1. Bridge Construction

2. VRML 3-D Image of a student’s bridge
Once you have designed your bridge on Bridge Builder,
you can make a VRML file to see it in 3-D. Go above
and below the deck to see how the trusses are joined
VRML 3-D Image of a student’s bridge

3. You have now completed the design of
your bridge. The most difficult part now
begins and that is the
construction of your bridge.
To build a bridge you must join
many separate pieces.
The stronger the joint,
the stronger the bridge.
We are going to view several methods
of joining your bridge together.

4. A Butt joint is the weakest type of joint.
Butted Joint
A Butt joint is the weakest type of joint.
Two pieces of wood joined at the ends,
do not support each other.
All that holds them together is the glue.

5. Scarf joints do provide more support.
If a force were applied downward on
this joint, one piece of wood, would
press against another adding strength.

6. The more two pieces of wood overlap,
Lap Joint
The more two pieces of wood overlap,
the more they can help each other.
The dotted line represents a pin.
A pin prevents the two pieces of wood
from pulling apart.

7. Half-Lap Joint
This is one of the strongest types of joints.

8. Lamination adds weight, but can provide huge amounts of support.

9. Notching locks pieces together
Notched Joint
Notching locks pieces together
and adds strength.

10. Tight fitting beveled joints prevent
gaps and spaces that weaken the bridge.
Beveled pieces can be pinned also.

11. View the next few slides for construction
techniques used on a real bridge.
Can you determine the
construction technique they used?

12. Photo By: Doug Porter

13. This is a half-lap joint
Photo By: Doug Porter

14. Photo By: Doug Porter

15. This joint combines
a notch and a bevel
Photo By: Doug Porter

16. Photo By: Doug Porter

17. This joint show an excellent example of
lamination. Pins and bolts were used to
hold the boards together
Photo By: Doug Porter

18. Photo By: Doug Porter

19. Here is an example
of lap joints
Photo By: Doug Porter

20. Photo By: Doug Porter

21. These joints show a butted joint and a notched joint side by side
Photo By: Doug Porter

22. Putting it all Together
Joining the trusses and adding the deck
Photo By: Doug Porter

23. Putting it all Together
Photo By: Doug Porter
Beveled and Notched Joints

24. Putting it all Together
Photo By: Doug Porter
Lap, Bevel and Notch Joints

25. Putting it all Together
Photo By: Doug Porter

26. Testing