Return to index: [Subject] [Thread] [Date] [Author]

RE: Beam info needed

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Unfortunately I was not the one to take the measurements. I briefed them in
advance as to the need to be very exact with the measurements. These are
bridge girders in pony truss bridges. We have no idea how old they are
because they used to be owned by a different level of government and they
were dragged through farmer's fields to their present location. When we
learned this it sure cleared up some questions...for instance, how does the
bottom chord get bent like it has buckled due to compression? This was one
of the points where the chains were wrapped around.
Anyway, I have gone with the 15X37.3 as suggested by Roger T. with the
Sx=54.1 in3. It wasn't the governing factor for load rating anyway. It is
very close to the one suggested by Harold S. The time period is likely the
1930's but I can't be sure within 20 years either way.
thanks


At 01:39 PM 6/15/00 -0400, you wrote:
>Harold (and others):
>
>Did you check page 20 of AISC's Iron and Steel Beams, 1873-1952?
>
>A. Roger Turk, P.E.(Structural)
>Tucson, Arizona
>
>Harold Sprague wrote:
>
>>>David,
>
>If this is from the same family and era, I would be a bit suspicious.  The
>standard beam series only goes up to a maximum flange width of 6.25".  The
>flange width of 6.75" indicates this to be a Bethlehem Beam B series.  The
>closest fit would be with a B15x36.0 with a web thickness of 0.280" and a
>flange thickness of 0.355".  This can be confirmed if you measure the flange
>thickness at the flange gage line at 0.50".
>        B15x36.0
>        Ix = 410.9 in4
>        Sx = 55.12 in3
>        Iy = 21.7 in4
>        Sy = 6.45 in3
>
>How sure are you of the measurements?  It is best to scrape the steel as
>clean as possible removing paint and mill scale in spots and measure with a
>caliper at multiple points along the length of the beam.  I would measure
>the flange thickness at the edge, the flange thickness at the gage line,
>depth, and the web thickness in a few spots.  The web thickness is a bit of
>a challenge to measure with accuracy.  I would venture that it is likely
>that the web thickness measurements have a good probability of being
>generous.
>
>Sounds like a B15x36.0, with a fairly high carbon equivalent,  local
>crystalline lenses through the cross section, cast in Pittsburgh,
>Pennsylvania, 1933, probably the last Wednesday in October, north side of
>the mill, with a shift supervisor named Raul (married with 3 children).
>Sorry.... I just got a little carried away.  Ignore this last paragraph.
>
>Regards,
>Harold Sprague<<
>
David Handy, P.Eng.
dhandy(--nospam--at)trg.ca
The Thompson Rosemount Group, Cornwall, Ont. Canada
Opinions expressed are personal only.