# The Physics of a Truss Bridge

There are many reasons that we need bridges in every day of our life, from sufficient means to pass over a roadway, waterway, railway, or other structure. You don’t even think about them because it takes no effort to get over them and they are just there for your use. So if you don’t think of them for I highly doubt that you would think of the physics that is involved in putting one together or the kind of force the bridge can actually take. I am going to show you the max force a truss bridge can take by demonstrating it to you in class and also by trying to calculate it. I am also going to go over the many ways that truss bridges can fail and come to a tumbling crash. Before I get into the physics of the bridge you need to know what a truss bridge is and how it works. A truss is a structure composed of members connected together to form a rigid framework. Members are the load-carrying components of a structure. In most trusses, members are arranged in interconnected triangles, as shown below.

Because of this configuration, truss members carry load primarily in tension and compression. Because trusses are very strong for their weight, they are often used to p long distances. They have been used extensively in bridges since the early 19th century; however, truss bridges have become somewhat less common in recent years. Today trusses are often used in the roofs of buildings and stadiums, in towers, construction cranes, and many similar structures and machines. An easy way to understand how a truss bridge works is to use a nutcracker and a string tied to the ends of the nutcracker. So even if you push down on the nutcracker it will not move or slide on the table. This is because the nutcracker is in equilibrium.

I am going to show you a little of a harder way of calculating it with three triangles that are in the shape of a truss bridge so you can understand how the bridge works 400N 800N A B C D E 2m 500 N 700 N

Sum of torques = (1m) (-400N) + (3m) (-800N) + (4m) (E) =0 E= 700N

Sum of forces = Ay +E -400N- 800N Ay = 500N.

Now that we know how the forces are laid out, let’s take a look at what is happening at point A. Remember that all forces are in equilibrium, so they must add up to zero.

500N 60° A T Ac T AB Sum of Fx = Tac + Tab Cos 60 =0 Sum of Fy = Tab sin 60 +500N = 0.

Solving for the two above equation we get

Tab = -577 N Tac = 289 N.

When you apply external loads to a structure, external reactions occur at the supports. But internal forces are also developed within each structural member. In a truss, these internal member forces will always be either tension or compression. A member of tension usually stretches, like a rubber band because the tension force tends to make a member longer. This is the opposite of compression.

When a member is in compression it is usually being squashed, like squashing a block of foam between your hands.

B 289 N 289 N 577 N TAB = -577 N TAC = 289 N B A A 577 N.

The negative force means that there is a compression force and a positive force means that there is a tension force. Now let’s take a look at point B.

700 N 500 N 2m E D C B A 800N 400N 577 NB 60° TBC TBD 400 N Sum of FX= TBD + TBC Cos 60 +577 Cos 60 = 0 Sum of FY = -400 N + 577 Sin 60 – TBC Sin 60 = 0.

Once again, solving the two equations

TBC = 115 N and TBD = -346 N.

If we calculated the rest of the forces acting on the various points of out truss, we will see that there is a mixture of both compression and tension forces and that these forces are spread out across the truss. When I am going to test the maximum force of my paper truss bridge, I have calculated that it should hold 5 kilograms with no problems and probably will even get up to 10 kilograms. My bridge weighs about 55 grams so my bridge should have a strength-to-weight ratio of over 90, which is very good, and if I can get it to hold 10 kilograms it will be wonderful. Once we hit the maximum load we are going to see my bridge come to a crashing end.

My crash will be due to overloading, but there is much more reason why bridges come to crashing ends. Some of the more common ones are overloading, collisions that cause damage to the bridge, poor construction, and wear and tear. There are many other things that could make a bridge fail but they get particular, like a bolt in a joint rusting out causing the whole structure to become unsound. Overall we have learned the physics that it takes to keep truss bridges stands, which is a lot. We also came to understand that there is a lot of tension and compression in a truss bridge and that it is a key component of the bridge even though you can’t really see it happening. Plus how bridges will eventually come to a crashing end and what causes them too and hope that what we will see happen to my bridge when I demonstrate it in class. Bibliography Boon, Garrett.

## Reference:

1. Model Bridge design. 2010. 30 11 2010. Britannica, Encyclopedia. truss bridge. 2010. 31 12 2010.
2. Buzzle. com intelligent life on the web. 2009. 31 11 2010. Donan Engineering. 2010. 29 11 2010.
3. Serway, vuille. College Physics. Belmont, CA: Brooks/Cole, 2009.

Calculate the price
Pages (550 words)
\$0.00
*Price with a welcome 15% discount applied.
Pro tip: If you want to save more money and pay the lowest price, you need to set a more extended deadline.
We know how difficult it is to be a student these days. That's why our prices are one of the most affordable on the market, and there are no hidden fees.

Instead, we offer bonuses, discounts, and free services to make your experience outstanding.
How it works
Receive a 100% original paper that will pass Turnitin from a top essay writing service
step 1
Fill out the order form and provide paper details. You can even attach screenshots or add additional instructions later. If something is not clear or missing, the writer will contact you for clarification.
Pro service tips
How to get the most out of your experience with MyStudyWriters
One writer throughout the entire course
If you like the writer, you can hire them again. Just copy & paste their ID on the order form ("Preferred Writer's ID" field). This way, your vocabulary will be uniform, and the writer will be aware of your needs.
The same paper from different writers
You can order essay or any other work from two different writers to choose the best one or give another version to a friend. This can be done through the add-on "Same paper from another writer."
Copy of sources used by the writer
Our college essay writers work with ScienceDirect and other databases. They can send you articles or materials used in PDF or through screenshots. Just tick the "Copy of sources" field on the order form.
Testimonials
See why 20k+ students have chosen us as their sole writing assistance provider
Check out the latest reviews and opinions submitted by real customers worldwide and make an informed decision.
excellent job
Customer 452773, August 26th, 2023
excellent job
Customer 452773, August 3rd, 2023
Thanks
Customer 452773, March 3rd, 2023
Thank you for your hard work and help.
Customer 452773, February 13th, 2023
Great job
Customer 452773, February 13th, 2023
excellent work
Customer 452773, March 9th, 2023
excellent job! got an A, thank you
Customer 452773, May 24th, 2023
always perfect work and always completed early
Customer 452773, February 21st, 2023
Thank you
Customer 452773, March 19th, 2023
History
Looks great and appreciate the help.
Customer 452675, April 26th, 2021
Management
Love this writer!!! Great work
Customer 452597, April 5th, 2021
Perfect
Customer 452773, February 23rd, 2023
11,595
Customer reviews in total
96%
Current satisfaction rate
3 pages
Average paper length
37%
Customers referred by a friend
Use a coupon FIRST15 and enjoy expert help with any task at the most affordable price.
Claim my 15% OFF Order in Chat