Monday, May 30, 2011

Rigger or Rigor ?

Snack or a meal ? It depends on how much you want to learn. I found that out as I began to explore and assemble for the Gin Pole and winch set ups that will be used to raise each assembled lattice bridge truss to vertical. Earlier in the project using what we learned about rough sawn lumber and calculating Board Footage we determined the weight of each truss as being 5,700 pounds. From Milton's book we saw how Gin Poles and winches were rigged and used to handle this kind of weight and raise a bridge truss to vertical by hand.  Alex and I tested this out using the 3/8 scale model shown in the pictures below.

There is some rigging at the top of the Gin Pole too but for now I will just be talking about the winch at the bottom.
After considerable comparison winch shopping I decided on a nice 2000 pound capacity geared winch with 25 feet of 3/16" wire rope (wire rope - sounds like an oxymoron to me). The wire rope was packaged separate and needed to be attached to the drum of the winch. Simple enough, right? Right off the bat I could see there were two small holes and one larger hole in the flange of the drum. Humm? I thought and then for all the "right reasons" picked a small hole and passed the cable through it to the clamp on the side (see picture below). This required considerable maneuvering to make the bend and hold the clamp and screw so the nut could be tightened clamping the wire rope securely. After several tries I got it!

Then I looked at the routing of wire rope and how it would be wound on the drum (see picture above). They say there is nothing scarier than the shadow of a doubt. The more I looked the more I wondered. Did I have it wrong? There is another saying too, "when all else fails look at the instructions." Good idea. Sure enough, ten pages and a pretty good picture showing the wire rope threaded in the larger hole and then there was the reference to winding under or over the drum? OK, time to get out the ol' Machinery's Handbook and get more input on the subject. Page 465, "Installing Wire Rope" First it talked about avoiding kinking and how to remove wire rope from a reel vs a coil. Oh, this was good! Then they went into right lay and left lay rope (the helix of the twist just like screw threads). Overwound or underwound on the drum and which drum flange to start winding against! I started out thinking this would be an little educational snack but I soon discovered there was enough new learning here for a seven course meal! I dug in and got more answers to my questions (I also got more questions to my answers!). Even the capacity of the drum. I needed to know if the drum could hold all the wire rope used in the block and tackle set-up to to raise the truss.
ABOVE - With the wire rope routed correctly ( no kinks, right lay, overwound and started against the right flange of the drum) the winding could begin.

The red tape marks the five "dead wraps" that must remain on the spool for anchoring by friction against the drum. The first layer held 7 feet of 3/16" wire rope. The Machinery's Handbook had a nice formula for calculating the capacity of the drum and introduced several new technical terms. Finally I went to the computer and did a Google search on this. Ingersoll-Rand has a great wire rope drum capacity calculator and plenty of info too. Looks like our winch will do the job just fine, with a 1/2" freeboard it will hold 50' of 3/16" wire rope.

Puzzler - What is the Recommended Working Capacity of this winch?

Tech Vocab - Total Drum Storage Capacity, Total Working Drum Capacity, Recommended Working Capacity, Dead Wraps, Freeboard, Barrel diameter, Flange diameter, Drum length, Cable diameter, Fleet Angle,    

Thursday, May 26, 2011

It Takes a Village to...

What has 2 really nice fenced in baseball fields with electronic scoreboards, basketball courts with glass backboards, volleyball courts, a massive kids play facility, trees and flower plantings along a 1/8 mile cement walking pathway, with soon to come shelter house, restrooms, gazebo and 32' Town Lattice Truss covered bridge connecting this recreational park to the local high school? If you guessed the park in the Village of South Wayne you are correct. I am amazed at what the community development group and local volunteers are doing and have accomplished. If you haven't been there here are some pictures. It is something to see and enjoy.

All of this comes from the tireless efforts over the past several years of the committee's and many volunteers involved in the different projects.  Another example effort and community spirit is demonstrated by the work being done by Ace Concrete a local Village of South Wayne business.

Here you can see the work they are doing in forming up the abutments for the South Wayne Bridge Project.
 The picture above shows the view as seen coming from the recreational area looking at the Black Hawk school and track area. When finished this bridge will literally be a connection between the Community and the School.  BHS students Bruce, Alex and other volunteers will be shining examples of how that educating a child and "Whole Village..." thing actually works.

Puzzler - Calculate the number of cubic yards of concrete in the abutments and footing piers. Abutment -  dimensions two at  2' x 4' x 10'     Piers  - 8 at  1' diameter and 4' long.

Tech Vocab - Cement - Concrete - Footing - "Blow-out" - Approach - Cubic yard - Panel Forms

Friday, May 20, 2011

Jigsaw puzzles anyone...

The time and energy spent assembling the 3/8 scale model several times for practice will prove its value later when we are working with the real 20 foot long 2 x 12 chord pieces that make up the lattice trusses for the South Wayne bridge project. 

Here Alex and Lynnan are pinning together chord layers 1 and 2 using two inch long trunnels. After figuring out the numbering and playing card identification system they carefully layed these two layers and will place one shortened trunnel into each group of three holes.

At the top of the picture, behind Alex you can see layers 3 and 4 in their bundles. Very important not to mix them up. 

With the layers 1 and 2 secured the first web layer, layer 3 was put in place and secured with a single trunnel in each end. This trunnel was three layers long.

After a little head scratching and hunting the process was in full swing. Layer 4 in the truss goes on.
The "pile of parts" in the picture above is something I hope we learn to avoid when we do this with pieces that are three times this size. The web pieces they are holding in the picture above will actually be 15 foot long 2 x 10's!). This would be a good time to use those math skills and calculate the board footage ( ( T" x W" x l ' ) / 12)= bd. ft. . Then knowing that KD Pine weighs in at about 2 pounds per bd. ft. find the weight for each web piece. Or you could just guess - 10 - 20 - 30 - 40 - 50  pounds each?  The goal is gain the understanding that packing the layer pieces will be as important as putting them together. It will be another teachable moment.  Oh, did I mention the actual trusses are going to be assembled in place over the waterway at South Wayne! There will be no nice blacktop like this to walk around on.

These guys are good! After just 1.5 hours there progress and what they now understand about the assembly has come a long way. Mention the word Camber to Alex or Lynnan or the process of using shortened trunnels as "drift pins" to assemble the truss layers and they get it!

They ran out of time for the day but I assured them that I would dis-assemble their work, re-bundle the pieces and they would have another opportunity to have some more "serious fun" and try it again. This time finishing the full assembly without any help. They said they were up for the challenge!

Puzzler - What is the difference between the two clamps in the picture below and how are they used in truss assembly?
Tech Vocab - Drifts - Camber - Chord - Web - Trunnels - Vaseline  

Monday, May 16, 2011

Multi-Tasking in today's world...

Here you can see Alex multi-tasking. At work setting up the transit with one hand and communicating with the other!
Gotta love today's youth and their ability to cope. Although this is "old school" technology Alex and his friend, Lynnan a student from the neighboring Shullsburg high school, took right to it. Alex had talked to Lynnan about the work he and Bruce were doing on the South Wayne Bridge Project #4 and she wanted to learn more about it.

The best way to "learn" about bridge building is to just "do it" and that is just what Lynnan did this past Sunday. They went to work setting in place and coming up with ways to anchor the false work. This false work is very important. It will form the working surface for building the bridges 32' long lattice trusses.
This false work will consist of two stringers of 4 x 4's that will be 42' in length, spaced 6' apart. They run parallel to each other. The stringers must be level and supported with cribbing. Across the top of the stringers a series of 12 foot long 4 x 6's will be placed 4' on center. This will form a grid that will support the truss chords and be out of the way for the over 200 clamps that will be used during the assembly of the 6 layers that make up each Town Lattice Truss. The 2 outside truss chords, the 2 lattice webs and the 2 inside truss chords. Very confusing to say the least, but more about this in the next post to come. 

After they layed out and fastened together the stringers they went to work with the transit to level them up. These guys did some impressive work and kept right at it.

Next, since we did not have the 12' long  4 x 6's  yet we had a "brainstorming" session. After the stringers were leveled how would each of us anchor the false work to hold it in place securely so it would not move when jacking against it to put the 4 inches of camber into the bottom and top chords of the truss? Ideas ranged from driving steel fence posts along side of the 4x4 stringers to braces and wooden stakes. We discussed the pros and cons of each and will do some testing when the 4 x 6's arrive. This is all we could do on the false work for now.

They were still interested in working some more so they took on the task of re-assembling the 3/8" = 1" scale model Town Lattice Truss (watch for this in the next post).  I have to say it was another great day of "serious fun".  From working with Bruce and Alex at South Wayne on Roof Rafter layout to Alex and Lynnan on the false work, these guys are impressive!

Many of the 21st Century Skills :
Critical Thinking
Problem Solving
Written & Oral Communications
Global Awareness

that Technical Education courses in high schools strive to achieve are being experienced by these bridge project participants. As a bonus when it is finished they will have a 32'  Town Lattice Truss bridge in South Wayne, WI  to show for it!

Puzzler - So how is the transit leveled?

Tech Vocab - Perpendicular - Adjusting Screws - Spirit Level - Tripod - Camber - False Work - Cribbing

Saturday, May 14, 2011

How much Finish to finish?

Well, as you can see the guys have been hard at work applying finish to the Roof Rafter assemblies and Floor Joists. They gave them two coats and it took 5 gallons. What have they been learning?

The finish really sets off the look of the rafters and doing it now before they are installed really is a labor savings. We will be finishing the underside of the roof boards before they are installed. Likewise the lattice trusses will be finished before they are assembled also. 

This step in the process presented a teachable moment for the guys.

We discussed finish coverage per gallon and project cost estimating. Along in the process I have been sharing with them the costs of materials going into this project. They understand and appreciate that this finish sells for $25 per gallon. In reading the label they found out the coverage listed as a range of 250 to 350 sq. ft. per gallon depending on surface texture. The question I put to them was could they "apply" what they have been taught in school to "learn" from their "actual experience" what the real sq. ft. coverage per gallon is for this project material? Then taking it a step further calculate with a degree of certainty the number of gallons that will be required for the entire bridge? My early estimate called for a total of 16 gallons. That is not considering the change in the roof covering. Will that be close?

They were up for it!  Easy answers, "a lot" and wild guesses "30 gallons" filled the air. As I pulled out my note pad, pencil and calculator you could see their body language change. They knew I meant business and the "serious fun" was about to begin. In the picture they are sitting on the 3" x 6" x 10' long floor joists. We started with these. They were like Deer in the headlights but we plowed forward.

The number of square feet of surface to be finished for one Floor Joist is.... Make your best guess.
  5  -  10 -  15 - 20 - 25 - 30 - 35 - 40 - 45 - 50 - 55 - 60 - 65 - 70 - 75 - 80 - 85 - 90 - 95 - 100 Sq. Ft.

The common mistakes were made right off the bat. Calculating volume, not changing the units so they were all the same and dividing by 12 not 144. If you guessed 15 sq. ft. of surface area per Floor Joist you are right! You have it made! You have a "gift" and for you coming up with the total number of square feet of surface area for the 6 Roof Truss Assemblies and 10 Floor Joists in the picture will be a snap. For the rest of us mere mortals some pencil and calculator work will be needed.

If you want to "play" along here are the numbers will need to know, or what's your guess?
400 - 425 - 450 - 475 - 500 - 525 - 550 - 575 - 600 - 625 - 650 - 675 - 700 - Sq. Ft. area total.

10 - Floor Joists - 3" x 6" - 10'
12 - Primary Rafters - 2" x 6" - 9'
12 - Secondary Rafters - 2" x 6" - 7'
12 - Collar Ties - 1" x 6" x 4'
6 - Cross Ties - 2" x 8" x 11'-6" (just had to do it :-)

If you calculated 579 total Sq. Ft of area we agree.  Note: Building this calculation into the spreadsheet would be a great application for the business students.

So applying two coats on rough sawn material they are getting about 116 Sq. Ft coverage per gallon.

Puzzler - In the original estimate I called for 16 gallons of finish for the entire bridge. Could you figure out what the actual number of gallons needed will be?

Tech Vocab - Perimeter - Area - Coverage

Sunday, May 8, 2011

Communication Questions ?

In the mid 80's I worked in industry. Colman Motor Products made sub-fractional DC electric motors and gear heads. From armature winding to hobbing helical gears, we went from raw stock to finished product.  The head engineer taught me the #1 problem in manufacturing was, "Communications!" and we made it our mission to communicate with everyone involved in the process. 5W2H (Who, What, Where, When, Why, How, How Much) was the creed and we lived it.

So let me communicate a story to you about the two pieces of wood below.

The South Wayne bridge committee communicated to me that they wanted to change the roofing material from steel to Cedar.  No problem just apply 5W2H, right? I started asking a lot of questions.  A Google search opened my eyes to the complexities of Cedar Roofing and related technical vocabulary.

I learned about, shingles vs shakes. Premium vs #1. Heavy vs medium. Sawn vs hand-split-sawn. Kiln dried vs CCA. 24" vs 18" length. 6d Stainless steel box nails vs hot dipped galvanized.  Under layment vs inter layment. Spaced sheathing vs solid sheathing. On and on it went. I decided I would need some samples of Cedar roofing material to better communicate with the committee. I communicated with a supplier online that offered free samples.
On 4-17-11,  I communicated my order for - 1 Hand-split Cedar Shakes / #1 Heavy 24"x 3/4" / Kiln Dried sample.

They sent me the sample on the right in the picture above. The sample had an ID tag right on it communicating it was just what I ordered.  To me it looked like a sawn Cedar shingle / #1  18"x 1/2" Kiln Dried sample. Along with the sample was a cover letter from the supplier that said, "I know that sometimes seeing a sample raises more questions than it answers." It sure did. These people are the experts, they are in the business. Could I have it wrong?
I communicated to the supplier my confusion and that I thought there was some mistake. For sure the sample was not 24" long or 3/4" thick but then a 2 x4 from the lumber yard is not 2" by 4" either. The shadow of a doubt crept into me mind. I communicated my doubt to the supplier and they said they would send out another sample.

On 4-28-11 UPS brought the second sample, shown on the left. Looked like just what I ordered. However, when I looked at the invoice it called for Hand-Split Cedar Shakes / #1  Heavy  18" x 3/4" / Kiln Dried. This sample was 24" long! At the bottom of the invoice, high lighted in orange, to communicate some special instructions was written, "Please ensure right material is shipped to client."
The supplier was very nice when I communicated back to them my concerns. They said sometimes things get mixed up at the "sample warehouse" but a "real order" comes from the actual manufacturer and would be correct.  I communicated that I would like to try a third time get a free sample. This time a 24"  Sawn Cedar Ridge Cap (they come in 18" and 24"). They communicated that they would send it out.

Their cover letter communicated, "I know that sometimes seeing a sample raises more questions that it answers." and it did just that !

Making the 3/8 scale model  Roof Truss will take a lot of communications. Seeing the sample rafter and going through the process of making one will hopefully raise more questions. Questions are a great thing and the more Alex and Bruce ask the more they will learn.

Now we'll give it a try.

Tech Vocab - Run, Rise, Pitch, Center line, Blade Clips, Plumb Cut, Seat Cut, Birds Mouth, Primary Rafter , Secondary Rafter, Collar Tie, Cross Brace, Lateral Braces

Wednesday, May 4, 2011

Before and After...

It was a nice day Sunday and Alex made the best of it. We got more material to work with.

Nice load of green, rough sawn pine 1x6's and 2x6's 
Alex and Bruce know what it takes to turn a pile of material like this into the Roof Trusses and Lateral Braces for a bridge. Better yet, they can do it! Later I will be having the guys do some reverse engineering when they make a 3/8 scale model of one of these roof rafters using the framing square.

Alex also took a turn at rigging the second Lifting Yoke and Ginpole on the 3/8 scale model. Tricky business, but now he understands more about the thinking that goes into a major project like this.

Puzzler - How long of a Ginpole will be needed? How long of a rope will be needed to rig the Ginpoles?

Tech Vocab - Cleat and Seat - Knee Brace