Truss Design Challenge Experiment - Group 1

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Experiment Description For this experiment, students in the lab were tasked with designing a truss or bridge to span a specific distance and withstand a 100 lb load in a four-point flexure test. All requirements for the bridge are clearly outlined below: • Span length of 400 mm • Width of 75 mm • Maximum height of 75 mm • Maximum weight: 100 grams • Must support 45 kg (100 lbs) • No adhesives, such as glue or tape, can be used for connections The challenge for students in this experiment was that their bridges had to be printed in separate parts due to their large size. Students had to design connections for these parts without using glue or other adhesives. The connection design was critical because it is the weakest point on their trusses. Information on Group 1's Bridge: This is the design from Group 1 in the laboratory. Their truss design is a Pratt Truss, commonly used in bridge construction. This group employed "truss pin" parts and "bridge clips" parts to connect the truss together. The truss pins resisted shear forces acting vertically along the truss's connections, while the bridge clips resisted normal forces (tensile and compressive forces) acting horizontally along the truss's connections. To ensure lateral stability, the group included "cross brace" parts to resist the bridge from overturning laterally when loaded. These cross bracing components were designed to be adjustable, allowing students to experiment with ideal locations. This bridge had a total weight of 86 grams and resisted a load of 68.9 lbs before failing due to lateral buckling. Note: The handout for this experiment will soon be available. A link to the handout will be provided in this description when it is complete, allowing you to perform this experiment with your students or independently.