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General Bridge Info

The type of bridge we were researching was the Manchac Swamp Bridge located in St. John the Baptist Parish, Louisiana, U.S.A. Our bridge is a trestle bridge, which is a sister of the beam bridge. The bottom of the road has trestles, which are these A-Framed supports that helps the bridge stay stable. The purpose of the bridge is to accommodate traffic across wide valleys, steep ravines, and large bodies of water. The main parts of our bridge are the concrete deck,the trestles, its beams, curbs, railing, and wires. The deck is not made of pure concrete, it is made of prestressed concrete which is a method for overcoming concretes natural weakness in regards of tension. Trestles are a framework made of a horizontal beam supported by A-Framed which is a frame that is shaped like a capital A. The beams are long sturdy supports that hold the bridge itself. Our team found this bridge interesting particularly of its length, it is one of the longest bridges in the world, it is approximately 22.8 miles long.

 

 

Development of Testable Question

 I focused on the main components of the bridge. Looking at our bridge we noticed that the bridge itself could carry a lot of live load because the bridge was spread out over a large area. I wanted to test if the bridge being a certain width could let the amount of force applied by live load make the force spread throughout the road or if it wouldn’t make a change at all. At first I wanted to my testable question was to see if the material choices of the bridge affected the amount of traffic the bridge could carry. I had to change this experiment due to the fact that I did not have the material necessary to test this experiment. Then I decided to change a specific part of the bridge, so I wanted to test to see if the width of the bridge affect how much load the bridge can carry, some changes that I had to do was to narrow the question more down because there was more than one type of load, live load and dead load. Dead load is the weight of the bridge itself and live load is the weight of the traffic that travels on the bridge. After that I chose if the width of the bridge affect how much live load the bridge can carry.

Analysis of Testable Question

The final testable question that I chose to experiment was “Does the width of the bridge affect how much live load the bridge can carry?”. Because the bridge already is one of the longest bridges in the world, I wanted to see if there was any correlation between the width of the bridge and the amount of traffic the bridge can support before there is any type of deflection. Throughout the bridge everything would be the same, but I would only change the width (variety of widths).  If we increase the width of the bridge, then our bridge will be able to carry more load because the bridge will have more space to distribute load. Testing the different widths can help see if the greater the width of the bridge, the more amount of force will be able to be spread throughout the road of the bridge. Not only will the bridge be able to carry a great amount of load due to its length, but due to a larger width, more load will be able to spread out throughout the road.

 

 

 

REFERENCES

http://www.thetruckersreport.com/facts-about-trucks/

http://www.warwickallen.com/bridges/BeamBridges.htm

http://www.design-technology.org/beambridges.htm

 

ROSA

Development of Testable Questions and Hypothesis

Experiment Design & Procedure

Experiment Design

The question I ended up investigating in an experiment was “Does the width of the bridge’s road affect how much live load the bridge can carry?”. The independent variable I was testing was the width of the bridge and the dependent variable was the amount of load the bridge can carry. The amount of load the bridge could carry would depend on the width of the bridge.Since I was going to change the width of the road, I would use the same cardboard material with the same height and all I would alter was the width of the bridge. I had to use a ruler and measure a different width for each road (3”-7”). After I marked by how wide I was going to make the bridge, I cut the cardboard, making a road with a different width. After I had my different widths all I was going to measure was how much live load the road can carry. To a certain point of deflection I would then press a Dual Range Force Sensor on the midpoint of the road and check how much force was applied once it reached a certain point of deflection. I kept the type of cardboard the same, the length of the road the same throughout, the support beams, and the amount of trials the same. I kept these constant to ensure that there weren’t any factors that would greatly change my data and to make sure that my data was reasonable.

Procedures

Experiment Reflection

My team member and I believed that we would have more time to perform our experiment, but due to the time shortage we had to hurry up and work with what we had. It was challenging because we already had an idea of what we wanted to accomplish but had to alter our experiments. After a while my cardboard would begin to bend and crease, once I pressed the board with the Dual Range Force Sensor the numbers weren’t the same and would fluctuate, making it hard to get accurate data. If I could do this experiment again I would use stronger material, I noticed that after a while the cardboard would break down or it would fall out of place and I would have to redo the set up. If I would improve these things then I think I would get way better data.

For gallery of experiment click HERE

Collecting, Analyzing & Interpreting Data

Data Collected

Analyzed Data

Interpreting Data

Conclusion

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