1. Bridge Construction
This is the week 5 PowerPoint presentation.

2. Your Truss Bridge Drawing
This is a profile of the bridge the student teams will make. All teams will use the same blueprint and end up with the same design. If they want to create their own bridge, Learning Activities 4 and 5 might be of interest.

3. Typical Bridge Joint 10mm x 10mm Tube 6mm x 10mm Tube 4mm Bar
These isometric drawings give an idea what most bridge joints will look like. The combinations of tubes and bars meet together at a gusset plate where they are glued together.
4mm Bar

4. Schedule of Truss Members
This Schedule of Truss Members chart identifies each member of the bridge, their dimensions, and the number of members required to build the bridge. Students will be constructing the members and then using them with the gusset plates to make their bridge.
The tube fabrication is very time consuming so you might assign more team members working as tube manufacturers.

5. Schedule of Gusset Plates
This Schedule of Gusset Plates chart identifies the nine different types of gusset plates, which truss members they join, and the number required to build the bridge.
Page 1-17 of Learning Activity #1 has a page layout of these gusset plates. I photocopied this page directly onto a manila file folder and the students simply cut out the pre-drawn gusset plates. Each team will need two copies for enough gusset plates.

6. Prefabricate the Bars 1) Draw 31, 4mm parallel lines
Detailed instructions are in Learning Activity #1.
The straightest cuts are accomplished by using the sharp knife but it requires two to three passes with light pressure. Too much pressure will result in crooked lines or jagged edges. Students may prefer using a pair of scissors, but that will result in jagged edges and may affect the robustness of the construction.
1) Draw 31, 4mm parallel lines
2) Carefully cut, requires multiple passes

7. Prefabricate the Tubes
Highly recommend going to Learning Activity #1 and carefully reading the construction section. These slides are taken directly from the book but they won’t include every detail. The book is very well written with lots of details, photographs, and diagrams.
Tubes are trickier to build. They have four sides and an overlapping flap for rubber cement. When drawing the lines on the folder, the students should press down hard on the pen as the indentations along the fold lines will make the cardboard easier to bend.
Tube templates to be drawn on file-folder
Tubes determine load carrying capacity

8. Tubes Continued Fold the tubes with a straight edge
Couple more major points.
Fold the tubes with a straight edge
Rubber cement the flap and inside free edge

9. Finished Tubes
The final steps to making the tubes. If done properly, you will end up with a nice tube like in the last photo.

10. Structure Construction
We used large pieces of cardboard behind drawing SD-1. This is light, cheap, and easy for pin penetration.
At this point the students will take off. Make sure they have copies of Learning Activity #1 as it answers many questions that arise.
Pin the gussets, wood glue the bottom chord, trim and wood glue the diagonal bars

11. Done!! The completed bridge, ready for testing
The completed bridges will look alike. Have the teams make sure their names or ID’s are written on them. Do not mind the ‘loose’ look of some of the bars. When they get loaded, the students will be able to observe the tension pull them taut.
The completed bridge, ready for testing

12. Acknowledgements
This presentation is based on Learning Activity #1, Build a Model of a Truss Bridge, from the book by Colonel Stephen J. Ressler, P.E., Ph.D., Designing and Building File-Folder Bridges
This Civil Structures module is heavily based on this book which is found in the documents directory of the module.
To model an engineering project, we will start with the truss structural analysis (Learning Activity #3) which takes Weeks 3 and 4 or this curriculum. Then we begin bridge construction (Learning Activity #1) in Week 5. After the students get the feel of constructing their bridge members, during Week 6 they will characterize the strength of different sized members (Learning Activity #2) to be able to calculate the Factor of Safety. Week 6 is also used to complete their bridge construction and do the weight testing.
This module does not address Learning Activities #4 and #5, but you are encouraged to complete them if time allows.