Bridge Design Project
The Project:
The goal of this project was to create a model bridge that has the greatest strength-to-weight ratio in competition against other students competing in The Annual Pennsylvania Society Of Professional Engineers Bridge Building Competition. All bridges had to be constructed of basswood strips and elmer's carpentry glue. Other construction criteria were that the bridge could not exceed 45 centimeters in length, 8 centimeters in width, 14 centimeters in height, and the height from the supports to the deck could not be more than 4 centimeters. In addition, no part of the bridge could extend below the support surfaces, the bridge must allow for mid-span loading, the mass of the bridge may not exceed more than 30 grams, and it must span a gap of 30 centimeters.
The Design:
For this challenge, a Beam-Bridge design was selected, because of their optimal performance under distances of 250 feet. The basic idea was to use laminating techniques to make the beams of the bridge as strong as possible, while keeping it relatively simple and lightweight. A similar competition, held at the Technology student association, also lent background knowledge, where after competing for several years, a number of participants found that the strength of the base or "pedestal" was more important than the over-structure. One of the ways of getting the pedestal to be strong was a technique called lamination, where beams are fastened together down their entire length, to make a bigger beam. This was done on the sides of the pedestal, while cross-bracings were added inside to prevent the bridge from bowing outwards.
The construction process was slow, and the materials available were not enough to construct h\the complete design. Multiple compromises were made to stay under the weight limit of the competition (the amount of materials used did not matter, as long as the weight limit was met) and to finish the bridge in time for submission.
The Results:
The final design had a mass of 20.8 grams, and when tested, held 2,586 grams, giving it an efficiency ratio of 125:1, the design also met competition specifications.
Experience, Lessons Learned:
The biggest lesson is about work ethic. The bridge barely made the deadline for submission, and was not of a very high quality. Had more time bee spent concentrating on designing and constructing the bridge, the results would have been different. Another lesson was on planning. When the material provided were not enough to satisfy the demands of the design, compromises had to made. If more planning had been done, this could have been avoided.
The goal of this project was to create a model bridge that has the greatest strength-to-weight ratio in competition against other students competing in The Annual Pennsylvania Society Of Professional Engineers Bridge Building Competition. All bridges had to be constructed of basswood strips and elmer's carpentry glue. Other construction criteria were that the bridge could not exceed 45 centimeters in length, 8 centimeters in width, 14 centimeters in height, and the height from the supports to the deck could not be more than 4 centimeters. In addition, no part of the bridge could extend below the support surfaces, the bridge must allow for mid-span loading, the mass of the bridge may not exceed more than 30 grams, and it must span a gap of 30 centimeters.
The Design:
For this challenge, a Beam-Bridge design was selected, because of their optimal performance under distances of 250 feet. The basic idea was to use laminating techniques to make the beams of the bridge as strong as possible, while keeping it relatively simple and lightweight. A similar competition, held at the Technology student association, also lent background knowledge, where after competing for several years, a number of participants found that the strength of the base or "pedestal" was more important than the over-structure. One of the ways of getting the pedestal to be strong was a technique called lamination, where beams are fastened together down their entire length, to make a bigger beam. This was done on the sides of the pedestal, while cross-bracings were added inside to prevent the bridge from bowing outwards.
The construction process was slow, and the materials available were not enough to construct h\the complete design. Multiple compromises were made to stay under the weight limit of the competition (the amount of materials used did not matter, as long as the weight limit was met) and to finish the bridge in time for submission.
The Results:
The final design had a mass of 20.8 grams, and when tested, held 2,586 grams, giving it an efficiency ratio of 125:1, the design also met competition specifications.
Experience, Lessons Learned:
The biggest lesson is about work ethic. The bridge barely made the deadline for submission, and was not of a very high quality. Had more time bee spent concentrating on designing and constructing the bridge, the results would have been different. Another lesson was on planning. When the material provided were not enough to satisfy the demands of the design, compromises had to made. If more planning had been done, this could have been avoided.