Engineering Science Fair Project
Which Bridge Type Will Support More Weight?


Projects by Grade Level
1st 2nd 3rd 4th 5th 6th
7th 8th 9th 10th 11th 12th
Home Advanced Award Winning Warning!
Project Information
Title: Which Bridge Type Will Support More Weight: Beam Bridge, Arch Bridge, Suspension Bridge?
Subject: Engineering
Grade level: Middle School - Grades 7-9
Academic Level: Ordinary
Project Type: Experimental
Cost: Low
Awards: 2nd place, Canada Wide Virtual Science Fair (2010)
Affiliation: Canada Wide Virtual Science Fair (VSF)
Year: 2010
Description: Three miniature bridges, beam bridge, arch bridge, suspension bridge, were built from glue sticks; increasing weights applied till bridge collapses; result recorded.
Link: www.virtualsciencefair.org...
Background

Bridge Strength

Bridges may be classified by how the forces of tension, compression, bending, torsion and shear are distributed through their structure. Most bridges will employ all of the principal forces to some degree, but only a few will predominate. The separation of forces may be quite clear. In a suspension or cable-stayed span, the elements in tension are distinct in shape and placement. In other cases the forces may be distributed among a large number of members, as in a truss, or not clearly discernible to a casual observer as in a box beam. Bridges can also be classified by their lineage, which is shown as the vertical axis on the diagram to the right.

A bridge's structural efficiency may be considered to be the ratio of load carried to bridge mass, given a specific set of material types. In one common challenge students are divided into groups and given a quantity of wood sticks, a distance to span, and glue, and then asked to construct a bridge that will be tested to destruction by the progressive addition of load at the center of the span. The bridge taking the greatest load is by this test the most structurally efficient. A more refined measure for this exercise is to weigh the completed bridge rather than measure against a fixed quantity of materials provided and determine the multiple of this weight that the bridge can carry, a test that emphasizes economy of materials and efficient glue joints (see balsa wood bridge).

A bridge's economic efficiency will be site and traffic dependent, the ratio of savings by having a bridge (instead of, for example, a ferry, or a longer road route) compared to its cost. The lifetime cost is composed of materials, labor, machinery, engineering, cost of money, insurance, maintenance, refurbishment, and ultimately, demolition and associated disposal, recycling, and replacement, less the value of scrap and reuse of components. Bridges employing only compression are relatively inefficient structurally, but may be highly cost efficient where suitable materials are available near the site and the cost of labor is low. For medium spans, trusses or box beams are usually most economical, while in some cases, the appearance of the bridge may be more important than its cost efficiency. The longest spans usually require suspension bridges.

The failure of bridges is of special concern for structural engineers in trying to learn lessons vital to bridge design, construction and maintenance. The failure of bridges first assumed national interest during the Victorian era when many new designs were being built, often using new materials.

In the United States, the National Bridge Inventory tracks the structural evaluations of all bridges, including designation as "structurally deficient" and "functionally obsolete".

See also: www.juliantrubin.com...

Source: Wikipedia (All text is available under the terms of the Creative Commons Attribution-ShareAlike License)

Useful Links
Science Fair Projects Resources
Citation Guides, Style Manuals, Reference
General Safety Resources
Electrical Safety FAQ
Engineering Science Fair Projects

Aviation Science Fair Projects

Engineering Experiments
Books

                   



Projects Home
Primary School
Elementary School
Middle School
High School
Advanced
Easy Projects
Award Winning
Popular Ideas
Branches of Science
Experiments

Science Fair Project Guide
Home
Science Fair Project Types
The Scientific Method - How to Experiment
The Display Board
Topics, Ideas, Sample Projects

Repeat Famous Experiments and Inventions
Science Jokes Science Trivia
Scientists & Inventors

Read for Free
The Science Fair
A Juvenile Science Adventure Novel
by Julian T. Rubin

Human Abridged Wikipedia Articles



My Dog Kelly

Follow Us On:
     

Privacy Policy - Site Map - About Us - Letters to the Editor

Comments and inquiries:
webmaster@julianTrubin.com


Last updated: January 2018
Copyright 2003-2018 Julian Rubin