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BRIDGE BUILDING ASSIGNMENT. Work with a partner to construct 1 bridge . Last Module Partner. Draw a full size truss pattern from one of the six truss examples. Construct the bridge using balsa wood. Test the efficiency & applied force of the bridge. BRIDGE SPECIFICATIONS.
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BRIDGE BUILDING ASSIGNMENT • Work with a partner to construct 1 bridge. • Last Module Partner. • Draw a full size truss pattern from one of the six truss examples. • Construct the bridge using balsa wood. • Test the efficiency & applied force of the bridge.
BRIDGE SPECIFICATIONS • Work as a team to design and construct a balsa wood bridge. • You may use no more than 7 - 24”x1/8” balsa sticks. (14 ft. total) • The bridge must have two identical trusses & a roadbed • The bridge must be exactly 10” in length. • The test block must fit between the two trusses. • No excessive glue blobs. • Support weight = Over 50 lbs. • Tape may only be used to hold pieces while glue dries. • Only two pieces of balsa wood may be laminated together.
BRIDGES GRADESHEET TRUSS VIEW DRAWING GRADE Lines are drawn with ruler. No wavy lines ____ pts. (20) Lines are 1/8” thick. ____ pts. (20) Drawing should have neat appearance. ____ pts. (20) Joints are clearly drawn. ____ pts. (20) Complete wood usage calculations. ____ pts. (20) • ____ pts. (100) BALSA BRIDGE CONSTRUCTION Two trusses must be stand vertically. ____ pts. (20) No excessive glue blobs. ____ pts. (20) Tight joints. ____ pts. (20) Roadbed & top pieces do not over hang trusses. ____ pts. (20) Over 50 lbs. = 20 pts.40 – 49 lbs. = 15 pts. Below 40 lbs. = 10 pts. ____ pts. (20) ____ pts. (100)
The truss bridge...consists of an assembly of triangles. Truss bridges are commonly made from a series of straight, steel bars. TRUSS BRIDGE
ROADBED LEFT ABUTMENT RIGHT ABUTMENT BRIDGE TERMS SUPERSTRUCTURE ABOVE ROADBED SUBSTRUCTURE BELOW ROADBED SPAN WATER
1 1 1 1 2 2 9 9 2 2 9 9 8 8 8 8 0 0 0 0 3 3 4 4 3 3 4 4 5 5 6 6 7 7 5 5 6 6 7 7 10 10 10 10 3 3 2 2 1 1 Baltimore Truss Warren Truss with Vertical Supports K Truss 1 1 2 9 2 9 8 8 0 0 3 4 3 4 5 6 7 5 6 7 10 10 3 2 1 0 1 Through Truss Triangular Truss 0 0 1 1 Underneath Deck Truss TRUSS EXAMPLES
3 2 1 0 1 WATER GRADING PROCEDURE Lines are drawn with ruler (no wavy lines) Lines are 1/8” thick. Appearance of drawing (Easy to read) Complete wood usage calculations. Joints are clearly drawn. GRID SIZE = .25 0 1 7 2 3 9 8 4 6 5 10 DO NOT SHADE IN THE LINES! TRUSS VIEW Drawn by: __________________________________ Block #_____ Date: ____________
3 2 1 0 1 WATER GRADING PROCEDURE Lines are drawn with ruler (no wavy lines) Lines are 1/8” thick. Appearance of drawing (Easy to read) Complete wood usage calculations. Joints are clearly drawn. GRID SIZE = .25 0 1 7 2 3 9 8 4 6 5 10 DO NOT SHADE IN THE LINES! Good joint Bad joint TRUSS VIEW Drawn by: __________________________________ Block #_____ Date: ____________
3 2 1 0 1 WATER 10 GRADING PROCEDURE Lines are drawn with ruler (no wavy lines) Lines are 1/8” thick. Appearance of drawing (Easy to read) Complete wood usage calculations. Joints are clearly drawn. 18.25 15.50 43.75 3.6 7.2 GRID SIZE = .25 0 1 7 2 3 9 8 4 6 5 10 8.25” 2.25” 2.25” 2.75” 2.75” 2.75” 2.75” 2” 2” 2” 2” 2” 10” TRUSS VIEW Drawn by: __________________________________ Block #_____ Date: ____________