Gibbon, Cozad & Western - "The 100th Meridian Line"

[Bsklarski]

You dont touch a truss, "engineer drawing" or not, I dont care of you have 4,001 PHDs on whatever. You DESIGN and BUILD a truss with a opening for a door. Cut that and you condemn the whole structure and cannot occupy it.

[Specter3]

I am pretty sure two or three HD capable PTZ cams and a 60 inch LCD to watch them on would be cheaper and far less damaging to the building. Im not in the industry but I too woukd never cut a truss like that when you have spelled out how thin the margins are in all areas of the building.

[C855B]

OK... getting mostly academic here, there's a way to do it (i.e., cut the bottom chord) without inviting disaster. What it requires is a fully-bearing support column from the peak of the roof/truss structure all the way down to the ground. This way you are converting the truss to what is essentially a braced rafter, neutralizing the tension on the bottom chord. In theory it would strengthen the structure, since as it currently stands it's mostly a big, flexing box. My builder commented that what I've already done with the wall under that truss substantially improved things.

This is how it's frequently done in structures with vaulted ceilings. It would help to have a collar beam between rafter centers to prevent any tendency to sag since the horizontal loads then are in compression. In my particular example this collar beam would be right around the top of the door frame.

I gave thought to this option several months ago and dismissed it in favor of redirecting truss tension forces around the door frame. Seeing that doing so makes me (and most of you) pretty uncomfortable, I'm going to devote my remaining 5% consideration of the balcony project to the idea of putting in a center support column. The biggest challenge there becomes pre-loading the column to bear the roof load, versus simply putting it in "as tight as we can" and let the creaks, cracks and groans happen when cutting the chord and the roof settles about an inch or so as it transfers the load.

[C855B]

Just got back from a work session. Nope... no column. Yes, it's doable, but would look like the hack it would be unless I reworked a fair amount of finished stuff. No thanks.

In grand review, the "balcony" is simply not going to work where it is currently located for multiple reasons. I will mull it over tonight and while errand-running tomorrow, but unless there is some great epiphany between now and then, it is going to come down in its present configuration.

Speaking of work session, the sub-grid for supporting the grid ceiling is going up:



That bit of insulation on the left needs its second layer before we can start the drywall up at the top rim, to receive the wall angles for the grid. Maybe tomorrow afternoon, or maybe after I delete the balcony.

[Mike C]

   Yea , the bottom of the truss is under tension , so cutting it would not be a good thing . I was going to suggest the column idea also , but using a column on both sides of the door with a large header and incorperating the diagionals wearever they hit the columns .  But it would still be a Hillbilly engineering project .  You're probably better off leaving the truss alone .

[SSW7771]

Just my two cents  ...

I agree with Mike C in addition to the column in the middle, you should put columns on either side of the door as well. However, to be on the safe side I would have a local consulting engineer review and signoff on the modification. This will also keep you in good graces with the building inspector, but also the insurance company should anything ever happen.

[C855B]

No worries, I'm abandoning the idea of going through the truss. I spent some quality time in the rafters this afternoon and muttered something like "What in the hell were you thinking?". This was especially after doing additional research on loading specs for this type of pre-manufactured truss and discovering how marginal they are to start out with. Live loading of the bottom chord of zero? Yikes. The center column approach was the only possible workable solution - again, neutralizing the truss's structural contribution - and it didn't solve the other issues with the balcony location.

Current working thought is a modest deck at roughly the 6' level, creating a soffit above the portions of the layout along the west wall. Something similar was in the game plan up until I was distracted by the cantilevered balcony idea. The lower deck height would also avoid the nagging issues with ceiling clearance and interference with the suspended lighting. I may still nix the whole deck idea.

One thing that has entered my mind is a crow's nest in the center, something I believe I saw in published pictures of a high-profile layout. It would certainly work in the nearly-square space. It was more of an operators' or dispatchers' perch than anything else. This would take a partial redesign of the layout. If I'm doing it for myself and crew, then possibly maybe, but the deck is still more visitor-friendly.

[marklin-au]

  Just a comment  from  down under.  I also have been  following this adventure for the last 12 months or so and from what you started with & what you are now almost finished is amazing .Even down here in Oz  we have similar building codes  maybe even stricter than yours & cutting  thru a bottom bearer of a truss is a  unforgivable sin . I have visited  the Greeley museum & climbed the viewing platform only  this  year . Yes a  nice view  but a  bit of a gimmick , I have seen many exhibition layouts both in USA   &  a lot in Europe & don't think I have come across many overhead platforms  except for Miniature Wonderland in Hamburg  De. Even there I think there is only 1 small one  & that is on the Swiss section of that awesome place  where we spent 2 full days exploring what was on view including a behind the scenes  tour. If I could throw something in I would recommend a below stage area  which is visible in various places  rather than a sky view .

Very interested in the lighting aspects of the layout as I  worked as a stage electrician in many Sydney live theatres  during my early 20's to  help with a house deposit  in between  fitting in my full time job as a Telephone Tech on Pabxs .
I cant wait to see what you will eventually install & the effects produced .
 Keep up the  good work & congratulate your dear wife  with the work she has produced along with all the problems  which have  been surmountable .


Cheers   Tom in OZ   & merry Xmas to all.

[C855B]

Thanks, Tom! And many thanks to all who've dispensed their two cents' worth of sanity check. To that end:

For Sale: Complete N Scale Layout Observation Balcony Kit

Unboxed, assembled, then disassembled. Never run. Complete with hardware; some wear on fasteners. Price negotiable, but buyer responsible for shipping.



Handy assembly tool included.

[x600]

Ah...would you be willing to sell some of the parts separately?
 

Greg O.

[GaryHinshaw]

Can you use your scissor lift as a mobile obs platform?   

[C855B]

Nyuk nyuk. The lift is going away after the building stuff is done. I do believe I've mentioned how clumsy it is, and it's not going to get anywhere within 100' of the BLMA bridges.   (It will likely have a home with the local tool rental store, where it can run free. Or at least reasonable.)

[MRLX1020]

Nyuk nyuk. The lift is going away after the building stuff is done. I do believe I've mentioned how clumsy it is, and it's not going to get anywhere within 100' of the BLMA bridges.   (It will likely have a home with the local tool rental store, where it can run free. Or at least reasonable.)

I can see your lift out frolicking through the fields around Centralia after you're done with it.  Sorry - funny mental image, had to share...

[C855B]

I can see your lift out frolicking through the fields around Centralia after you're done with it.  Sorry - funny mental image, had to share...

Maybe. I'm visualizing it bouncing around in the field behind the Rec Center, doing its best to retrace the trail left when they dragged the caboose over to the museum.

Minor progress, but it's sort of a cross between a milestone and the first step of another thousand-mile journey:



This is a "dimmer pack". The significance is this is our very first installed bit of theater lighting electronics, so is another light-at-end-of-tunnel item. A dimmer pack is an electronically-controlled cluster of light dimmers, in this case controlling four circuits. This one will control four rows of white spots and fill lights, for the west half of the layout. Another will take care of the east half.

Further significance is the Unistrut, which gets past a serious mental block I was fighting on the lighting system structural support. The design work for this was being seriously obfuscated by the whole balcony issue and the cascading impacts it had on the ceiling-related engineering around it. With that out of the way the last of the electric support can be run, which includes conduit for four circuits attached to this strut and its mirrored pair on the east half.

Work will cease for the next few days as our college kid whisks in and out of town for a holiday-ish "Hi!/Bye!". Since he's a music major he has Christmas-related performance commitments and has to be back at school on the 23rd. If he could have stayed for a couple of weeks there would have been a chance of making headway on the drywall. Rats!

[C855B]

Aaaaaaaaand... progress comes to a screeching halt.

I am "off" of heavy work/lifting for the next six weeks. The circumstances have to be shared because of the irony. It's funny. I tore my right oblique this afternoon... now get this... lifting a railroad tie. A 1:1 railroad tie. For the layout building hardscaping. Can't tell you what railroad it came from, all I can tell you is that it was heavy, and that the muscle tear f------ hurts. Crap.

I might tinker with the electrical if I can make headway without big lifting, but I doubt there will be much to report until February.