Pictures of the Set of Bridges

Presentation - Conclusion

In conclusion building bridges with extra compression members that are placed in the correct places could help the bridge in its weight bearing capacity.
These compression members may help in reducing the possible failure of the bridge but in real life the extra members will cost more to produce.
Although Truss bridges seem to be the best decision for a real life application, its vertical members can cause a distraction to any driver when going through the truss configurations.
A real life application of any bridge but first be decided on the surroundings of when it is to be placed. If the distance from A to B is vast and at a significant height then it might be best to choose a expansion arch bridge. As for shorter distances, girders or rigid frames might make a better decision.

Presentation - Results

As a result, the truss (Sonny Truss) with an extra compression member was able to hold the most amount of weight due to it’s extra member which allowed it to distribute weight more efficiently.
The second best bridge in weight bearing capacity as compared to its design was the Pratt Truss Bridge that with stood 32 pounds.
As for the most efficient bridge in the series, the Sonny Truss also took place for being the most efficient bridge
As a result, compression members added to any truss bridge when placed in the correct spot can be very useful in the even distribution of weight from the center of the bridge to the foundation of the bridge itself.
Without the correct placement of a tension/compression member, the bridge might have had an early failure and would have led to a skew in the experimentation process.

Presentation-Testing Method

This were I tested my different bridge types with different loads sizes. The way that this will work is by connecting a bucket on to the bridge and then putting in loads one at a time until the bridge fails to maintain its self then that’s when I shall count the loads and see how much it was able to sustain. In order to keep the bridges from skewing and not receiving the correct results I decided to add an extra wall so that the bridge would not collapse to its side. This would then allow for better testing of the bridge's actually design.

Presentation- Distribution of Loads

This picture illustrates how the arch bridge works and how the load or the loads of the weigh on top of the arch bridge is distributed. This a very good demonstration of how the loads on a arch bridge is distributed.

Presentation- Truss Bridges

The truss is a simple skeletal structure. In design theory, the individual members of a simple truss are only subject to tension and compression forces and not bending forces.
Trusses are comprised of many small beams that together can support a large amount of weight and span great distances. In most cases the design, fabrication, and erection of trusses is relatively simple. However, once assembled trusses take up a greater amount of space and, in more complex structures, can serve as a distraction to drivers. Trusses can come in many different types of forms and bracing styles.

Presentation- Beams

A girder bridge is perhaps the most common and most basic bridge. A log across a creek is an example of a girder bridge in its simplest form. In girder bridges there are actually two types of bridges. These bridges are the I-beam bridge and the box beam bridge. These are two different types of commonly used bridges in the united states.
1.Girder-a beam made usually of steel; a main support in a structure.
Here are to illustrations of the bow and I-beam.
The top illustration is the I-beam and it is very noticeable of why it is called the I-beam. The lower illustration is the bow beam which takes form of the box.
The inner plate is known as the web and the top and bottom beams are known as the flanges.

Presentation - Arch Bridges

After girders, arches are the second oldest bridge type and a classic structure. Unlike simple girder bridges, arches are well suited to the use of stone. Many ancient and well know examples of stone arches still stand to this day. Arches are good choices for crossing valleys and rivers since the arch doesn't require piers in the center. Arches can be one of the more beautiful bridge types.
1.Arch-a curved shape in the vertical plane that spans an opening
2.Arch-a masonry construction (usually curved) for spanning an opening and supporting the weight above it
Arches have been used in many places through out the world such places like Rome and there Aqueducts which was a long bridge that transported huge amounts of water to an aquifer in Rome.
The arch bridge works in a form called compression. It allows the load of the bridge to be evenly distributed. Jus as in the pictures.

Presentation- Variables

Independent Variables that will be included in the construction of the bridges are the amount of glue used in each joint of the bridges.

The wood glue used in each joint will influence the outcome of the make amount load/weight that the bridge can withhold.

Variable that will effect the testing of the bridge include the thickness of the wood.

Presentation- Materials

Good Glue

1/32”x 20” Bass wood

18”x 6” paper

Sand for creating a load weight on the bridges.

Camera & Tripod

18” Ruler

Foam board

Pushpins

Presentation- Hypothesis

From my research in the way that bridges work through compression and tension I predict the Truss bridges will be the most weight bearing for two reasons.

More compression and tension members than any other bridge will give it the advantage at maintaining a even distribution in load/weight.

Another reason for the hypothesis is because Truss bridges have the power to direct load/weight in many directions until it has distributed into the earth on which it was built.

Presentation- Problems

Deciding on which bridge to build for a particular location depends on many factors. What type of traffic it will cause? What passes underneath the bridge? What locations are available for foundations for the bridge? What is the budget for the construction? As well as what materials are to be used for the construction of the bridge?

Which bridge type will be the strongest and most efficient? This will largely rely on the surroundings of where the bridge is most needed. Just like in any construction project, the foundation of the structure will tell the future of structure.

Which bridge type will have the greatest strength to weight ratio?

Presentation- Introduction

—Within the United States and many other industrialized countries of the world bridges, have be helping in transporting us from point ‘A’ to ‘B’.

—There are many different types of bridges that range from the most simplest Girder bridge to the large and elegant suspension and arch bridges.

—For my experiment I will be testing a series of bridges to see which of all the bridges to be tested is the most weight bearing as well as efficient.

Retesting and the results

After the first round of experiments, i discovered that the results were not very clear for the experiments themselves. The first set of bridges, I found out to be skewed. Therefore, I had to retest the bridges and modefy the testing rig to get clear results that were easy to understand. When testing the first bridges, I discovered that three dimensional bridges are not as easy to experiment on as compared to two dimensional bridges. Since there is a extra dimension added to the bridges, it leaves more room for error. Therefore, the testing rig had to have a set of walls added to it in order for the bridge design to be tested correctly. Adding a set of walls would then all for the loads to be distributed evenly on the compression and tension members and not necessarily on the horizontal members connecting one side of the bridge to the other face of the bridge. These Are the results.

Before the City Wide Science Fair

Before the City Wide Science Fair

• I retested the bridges
• Recreated the power presentation to include the new information gained after the third trial of experiments.
• Did not receive award at school wide.

Research Plan

1. The goal in this experiment is to experiment with many different types of bridges that include the Arch, Truss, Warren, Pratt, Rigid Frame, Girder and my own designed bridge. The question is to find out which of all the bridges tested is the most efficient bridge for its design as well as figuring out which is the most weight bearing.
2. The main hypothesis throughout the experiment is that the Arch Bridge will be the most efficient bridge in the series of bridges being tested. Since it uses arch technology, it will distribute the weight much more evenly than that of any oter bridge, making it the most efficient than the others. The other part of my hypothesis predicts that the Sonny Truss (Own design) will be the most weight bearing as compared to the other bridges due to its extensive amount of compression and tension members within the design of the bridge.
3. Procedures: The first step in this experiment is to first identify the types of bridges you would like to test, such as truss bridges or arch bridges.
1. The second step is to then draw these bridges on a 18”x 6” paper. If you were to be doing a Truss bridge then it would also be nice to be able to do different truss bridge configurations.
2. The third step is to purchase __ x__ cm bass wood to construct your bridges.
3. Then on comes the fourth step the drawing of the pictures you will need to cut out the wood in the exact same size so that it all fits in one same place like on the pictures. Another important detail is that it is also necessary to cut the pieces of wood at the angles needed.
4. After all of that is done comes the fifth step. What you will need to do is put those pieces of wood on a board with some push pins to hold them down in order to glue them down. When it comes to the glue it would be specific glue called wood glue. Wood glue it much more power full and in some instance it can even be much stronger then actual wood itself. After the wood has dried over night then it has fully hardened and it is then ready to test.
5. The next step is to then test these different bridges with small weights ranging from ½ to 5 pound incensements. These will now be known as the loads on the bridge. Basically see how much load a bridge can hold before collapsing. These loads will be in a weight range from around 0.5 to about 1.0 LBS. For the experiment I will then be putting the bridges on a table and then a bucket and then the loads will be added until the bridge fails.
6. After wards count the amount of loads that the bridge took and I will make a graph to record those results.
4. Data Analysis- To analyze the results I I will create a chart that outline the ‘TOW’ which represents the Times its own weight factor of efficiency. I will also create a chart to outline the amount of deflection created by the bridge during the experimentation and its weight increments. This chart will then allow for a better conclusion as to which bridge was the most weight bearing, efficient, and best overall bridge.

My Presentations' Terminology

Beam
A structural member, usually horizontal, with a main function to carry loads cross-ways to its longitudinal axis. These loads usually result in bending of the beam member. Examples of beams are simple, continuous, and cantilever.

Beam-Column
This is a structural member whose main function is to carry loads both parallel and transverse to the longitudinal axis.

Cantilever
Cantilever refers to the part of a member that extends freely over a beam, which is not supported at its end.

Collateral Load
Collateral load is additional dead loads (not the weight of people and not the weight of the building itself), such as plumbing, duct work, ceilings, and other components of the structure.

Column
A column is a main vertical member that carries axial loads from the main roof beams or girders to the foundation parallel to its longitudinal axis.

Continuity
Continuity is the term given to a structural system describing the transfer of loads and stresses from member to member as if there were no connections.

Damping
Damping is the rate of decay of amplitude for floor vibrations.

Dead Load
Dead load describes the loads from the weight of the permanent components of the structure.

Deflection
Deflection is the displacement of a structural member or system under a load.

Dynamic Load
This type of load varies over time.

Footing
A footing is a slab of concrete under a column, wall, or other structural to transfer the loads of the member into the surrounding soil.

Foundation
A foundation supports a building or structure.

Load
An outside force that affects the structure or its members.

Torsion Loads
A load that causes a member to twist about its longitudinal axis. A couple or moment in a plane perpendicular to the axis produces simple torsion.

Compression The force that makes the bridges' ends want to come together.

Tension The force that tries to separate the bridges' ends.