Bridge Design Event
Event Coordinator: Ken Moliterno
objective of this project is to design and build the
lightest bridge capable of supporting a given load.
The bridge is a cantilevered wooden structure,
which will be attached to a vertical- testing wall at
one end, and supporting a load at the distal end.
A TEAM OF UP TO:
The bridge is to be a SINGLE structure
constructed of wood and bonded by glue.
No other materials shall be used.
Bamboo is NOT a wood.
The bridge must be constructed of pieces of wood
no larger than ¼ high and ¼ wide.
Any dowels used cannot have a diameter greater than
It may have an attachment base which may be of
any type of wood not to exceed 30 cm x 15 cm x ½ thick.
The attachment base MUST be permanently attached
to the bridge.
Particleboard, wood products, or commercially
laminated wood may not be used, except for the
There is no limit on the length of individual
wood pieces used in the construction, with the exception
noted for the attachment base.
Any type of bonding material (glue) may be used.
All construction must be completed prior to
Sound engineering practices such as good truss
construction, gussets and mitered joints are encouraged.
Do not coat the bridge with any materials (i.e.
paint, stain, or glue).
Unlimited lamination (i.e. bonding together
layers of wood) by the student is allowed.
Commercially laminated wood is only allowed for the
The bridge must be constructed to meet the
It must be designed in such a way that it can be
attached to the vertical-testing wall with one or two ¼
bolts. The bolts will be precisely
20 cm apart on center horizontally.
The bridge may have an attachment base (which may be one
or two separate pieces) or designed in such a fashion
that it can be attached to the Testing Wall.
The bridge must support the loading block at a
minimal horizontal distance of 40 cm from the
No part of the bridge may touch the
vertical-testing wall further than 15 cm below the
All bridges will be assessed prior to testing for
construction requirements and dimensions.
Students must wear eye protection during loading
The loading block, testing wall, attachment
hardware and loading material will be provided.
The vertical testing wall will be a piece of ¾
thick plywood or other suitable material around 45 cm
wide and 30 cm high with two ¼ diameter holes 20 cm
apart on center horizontally 5 cm from the top.
The bridge will be attached to the
vertical-testing wall with one or two 2 inch long ¼
washers (not to exceed ¾diameter) and wing-nuts through
the holes in the
testing wall. The bolts will be
placed so that the
head of the bolt is on the same side as the
The center of the loading block will be placed on
the bridge beam a minimum of 400 mm from the
vertical-testing wall. Remember that
the loading block is 50 mm wide so the length of the
bridge should be GREATER than 400 mm.
The load will be applied to the loading block by
an eyebolt and S-hook.
The loading block will be 50 mm long and 50 mm
wide and 20 mm high.
A bucket will be attached to the S-hook, and the
S-hook is attached to the eyebolt on the loading block.
The student will add sand to the bucket.
The maximum allowable time for set up and loading
will be ten minutes. If the time
expires, the bridge is ranked with those that could not
hold the 15kg.
The student will add sand to the bucket until
failure occurs or the maximum load (15 kilograms, 33lbs)
is supported. The maximum load (15
kg) incorporates the total mass of the loading
apparatus, bucket and sand.
Bridges that experience failure before reaching
15 kilograms will not be disqualified.
Failure is defined as the inability of the bridge
to carry additional load without breakage or the
inability to hold the maximum load for 5 seconds.
Excess sand added after failure will be removed.
The score (Structural Efficiency) will be
determined by the equation:
Structural Efficiency = Load supported (grams)/Mass of
Bridge (grams). The maximum load
supported cannot excel 15 kg.
The bridge that held all 15 kg for 5 seconds with
the highest structural efficiency would be the winner,
while others with lower efficiencies would place next.
Bridges that meet all the specifications under
Materials and Construction, but did HOLD the entire 15
kg will be ranked next.
All bridges with Construction and Materials
programs will be ranked next.