1. BRIDGE BUILDING ASSIGNMENT 1.Work with a partner to construct 1 bridge. 2.Last Module Partner. 3.Draw a full size truss pattern from one of the six truss examples. 4.Construct the bridge using balsa wood. 5.Test the efficiency & applied force of the bridge.

2. BRIDGE SPECIFICATIONS Work as a team to design and construct a balsa wood bridge. You may use no more than 7 - 24x1/8 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.

3. EXAMPLES OF TRUSS BRIDGES

4. UNDERNEATH DECK TRUSS

5. THROUGH TRUSS

6. TRIANGULAR TRUSS

7. K TRUSS

8. WARREN TRUSS WITH VERTICAL SUPPORTS

9. BALTIMORE TRUSS

10. 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) 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)

11. TRUSS BRIDGE The truss bridge... consists of an assembly of triangles. Truss bridges are commonly made from a series of straight, steel bars.steel

12. WATER RIGHT ABUTMENTLEFT ABUTMENT SPAN ROADBED BRIDGE TERMS SUBSTRUCTURE BELOW ROADBED SUPERSTRUCTURE ABOVE ROADBED

13. 1 2 3 10 9 8 1 2 34 567 0 0 1 9 8 1 2 34 567 0 Warren Truss with Vertical Supports 1 2 3 10 9 8 1 2 34 567 0 Baltimore Truss 0 1 10 9 8 1 2 34 567 0 K Truss 1 2 3 10 9 8 1 2 34 567 0 Through Truss 0 1 10 9 8 1 2 34 567 0 Triangular Truss Underneath Deck Truss TRUSS EXAMPLES

14. EXAMPLES OF JOINTS USED IN BALSA BRIDGE BUILDING

16. WATER 3 2 1 0 1 9 8 0 1 23 4 5 6 7 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. GRID SIZE =.25 DO NOT SHADE IN THE LINES! TRUSS VIEW Drawn by: __________________________________ Block #_____ Date: ____________

17. WATER 3 2 1 0 1 9 8 0 1 23 4 5 6 7 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. GRID SIZE =.25 DO NOT SHADE IN THE LINES! TRUSS VIEW Drawn by: __________________________________ Block #_____ Date: ____________ Bad joint Good joint

18. WATER 3 2 1 0 1 9 8 0 1 23 4 5 6 7 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. GRID SIZE =.25 TRUSS VIEW Drawn by: __________________________________ Block #_____ Date: ____________ 10 8.25 2.25 2.75 2 2 2 22 10 18.25 15.50 43.753.6 7.2