Wednesday, August 31, 2011

South Wayne Communtiy Bridge Topped Out !

Well it has been quite a process but Alex and I have finally topped out the South Wayne Community Bridge Project!

Alex did not believe me when I told him of this tradition and how it was necessary to show respect to Mother Nature for all the trees that were harvested to produce this fine bridge, but now he knows and understands. We have finished the gable ends and lookouts to trim out the bridge and give it some style. She's a beauty!

Harry Seffrood, a local South Wayne roofer has offered to install the roof boards and cedar shingles and we welcome the help and community participation to finish off the project. They will be doing the work in the next few weeks. In the mean while we get to clean up and enjoy the structure with the natural lighting streaming in through the open roof. I have included a few pictures of the bridge from different angles for your viewing pleasure. Alex goes back to school tomorrow and I hope this experience gives him plenty to talk about and he can look back upon how he spent part of the summer of 2011. He's a worker (if you can get him to put down his sell phone) :-) !

Well the experience has been as they say "priceless" and I look forward to taking a break for a week or two from bridge building and shift to cutting mitered dovetail joints to help a local fella restore a 150 year old log cabin. Should be some serious fun!

Want to pass on some stats to those of you who have been following this blog and progress of the South Wayne Community Bridge Project.

Can report that there have been over 1600 views of the blog and people from 17 countries have looked at the blog. It has been a pleasure learning, building and blogging about this project. I will continue blogging with the log cabin restoration and then later this fall begin another 32 foot Town Lattice bridge that will go on my own land. It will be on one of the walking paths that lead to the log cabin I built in 2004. Gee this is fun!

Puzzler - What will be next?
Tech Vocab - Topping Out, Look Outs, Gable Ends, Rake End, Fascia, Lateral Bracing

Saturday, August 27, 2011

Doesn't get any better than this...

Raising a Town Lattice bridge truss by hand with good help... priceless! I don't know about other people but I  never get tired of looking down a row of pegs in a cambered truss. Wow!

Very nice raising. All went as planned. Even the weather cooperated!
Again the Gin Poles did their job.
How the simple Gin Poles work is a puzzle to many so I think they deserve two pictures. It is hard to see but the cable is anchored at the top of the pole. Brought down and attached to the top chord of the truss then taken back to the top of the pole and through a fixed pulley. The cable then back to the bottom and attached to the winch. Milton and his son's used 7 of these at one time to raise the 240 foot truss that they built in 1978 - 1979 in  Frankenmouth, Michigan for the Zehnder family. Tomorrow the deck.

Puzzler - Then what and how?
Tech Vocab - Fixed pulley, Movable pulley, First class lever, Second class lever 

Friday, August 26, 2011

Things they never told you in school...

If anyone would have  told me that the hardest part of raising a truss would be getting the Gin Poles stood up I would have listened carefully and asked them what advise they might be able to give me from experience.
Ok so raising a 500 to 600 pound 25 foot pole to be used to raise the truss is the first order of business. First a 4:1 block and tackle was assembled from a collection of hay rope pulleys I had. Then a set of fence stretcher block and tackle stabilizers was added and anchored. You can see from the picture above that 100 feet of hay rope would not do the job. A 15 foot tag line was added. Good math exercise to determine this length. Remember the blocks will only pull for 25 feet of distance.

This was solved by tying on some lead ropes. After all calculations were made to make sure that the block and tackle could make the necessary pull distance to stand the pole the process was begun. All went well until the knot reached the top pulley! RATS!!! It was a nogo. Needed a wide style like I had used in making the block and tackle. The raising would have to wait until tomorrow while I hunted down the correct pulley I needed for the job.

So with the fixed end of the block on the top of the existing truss and anchored to the ground everything was in place. Two men could supply the force to lift the pole. Two men could stabilize the pole during the lift and one man could be the eyes to aim the pole into the lifting yoke. All went as planed and Truss #2 will go up tomorrow. Soon it will start to look like a real bridge.
Puzzler - So what are we looking at in the picture above?

Tech Vocab - Rigging, Anchor, Movable block, 4:1 ratio

Tuesday, August 23, 2011

On to truss #2 ...

Alex suggested that we use a running gear pulled by his prize John Deer tractor to take the parts for truss #2 from the COOP to the bridge site. And that's just what we did. Worked great!
Although it took us most of the morning to re-set the cribs that provide support for truss #2  parts as they are re-assembled. We got a good start and after a morning of rain were able to get the first four layers in place.
Alex has a good grip on the Town Lattice truss re-assembly process and here has laid his first layer of Bottom Outside Chord pieces.
So tomorrow we should finish up driving the rest of the trunnels and then it will be on to raising those pesky Gin Poles. Who would have ever thought raising these would present such a challenge. Great problem solving challenge though.

Puzzler - How would you raise the 25 foot Gin Poles by hand? Any sailboat sailors out there?

Tech Vocab - Running gear, Abutment sizing, Truss bracing placement.

Sunday, August 21, 2011

It takes a Village to raise a truss...

And that is just what we did in the Village of South Wayne, Wisconsin Saturday morning. Putting everything I learned from reading Milton's book and firsthand experience with fellow Timber Frame Guild member Grigg Mullen from VMI we had a successful quiet lift!  Many thanks to the fine helpers and their patience as we jacked, cranked, blocked and leveled the first truss for 2 hours of serious fun!
At the pit meeting I went over safety, the details of the different stations and what would be required at each of them. We began the process.

Handyman jacks were used on the ends to assist the winches with the early phases of the raising.

With the heaviest lifting now done the winches took over.  Keeping a close eye on the camber in the bottom chord these guys compensated for the arch of the camber to support and keep the bottom chord straight as it was rotated. 

And walla! Truss #1 plumbed and braced. Now all we have to do is reset the cribbing on the other side, re-assemble the 2nd truss, rig it and repeat the process again next Saturday. Simple as that. Should make for an interesting week. If you are in the area stop in and visit or give me and Alex a hand.

Puzzler - During the first day of the school year how will Alex answer the age old question, "What did you do over the summer?"
Tech Vocab - Plumb, Brace, Camber arch support

Friday, August 19, 2011

Tomorrow we will be putting our heads together...

in these hard hats and putting everything from Milton's book and helping build the Pratt truss bridge with the Timber Framers Guild for the community of Chester, NH last month. We are ready to raise truss #1 one for the South Wayne Community Bridge project.
After getting the Gin Poles up and in place we had to do some "tweaking" of them to make sure they were in position.

This required some pulling with the come-a-longs pulling them into alignment.
Then Alex and I went to work rigging them for tomorrow. The block, tackle and winch to lift the truss will be aided by two handyman jacks, one at each end of the top chord. The bottom of the Gin Pole is secured from kicking out with a come-along to the bottom chord. Another come-along holds the bottom chord from slipping out during the lift by being tied to an anchor point. Also to this anchor point a block and tackle is attached to the top chord to prevent the raised truss from over turning past vertical. Finally the anchor point is tied back with a stake and ratchet strap. One final detail will be to use the threaded jack posts to support the arch of the camber that is in the bottom chord and keep the bottom chord truss from sagging during the lift.
OK that should do it.

Puzzler - What have we not thought of?
Tech Vocab - Block and Tackle, Come-Along 

Wednesday, August 17, 2011

When "pegs" fly...

The re-assembly of the first truss went very well. Alex and Tom brought the team to three and I think we will be able to re-assemble truss #2 in one day if we get some help hauling the parts from the COOP to the site.

Everyone was fresh and and the pegs really flew. Tom did the support work from below. Alex ran the hammer and I handed him pegs and tried to plan out the placement of the pegs radiating out from the center of the Web and jack or pull the pieces into alignment.

Remembering to grease the holes so that the shorter pins could be easily pushed out as more layers and longer pins were added was tricky but the greaser head tool did the job well.
You can see that a considerable amount of force is needed to drive in the pegs. With each blow the peg goes in 3/4" to 1" but the first driving cap really took a beating and had to be replaced. The dome of the 1.25" pipe cap works nicely to protect the chamfered head of the peg but became concave in the process. I think I will be welding a 1/4" disc of steel to the top and welding it around the circumference. This will help spread out the force of the hammer blows. We'll see how it works on truss #2.
And there you have it.  Pretty as a picture, Town truss #1 for the South Wayne Community Bridge Project re-assembled in place on the abutments and ready for rigging and then raising this Saturday.

Puzzler - How will we safely and easily raise the two 25' electric poles that will be used to raise this truss?

Tech Vocab - Driving Cap, Movable Pulley, Anchor Point, P/Sq In, Lifting Yokes

Tuesday, August 16, 2011

One down 107 to go...?

To paraphrase, Even the longest of Town Truss's begins with a single trunnel!

Monday was a long day. We started off slow but then picked up speed as Alex got his trailer and we loaded on truss number two in Darlington.
 After unloading at the South Wayne site we started laying chord layers one and two on the cribbing.
During the driving of each trunnel we supported the area with a nice adjustable brace leg that I made for this task. Alex questioned my methodology and I gave him the quote from member Mcarthy or Beemer , "perfect is good enough". Stopped him dead in his tracks, he didn't know what to think or say?!
So there you have it. We got the first three layers pinned. A good days work! Can only imagine the possibilities that are ahead for Alex. Remember when during the first days of school people asked you, "Hey, what did you do over the summer...?"

Puzzler - Actually how many individual trunnels will be driven to assemble just one truss? Remember the process of pinning the first two layers with a 4" trunnel and then each following layer with a trunnel 2 inches longer. This is tricky but you will need to know this when you call Judy Northcott and place the trunnel order for your bridge.

Tech Vocab - Layers, Cribbing, Trunnels, Greasing

Sunday, August 14, 2011

Not for the faint of heart...

Oh brother, what a learning experience! Have spent the better part of the past two days thinking, drawing, calculating and setting up the rigging for the raising of the trusses. Once again it looked pretty simple and straight forward, get a couple of electric poles, put some pulleys on them and lift away. Right?  However, like everything else once you get down to the details you better have all your ducks in a row or you will have 1500 pounds of trouble on your hands.
Watching the experienced professionals do it in New Hampshire a few weeks ago was enlightening. I can now appreciate all the work that went into making it look that easy.

Reminds me of the ol' joke, What are the three biggest lies in the world?  #1 The check is in the mail. #2 I am from the government and I am hear to help you. #3 It's easy, it will only take a minute.

Calculating the lengths of everything was a great math application. A drawing however was in order to proof it out. Below you can see the Gin Pole as it will be set against the top chord and then how the pole will end up when the truss has been raised to vertical. Coordinating the placement of the cribbing and clearance for the poles was just as involved as it was with the false work clamp placement and drill clearance!

Above you can see the anchor point. To this will be attached the come-along to keep the bottom chord from kicking out and the block and tackle that will be attached to the top chord to keep the truss from going over center. The short piece of post against the top chord represents the Gin Pole.

Above you can see a 2x3 Oak piece notched into the pole one foot above the bottom to prevent the pole from sinking into the ground. A worm gear 40:1 ratio winch is mounted 2 feet above ground level.

With the wire rope fastened to the top of the pole and a set of pulleys between them the rigging is complete.

The calculations for the life are: The load of the 6000 pound truss in the horizontal will be split between the abutments. 3000 lbs on the abutments and 3000 lbs on the Gin poles. The Gin poles will share this 3000 pound load at 1500 lbs each. The 1500 lbs load on each Gin pole will be carried through pulleys by 3 wire ropes at 500 lbs each. The 40:1 winch ratio will require 12.5 lbs of turning effort. It should go slowly by surly!

Tomorrow we will be taking everything to the sight and begin the truss assembly.

Puzzler - What lengths will be required for each of the following: the Gin Pole, the Wire Rope, and the rope used in the block and tackle as a hold back ?

Tech Vocab - Snatch Block, Come-Along, Block and tackle, Gin Pole, Wire Rope.

Monday, August 1, 2011

Vacation at Wason Pond

Took a break from working on the South Wayne Community Bridge project and flew to Manchester, NH to work on a Timber Frame Guild project. Ten days of serious fun at Wason Pond in Chester NH. There  I got in on the action and some first hand experience helping experienced timber framers build a 25 foot Pratt Truss bridge with the community of Chester folks. Here are some pictures of the process.

If you would like more information just Google   and click on project report   for a day by day blog of the vacation fun we had.

Now it is back to work on South Wayne's bridge. Will be working on the rigging for the raising.

Puzzler - What equipment will be needed to raise the 32' Town Lattice South Wayne truss?
Tach Vocab - Gin Pole, Block and Tackle, Choker Sling, Worm Drive Winch, Bracing, Trunnels, Stakes