CONCREaTE

Accommodation registrations have started. To register for accommodation, click here.

"There I always a way to make it better, all you have to do is find it"

- Thomas Edison

First used in the early 6 century BC, Suspension bridges have come a long way in shaping the way transport is done. Be it the Golden Gate or the Brooklyn, stronger than any other in their league, these beauties are the pride of every city that uses them and building one is an engineering marvel in itself. Techfest 2009 gives you CONCREaTE, a chance to own your very own suspension bridge with nothing but popsicle sticks.

1. Problem Statement

Design a Suspension Bridge using Popsicle sticks (ice-cream sticks) satisfying the stated constraints.

Prizes worth INR 13,000 to be won.

View the Bridge Specifications »

Registration for CONCREaTE has started. Click here to register.

For further queries contact:

Agyeya Sharma

Manager, Dimensions
Techfest 2009
+91 98199 02815
agyeya[at]techfest[dot]org

Sidharth Mishra

Manager, Dimensions
Techfest 2009
+91 98198 14256
sidharthmishra[at]techfest[dot]org

2.1 Construction Details

Definition of suspension bridge: - A bridge having the roadway suspended from cables that are anchored at either end and usually supported at intervals by towers. (Reference - www.answers.com/topic/suspension-bridge?cat=technology)

Construction of a suspension bridge involves sequential construction of the four major components: the towers, cable anchorages, the support cables and the deck structure.
The structure required in the competition will have two towers and the suspended bridge in between should be of 700 mm in length.
The cable anchorage will be provided by the organizer. They will be a C shaped channel section 200 mm high. The bridge deck will be fixed to the channel section with help of 4 clamps, 2 on either side. The clamps will be provided by the organizers. The main cables will be anchored to these clamps.
The length of the bridge extending out of the tower to the anchorage will be 150 mm on each side of the tower.
All the cables in the suspension bridge will be made up of single layer of string. Use of multiple layers of strings is not allowed.
The string can either be glued to the deck or you can knot the string.
Total number of cables between the two anchorages (700 mm clearway) should not more than 70 i.e. a maximum of 35 string on each side is allowed.
The width of the bridge will be equal to the 170 mm. The width will be measured at any length of the bridge.
The minimum clearance of the bridge from the bottom should be 200 mm.
The suspension bridge must have a level, seamlessly constructed roadway. A loaded trolley will be moved along the deck of the bridge.

Figure 1

2.2 Plot Specifications

Shown below is the platform on which your bridge will be mounted.

Two steel channel sections will be provided as shown in the figure. The centre of the steel section will be 1000 mm apart.
A total of 4 clamps (2 on both the section) will be fixed at both of the steel section. Your deck will be supported by this clamp.
The pillar structure will be mounted on the 2 zones shown in red. Each zone is 80 mmx80 mm with a depth of 50 mm. Distance between the centers of the two zones is 700 mm. They are placed 150 mm respectively from each channel section.

Figure 2: Top View

Figure 3: Side View

The board will be provided by the organizers.

View the Competition Details »

3.1 Material Constraints

Popsicle sticks (maximum length 113 mm, width 10 mm and thickness 3 mm), threads (cotton only, synthetic material threads will be disqualified) and adhesives (Synthetic white adhesive or single component cyano-acrylate adhesive) can only be used to build the structure.
Adhesive can only be used to join Popsicle sticks together; however adhesives cannot be applied on the free surface of a member made of Popsicle sticks to increase its strength (Adhesives such as M-Seal^® are not allowed).
The maximum diameter of a string member that can be used is 1 mm. Suggested string is the cotton string used by cobblers. To verify this constraint each team must bring a 1 m long sample of the string used by them. (To verify the diameter of the string, it will be wound about a cylindrical object (like a pen). 10 turns will be wound about a cylindrical object. The length of the string will be measured along the axis of the cylinder. Thus the diameter of the string would be equal to the length of the string along the axis of the cylindrical object divided by number of turns wound about it.)
The Popsicle sticks can be cut or trimmed to any shape or size.
Structures built using any other materials except those mentioned above will be disqualified.

3.2 Test Condition

Prior to evaluating the bridge, the student builder must demonstrate that the road bed (between the two bridge piers) is actually supported by the cables. The student will be asked to raise and lower the cables demonstrating that the road bed will actually rise and fall.
The bridge will be loaded by moving a trolley along the deck of the bridge caring some weight.
Each team will be given three chances for testing. The team members will decide how much weight the trolley will carry, i.e. 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 kg.
The testing will involve running of a trolley of the three different chosen mass on whole of the bridge length.
The trolley will be fabricated and provided by the organizers.
The participant will be required to pull this trolley on the full length of the bridge. A string will be attached to the trolley for the same purpose and can be pulled by the application of a force which must lie in a plane parallel to the bridge surface.

3.3 Definition of Failure

Structure fails to satisfy any of the constraints specified above.
Any part of the structure touches any point on the board except the red area marked over the ply-board during the course of testing.
Structure breaks (any string or Popsicle stick) or is not in a condition to carry the load over it.

3.4 Judging Criteria

If the structure does not fail it will be scored on the following basis:

Strength Ratio is defined as the ratio of the maximum weight sustained by the structure (10 to 20 kg) over the weight of the structure.
The team with the highest strength ratio will be declared as a winner.

View the Rules »

4.1 General Rules

Shape: Structure could be of absolutely any shape satisfying the above constraints
Once the structure is weighed, you are not allowed to modify your structure in any way.
If the structure fails to satisfy any of the above constraints then it will be summarily rejected.
Any team that is not ready at the time specified will be disqualified immediately.
Judges' decision shall be final and binding on all.
The organizers reserve all rights to change any or all of the above rules as they deem fit. Change in rules, if any will be highlighted on the website.

4.2 Team Specification

Each team may have a maximum of 2 team members. Participants from different institutions can form a team.

4.3 Eligibility

All students with a valid identity card of their respective institutes are eligible to participate in CONCREaTE in Techfest 2009.

4.4 Certificate Policy

Certificate of Excellence will be given to the top teams emerging from this competition.
Certificate of Participation will be given to all the teams which satisfy the rules mentioned and are able to withstand a weight of 10 kgs.

4.5 Registrations