Two weeks ago, Lehigh University participated in ASCE’s Mid-Atlantic Region Student Conference hosted by Drexel University. One of the competitions Lehigh participated in was the Steel Bridge Competition. Since it was my first time going to the event, I was really excited to see what the competition was all about. (Throughout this semester, I helped in the construction of the bridge by cutting some of the angle-pieces, etc. and I was really excited to see where all my work was being used!) The build-team, which consisted of 5 students from Lehigh, ended up building the bridge in under 45 minutes, from which I understand is a big improvement from last year’s time.
working hard, working together!
Although the bridge passed the lateral test, it did not pass the vertical loading test. Our bridge deformed to an extent where the arches appeared to buckle under the weight added to it.
Before the bridge deformed
As I watched the bridge deform under the load, all that came to mind was Mech003, which I took instead of CEE3: Engineering Statics, and the stuff we learned about bridges, distributed loads, stress concentrations, plastic deformations, bending, etc. It was really cool seeing what I had learned in a class setting I was seeing in real life and how the concepts and equations applied to real structures. As finals begin next week for all Lehigh students, the deformation of our bridge will definitely help me remember some of the equations used in Mech3 as I now have visual aids to help me remember!
Our bridge deformed.
Ever since we returned from spring break, we have been putting in a lot of time up at ATLSS to work on the bridge. All of the steel is cut, now we just have to weld it all together. There are only a few weeks left until the competition, so we are going to be working really hard until then. We bought another welder, so our production can double, which will be really helpful. Other than welding, we have to drill some holes in some of the pieces. Once everything is done, we’ll be able to test it and practice putting it together.
This week has been a little rough because exams started, but next week, more people should be able to come and work on welding the members. Hopefully we can get everything together without any issues!
As the competition gets closer, we are working harder to finish the bridge. We have almost everything cut and ready to go. This is a picture from yesterday of one of the members grinding down the steel plates that we will use for the connections. Pretty cool!
The first semester of the Steel Bridge project is all design. There is a 40 page set of rules that we have to follow. Well, we finally have the design mostly complete-just a few more changes, probably. Below is the initial design.
The arch on the top was intended to reduce deflection, which it did, but the bridge weighed over 400 lbs. Way too much weight. So, we got rid of it, and it dropped a couple hundred pounds. Removing the arch will also make building the bridge during the competition easier and reduce the time it takes to build it. The new bridge is below.
The pink squares are the connections between the members. They are basically interlocking joints.
In the program, all of the design constraints are met. The maximum vertical and horizontal deflections are not exceeded, and the weight is relatively low. We will only really know if the physical bridge works after we build it. Our welds have to be strong and neat which will be a challenge since only 3 of us know how to weld, and we’re not the best. However, I’m confident that the bridge will be successful in the end we will have a lot of fun building it!
With the new semester comes the next phase of Steel Bridge. We designed the bridge, and we just need to do a little tweaking to it. It won’t be long before we start building it. Before we can do that though, we have to make sure everyone gets a safety tour of ATLSS and knows the rules. After that, we can teach everyone how to weld and use the tools. Hopefully we’ll start fabrication within a month!
Unfortunately, we haven’t been able to do that much for Steel Bridge. We’ve had some major software issues that set us back quite a bit. In the meantime, we went on a tour of ATLSS, the large structures lab on Mountain Top, which is where we fabricate the bridge. We’ve finally gotten things straightened out, and everyone has started designing bridges, so the bridge design phase is picking up!
ATLSS Large Structures Lab
Steel Bridge has been of to a bit of a slow start this year. We have a new President, so him and I, as the VP, have been working hard together to do everything that has to be taken care of. We are learning a lot in the process. We’ve had really good turn outs at all of out meetings so far, which is really encouraging. Most of our members are either freshman or sophomores, though, so we really need to start at the basics for bridge design. To do that, we wanted to get a faculty member to give them a crash course in bridge design. After talking to a few people, I ended up meeting with the guy who actually teaches a bridge design course here, Dr. Roy. He seems really interested in helping us and wants to do more than just give a crash course. He told me that he’d like to be part of the whole project, and help us with everything he possibly can. Dr. Roy has a lot of connections to firms in the Lehigh Valley (donations???), and when he was a grad student, he actually was a judge for a Steel Bridge Competition. He also knows some current grad students who would be interested in helping us as well. Obviously, having Dr. Roy would be a huge asset to our team, so we are in the process of getting him on board. Once we get him involved, the design process will surely pick up speed!
Also, check out our new website: http://lusteelbridge.com/