|
The Plan
|
| (a) Shoe |
(d) Handrail uprights |
| (b) Arch beam |
(e) Handrail arch frame |
| (c) Decking boards |
(f) Handrail capping board |
|
|
 click to enlarge
|
Making the template for the arch
To make the arch template, 3 stakes will need to be firmly hammered into the
ground and braced opposing the bending force.(see picture).
Space the stakes as per the dimensions shown in the accompanying picture.
The arch beams the are made by bending and gluing and screwing four lengths of 100x25 (1x4) treated pine together.
When the glue is dry (the next day) this newly made laminated arch beam can be cut down the middle (lengthwise) to create two
arch beams for the base of the bridge. (See section "cutting the arch boards")
The arch handrail is made the same way, using the same template.
|
 click to enlarge
|
Making the laminated arch beam
Bend a piece of 100x25 (1x4) knot free board, 2400mm (8ft) long, between the arch template pegs. Bend a second board against the first putting a generous amount of glue between the two boards. Repeat this action until four boards are in place forming the arch.
Clamp the boards together and also screw along the arch approx every 300mm (12") with 50mm (2") stainless steel screws on both sides.
Ensure the screws are not put along the center line of the arch beam as this line
is to be cut.
|
 click to enlarge
|
Making the laminated handrail arch
Use the same template for the handrail arch as the beam arch (see picture).
Make the laminated handrail arch (on top of the beam arch
which is still lying in place until glue has dried) in the same way as the laminated arch beam, but
use only two 100x25x2700 (1x4x 9ft) boards and not four.
Be careful not to glue the handrail arch to the beam arch.
|
 click to enlarge
|
Cutting the laminated arch boards
Using a power saw, cut the laminated arch boards in half, along the length of
both the beam and the handrail (see picture). This will give you
two laminated arch beams and two laminated
handrail frames.
Trim the arch beams to the dimensions shown
Here click
|
 click to enlarge
|
Making the sides
Cut a length of 100x40x2400 (1 1/2"x 4") treated pine in half (lengthwise) and make 8
handrail uprights at 600mm (2ft) long.
Bolt the handrail uprights to the arch beams so that 4 uprights are spread evenly
along each arch beam and so that each upright is at right angles to the arch beam.
Make a timber washer and glue to the inside of the arch beam (see picture).
Drill and nail the handrail arch frames on top of the uprights. Secure each end with metal strap plates.
|
 click to enlarge
|
The bridge frame
Cut 3 spreaders 100x40x540 (1 1/2"x 4"x 21 1/2"} and fix between the side frames, one in between the middle of the
arch beams and one near each end. Secure with metal strap brace. (see picture).
Nail 3 temporary spacers on top of the handrail arch frame to keep parallel until the decking boards have been nailed on.
Nail and glue the shoes to the underside of the arch beams, one at each end.
Nail a temporary brace from shoe to shoe until the decking boards have been nailed on.
|
 click to enlarge
|
The decking and handrail
Nail the decking boards 100x40x680 (1 1/2"x 4"x 27") onto the arch beams with 90mm (3 1/2") flathead galvanized nails.
Begin at each end and work towards the middle. The final piece will have to be cut to fit and the deck boards will need to be checked (cut) around the handrail uprights.
Trim the ends of the handrail arch frames (at right angles to the end of the arch beam) and bend fix two handrail capping boards 100x25x3000 (1"x 4"x 10ft) to the top of the
handrail arch frames. Secure with glue and m10 (3/8") coach bolts and washers, 4 each side. Countersink the head of the bolts into the capping board.
|
 click to enlarge
|
|
Eazy az. The finished bridge.
|
 click to enlarge
|
The Plan
