The Covered Bridge over the New Dam was actually an afterthought during the time of the dam construction to replace the galvanized handrailings shown in the engineering drawings. Volunteer Peter Sporring came up with suggestion and design and many thanks to Bryan Keene of Quinte Conservation for providing the finished architechtural drawings for this project. All of the structural elements were prefabbed at Peter's workshop on Jones Road.
March 23, 2012. (photos by Peter Sporring)
On this day,Volunteers Peter and Ralph went over to Empey Lumber and picked up two trailer loads of pine timbers and began prefabricating some of the components that will form this building structure. On the following Monday, while we started on prepping the 8x8x8 foot timbers for the main columns, Ralph Precut all of the knee braces and assisted Peter in cutting the tenons on the band mill.
Peter cutting spline mortises in the 8x8 columns. Many thanks to Randy Roels for the use of this tool which will save many hours of work with mallet and chisel.
Ralph cutting knee braces on O'Hara Mill's first newly aquired tool, a 12" DeWalt cutoff saw. This is our first capital tool expenditure in all the projects we have done and a must for this particular project.
After scoring the the initial depth cuts with a skill saw, trimming off the excess on a band sawmill (above) gave the quickest and most accurate results for making the many tenons that will go into this project.
On March 27, Gerrard Forestell of Madoc TimberMart donated the use of his boom truck and driver to pick up the larger pine timbers from Empey Logs and Lumber and deliver them to the shop yard we had the use of. This is the kind of community effort that makes a large volunteer project like this run smoothly.
Another very handy tool loaned to us by Randy Roels is this timber cart that is making it very easy for us to move these large pine timbers in and out of the shop as we work on them.
Today was mostly rafter prep day. Ralph had previously cut all the rafters to length and now came the job of notching out the "birds mouths" where the finished trusses will sit on the walls. While Ralph made the initial cuts on the chop saw using a jig, Dave completed the cuts with a hand saw. 49 of these were made today with another 49 to go.
Timber Framing Terminology.
For those who may not know what some of the descriptions are of parts being made in the previous and following text, we've included this drawing of one of the twelve 16 foot sections of wall that will form this covered bridge structure. Here are some of the names of parts we are making and their use.
Plates: The bottom plate, or timber in this case, is the horizontal part of the framework that will be bolted to the concrete deck of the dam. The top plate rests on top of the columns and supports the roof trusses.
Columns: The vertical support timber between top and bottom plates. These have Tenons cut out on both ends which fit snuggly into Mortises, or pockets, cut or chiselled into the plates, in this case at 8 foot intervals. Once the parts of a wall section are all dry fitted together and checked for square, a pair of 1" holes are drilled through the plates at each tenon and wooden pegs are driven in to secure the whole assembly.
Knee Brace: These are braces placed at a 45 degree angle at the junctions of plates and columns to provide lateral support.
Spline: A piece of dimention lumber, in this case white oak, used to join two wall sections together at the top plate. Wooden pegs, here again, make the joint secure. (see exploded view below). The bottom plates do not require this treatment as they are bolted to the deck.
All timbers in the wall sections are 8" x 8" white pine. Knee braces are 3" x 6".
Here is an exploded view, on the left, of how two wall sections are connected at the top plates. The spline goes straight through the common column and fits into 4" mortises in the ends of the two top plates. All is locked in place with wooden pegs. The drawing on the right shows the parts of the 49 roof trusses that are being made for this project.
Saturday, March 31.
Dave Notching the last 4 of the 24 columns where the handrails will be fastened.
Rod and Ralph trimming the 49 bottom cords to length for the trusses.
After the mortises were cut in one of the 300 lb bottom plate beams, Ralph maneuvers it onto the band mill, an easy job with the use of Randy's log cart. Due to some inconsistancies in the surface of the concrete surface of the dam, all of these bottom plates have to be trimmed by Peter so that the wall sections will sit level.
Ralph Cutting the "pointy ends" on the 49 king posts for the Trusses.
Dave, Rod and Ralph discuss the day's progress after the tenons had been cut on the last of the 26 columns. At this point we are about 80% complete in making the 400 structural elements that will go into the covered bridge. Not bad for a week's work for four Old Boys!!
Monday, April 2.
Today the mortising of the last 5 of the 16' bottom plates was finished and Ralph, Dave and Rod completed cutting out the last of the rafters and bottom cords. Just as we were to run out of material, Gerrard picked up and made the final delivery of material from Empey Lumber. By end of day most of the structural components have been made. Tomorrow we will finish mortising the 12 16' top plates and the Boys will start assembling the trusses.
All of the material delivered yesterday has been cut up into parts. Six of the 12 top plates have been finished, Rod has sprayed ECO Preservative on most of the timbers, and Ralph and Dave have about half of the roof trusses put together.
All of the roof trusses have now been built and are ready for the ECO Preservative. This is a non toxic spray or brush on application that has been used for many years. It is the preservative of choice used by Parks Canada for all of their signs, picnic tables and out buildings. It turns new wood a nice antique brown within hours, and takes on that silvery gray hue of aged wood within a couple of months.
As Ralph completes the last mortise of the project, Dave fine tunes some of them with mallet and chisel.
Dave trues up the many knee braces with a belt sander after they have been cut to shape on a band saw.
Today Ralph and Rod applied the ECO preservative to the remaining top and bottom plate beams, all of the columns and about one half of the trusses. We had tried a sprayer for doing this but found there far to much waste. So we modified a couple of natural bristle floor brooms and this worked very well.
Ralph, Walt and Dave apply the Eco preservative to the last roof truss.
Assembling the first wall section usng Peter's tractor to force the mortise & tenon joints together.
Dave driving wooden pegs at a mortise and tenon connection.
Ralph drilling for pegs at a spline connection.
Dave and Ralph lift a finished wall section with the overhead gantry in the shop yard. All sections are assembled in the reverse order of the way they are installed. In other words, The last section loaded on the truck for delivery to the dam site will be the first one off and installed. So, we have to constantly be thinking double backwards and upside down when putting these things together. A printed flow chart has been made that coincides with all the labeled parts and sections.
Dave lagging knee braces. At the top right you can see a finished spline connection where two wall sections will fit together. As of Thursday the 26th we have 5 sections completed with 7 to go.
At the end of the day we had 7 wall sections completed. The first six represent the first truckload that will be taken to the Mill and will span the south half of the dam for a length of 48 feet.
Section # 7 going together.
Today Dave and Ralph finished the last two of the 12 wall sections that will span the 96 foot dam. The 216 custom made metal truss gusset plates were picked up and prepped for priming and painting. We are now in the count down stage of raising this building which may occur in the next week if we can track down the building inspector to obtain the permit.
The final touches to the wall sections was drilling all of the bottom plates at four foot increments where the concrete anchor bolts will be installed.
Today at 9am we received our building permit from the Madoc Twp. Inspector and the go ahead to start raising the building on site. As a result, Gerrard Forestal From Madoc TimberMart and boom operator John arrived at noon with two trucks. These were loaded, 6 wall sections per truck and will be stored at TimberMart's yard at Madoc which is only minutes from O'Hara Mill. Our tentative day for raising the bridge structure is Wednesday, May 9th., weather permitting.
Below are some images of the move.
Second truck loaded and both off to TimberMart till Wednesday.
Today we had 7 volunteers show up at the dam site and by noon all of the temporary handrails and the gantry were removed in preparation for installing the wall sections of the covered bridge. Security fencing was installed at both ends to limit public access during construction so the foot bridge will be used for the time being.
May 9th. RAISING DAY.
After spending several weeks putting all these pieces together, it was a real treat to see everything go so smoothly. After the first two sections went up everyone one knew exactly what to do and all went together like a big Leggo set.
1st wall section goes up at 8am
The TimberMart Crew places section 5. Under Gerrard's promptings, Bryan Moorcroft's super fine touch on the hydraulic controls inched the sections vertically down and the horizontally into place like the pieces of a giant jigsaw puzzle.
The Town & Country Construction crew install the first roof truss when the wall raising crew move to the north end. It was a very methodical race to see who would get done first.
Half way there at 11am.
Pegging two wall sections together.
Pulling two wall sections together with a come-along and chain.
Last wall section going into place. 2:15pm.
....The raising crew.
All of the siding goes on in two days. (above)
On May 14th and 15th most of the roofing boards went on. We hope to have the steel pretty well on by end of week.
On May 21st, the north and south ends of the structure were box beamed. Box beaming is an architectural term for partialy framing the ends of an open building and fortiying it with 3/4" plywood with a heavy nailing pattern. This provides conciderable lateral strength to the structure during any high wind event. it also looks pretty nice!!
We are now ready to install the steel roofing which will done the morning of May 23rd, compliments of Peter Danielis and his crew from Town & Country Construction.
At the end of the day, all of the steel roof is finished, the north and south ends have been boxed beamed and sided inside and out and preservative applied. We are now 98% complete with only some finish trim work to do.