Bridge building contests:
For fun and profit (someday)

by Cindy Blobaum

When they heard the signal, the Iowa State University (ISU) bridge building team rushed to the bridge assembly area on the floor of the Minnesota State University gym. They’d been practicing the assembly for the past week in the halls of Town Engineering Building at Iowa State. Now it was time to show their stuff.

The six ISU builders’ precise movements showed their practice. Each of the 56 bridge pieces was picked up by a certain person in a specific order. A rod here. A bolt there. With the judges watching, this was no time to get nervous. Bumping the footings or stepping into the imaginary river marked in blue on the floor would earn a penalty.

Teams from other schools watched quietly from the bleachers. Supporting members of the ISU team sat, kneeled, and stood on the floor behind the boundary line.

9 minutes and 35 seconds later, it was done. The 196-pound ISU Steel Bridge entry in the 2007 competition was up. The 6 team members returned the staging yard to watch the load test and hear their score.

With high fives, thumbs-up, and back slaps, the other team members waited as well. The timed assembly was only the final and most dramatic phase of the contest. It had taken months of work by many others to make this moment possible.

Specifying success

It began in September. Members of the ISU student chapter of the American Society of Civil Engineers (ASCE) downloaded the copy of the 2007 rules for the Student Steel Bridge Competition. The rules were basically a blueprint for the teams to follow. The blueprint didn’t dictate what the bridge would look like when it was done, but it did outline the following:

• the safety standards
• the imaginary building site
• necessary bridge dimensions
• suitable building materials
• the load the bridge needed to be able to support

Other important factors for the team to consider were aesthetics, stability, and cost. These are similar to the information that civil engineers receive when a working bridge is first conceived.

Civil engineers are the professionals trained and hired to design, build, and maintain bridges, roads, canals, dams, and other public works. Civil engineers work for engineering firms and private contractors as well as for local, state, and federal governments.

But civil engineers are not the only ones involved in bridge building. During a post-contest meeting, Ben Curry, the ISU Steel Bridge team president, talked about recruiting new team members. Specifically, he wanted to target students studying mechanical and industrial engineering. They would be able to bring new knowledge and skills to help with next year’s entry.

If they were building a real bridge, they would have wanted to consult with soils engineers, traffic and safety experts, and surveyors as well. As it was, the team had their hands full. Some worked on designing the bridge. Others raised money and asked for material donations. When the design and materials were in place, there was a lot of work in cutting and joining pieces together. The final step was to assemble it.

Building options

So, how do you go about designing and building a bridge—even a model one?  Maybe as a child you made simple ones using sticks and logs, Tinkertoys, and Erector sets. Kids continue to do that, with some new options.

Borrow a bridge kit

Jay Staker, director of Iowa State University’s Extension - Science, Engineering and Technology (E-SET) program, developed a bridge building kit that has been used by kindergarteners through adults across Iowa. The 25 pieces of aluminum tubing and wooden dowels create a 6-foot long bridge. When 4 pieces of plywood decking are added, the bridge can support 250 pounds. So when they’re done, builders get a chance to climb through it.

Then they are given detailed requirements and challenged to design and build their own model bridges using K-Nex brand toys. Trial and error is a part of the process.

Compete in a high school Physics Olympics

There is less time and tolerance for trial and error in contests. Andria O. and Anna V.* of Prairie High School learned this during the 2006 Iowa Physics Olympics. “We went over the rules about a dozen times to make sure we really understood what we needed to do.”

Their bridge could be built using only wooden toothpicks and Elmer’s woodworkers glue. The finished bridge could be up to a certain height, width, length, and weight. It had to have enough room for a board to pass under it. The winning bridge would be the one that withstood the greatest amount of applied force.

Andria and Anna brought a tall, pointed bridge to the contest. “We had learned through research that points are very good at supporting weight, and we figured that a taller bridge would have more room for the weight to distribute to.” However, during the contest, the top of the bridge twisted as weight was applied. The rules stated if a bridge moved more than .5 centimeters in any direction, it would be disqualified. Their bridge was out.

They tested it after the contest, and it held quite a bit of weight. Would the twisting have been a problem on a real bridge? Maybe.

London’s Millennium Foot Bridge across the Thames was closed just 8 days after it opened. The thousands of people walking across it often stepped down at the same time. This caused the bridge to sway up to 70 millimeters. Some people said this swaying made them seasick. It took 2 years and 700 tons of materials to reduce the sway to just 1 millimeter.

Today, civil engineers may build model bridges, but usually just for show. They rely on computer programs to test most conditions and factors. Members of the ISU Steel Bridge Team played around with free virtual bridge design software developed by West Point. This program was not the one actually used by the team designer, but it allowed new team members to get a feel for the process.

Making connections

Getting a feel for the process is one reason students take part in bridge building contests. Andria said, “I can honestly say it has helped me a bit in career decision. Recently I’ve come around to wanting to be an engineer. This experience in building the toothpick bridge came to my mind.”

Civil engineering students Katie Gierut and Jared Augustine of the ISU Steel Bridge team both said, “The Steel Bridge Building Contest was the fastest way to be involved in an engineering project from start to finish. It is the best way to get hands-on experience.” Jeff Casmer said, “It was a great way to apply what is introduced in the classroom. Here’s the problem, solve it.” Karen Grey couldn’t help adding, “It was also a way to meet upperclassmen.”

Club president Ben Curry stressed its value in job hunting. “Many engineering companies are familiar with the Steel Bridge Contest. If they didn’t compete in it themselves, they may have been approached to provide support for a student team. It gives you a talking point during an interview, a way to make a connection between school and the real world.”

Connecting is the key. Although the 2007 ISU Steel Bridge did not place high enough to be invited to the national contest in California, the bridge will continue to make connections. Team members plan on having it at various campus events to showcase the engineering program and encourage more people to join the team. And they all know that a good bridge design, whether it is of steel, toothpicks, or pixels on a computer, could possibly transport them much farther than the footings at one end or the other.

For more information

For information about the programs mentioned above or careers in civil engineering, check out the following links:

• ASCE career center
• Iowa State University’s Extension - Science, Engineering and Technology
• Iowa Physics Olympics
• Iowa State University Steel Bridge Team
• 2007 AISC Student Steel Bridge Competition
• West Point Bridge Design Contest This program is open to all interested participants.

 

* Last names of minors are withheld unless parental permission is sought and granted.