in) = 3.464
Cx(in) = 6.000

RECTANGLE, Bending about CG
d(in) = 12.00
b(in) =6.000
A(in^2) = 72.00
Ix(in^4) = 864.0
Sx(in^3) = 144.0
Rx(in) = 3.464
Zx(in^3) = 216.0
Iy(in^4) = 216.0
Sy(in^3) = 72.00
Ry(in) = 1.732
Zy(in^3) = 108.0
Cx(in) = 6.000
Cy(in) = 3.000


So, to summarize: you are absolutely correct as to the timber section
properties I used. AND you are absolutely correct that I did not use
the max permissible load as a specimen load for either the timber, or
the steel section.

So what?

Please try to make the dialog meaningful, The innocent bystanders may
be questioning one's probity.

I certainly am!

Brian Whatcott Altus OK
  #20   Report Post  
Rob Munach
 
Posts: n/a
Default

Brian Whatcott wrote:

On Tue, 22 Mar 2005 11:51:26 GMT, Rob Munach
wrote:


Brian Whatcott wrote:

On Mon, 21 Mar 2005 10:44:00 GMT, Rob Munach
wrote:



A specimen load for a 6X12 in wood beam at 13 feet is 200lb per foot
uniform loading, for which the max deflection is 0.1 inch This has a
safety rating of X2 to failure for reasonable assumptions:
Youngs 1.5E6 psi limit stress 1.2 kips

A steel I beam: W8X15 deflects 0.09 inches for this load,
a W8X13 deflects 0.11 inches.
Youngs 29E6 yield stress 36 ksi

Respectfully

Brian Whatcott Altus, OK

Brian,



You may want to re-check your calcs.

6x12 (assuming 5 1/2 x 11 1/4 - which is larger than the (3)2x12
specified) S = 116


I made explicit my inputs, as to Youngs, limit stress and dimensions
for both the wood beam and the steel beam.
You note that you used commercial "finished" dimensions rather than
gross rough-sawn, and that's a not unreasonable basis for the
difference in your wood beam calcs, I certainly agree.

Respectfully

Brian Whatcott Altus, OK


Actually, Brian, 5 1/2x11 1/4 is the finshed dimensions of a 6x12.



Let me say this again, slowly:

a finished (planed) 6X12 may measure about 5 3/4 X 11 3/4, I believe
depending on its moisture content.
A finished composition of 3 off 2 X 12 may measure about 5 1/4 X 11
3/4,I believe. These figures may or may not represent your
experience, probably not. Still, I could care less, because it is
not material to my response.

If I say that a rough sawn 6 X 12 inch measures 6 X 12 inch, (duh)
and provide the Code approved results for such a beam, given the
Youngs and stress limit I specify, then I have provided an engineering
calculation which is explicitly correct.

If you wish to say that your planed, finished beams are 5 1/2 X 11
1/4 that's just fine by me too. And your figures may be accurate for
these dimensions. Or not. I haven't checked.

Wouldn't it be better to ask the questioner what are the ACTUAL
dimensions of the beam he has in mind, rather than playing "I'm
smarter than you"?
[People don't usually win these games with me, Rob!]
:-)

Sincerely

Brian Whatcott Altus, OK


Brian,

/// For 0.1" deflection and an E of 1.5, the
moment of inertia of your wood section is 856 in4 which is the moment of
inertia of a true 6x12 (6"x12") The section modulus of this beam is
144in3. For a 4225ft-lb moment, the bending stress is 352 psi!"

Based on the deflections you gave, the section properties compute to a
"true" 6x12, but your bending stress doesn't even copme close to this
section. You have an error!



Forgive me for seeming to be picky with this illustrious band of
professionals who presumably make a living at getting structures
right, but here are the section properties I used (notice I ran them
two ways, for a cross-check) I lifted then straight out of Archon
Beam.

I did not use a LIMIT load, but as specified I used a specimen load of
200 lb/ft.

What is the conceptual problem with you fellows? Civils can't ALL be
wrong, not all the time! :-)

TRAPEZOID, Bending about CG
d(in) = 12.00
b(in) = 6.000
b1(in) = 6.000
A(in^2) = 72.00
Ix(in^4) = 864.0
Sx(in^3) = 144.0
Rx(in) = 3.464
Cx(in) = 6.000

RECTANGLE, Bending about CG
d(in) = 12.00
b(in) =6.000
A(in^2) = 72.00
Ix(in^4) = 864.0
Sx(in^3) = 144.0
Rx(in) = 3.464
Zx(in^3) = 216.0
Iy(in^4) = 216.0
Sy(in^3) = 72.00
Ry(in) = 1.732
Zy(in^3) = 108.0
Cx(in) = 6.000
Cy(in) = 3.000


So, to summarize: you are absolutely correct as to the timber section
properties I used. AND you are absolutely correct that I did not use
the max permissible load as a specimen load for either the timber, or
the steel section.

So what?

Please try to make the dialog meaningful, The innocent bystanders may
be questioning one's probity.

I certainly am!

Brian Whatcott Altus OK

Brian,

What is confusing is this paragraph:

uniform loading, for which the max deflection is 0.1 inch This has a
safety rating of X2 to failure for reasonable assumptions:
Youngs 1.5E6 psi limit stress 1.2 kips



The original poster wanted to know a steel beam that was equivalent to
(3)2x12 at 13'. The ONLY way to do this (other than by testing) is to
analytically determine the strength and stiffness of the existing beam
and find a substitute beam whose properties exceed those.

I don't know how a 6x12 or 200 plf even entered into your calculations.
You have proven, however, that you can enter numbers into a computer
program:

Regards,
--
Rob Munach, PE
Excel Engineering
PO Box 1264
Carrboro, NC 27510


  #21   Report Post  
Rob Munach
 
Posts: n/a
Default

Ok, now I see what you did (I think). You put a 6x12 (which is larger
than the beam in question) in your beam program and placed an arbitrary
load of 200 plf on it. You then let it come up with steel beams that had
simlar deflections and were not overstressed.

The problems with this approach are as follows:

1) This will give conservative stiffness results (not necessarily bad)

2) This *may* give you a steel beam that is overstressed as your 200 plf
load may be less than the actual service load. You would have been
better off using the correct section ( three 2x12's ) and a load that
was at the limit stress for this section.


Regards,


--
Rob Munach, PE
Excel Engineering
PO Box 1264
Carrboro, NC 27510
  #22   Report Post  
Brian Whatcott
 
Posts: n/a
Default

On Tue, 22 Mar 2005 13:39:19 GMT, Rob Munach
wrote:

[Days ago, I wrote this - Brian]
A specimen load for a 6X12 in wood beam at 13 feet is 200lb per foot

//
uniform loading, for which the max deflection is 0.1 inch

//

[Rob]
Brian,

What is confusing is this paragraph:
[brian]
uniform loading, for which the max deflection is 0.1 inch This has a
safety rating of X2 to failure for reasonable assumptions:
Youngs 1.5E6 psi limit stress 1.2 kips


Regards,
Rob


Ah, yes: I suspected that this might be the root of the confusion.

1) For any load at all, on any beam at all, there is a place on the
beam that experiences maximal deflection (for that load).

2) For a limit load on a beam, there is a point that shows a maximal
allowable deflection for that beam.

You know that: I know that: and I possibly made it to easy for you to
suppose that the maximal beam deflection of type 1) was referring to a
deflection type 2)

Moreover I suggested that this specimen load might be half of the
load at failure. It probably isn't though, wouldn't you say?

Now for one interesting feature of using beam programs (as every
professional would be well-advised to do

steel beams have pretty uniform parameters, so very much derating is
unnecessary. Wood in contrast, has rather variable parameters and as
an anisotropic material, there are just plain more of them too!

So a program offering wood beams had better provide low-ball values of
important parameters. Nobody will disagree with me on this, I don't
suppose.

Now here's the kicker:
Say we want to replace a wood beam with a steel beam, for strength,
for reduced deflection, or most likely,for reduced depth wasted.

In this situation we DON'T want the low ball safety values, we want
the HIGH ball values for the wood, in order to guarantee the same or
better performance when we match strength or stiffness in steel.

The reason is because the previous (wood) beam may have been a lucky,
strong example at the upper end of the distribution: it is vital not
to degrade values of that rare HIGH end sample.

That has been the other issue: everyone has been so comfortable
with their timber or steel beam program, it was easy to forget that
the brain has to stay engaged, for the safety of the public, whom one
is mandated to keep safe.

This has turned out to be a remarkably civilized thread, in the end.
I salute you all!

Brian Whatcott Altus OK
  #23   Report Post  
Brian Whatcott
 
Posts: n/a
Default

Err...forgive me for harping on the topic, Rob, but it was *I* who
provided the stiffer stronger steel sections.
It was *you* who included two sections that were closer to being
overstressed.

Still, your recommendations below are sound.
The only issue left seems to be the rough-sawn versus finished issue
which I think we have kicked around pretty well.

Regards

Brian Whatcott Altus OK

On Tue, 22 Mar 2005 16:41:53 GMT, Rob Munach
wrote:

Ok, now I see what you did (I think). You put a 6x12 (which is larger
than the beam in question) in your beam program and placed an arbitrary
load of 200 plf on it. You then let it come up with steel beams that had
simlar deflections and were not overstressed.

The problems with this approach are as follows:

1) This will give conservative stiffness results (not necessarily bad)

2) This *may* give you a steel beam that is overstressed as your 200 plf
load may be less than the actual service load. You would have been
better off using the correct section ( three 2x12's ) and a load that
was at the limit stress for this section.


Regards,


  #24   Report Post  
Rob Munach
 
Posts: n/a
Default

Brian Whatcott wrote:

On Tue, 22 Mar 2005 13:39:19 GMT, Rob Munach
wrote:

[Days ago, I wrote this - Brian]

A specimen load for a 6X12 in wood beam at 13 feet is 200lb per foot


//

uniform loading, for which the max deflection is 0.1 inch


//

[Rob]

Brian,

What is confusing is this paragraph:
[brian]

uniform loading, for which the max deflection is 0.1 inch This has a

safety rating of X2 to failure for reasonable assumptions:
Youngs 1.5E6 psi limit stress 1.2 kips



Regards,
Rob



Ah, yes: I suspected that this might be the root of the confusion.

1) For any load at all, on any beam at all, there is a place on the
beam that experiences maximal deflection (for that load).

2) For a limit load on a beam, there is a point that shows a maximal
allowable deflection for that beam.

You know that: I know that: and I possibly made it to easy for you to
suppose that the maximal beam deflection of type 1) was referring to a
deflection type 2)

Moreover I suggested that this specimen load might be half of the
load at failure. It probably isn't though, wouldn't you say?

Now for one interesting feature of using beam programs (as every
professional would be well-advised to do


I use them, however, for simple span beams with uniform or central point
loads, I can calc 'em much faster by hand then using a beam program. I
probably do 20 a day by hand.




steel beams have pretty uniform parameters, so very much derating is
unnecessary. Wood in contrast, has rather variable parameters and as
an anisotropic material, there are just plain more of them too!




True, but if you do this long enough you will have memorized S, E and I
for most of the sections. When I go into the field, I rarely need a
cheat sheet or beam program. I simply use my calculator and my brain.

So a program offering wood beams had better provide low-ball values of
important parameters. Nobody will disagree with me on this, I don't
suppose.


It shouldn't lo-ball anything. It should use the design values set forth
in the NDS. Believe me, not only is there a huge factor of safety in the
material, there is also a huge factor of safety on the loads. It is
rare, if ever, the structure even comes close to seeing its design
gravity live loads. Additonally, there is no accounting for the large
amount of unintended composite action going on in light frame
structures. Although, I am starting to believe that the NDS modulus of
elasticity numbers are high. I am seeing in the field, members that are
deflecting signifcantly more than they should.


Now here's the kicker:
Say we want to replace a wood beam with a steel beam, for strength,
for reduced deflection, or most likely,for reduced depth wasted.

In this situation we DON'T want the low ball safety values, we want
the HIGH ball values for the wood, in order to guarantee the same or
better performance when we match strength or stiffness in steel.


Exactly what you did. While safe and conservative, it won't keep you in
business too long as you will get a reputation for being "too
conservative" However, with all due respect, you probably dont' do a lot
of this type of work anyway.

FWIW, serviceability controls most beams designs in light frame
structures. I have seen plenty of excessively sagged beams, but have
never seen one break.

The reason is because the previous (wood) beam may have been a lucky,
strong example at the upper end of the distribution: it is vital not
to degrade values of that rare HIGH end sample.

That has been the other issue: everyone has been so comfortable
with their timber or steel beam program, it was easy to forget that
the brain has to stay engaged, for the safety of the public, whom one
is mandated to keep safe.

This has turned out to be a remarkably civilized thread, in the end.
I salute you all!


Agreed.

Brian Whatcott Altus OK


Regards.
--
Rob Munach, PE
Excel Engineering
PO Box 1264
Carrboro, NC 27510
  #25   Report Post  
The Good Guy
 
Posts: n/a
Default

Your guys talked a lot about beam strenth. But how do you deal with
longgivity of the beam support? I meanm how do you prevent the rust
on the beams, and particularly the support colummns? The columns rest
of the comcrete pads, and bottom parts are buried under

Before my house was completed in 2000, I noticed the columns rests on
the concrete pads that were submerged under water. There are rusts on
the columns. After I raised the issue, the builder sprayed some black
rustproof stuff on them. I don't think that solves the problem. But I
don't see rust develops on the columns above ground.

Do you suppose to change support columns every a few decades? I now
finished the basment, and all the columns/beams are behind drywalls.




  #26   Report Post  
Bob Morrison
 
Posts: n/a
Default

In a previous post Brian Whatcott says...
Now here's the kicker:
Say we want to replace a wood beam with a steel beam, for strength,
for reduced deflection, or most likely,for reduced depth wasted.

In this situation we DON'T want the low ball safety values, we want
the HIGH ball values for the wood, in order to guarantee the same or
better performance when we match strength or stiffness in steel.

The reason is because the previous (wood) beam may have been a lucky,
strong example at the upper end of the distribution: it is vital not
to degrade values of that rare HIGH end sample.

That has been the other issue: everyone has been so comfortable
with their timber or steel beam program, it was easy to forget that
the brain has to stay engaged, for the safety of the public, whom one
is mandated to keep safe.

This has turned out to be a remarkably civilized thread, in the end.
I salute you all!


Brian:

Here's how I approach this situation if I am unable to determine the
anticipated service loads, but want to have the "new" section at least
as strong and as stiff as the existing section:

1) computer section properties for existing section
2) Using NDS (assumes 3-2x12) and allowable design stresses for the
material, compute an allowable bending moment, then use that to compute
an allowable uniform load.
3) Set a defection limit, typically L/360 for live load, but can be
conservatively used for DL+LL. Using section properties, deflection
limit and "E" for the original material compute an allowable uniform
load.
4) Design of new beam is now governed by the both loads.
5) Since the allowable design stress for Douglas Fir is about 1/20 that
of steel and the "E" for Douglas fir is conservatively about 1/20 that
for steel, you can reasonably design the new steel beam for the lower of
the two loads you computed above.

Now for a really interesting problem, let's say you want to take out a
post and increase the span of the 3-2x12 from 13 feet to 18 feet, but
you must leave the 3-2x12 in place. "Flitch" beams are allowed. Do you
compute combined section properties of wood and steel or do you simply
let the steel carry all the load and the wood becomes "filler"? This
problem has a trick in it that I will not divulge.


--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA
  #27   Report Post  
Tony Bryer
 
Posts: n/a
Default

In article t, Bob
Morrison wrote:
Now for a really interesting problem, let's say you want to take
out a post and increase the span of the 3-2x12 from 13 feet to 18
feet, but you must leave the 3-2x12 in place. "Flitch" beams are
allowed. Do you compute combined section properties of wood and
steel or do you simply let the steel carry all the load and the
wood becomes "filler"? This problem has a trick in it that I will
not divulge.


I look forward to the trick. In the meantime we have a page on the
approach to flitch beam design we use in our UK SuperBeam program at
http://www.sda.co.uk/info/sbw/flitch.htm.

One of the crunch things in your question is that the steel plating
to an existing beam will do nothing unless you jack the timbers first
to remove the load they are carrying.

--
Tony Bryer SDA UK 'Software to build on' http://www.superbeam.com

  #28   Report Post  
Bob Morrison
 
Posts: n/a
Default

In a previous post Tony Bryer says...
One of the crunch things in your question is that the steel plating
to an existing beam will do nothing unless you jack the timbers first
to remove the load they are carrying.


Tony:

That certainly would help and would be considered good construction
practice. However, if you apply the steel plates BEFORE you take out
the post then loads will transfer to the steel plates.

BTW, I will post the "trick" part of the question later today.


--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA
  #29   Report Post  
Rob Munach
 
Posts: n/a
Default

Bob Morrison wrote:

In a previous post Tony Bryer says...

One of the crunch things in your question is that the steel plating
to an existing beam will do nothing unless you jack the timbers first
to remove the load they are carrying.



Tony:

That certainly would help and would be considered good construction
practice. However, if you apply the steel plates BEFORE you take out
the post then loads will transfer to the steel plates.

BTW, I will post the "trick" part of the question later today.


If you want to real tricky, you can overjack the timbers then even a
larger percentage of the load will be transferred to the steel. *May* be
helpful if the wood fiber stress is controlling your flitch.

--
Rob Munach, PE
Excel Engineering
PO Box 1264
Carrboro, NC 27510
  #30   Report Post  
Tony Bryer
 
Posts: n/a
Default

In article
, Rob
Munach wrote:
If you want to real tricky, you can overjack the timbers then even
a larger percentage of the load will be transferred to the steel.
*May* be helpful if the wood fiber stress is controlling your
flitch.


The latest structural innovation - a prestressed flitch beam!

--
Tony Bryer SDA UK 'Software to build on' http://www.superbeam.com



  #31   Report Post  
Brian Whatcott
 
Posts: n/a
Default

On Wed, 23 Mar 2005 12:27:36 GMT, Tony Bryer
wrote:

In article t, Bob
Morrison wrote:
Now for a really interesting problem, let's say you want to take
out a post and increase the span of the 3-2x12 from 13 feet to 18
feet, but you must leave the 3-2x12 in place. "Flitch" beams are
allowed. Do you compute combined section properties of wood and
steel or do you simply let the steel carry all the load and the
wood becomes "filler"? This problem has a trick in it that I will
not divulge.


I look forward to the trick. In the meantime we have a page on the
approach to flitch beam design we use in our UK SuperBeam program at
http://www.sda.co.uk/info/sbw/flitch.htm.

One of the crunch things in your question is that the steel plating
to an existing beam will do nothing unless you jack the timbers first
to remove the load they are carrying.



I am not exactly enthused about the timber beam application code
approach to flitch plates. Seems like an inefficient use of material
to sandwich a verical plate between two wood beams.

I think it might be worth considering "flange doublers" top and bottom
- which is an aircraft main spar approach. Leave the timber as shear
and anti buckle and apply steel strips top n bottom of each side,
bolted through I haven't worked the numbers, it's true.

Brian Whatcott Altus, OK
  #32   Report Post  
Tony Bryer
 
Posts: n/a
Default

In article , Brian
Whatcott wrote:
I am not exactly enthused about the timber beam application code
approach to flitch plates. Seems like an inefficient use of
material to sandwich a verical plate between two wood beams.


It's not very efficient, but in certain cases is preferred by
contractors as being more buildable. In the UK loft (attic)
conversions are a favourite way of creating more space which
generally means having to introduce new beams to support the new
floor and existing roof sans struts and purlins. The options are
basically (a) full length steel beams craned in by mobile crane -
not always possible if there are trees or overhead wires; (b) steel
beam with splices - high fabrication costs + space taken by splice;
or (c) a flitch beam, the plate part of which is generally much
lighter than a steel would be. In this context the flanking timbers
make it fixing joist hangers and providing fire resistance much
easier

--
Tony Bryer SDA UK 'Software to build on'
http://www.superbeam.com

  #33   Report Post  
Rob Munach
 
Posts: n/a
Default




I am not exactly enthused about the timber beam application code
approach to flitch plates. Seems like an inefficient use of material
to sandwich a verical plate between two wood beams.

I think it might be worth considering "flange doublers" top and bottom
- which is an aircraft main spar approach. Leave the timber as shear
and anti buckle and apply steel strips top n bottom of each side,
bolted through I haven't worked the numbers, it's true.

Brian Whatcott Altus, OK

Ideally - Yes. However, practically, there would be alot more holes to
drill - which is usually 50% of the steel cost. Additonally, your holes
would be fairly close to the edge of the wood member unless large pieces
of steel were used at which point, you might as well use standard
vertical plate. I imagine, also, if you worked out the numbers, you
would need alot of bolts Most of my clients prefer to use I-beams
anyway instead of flitches as do I. They buy blank pieces of steel and
ramset the top nailer on. It is a lot cheaper than the flitch -
especially for large loads. Additionally, 8" I-beams work nicely as
flush beams in 2x10 floor systems. Pocket the joists into the web, block
between the joists and shoot a nailer on top - quick and easy and at
least 1/2 the cost of a flitch and alot lighter as well.

Regards,

--
Rob Munach, PE
Excel Engineering
PO Box 1264
Carrboro, NC 27510
  #34   Report Post  
Bob Morrison
 
Posts: n/a
Default

In a previous post Bob Morrison says...
BTW, I will post the "trick" part of the question later today.



Okay gang here's the question I posed the other day:

Now for a really interesting problem, let's say you want to take out a
post and increase the span of the 3-2x12 from 13 feet to 18 feet, but
you must leave the 3-2x12 in place. "Flitch" beams are allowed. Do you
compute combined section properties of wood and steel or do you simply
let the steel carry all the load and the wood becomes "filler"? This
problem has a trick in it that I will not divulge.



The "trick" in the question is that nearly all wood beams are split over
posts making them simple spans. If you want to move the post to
increase the span then you must take in account that there is no moment
transfer at the existing post location. The easiest way to do this is
to ignore the contribution from the wood for section modulus and moment
of inertia UNLESS you want to get into a complex shear transfer analysis
for those parts of the beam located away from the existing support. In
most residential projects this is simply not feasible (and I doubt in
most commercial jobs either).

So, the short answer is to design the "flitch" beam in such a way that
the steel carries all the load for bending and deflection and the wood
is simply "filler". It is a different matter when one gets to the
supports. The wood may be used as long as allowable shear and bearing
stresses are not exceeded.

Here's another way of looking at it: If the wood has an E of 1.8x10^6
and you do a section transform to steel for your "composite" beam, then
a 6x (5-1/2" wide) will have a transformed width of 0.34". In other
words your 6x suddenly becomes a very small part of the beam and can
safely be ignored.



--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA
  #35   Report Post  
Bob Morrison
 
Posts: n/a
Default

In a previous post Brian Whatcott says...
I am not exactly enthused about the timber beam application code
approach to flitch plates. Seems like an inefficient use of material
to sandwich a verical plate between two wood beams.


Brian:

You are correct when you say "flitched" beams are not very efficient,
but it is generally the labor involved in building them that makes this
so. The wood side members allow easier attachment of wood framing at
right angles to the "flitch", which was important before joist hangers
became common. "Flitch" beams were commonly used on the east coast
where steel was easy to get and large timbers were not.

Out here on the west coast large timber have almost always been easier
to get than steel, so "flitched" beams are not very common, except when
needing to retrofit an existing structure.

In our example case of moving a post (or more commonly removing a post
and doubling the span), there is often a lot of other stuff already
attached to the existing wood beam. It becomes more practical to add
steel to the sides of the wood than to remove it entirely. I cannot
think of a case where I would design a "flitched" beam for new
construction, but would instead go with either all wood or all steel.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA


  #36   Report Post  
BobK207
 
Posts: n/a
Default

Rob-

you wrote:

Although, I am starting to believe that the NDS modulus of
elasticity numbers are high. I am seeing in the field, members that are
deflecting signifcantly more than they should.

I'm glad I'm not the only one questioning those number; they seem a
little high.
Maybe the "poor" deflect behavior is due to lower grade timbers being
wrongly upgraded? Modulus is a strong function (at least I was told)
of density (ring spacing), maybe the currecnt timber is just grown too
fast?

cheers
Bob

  #37   Report Post  
Bob Morrison
 
Posts: n/a
Default

In a previous post BobK207 says...
I'm glad I'm not the only one questioning those number; they seem a
little high.
Maybe the "poor" deflect behavior is due to lower grade timbers being
wrongly upgraded? Modulus is a strong function (at least I was told)
of density (ring spacing), maybe the currecnt timber is just grown too
fast?


Bob:

I think you are also seeing the effect of long term creep due to the
wider ring spacing. It might be prudent to use higher than required DL
deflection limits, or perhaps take a look at deflections using something
like 1.5DL for service loads to account for the long term creep effects.

This would be similar in methodology to that used in concrete design.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA
  #38   Report Post  
Doug Miller
 
Posts: n/a
Default

In article .com, "BobK207" wrote:

Maybe the "poor" deflect behavior is due to lower grade timbers being
wrongly upgraded?


If structural timber is graded similarly to furniture-grade timber... there's
little doubt in my mind that this explanation is correct. All the time, I see
furniture lumber being sold as "FAS" that should have been graded #1COM. It's
also not unusual to see lumber sold as "#1 COM" that doesn't even meet minimum
standards for #2 COM, and should have been graded #3.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?
  #39   Report Post  
Rob Munach
 
Posts: n/a
Default

BobK207 wrote:
Rob-

you wrote:

Although, I am starting to believe that the NDS modulus of
elasticity numbers are high. I am seeing in the field, members that are
deflecting signifcantly more than they should.

I'm glad I'm not the only one questioning those number; they seem a
little high.
Maybe the "poor" deflect behavior is due to lower grade timbers being
wrongly upgraded? Modulus is a strong function (at least I was told)
of density (ring spacing), maybe the currecnt timber is just grown too
fast?

cheers
Bob

I agree. It most likely has to due with the fast growth timber. I even
see this in LVL beams. I got a complaint from a customer last year that
his 9' span garage door header that I designed was sagging. It was a 3
1/2x14 LVL with a computed dead load deflection of less than 1/8". It
was sagging 3/8" before the sheetrock even got installed. The
manufacturer inspected it and did nothing about it. We ended up
sistering it with a piece of steel as he did not want to pursue it.
Typically, in my designs, I won't even come close to code allowed
deflections. It doesn't cost much to go up 2" or 4" on an LVL, but you
get a significantly stiffer beam and no call backs.

--
Rob Munach, PE
Excel Engineering
PO Box 1264
Carrboro, NC 27510
  #40   Report Post  
Bob Morrison
 
Posts: n/a
Default

In a previous post Rob Munach says...
Typically, in my designs, I won't even come close to code allowed
deflections. It doesn't cost much to go up 2" or 4" on an LVL, but you
get a significantly stiffer beam and no call backs.


And particularly important when the beam is a window or door header!

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
dry wall question? Joe B. Home Repair 7 December 10th 04 02:35 AM
Wall heater thermostat question... Speedy Jim Home Repair 3 December 10th 04 01:49 AM
Removal of supporting wall raden UK diy 2 August 30th 04 02:57 AM
HELP: vertical foundation crack in new construction Zhixin Tang Home Repair 46 October 26th 03 02:53 PM
HELP: vertical foundation crack in new construction Zhixin Tang Home Ownership 25 October 26th 03 02:53 PM


All times are GMT +1. The time now is 03:10 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"