Bridge Competition!

Efficiency rating = Weight it can hold (up to 15 kg) / Weight of the bridge

Bridge HW Grade based on:

• 25% Design 
• Creativity (your own design? or just something from the internet?)
• Aesthetic appeal
•  Homogeneous distribution of weight

• 25% Use of materials (what material did you use, and why?)
• Cost efficiency (the cheaper the better)
• Strength/weight ratio
• bonding agents & designs

• 25% Efficiency rating
• Class weighted; Top 33% = A, next 33% = B, lowest 33% = C

• 25% Adhere to all of the rules
• It's long enough for the span?
• It is able to be loaded with the 5cm loading block?

Prize:
Person with the highest efficiency rating in each class does not have to take the final.

Basic set-up:
A 5cm by 5cm by 2 cm wood block with a hook in the center will support the weight (see the top green arrow)

Weight will be added to your bridge by adding sand to a bucket suspended to your loading block. 



TuTh:
18 inch span

Wed. night
3feet span

** Your bridge will need to be slightly longer than what it needs to span!  Span = the distance between the tables your bridge will be resting on. 

Rules:

• The bridge will just rest on the table surface - you cannot anchor it with duct tape etc.

• You can make your bridge out of any material you want, but remember efficiency is determined by your bridge weight, so choose materials carefully!

• Failure will be defined by either the bridge breaking, or deforming more than 5 cm.  

• You will need to fully load your bridge in 8 minutes or less.  

Tips:

• Pay attention to your joints - make the connections solid!  

• Use clothespins, bent hairpins, paperclips, or small C-clamps (from the dollar store) to hold pieces together while it dries:

• Wax paper makes a great building surface - the glue won't stick to it.

• Build it in sections - don't try to build it all at once!

Bring your bridge in to test:

• Tu/Th class - Thursday 11/13/2014
• Wed class - Wed 11/19/2014

Good luck!Wed
#1:

#2