bridge building assignment
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
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.
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.
EXAMPLES OF TRUSS BRIDGES
UNDERNEATH DECK TRUSS
THROUGH TRUSS
TRIANGULAR TRUSS
K TRUSS
WARREN TRUSS WITH VERTICAL SUPPORTS
BALTIMORE TRUSS
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)
TRUSS BRIDGE
The truss bridge...consists of an assembly of triangles. Truss bridges are commonly made from a series of straight, steel bars.
WATER
RIG
HT A
BU
TM
EN
T
LEFT
AB
UTM
EN
T SPAN
ROADBED
BRIDGE TERMS
SUBSTRUCTUREBELOW ROADBED
SUPERSTRUCTUREABOVE ROADBED
1
2
3
10981 2 3 4 5 6 70
0
1
10981 2 3 4 5 6 70
Warren Truss with Vertical Supports
1
2
3
10981 2 3 4 5 6 70
Baltimore Truss
0
1
10981 2 3 4 5 6 70
K Truss
1
2
3
10981 2 3 4 5 6 70
Through Truss
0
1
10981 2 3 4 5 6 70
Triangular Truss
Underneath Deck Truss
TRUSS EXAMPLES
EXAMPLES OF JOINTS USED IN BALSA BRIDGE BUILDING
WATER
3
2
1
0
1
980 1 2 3 4 5 6 7 10
Total inches for vertical pieces in.+
Total inches for horizontal pieces in.+
Total inches for diagonal pieces in.
=
Total inches for one truss 12 = # of feet to build one truss (round to the tenth place)
x 2
= # of feet to build two trusses (round to the tenths place)
Wood Usage Calculations: 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: ____________
WATER
3
2
1
0
1
980 1 2 3 4 5 6 7 10
Total inches for vertical pieces in.+
Total inches for horizontal pieces in.+
Total inches for diagonal pieces in.
=
Total inches for one truss 12 = # of feet to build one truss (round to the tenth place)
x 2
= # of feet to build two trusses (round to the tenths place)
Wood Usage Calculations: 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 jointGood joint
WATER
3
2
1
0
1
980 1 2 3 4 5 6 7 10
Total inches for vertical pieces in.+
Total inches for horizontal pieces in.+
Total inches for diagonal pieces in.
=
Total inches for one truss 12 = # of feet to build one truss (round to the tenth place)
x 2
= # of feet to build two trusses (round to the tenths place)
Wood Usage Calculations: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
” 2.25”2.75
”
2.75
”2.75”
2.75”2” 2”2”2” 2”
10
18.25
15.5043.75 3.6
7.2