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B r i d g e S e t
B r i d g e C h a l l e n g e s f o r S t u d e n t s
12
Bridge Challenges for Students
Perhaps the best way for students to learn about bridges is to give them a task to accomplish wth limited
resources by any means possible. Here are two suggestions to challenge your students.
Span a Gap
Give each group a set of plastic, half of a Bridge Set or a Truss Set. The goal is to span a gap of 60 cm. Then find
the member with the greatest compression and change the design of the bridge to minimize the maximum com-
pression.
Least Deflection Under Load
Give each group a Bridge Set. The goal is to span a given distance with a bridge that has the least deflection
under load. The bridge is loaded with a particular load that the bridge must be able to bear. The bridge that has
the least defection is the winner.
Measuring Static and Dynamic Loading
Static Load
Apply a static load to the bridge by hanging a
hooked mass from one of the floor beams and
insert load cells into the structure as shown in
Figure 26. Loosen all the screws in the struc-
ture so the members are resting on their pins.
This will eliminate any extra moments due to
the screws and the tension and compression
readings will agree with the calculated values.
Dynamic Load
With the load cells inserted as shown in Figure 27, push the Mini-car with its extra mass across the bridge. Zero
the load cells before the measurement. Examine which members are under tension or compression.
Figure 26: Measuring a Static Load
Figure 27: (Above) Recording the forecs measured by the load cells as
the car traverses the bridge. (Right) DataStudio plot of load cell data