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COMPETITION RULES |
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COMPETITION RULES |
DESCRIPTION:
The competition
will consist of the construction and testing of a model timber bridge on the
home site of each team.
ELIGIBILITY:
The competition
is open to all student chapters of American Society of Civil Engineers and
Forest Products Society in the United States and Canada. Joint and multiple entries from one school will be accepted.
COMPETITION
SPECIFICATIONS:
Each contestant
(team) will be required to design, build and test a bridge constructed from
wood structural members. The wood
used in this project must be from a commercially available species. Contestants
may use donated materials and/or services, however, donated services may not
include any form of fabrication or preparation of composite bridge members. Be sure to check out our list of more than two dozen
links to wood products design data, technical values, specifications,
treatment information, supplies, etc. on the main page for the Competition.
WOOD
TREATMENT:
All wood members
must be treated to AWPA standards.
Retention levels for bridge members not in contact with the ground
(deck, rails, upper trusses, etc.) may meet "above ground use"
standards. Retention levels for
bridge members to be in direct contact with the ground must meet “ground
contact” standards. See www.awpa.com
for details on ordering publications and standards or go to Western Wood
Preservers Institute,
(link:
www.wwpinstitute.org/mainpages/guidetochar-use/selection.html) then select
preservative type for standards tables.
NOTE:
Since all the most common procedures for meeting AWPA standards require
pre-treatment in a pressurized environment to attain adequate retention
levels, the treatment type and process should be part of the bridge design
process, rather than a post-treatment alternative.
There are plenty of safe treatment materials available, so student
safety should be considered, but not prohibitive. The life expectancy of all
metal fasteners, cables, plates and other non-wood components should be
considered for all bridges expected to have a “life after competition”,
however, this will not be a competition requirement.
DESIGN
CRITERIA:
Design
Span: 3.8 meters from
center line to center line of supports. The
maximum length of an individual piece in any member shall not exceed 2.1
meters. There is no length
limitation on built-up and laminated members prepared by contestant, provided
that the individual pieces, including plywood, used in making the member do
not exceed the specified maximum length.
Maximum width of supporting base plates is 60 mm.
There is no length constraint on cables, straps, rods or other
tensioning devices.
Horizontal
Clearance: 1.4m inside
curb to inside curb.
Vertical
Clearance: 2.5 meters from
deck surface (overhead clearance).
Depth
of Understructure: Maximum
of 500 mm at center-span and 1000 mm at support base measured from top surface
of deck to lowest point of support structure.
Test
Load: 20 kN for 1 hour. (See test
setup for location of loading blocks.)
Load
Application and Deflection Measurements:
The load will be applied in 4 equal increments of 5 kN each, with the full
load of 20 kN being achieved in not less than 5 minutes or more than 20
minutes. Deflection readings will
be recorded at each 5kN load increment. Then,
four deflection readings shall be recorded at 15-minute intervals during the
1-hour full-load duration.
Maximum
Vertical Bridge Deflection:
Maximum allowed bridge deflection is 9.5
mm as recorded at midspan of the longitudinal beam receiving the greatest
loading. Subtraction from deflection due to compression of supports
will not be allowed. If two or
more longitudinal beams are predicted to receive equal loading, select only
one to monitor, or monitor all such beams and submit average deflection
(contestant's choice).
Maximum
Vertical Net Deck Deflection:
Maximum allowed net deck deflection is deck span divided by 100, with deck
span being measured as the shortest side of the largest “deck panel”
formed by 2 longitudinal members and 2 transverse members, if applicable.
"Deck panel" is defined as any area of clear-span deck
bordered (i.e. defined) by the 2 nearest longitudinal bridge support members
and the 2 nearest transverse support members, if applicable.
In other words, deck span is the distance between points monitored by
the 2 gauges at points 3 and 4 below. However, note that deck span is actually
measured from inside structural member to inside structural member.
Gross deck
deflection shall be measured under the centroid of the loading point placed
where the deck is calculated to experience maximum deflection under full
loading if the 4-point was moved anywhere on the deck. This point should be
the same as the center of the largest “deck panel” described above.
The selected loading point must be at the deck’s weakest point. It
must be halfway between any transverse members such as floor beams, deck
stiffeners, cross-bracings, diaphragms, etc. that make contact with the deck’s
underneath surface. It must also be halfway between any adjacent longitudinal
support members.
Net deck
deflection shall be determined by subtracting the average of the deflections
recorded in the 2 bridge structural members forming the longer side of the
largest bridge “deck panel” as recorded at midpoint of the longest sides
of the “deck panel” and as measured by gauges at points 3 and 4 below. See
“Test Setup” sketch for details on placement of the 4 loading points, size
of bearing plates, etc.
Note that more
than one loading setup may be required to properly measure both bridge
deflection and deck deflection at their weakest points, i.e. at points of
expected maximum deflection. Some designs may, however, allow for one loading
setup to monitor both defections. If needed, the 4-point loading setup may be
moved as a unit transversely only to monitor Maximum Vertical Bridge
Deflection, but it may be moved as a unit both transversely and longitudinally
to monitor Maximum Vertical Deck Deflection, thus
placing any one of the four loading points over the center of the
largest “deck panel”.
Drawings must
clearly document location of load points. Location of all monitoring gauges
for each loading set-up must also be shown as follows:
1.
Midpoint of
longitudinal beam predicted to experience maximum loading. Resulting
deflection is Maximum Vertical Bridge Deflection.
2.
Centroid of
largest “deck panel” as described in Maximum Vertical Net Deck Deflection above.
Resulting deflection is Maximum Gross Deck Deflection.
3.
At midpoint
of one of the longest sides of the selected “deck panel”.
4.
At midpoint
of the other longest side of the above “deck panel”.
Note
that distance between point 3 and point 4 is Deck Span. Net Deck Deflection is
deflection measured at point 2 subtracted by the average of the two
deflections measured at points 3 and 4. Failure
of drawings to clearly document location of above 4 gauge points and the
location of the 4 loading points (at one or both setups as applicable) will
result in disqualification. Disqualification
may also occur if photos “c” and “d” below (See Documentation)
contradict drawings.
Bridge
Deck: The bridge deck does
not have to be wood, but note 25% by weight non-wood restriction on total
bridge weight. Any material can
be used as long as it is designed to effectively transfer loads at all
locations on its surface to the support structure, is not an open grid, can be
treated to withstand weather-related deterioration, can withstand repetitive
traffic loading and wear, and is capable of supporting the complete
4-load combination moved anywhere on the deck surface.
In other words, it must work in real-life application!
The maximum length per piece limit (2.1 meters) still applies to deck
materials. The deck must be
uniform in thickness, material, etc. throughout (i.e. “beefed up” deck in
the area of the load point selected for gauging deck deflection will cause
disqualification).
Pre-stressing:
Pre-stressing will be allowed provided it is done 48 hours before
testing.
Bridge
Weight: Bridge must be
weighed before testing and must include all bridge parts forming a part
of the bridge as a structural system. Note
that total non-wood components cannot exceed 25% of total bridge weight.
Curb: The curb does not need to resist a force but must be connected to the
bridge. The curb may be a part of
arch or truss members. Curb material must meet same requirements as Deck
except for load bearing.
DOCUMENTATION:
Contestants will
be required to submit by email:
1.
Digital
Photographs: Transmit in .gif, .jpg, .tif or .bmp format.
No .pdf files can be received.
Photos must be no larger than 640 x 480 pixels in size; and if
possible, with 300 dots per inch resolution or better. Transmit to
bennie.hutchins@ms.usda.gov
as attachments to one email, with each file titled showing school name
abbreviated and photo labeled per rules.
For example, “MSU side view finish.gif”. Color prints will be accepted only if contestant does not
have access to digital camera. Following photos are required (no more, no
less!):
a.
Four photos
of bridge construction featuring key structural components of bridge, such as
deck, longitudinal supports, transverse beams, connectors, etc. as applicable.
No more than 4, please!
b.
One photo of
weighing bridge
c.
One end view
of loading setup
d.
One side view
of loading setup
e.
One photo of
each deflection monitor at full loading, with identification sign indicating,
"deck", "beam left", "beam right", “bridge”.
f.
One side view
of finished bridge from above plane of bridge deck
g.
One end view
of finished bridge from below plane of bridge deck
h.
One trimetric
view of bridge (showing both side and end)
i.
One group
picture of design team either on bridge or with bridge in foreground from a
trimetric view
NOTE: In pictures
"h" and "i" above, try to avoid background and foreground
clutter. Adding a sign with school name is advisable for future publicity.
2.
Digital
Drawings:
·
Must
be adequate to inform judges of bridge dimensions, including size and spacing
of all longitudinal and transverse components,
·
Must
show 3 views (overhead, side, and end) or show 1 trimetric view
(preferred!) if all required details can be shown,
·
Must
show location of the selected load point monitored for deck deflection, the
location of the 4-point load setup for bridge deflection, and the
location of all gauges monitoring structural member deflections for
determining both deck and bridge deflection.
·
Must be transmitted as e-mail attachments in either .jpeg (preferred) or .gif
at size of approximately 640 x 480
pixels. No autocad or .pdf
files can be received. Name file as "msu side draw.jpg", etc.
showing school name, then view.
·
NOTE:
Be sure lettering is large enough to read easily on computer screen! Avoid
light colors for lines and numbers; avoid black backgrounds.
Following
materials should be mailed to reach
Competition coordinators by deadline:
1.
Drawings:
Mail an 8 1/2-inch x 11-inch hard copy of bridge drawing(s) entered online.
See Drawings requirement above. This
item is mandatory.
2.
Certification
and Entry Form (print from website). This
item is mandatory.
3.
Any
photographs required in "a" through "i" above or a
computer disk containing the digital photos. No zipdisks, please! Neither of
these are required if the required digital photos were successfully
transmitted in the format and size stated, but is recommended.
4.
A complete
printout of the Online Entry. This
item is optional, but recommended.
REPORT:
A technical
report must be submitted online (via Internet) using templates provided in
Online Entry and will include:
1.
Abstracts:
Using maximum of 500 words, explain the bridge design concept and explain what
was done to optimize stiffness while attempting to minimize weight of the
structure.
2.
Table of all
recorded test results of deflection measurements.
3.
An itemized
materials list showing weight of non-wood components and total weight of
bridge. The total weight of
non-wood material must be less than 25% of the total weight of the bridge.
Glue is non-wood.
4.
A short
summary (max. 500 words) describing the bridge and its behavior under load.
5.
Short
description of major bridge components (10 words or less per component).
6.
Description
of preservative treatment used and why it was selected.
7.
Project
impact. Was the experience beneficial to design team? What end-use did the
bridge have after testing?
JUDGING:
A panel of three
independent judges not affiliated with any contestant institutions will select
the winners. Entries that do not
meet all rules and performance criteria will be disqualified for consideration
for Performance and Best Design Awards but will be eligible to compete for
Special Awards. No single entry
shall be eligible to receive more than three awards.
AWARDS:
1.
Best Overall Design (1st-$550, 2nd-$400, 3rd-$250). This award is intended to reward intellectual effort,
regardless of how the design meets the performance-related standards.
Judged using following points:
·
Design is a
configuration of structural elements that can be optimized through normal
engineering methods (20%)
·
Design makes
efficient use of structural materials (20%)
·
Design is
based on structural concepts that have broad applications (20%)
·
Design shows
intellectual efforts (20%)
·
Judges'
Review/Report (20%) (adequate documentation, clarity, neatness, content,
abstract, photos, video)
2.
Performance
Awards
·
Maximum
Bridge Deflection 30%
·
Total Bridge
Weight 10%
·
Percent
Nonwood (total bridge) 10%
·
Practical 20%
·
Innovative
– Structural Design 15%
·
Innovative
– Materials 15%
·
Net Deck
Deflection 30%
·
Total Bridge
Weight 10%
·
Percent
Nonwood (total bridge) 10%
·
Practical 20%
·
Innovative
– Structural Design 15%
·
Innovative
– Materials 15%
3.
Special
Awards: (Each category: 1st-$300, 2nd-$300, 3rd-$200)
·
Most
Practical Design - Design that can be practical to implement in
real-life design and construction; low-tech and easy to construct (low
materials and labor costs).
·
Most
Aesthetic Design
·
Most
Innovative Design (in the use of new and non-traditional materials and/or
construction methods)
DEADLINES:
Deadline for
online entry (www.msrcd.org) and receipt of mailed material is April
6, 2007.
Mail to SW Mississippi RC&D, 1395 Johnny Johnson Dr., Suite E,
Brookhaven, MS 39601.
Enclose following information with mailed material:
College or University
Student Chapter name, address, phone, fax, e-mail.
Be sure address is a permanent department mailing address; will be used
for mailing awards check.
Faculty advisor
Contact person.
All materials
received by RC&D will become the property of RC&D.
NOTE:
This deadline may be inconvenient for schools on the quarter system wishing to
incorporate participation into spring or summer coursework. However, these
schools may compete in the 2008 Competition by following 2004 rules posted on
this website. The award amounts may change from year to year.
RESULTS:
Winners will be
announced online by May 4, 2007. In
addition, the full entries of all participants will be released online and
available for all contestants as well as any Internet user to review.
Each can learn from the successes and failures of others! The results
will also be publicized through various publications.
ADDITIONAL
INFORMATION:
Submit questions
by e-mail to
bennie.hutchins@ms.usda.gov, or contact Bennie Hutchins, SW MS RC&D,
phone 601-833-5539, fax 601-835-0054. Check
Q&A/Updates regularly for valuable competition updates, rules
clarifications, etc.
