FileFolderA-Truss-construction view - Project Physics Webpage.

clanmurderUrban and Civil

Nov 15, 2013 (3 years and 8 months ago)

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The Design

10 mm x 10 mm Tube

Doubled 4 mm Bar

Doubled 2 mm Bar


Design Requirements:


Span

30 cm


Loading

5 kg

(
at midspan)

We’ll talk about how it was designed later...

Our A
-
Truss Bridge

List of Members

Dimensions



Base x width x length


(1.0 cm x 1.0 cm x 22.5 cm)


(1.0 cm x 1.0 cm x 2.0 cm)


(1.0 cm x 2.0 cm x 6.0 cm)


(1.0 cm x 1.0 cm x 6.0 cm)


(2 mm x 30 cm) Beam


(4 mm x 20 cm) Beam

Quantity



4


2


1


3


4


4

Materials & Equipment


File folders


Yellow carpenter’s glue


Building board (Styrofoam or cork)


Pins


Scissors


Metal ruler
*


Hobby knife or single
-
edge razor blade
*


Rubber cement
*



*Required only for prefabrication of structural members

Prefabrication of Members


Cut out bars


Cut out and assemble tubes


Cut out gusset plates


Trim bars and tubes to length

Gluing Flap
Rubber Cement
Gluing Flap
Rubber Cement
Trim Bars and Tubes to Length

Bottom Chords

(2 per team)

Trim Bars and Tubes to Length

Bottom Chords

(2 per team)

Trim Bars and Tubes to Length

Verticals

(2 per team)

Trim Bars and Tubes to Length

Verticals

(2 per team)

Trim Bars and Tubes to Length

End Posts

(2 per team)

Trim Bars and Tubes to Length

End Posts

(2 per team)

Set up the Building Board


Place the layout drawing on your building board.

Each Team Member:

Set up the Building Board


Place a sheet of plastic wrap over the layout drawing.

Add Gusset Plates


Place Gusset Plate A at its correct location on the layout
drawings.


Hold it in place with two pins.

Add Gusset Plates


Repeat the process for Gusset Plates B, C, and D.

Add Bars


Apply a line of glue along the bottom edge of Gusset Plates
A, B, and C.


Place a 2 mm bar in position as the bottom chord AC.


Stretch tight and hold in place with two pins.

Add Bars


Apply glue to Gusset Plates B and D.


Place a 4 mm bar in position as the vertical member BD.


Stretch tight and hold in place with your fingers.

Each team should now have
two

of these subassemblies


the
lower half

and the
upper half

of one truss.

Add Tubes


Apply glue to Gusset Plates A and D.


Place a 10mm x 10mm tube in position as end post AD.


Hold in place for a minute until the glue sets.

For the
bottom half

of the truss (one per team):

Add Tubes


Apply glue to Gusset Plates C and D.


Place a 10 mm x 10 mm tube in position as end post AD.


Hold in place for a minute until the glue sets.

Add Tubes


Cut a 2 cm length of 10 mm x 10 mm tube.


Apply glue to Gusset Plate B.


Place the tube vertically on the gusset plate.


Hold in place for a minute until the glue sets.

The Finished Half
-
Truss


Allow all glue joints to dry.

Assemble the Two Halves


Pull out all of the pins on both halves of the truss.


Carefully

separate the upper half of the truss from the plastic
wrap.


Keep the lower half of the truss on the building board.

Assemble the Two Halves


Put glue on the tubes at A, B, C, and D.


Place the upper half onto the lower half.


Stretch the bars tight and hold until the glue has set.

Assemble the Two Halves


Allow all glue joints on the completed truss to dry.

Finish the Truss


Trim off the excess length on both
bottom chords (AC) .

Place the Structure into Service

The completed bridge

Load test with 5 kg of sand

suspended from midspan