"Leon Fisk" wrote in message ...

On Tue, 23 Mar 2021 09:19:51 -0400
"Jim Wilkins" wrote:

If welding plates on the outside of the channel flanges to thicken and
strengthen them at the central splice is technically (if not economically)
sound, they provide much more thread engagement for splice plate bolts in
tapped holes, that don't interfere with the trolley wheels rolling on the
lower flange.

All the examples I've found of bolted beam splices accept the loss of net
flange area at the bolt holes and instead suggest locating the splices away
from the most heavily stressed parts of the beam.

A patent here that uses wedges or teeth on plates and beams that would
transfer stress over a broader area:

https://patents.google.com/patent/US20030129026A1/en

Maybe poke around in the patents for a bit, give you some more ideas to
work with...

--
Leon Fisk
Grand Rapids MI

-----------------------------------------

From my reading it appears that a properly designed, prepared and torqued
slip-critical splice joint is as strong as the undrilled flanges, due to
friction around the bolts. One suggested preparation is to wire brush the
loose rust off by hand, but not with a power brush which makes the surfaces
too smooth.

I expect to have to customize the bolts to ensue their shear planes pass
through the full shank diameter, IOW extend the threads up a longer shank
and cut the bolt short, so I want them and their tapped holes reuseable and
won't tighten them anywhere near the yield point. Also the rust inhibitor I
use on outdoor steel and galvy dries to a soft wax that works fairly well as
a high pressure lubricant. The splice will have to depend on bolt shear and
bearing.

That grooved pattern is used to locate top jaws for lathe chucks. I've
considered other proven interlocking patterns such as the Christmas tree
that retains turbine blades and the doll's head on double shotguns. I don't
have CNC and doubt I could mill them accurately enough to share the load and
keep the splice from sagging. However I can custom-fit bolts tightly enough
to keep the joint snug and straight, as on my 3" gantry and sawmill's track.

I think I could make and weld on a multi-leaf knuckle joint (pinned hinge)
though its height would require a custom lowered bar between the trolley
side plates.

Incidentally, while researching bolt and rivet patterns I found that Titanic
was joined with strong steel rivets in the center but softer hand-set
wrought iron ones at the end where the hydraulic riveter wouldn't fit:
https://www.gjenvick.com/OceanTravel...gTheHulls.html

There is survivor testimony and sonar evidence that the hull plate seam(s)
opened from near the bow to all the way back to the forward coal bunker in
boiler room 5, half way between the first and second funnels, and possibly
into the piping space below the floor in boiler room 4 behind it, at the
base of the second funnel. A gap that long that averages the width of a
finger would account for the rate of flooding. Such extensive hull breaches
flood modern passenger ships, namely the Costa Concordia and Mikhail
Lermontov. (DUH!)

Britannic, the last of the trio, was modified during construction to cure
Titanic's flaws. Nevertheless, during WW1 she hit a mine, was damaged in the
same places, and sank twice as fast.

Olympic, the first, survived two of the normally expected ship-to-ship
collisions, smacking into huge immobile white icebergs being either very
rare or a cause of mysterious unexplained all-hands losses. The second was
with an attacking U-boat that slid under the hull into the propellers,
though some of its crew lived. Olympic was dinged but didn't leak and
remained in service well into the Depression.