Building Your Bridge - back to top
A. Bridge Contest Summary:
Teams will construct balsa wood bridges to be load tested on the day of the event.
Four awards will be given (1st, 2nd, 3rd, and 4th Place) in each category to the
team with the highest score determined from the Bridge Efficiency. Bridge Efficiency
is a ratio of how much load the bridge can handle to the mass of the bridge.
Efficiency of your bridge will be determined using the following formula:
| E = Efficiency = |
(LOAD IN kg) (1000 grams) = |
|
| (MASS OF BRIDGE IN grams) |
The load will be measured in kilograms, while the mass of the bridge will
be measured in grams.
Example: If your bridge weighed 22 grams and supported 42 kilograms of weight
for 30 seconds during the test, you would calculate efficiency as follows:
| E = Efficiency = |
(LOAD IN kg) (1000 grams) = |
(42)(1000) |
= 1909 |
|
|
|
| (MASS OF BRIDGE IN grams) |
(22) |
|
One additional award will be given in each category for Bridge Aesthetics.
B. Dimensional Parameters for Bridges:
* Test Block (50mm x 50mm) must be able to pass through bridge.
* Judges will provide blocks to use on day of event.
* Bridges must have a deck structure to support the test platform (provided).
* Bridges shall be loaded only on the bottom of the truss (deck and lower chord).
* Bridge decks must be accessible to test platforms.
* See Diagrams 1 and 2 for a schematic of the testing platforms.
The bridge must be built within these dimensions (See Dimensional Envelope):
| |
Bridge |
Roadbed |
Optional
Underhang |
Testing
Platform* |
| Length |
250 to 300mm |
200 to 300mm |
Less than 180mm |
50mm |
| Width |
50 to 75mm |
50 to 75mm |
50 to 75mm |
50mm |
| Height |
Less than 100mm |
Less than 50mm |
Less than 20mm** |
7mm |
* Testing Platform will be provided and should be integrated into your bridge.
** Included in the overall height of the bridge
Note:
It is imperative that bridges are built to the dimensional envelope shown within
these rules. Bridges not meeting the geometric requirements will be disqualified.
* Bridges may undergo repairs to meet the dimensional specifications. Only
the respective team members shall be allowed to make alterations to the structure.
Blueprints or plans of the bridge will be very helpful prior to final construction
of the bridge.
C.Wooden Test Platform:
A 50mm square wooden board will be used during testing to apply stress to the
bed of the bridge. Please allow space in your design so that the testing crew
can place this in the center of your bridge. Teams can use a 50mm cardboard square
to mimic this board.
For Category I and II bridges, the load will be applied to this board from
below. The hook, illustrated in Diagram 1, must be able to pass below the bed
where the load cell will be connected.
For Category III teams, the applied stress will be applied to the board by
a dowel rod from above. Again, make sure the dowel can be centered on the bridge
deck from above. See Diagram 2.
Diagram 1
Diagram 2
D. Construction Requirements & Techniques:
- Only the provided materials can be used in the construction of the bridge.
- All bridges must contain a truss design element (vertical triagnles).
- Splitting of members (wood pieces) is not allowed.
- Wood pieces may be bonded together with glue only at joints. If two or more
strips of wood are placed parallel to each other, they must be at least the thickness
of this page apart from each other.
- No laminating of members (wood pieces) is allowed for Category I or Category
II.
- Laminating is allowed for Category III teams only.
- The term “Laminating” for purposes of this competition is defined
as bonding (gluing) together multiple pieces of wood, parallel to one another
to create a larger composite truss member.
- See sketch below for allowed types of connections.
The Following Types of Connections Must be Considered For Your Bridge:
Tips for Building your Balsa Bridge:
The best advice for building winning structures starts with commitment. Your
dedication and attention to detail is the winning combination. The list of tips
below will help you succeed, but only if you are dedicated to the project. Be
sure you understand the event rules before designing your prototype.
1) Draw your preliminary design with full wood outlines. This should help
you to decide whether to use butt joints or lap joints.
2) ALL joints should have absolutely flush surfaces before applying glue.
Any time glue is used as a "gap filler", it dooms the structure! Cut
the wood precisely and carefully sand each part so that it fits flush. Then,
number each part and use it as a template to make numbered duplicates in assembly
sequence (i.e.: two for bridges, four for towers).
3) Structures are symmetric. When building a bridge or a tower with two or
four sides, build the two primary sides one on top of the other. Once the first
side is built, cover it with wax paper and build the second side directly on
top of the first. This helps insure the structure’s symmetric integrity.
4) Most competitions require these structures to be weighed. Up
to 20% of the structure's mass may be from over-gluing. Adhesives do not work better when
they are drooled all over the structure. Use the adhesives sparingly. Any more
than a translucent, moist surface becomes wasted, excess mass.
5) When building a balsa wood structure, pre-test all
the strips for tensile strength before assembly. A simple deflection test works best. Anchor half of
the strip on a surface and ballast the free end using clay on a bent straight
pin. Use a simple gauge to categorize the strips. Group similar tensile strengths
together. The strips that deflect the least are the strongest. Use those for
the longest pieces. The ones that defect the most use as the shortest pieces.
When the structure is finished, it should have a relatively consistent load carrying
capability.
The above tips can also be viewed at the following URL:
http://www.midwestproducts.com/structtips.htm
E. Recommended Tips for Contructing Your Bridge
Four views should be drawn:
1. END VIEW
2. SIDE VIEW
3. ROADBED
4. TOP VIEW
Recommended Construction Materials & Tools:
- Building Board
- Straight Pins, to hold pieces in place as glue dries
- Single Edge Razor Blade or X-Acto® knife for cutting
- Waxed Paper to cover the plan (blueprint) as you build on top of it
- Ruler or other device for measuring
- 15 pieces of wood and a 2/3 oz. bottle of glue (supplied)
Results of the 2008 Event
Category I | Category II | Category III
Category I Results
Cat
|
School
|
Student1Name
|
Student2Name
|
Student3Name
|
Team ID
|
Weight (g)
|
Load (kg)
|
Efficiency
|
I
|
Stonehedge ES
|
Annika Bergquist
|
Madeline Shuron
|
Elizabeth Zoanetti
|
277
|
5.965
|
8.18
|
1371.33277451802
|
I
|
Split Rock ES
|
Karen Awayda
|
Kamel Awayda
|
Victoria Lee
|
259
|
12.195
|
16.49
|
1352.19352193522
|
I
|
Split Rock ES
|
Mark Dellefave
|
Joseph Brogan
|
|
258
|
20.415
|
25.3
|
1239.28483957874
|
I
|
Tully ES
|
Spencer George
|
Brendan McGinn
|
|
307
|
14.295
|
12.98
|
908.009793634138
|
I
|
Jamesville DeWitt MS
|
Rachel Arcaro
|
Yahteiana Williams
|
|
435
|
8.94
|
7.48
|
836.68903803132
|
I
|
Lincoln
MS
|
Brandon Hughes
|
Nicole Martin
|
|
520
|
14.785
|
11.49
|
777.138992221846
|
I
|
Gillette Road
MS
|
Jared George
|
Paul Haberek
|
Mohammed Ashkar
|
397
|
19.945
|
13.17
|
660.315868638757
|
I
|
East Hill ES
|
Lauren Reilly
|
Maura Philippone
|
|
276
|
17.655
|
10.95
|
620.220900594732
|
I
|
East Hill ES
|
Aimee LaVine
|
Sydney Gilmore
|
Sohpia Bufano
|
342
|
11.53
|
6.66
|
577.623590633131
|
I
|
East Hill ES
|
Matthew McDonald
|
Jack Barrett
|
Stephen Anderson
|
264
|
26.79
|
15.2
|
567.375886524823
|
I
|
Fairgrieve ES
|
Jacob Bailey
|
Spencer Volno
|
Josh Hudson
|
326
|
21.5
|
11.81
|
549.302325581395
|
I
|
Wellwood MS
|
Oliver Wang
|
Christopher Spinelli
|
|
466
|
15.73
|
8.57
|
544.81881754609
|
I
|
Onondaga Road
ES
|
Sarah O'Neil
|
Mackenzie Gross
|
|
362
|
17.17
|
9
|
524.17006406523
|
I
|
Gillette Road
MS
|
Matthew Gorman
|
Thomas Pickering
|
|
406
|
23.7
|
11.38
|
480.168776371308
|
I
|
Roxboro MS
|
Michael Schroeder
|
Tyler Shepard
|
|
341
|
13.365
|
5.88
|
439.955106621773
|
I
|
Jamesville DeWitt MS
|
Erin Noble
|
Rebecca Fuller
|
|
420
|
9.82
|
4.24
|
431.771894093686
|
I
|
Gillette Road
MS
|
Jordan Bourgeois
|
Zachary Garofalo
|
Michael Copagni
|
404
|
14.285
|
6.11
|
427.721386069303
|
I
|
Gillette Road
MS
|
Kalli Miller
|
Joshua DiFabio
|
Kierra Kairis
|
395
|
11.295
|
4.63
|
409.915891987605
|
I
|
Gillette Road
MS
|
Brian Emigholz
|
Daniel Harbaugh
|
Nick Miller
|
405
|
17.97
|
6.62
|
368.391764051196
|
I
|
Gillette Road
MS
|
Julia King
|
Caroline Morison
|
Shaela Maring
|
399
|
22.74
|
8.22
|
361.477572559367
|
I
|
Gillette Road
MS
|
Jillian Berti
|
Cheyanna Colin
|
|
398
|
19.65
|
7.01
|
356.743002544529
|
I
|
Jamesville DeWitt MS
|
Jacob Cline
|
Connor Rumble
|
|
425
|
9.865
|
3.46
|
350.734921439432
|
I
|
Gillette Road
MS
|
Tricia Colunio
|
Maggie Morgan
|
Jenna Hoffman
|
356
|
16.42
|
5.56
|
338.611449451888
|
I
|
Lincoln
MS
|
Jacob Revette
|
Josh Coker
|
|
525
|
18.6
|
6.27
|
337.096774193548
|
I
|
East Hill ES
|
Morgan Lundy
|
Luis Castro
|
Billy O'Brien
|
261
|
8.9
|
2.95
|
331.460674157303
|
I
|
Lincoln
MS
|
Chelsea Parker
|
Natajah
Bell
Martin
|
Kayla Green
|
521
|
17.075
|
5.49
|
321.522693997072
|
I
|
Gillette Road
MS
|
Nathaniel Sanders
|
Emily Cross
|
|
402
|
15.36
|
4.82
|
313.802083333333
|
I
|
Lincoln
MS
|
|
Zakiah Scott
|
Desiree Podeswik
|
508
|
9.155
|
2.87
|
313.489896231567
|
I
|
Jamesville DeWitt MS
|
Hannah Gibson
|
Junghye Kim
|
|
416
|
7.41
|
2.25
|
303.643724696356
|
I
|
Gillette Road
MS
|
Eddie Fletcher
|
Gavin Brown
|
Jonathin Petrin
|
355
|
14.685
|
4.28
|
291.453864487572
|
I
|
Onondaga Road
ES
|
Eva Young
|
Marisa Hurst
|
|
361
|
16.995
|
4.94
|
290.673727566931
|
I
|
Gillette Road
MS
|
Leeda Mannise
|
Andrea Petrusch
|
Bryar Cummings
|
408
|
16.4
|
4.71
|
287.19512195122
|
I
|
Jamesville DeWitt MS
|
Jeffrey Marsh
|
Patrick Saba
|
|
417
|
10.57
|
2.83
|
267.738883632923
|
I
|
Dr. Weeks ES
|
Isaiah Mann
|
Adiba Alam
|
Javanni Portopillo
|
236
|
33.275
|
7.32
|
219.984973703982
|
I
|
Stonehedge ES
|
Brennan Costello
|
Gabrielle Shuron
|
|
281
|
10.175
|
2.09
|
205.405405405405
|
I
|
Lincoln
MS
|
Justin Hughes
|
Shamare Eagan
|
|
514
|
17.41
|
3.34
|
191.843767949454
|
I
|
East Hill ES
|
Jack Soltys
|
Jesse Elmer
|
Shauna Elmer
|
327
|
13.34
|
2.09
|
156.671664167916
|
I
|
Tully ES
|
Charles Petit
|
Walter Abrams
|
|
496
|
23.835
|
3.69
|
154.814348646948
|
I
|
Lyncourt UFSD
|
Ryan Minor
|
Gianna Pennisi
|
Austin Longo
|
482
|
9.47
|
1.43
|
151.003167898627
|
I
|
Chittenango MS
|
Michaela Watt
|
Sarah Moon
|
Kate Boyer
|
223
|
8.28
|
1.23
|
148.550724637681
|
I
|
Gillette Road
MS
|
Rachel Lingenfelter
|
Morgan Silfer
|
Kate Wagner
|
393
|
24.15
|
3.26
|
134.989648033126
|
I
|
Lyncourt UFSD
|
Gabriella Maggi
|
Alaya Kimbrough
|
Anthony Quinn
|
487
|
14.755
|
1.94
|
131.480853947814
|
I
|
Dr. Weeks ES
|
Shalill Scott
|
Mariah Schroeder
|
|
448
|
32.92
|
3.93
|
119.380315917375
|
I
|
Lincoln
MS
|
Trequon Short
|
Conell Steoheny
|
Jonathan Nulty
|
519
|
14.25
|
1.66
|
116.491228070175
|
I
|
East Hill ES
|
Jarrod Scutari
|
Jim Grabowski
|
Nathan Grabowski
|
437
|
17.58
|
1.97
|
112.059158134243
|
I
|
Jamesville DeWitt MS
|
William Cote
|
Saqif Badruddin
|
Steven Wang
|
421
|
9.435
|
0.96
|
101.748807631161
|
I
|
Lincoln
MS
|
Imani Higgins
|
Medgine Mede
|
|
522
|
15.85
|
1.39
|
87.6971608832808
|
I
|
Gillette Road
MS
|
Kyle Pudney
|
Stephen Dorn
|
Robby Ruley
|
358
|
15.555
|
1.12
|
72.0025715204115
|
I
|
Lincoln
MS
|
Tyler Hewitt
|
Emily Heifferon
|
Thomas Sheffler
|
518
|
21.08
|
1.35
|
64.0417457305503
|
I
|
Kenney MS
|
Jacob Whitcomb
|
Nathan Welling
|
|
267
|
15.695
|
1
|
63.7145587766805
|
I
|
Jamesville DeWitt MS
|
Sarah Nevin
|
Marion Maxwell
|
Amanda Mikesell
|
424
|
10.825
|
0.65
|
60.0461893764434
|
I
|
Lyncourt UFSD
|
David Hakes
|
Patrick Pallotta
|
|
492
|
10.52
|
0.61
|
57.9847908745247
|
I
|
Gillette Road
MS
|
David Verrett
|
Joshua Stevens
|
Noah Poirier
|
400
|
14.175
|
0.69
|
48.6772486772487
|
I
|
BVM
Academy
|
Zachary Bobka
|
Jmaes Kimball
|
Michael Hanson
|
452
|
13.71
|
0.57
|
41.5754923413567
|
I
|
Gillette Road
MS
|
Taylor Lessard
|
Caelan McCaffrey
|
|
403
|
12.685
|
0.49
|
38.6283011430824
|
I
|
Gillette Road
MS
|
Rachel Oakes
|
Rebekah Herman
|
Kira Kullman
|
401
|
18.33
|
0.57
|
31.0965630114566
|
I
|
Chittenango MS
|
Cassie Fraser
|
Michaela Boswell
|
John Davidson
|
251
|
8.715
|
0.26
|
29.833620195066
|
I
|
Fremont
ES
|
Nathan Mascari
|
Kyle Reader
|
Brandon Santillo
|
536
|
9.395
|
0.26
|
27.6742948376796
|
I
|
Lincoln
MS
|
Dayvonna Oliver Reid
|
Tiffany Curcie
|
Tahlasha Griswold
|
513
|
16.175
|
0.41
|
25.3477588871716
|
I
|
Danforth MS
|
Kana
Campbell
|
Quintia McClain
|
|
528
|
12.24
|
0.3
|
24.5098039215686
|
I
|
Lyncourt UFSD
|
Riley Keene
|
Jacob Nobile
|
Antonino Tartaro
|
483
|
14.03
|
0.3
|
21.3827512473272
|
I
|
Gillette Road
MS
|
Brittany Pratt
|
Sophie King
|
Kaci Toms
|
394
|
17.08
|
0.3
|
17.5644028103045
|
I
|
Stonehedge ES
|
Katherine Lannon
|
Kaitlin Holdrege
|
|
340
|
15.68
|
0.26
|
16.5816326530612
|
I
|
Gillette Road
MS
|
Anna Carrine
|
Victory Giudice
|
Jillian Norris
|
409
|
167.5
|
1.47
|
8.77611940298507
|
I
|
Lyncourt UFSD
|
Antonio Pallotta
|
Savannah St. Andrew
|
|
490
|
13.57
|
0.02
|
1.47383935151069
|
I
|
Chittenango MS
|
Brandon Zaccanelli
|
Dan Mosack
|
|
255
|
11.06
|
0
|
0
|
I
|
BVM
Academy
|
Carl Dickhut
|
Damien Hall
|
Connor Edwards
|
451
|
10.735
|
0
|
0
|
I
|
East Hill ES
|
Mirabel Reid
|
Priscilla Grooms
|
|
375
|
7.87
|
0
|
0
|
I
|
BVM
Academy
|
Elizabeth Volles
|
Mary Cioci
|
Katie Mullen
|
453
|
22.25
|
0
|
0
|
I
|
Danforth MS
|
Brandon Ashley
|
Tarius Brewer
|
K'fir Gilbert
|
529
|
10.29
|
0
|
0
|
I
|
East Hill ES
|
Alice Gavin
|
Hannah Gavin
|
Mackenzie Foor
|
263
|
10.04
|
0
|
0
|
I
|
Danforth MS
|
Johnae Jacobs
|
Louis Ceaser
|
|
530
|
8.16
|
0
|
0
|
I
|
East Hill ES
|
Sean Stanistreet
|
Ryan McDonald
|
John Sullivan
|
260
|
7.65
|
0
|
0
|
I
|
Fremont
ES
|
Dana Mascari
|
Hyemin Han
|
|
537
|
8.615
|
0
|
0
|
I
|
Lincoln
MS
|
Tavaughn Barrot
|
Kygelik Price
|
|
516
|
15.35
|
0
|
0
|
I
|
Chittenango MS
|
Noelle Milnamow
|
Allison Henry
|
|
256
|
10.59
|
0
|
0
|
I
|
Chittenango MS
|
Andrew Clark
|
Gabby Burleigh
|
Grace Nicholas
|
253
|
7.21
|
0
|
0
|
I
|
Lyncourt UFSD
|
Loren Scripa
|
Dan Heinley
|
|
485
|
10.595
|
0
|
0
|
I
|
Jamesville DeWitt MS
|
Caroline Kopp
|
Kallen Prosak
|
Morgan Clark
|
419
|
7.08
|
0
|
0
|
I
|
Fremont
ES
|
Jenna Anderson
|
Kelsey Hall
|
|
538
|
13.245
|
0
|
0
|
I
|
Chittenango MS
|
Nate Lanning
|
Evan Capella
|
Bradley Markowski
|
254
|
6.355
|
0
|
0
|
I
|
Lincoln
MS
|
Quiarra Albright
|
Destiny
Jackson
|
|
511
|
16.25
|
0
|
0
|
I
|
Lyncourt UFSD
|
Lewis St. Andrew
|
Tyler Davis
|
Rachel Smith
|
491
|
11.375
|
0
|
0
|
I
|
BVM
Academy
|
Stephen Hanson
|
David Mullen
|
Kurt Dickhut
|
441
|
8.6
|
0
|
0
|
I
|
Chittenango MS
|
Tristan Julian
|
Dane Johnson
|
Michael Lavoie
|
250
|
8.975
|
0
|
0
|
I
|
Lyncourt UFSD
|
Samantha Polidori
|
Kathyrn Nicholson
|
|
481
|
11.06
|
0
|
| 