Structural Design: Bridges
Erin Mowbray Principles Of Engineering WTHS 11/24/14
Design Brief:
Client Company:
Harlan Inc.
Designers:
Erin Mowbray
Problem Statement:
Design and create a bridge utilizing west point bridge designer that is capable of withstanding a trucks weight.
Design Statement:
design a bridge using the least amount of materials that can still hold its own weight based off the geometric shapes that make up the bridge.
Design Constraints
Harlan Inc.
Designers:
Erin Mowbray
Problem Statement:
Design and create a bridge utilizing west point bridge designer that is capable of withstanding a trucks weight.
Design Statement:
design a bridge using the least amount of materials that can still hold its own weight based off the geometric shapes that make up the bridge.
Design Constraints
- Bridge must cost under $400,000
- Must be 24 meters above the river
- Must not exceed 8.5 meters over the top of
the river banks - Must not have more than 50 joints and 120
members - Must be able to hold a truck
Research Summary:
The research I collected is based on the information I have learned about trusses thus far in other activities and notes as well as the experimentation of different materials while using this software. Based on my research, I concluded I needed to design a bridge using triangles, because I have learned that they are the most stable shape for a truss. So, if I wanted to insure that my bridge would be effective I needed to make sure it was made out of only triangles; to insure its stability. Once I designed the basic sketch as to what I wanted to build, I had to make sure it was in budget. In order to stay in budget and keep the overall bridge design I wanted I had to experiment with other materials to find a functional cost efficient route to ensure my bridge design was the bomb.com
Brainstorming Sketches:
Modification Sketches:
Final Design Justification:
References:
West Point Bridge Designer Software
Conclusion Questions:
1. How does the type and direction of stress applied affect the selection of the material type and the cross sectional area?
It greatly affects it. If the material is in compression, it would be a good idea to use the harder material like the carbon-steel so it will not crack and break. It would also be smarter to use these in the members with lower cross-sectional areas. If the material is in tension, the hollow tube would be better because it can be pulled harder and farther.
2. How can the forces of compression and tension work together to make a stronger bridge?
The pushing and pulling forces on the members of the bridge keep the materials in line so they don't sway and break. The forces balance each other out and keep the bridge stable. Tension and compression can counteract each other to distribute the weight more evenly.
It greatly affects it. If the material is in compression, it would be a good idea to use the harder material like the carbon-steel so it will not crack and break. It would also be smarter to use these in the members with lower cross-sectional areas. If the material is in tension, the hollow tube would be better because it can be pulled harder and farther.
2. How can the forces of compression and tension work together to make a stronger bridge?
The pushing and pulling forces on the members of the bridge keep the materials in line so they don't sway and break. The forces balance each other out and keep the bridge stable. Tension and compression can counteract each other to distribute the weight more evenly.