Update 13

Acaccelerated Bridge Construction

The steel bridge competition consists of three scored sections. These sections include weight, deflection, and construction time. With fabrication completed, the weight and deflection portions of the bridge are mostly set in stone. The final variable score is the time of construction on site during the regional competition at NJIT. To ensure a quick build time ABC (Accelerated Bridge Construction) techniques were implemented. The major techniques that were implemented included using multiple piers, consistent building steps, and assemblies. Multiple piers allow for the bridge to be supported without a team member needing to hold it. This results in more efficient construction as team members can constantly be moving and building. Consistent building steps result in a methodical and repeated process of building the bridge efficiently and without delay. The final technique was using assemblies. Assemblies are two members that are connected in the construction zone and then moved by two members into position on the bridge. These are beneficial because they allowed the team to span the river and not have to connect the upper and lower sections once in place. Overall these methods have allowed for extremely quick build times that will make the team competitive at the competition.

Update 12

Bridge Transportation

With the fabrication and aesthetic components of the bridge complete, the next major concern was the transportation of the bridge. Given that our competition will be conducted at NJIT, it is necessary to develop a method for moving the bridge to the competition site. Along with the physical members of the bridge, numerous other items must be transported. These items include our piers, safety helmets, construction tools, tool belts, and other miscellaneous items. Using readily available materials, the team decided to construct a box with wheels that would be able to hold all of the listed items. A second level made out of plywood and 2×4 boards was used to split the container in half to increase its organization and capacity. Additionally, screws/holes were put into the walls of the box in order to organize each of our tools. The final step was to put rails through the box so that it could be lifted in to the back of our school van on competition day. The previous years name plate was also mounted to the side of the box which is a tradition we hope to continue.

Update 11

The bridge is painted! The team selected a matte black for the outer members and a metallic gold for the lateral bracing and inner support members. Additionally, the team developed a marking system to indicate which members connect to each other, and where they belong within the overall structure of the bridge. The marking system is pictured below:

The team also constructed and attached a name place to the bridge as required by the competition specifications.

Finally, the team has been practicing the construction process in order to minimize the time of construction for the competition. The sequencing has been tweaked a variety of times in order to maximize the use of the piers and the efficiency of each builder.

 

Update 10

With the fabrication complete, the next big step was to load the bridge. This was done to determine weather the bridge will be able to withstand the applied load during the competition in late April. Safety provisions were implemented to ensure that the bridge could deflect no more than two inches to prevent failure or risk to students. To simulate the applied load, two grates were placed on the bridge in the most critical locations. Students then sat on the grates to replicate the angle irons that will be used to test the bridge. Constant visual checks were completed to ensure that failure was not imminent. Overall, the bridge passed the test and was able to withstand approximately 80% of the competition load with ease. Prior to this testing the tension connection strength on the bridge was verified. This was done because it was the location of last years bridge failure, and overall the most critical connection on the bridge. The Tinius Olsen testing machine was used to determine the strength of a single shear and modified connection using our bolts. Both tests exceeded our expectations and helped verify our our calculations. Going forward we will be painting the bridge, practicing construction, and preparing our materials for transportation to the competition. Additionally, design reports and presentations will be updated in the coming weeks. Stay tuned to the pictures of the painted bridge!

Update 9

The bridge fabrication is complete! After spending lots of time in the shop over winter break and at the beginning of this semester, the team has finally finished the last welds and assembled the bridge. The site plan has also been laid out in the building and will be used by the team to practice construction techniques. Fabrication went as expected and minimal redesign was necessary throughout the process. In the next few weeks the team plans to load the bridge and simulate the competition. This will ensure that the bridge will perform optimally on competition day. Additionally, the bridge will be painted within the month as well as attaching the name plate. Overall the team is very pleased with the bridge and owes many thanks to machine shop head Joe Zanetti. Stay tuned to the results of the loading test and the painted bridge!

Update 8

As the Fall semester came to a close, the full shipment of materials had arrived in the machine shop. Over the course of winter break, the team spent over three weeks working on the fabrication of the bridge. The first step was to cut all of the materials down to the size specified in our working drawings. Each piece was finished and filed down as to be able to interact with one another smoothly. The two bridge supports were first set in place, and then tack welded to maintain its position. The same process was completed with the truss members and the lateral bracing. Holes were drilled where necessary and checked to make sure they would adequately hold members together. It was crucial to ensure members were level and interacting as expected throughout the fabrication process. The final steps are to finish weld the bridge, and ensure that there were no mistakes made. Going forward we plan on testing the bridge, practicing the construction process, and making any improvements that we see fit.

Update 7

tension member

The team has completed 3D modeling and Strand7 Analysis of the final bridge design. Using results from Strand7, the lateral support design was found to be deficient and has since been redesigned and retested. Additionally, working drawings were developed using AutoCAD Fusion 360 for each member assembly and each individual steel member.  Steel quantities were calculated based on the amount of each material needed and the steel order was placed with the delivery expected within the next few days.

Update 6

studs

On November 2nd the team presented the design constraints and alternatives before the Civil Engineering faculty. The team discussed the realistic and design constraints that will be present for the competition. Additionally, a final truss design was selected. Design work is complete for the bridge supports and lateral bracing. Moving forward, the team will analyze the final bridge design using Strand7 to get a more accurate display of how the bridge will deflect under the loads. Additionally, material quantities and working drawings are nearing completion.

View the presentation here:

Final Presentation 1

Update 5

Full length drawing

Design Update

The team has developed a 3D model of the tentative bridge design in order to better manipulate the dimensions of individual members and design connections. The model also allows the team to better visualize the depth of each material type and how they interface with each other. Lateral bracing and support design are also well under way and will be mentioned below.

 

connection

Connection Update

The team has been exploring a variety of possibilities for connections. Depicted is a possible sliding connection solution at the interface of the top and bottom truss members. Compression members will be connected with telescoping box tubing, and the tension members will potential utilize a version of the connection above. This type of connection allows the weld to bear the majority of the forces and could minimize potential bolt failures. The cantilever side will have some unique connections due to the geometry that are also being considered.

 

lateral

Lateral Bracing Update

Several lateral bracing configurations and materials have been considered in order to resist the lateral load test and minimize the weight of the bridge. Potentials designs are being modeled in visual analysis and will eventually be added to the CAD model.

 

Supports

Support Design

The team has also been at work modeling potential designs for the supports. The supports must hold the weight of the bridge and add loads, and also resist sway during the lateral loads tests. Above is one of the potential support designs. When the supports are finished with selected materials, they will be modeled in 3D in CAD and added to the overall design drawing.