EPICS Time Team Education Group

EPICS Time Team Community Outreach

John Witherspoon Middle School Engineering Club

Lesson Plan: Bridging the Great Divide Objective: To encourage independent analytical thinking and engineering design through hands-on learning. To address the engineering principles in bridge design. Materials: A set number of K’Nex pieces (Per Team of 3-4 Students) Two level surfaces Small, stackable weights Procedure: Form groups of 3 or 4 students each, preferably with varying levels of engineering skills and background. Give brief introduction to the engineering principles in bridge design. (10 minutes) Work on the bridges. (30 minutes) Assess the weight capacity of the bridges and award prizes. (15 minutes) Worksheet for Students: The worksheet will include a page for a sketch of the final bridge design and space for explanations of the key design components.

EPICS Time Team Education Group

Guidance: A truss-like form provides stability for the bridges, with the diagonal bracing aiding in stiffening the structure and transferring loads. An improvement upon this truss-form is to build a cantilever bridge, similar to the Quebec Bridge (see below).

http://www.civeng.carleton.ca/Exhibits/Quebec_Bridge/images/p2.gif A cantilever is a beam supported on only one end; to build a bridge like the Quebec Bridge, two cantilevers would be constructed, and then a deck inserted in the middle (this can be dropped down in between the structures). An easy way to think of cantilevers is to picture the form as a diving board. Much like this, the bridge is constructed outwards, with—until construction completion—one “arm” hanging in the air.

EPICS Time Team Education Group

Another Approach: Another approach to the bridge construction could be a simple arch bridge.

http://www.westcoastroads.com/california/images151/ca-154_cold_spring_bridge_10.jpg In an arch bridge, the loads (e.g., live load (the weight applied to the structure, like cars or trains passing over)) are transferred from the deck to the arch, which then can transfer those loads to the supporting abutments (concrete connection to the mountain, as shown in the picture above). Essentially, the loads flow from the deck to the arch and then to the abutments.

EPICS Time Team Education Group

K’Nex Examples:

Arch Bridge

http://www.brightminds.co.uk/products/images/large/B7836.jpg

Arch Bridge

http://images.amazon.com/images/P/B00005KANP.01.LZZZZZZZ.jpg

EPICS Time Team Education Group

Truss

http://blockplay.blogspot.com/2007/06/bridges-towers.html

Awarding of Prizes: All groups will be awarded small prizes. The group whose bridge can support the maximum load will be awarded an additional prize.