NORTH ADAMS -- It isn't every day that students get to see the practical applications of geometry, trigonometry and algebra.
That was the goal Tuesday, as sixth- and seventh-graders in the North Adams Public School's "Imagineering Summer Science Camp" toured the underside of the Hadley Overpass with Resident Engineer Charles Najimy, a member of the state Department of Transportation team overseeing the site.
"These are triangles, so I need to know how to figure out the length of the side of a triangle Pythagorean theorem -- I use it every week," Najimy said, while pointing to a page in a 100-page book of blueprints for the bridge. "At some point, you're going to come to trigonometry, which is even more helpful."
He stressed that every member of the construction crews -- totaling more than 40 individuals over the last four years -- has had to have a background in math, ranging from algebra to trigonometry, to perform their daily tasks.
According to science teacher James Holmes -- whose class was at the site along with those of teachers Wendy Nelson and Lisa Marceau --Tuesday's tour was part of a week-long program on bridges.
"The whole six-week camp is focused around engineering," he said. "The first week, we did a unit on dams and hydroelectric power. We went up to the old Yankee Rowe site. This week, our unit is on bridges, so we'll be going to see the Bridge of Flowers in Shelburne Falls and the French King Bridge and some covered bridges in Vermont. What's great about this is that the kids can see the project as it unfolds and learn about how it's all being done. They're also seeing the role math and science play in it."
Holmes added, "Our claim to fame with the summer camp is that we really try to put our kids in hands-on situations. We want our kids to know that engineering is not just building with a Lego set."
Najimy explained to the group that the rehabilitation of the Hadley Overpass, which started in 2008, has been complicated by its unique structure. The bridge is a combination of I-beam construction and a truss -- the only known bridge of its kind within District One, which includes all of Berkshire County and parts of neighboring counties. Unanticipated damage to the truss has pushed back the completion of construction until the end of next summer.
"Over here, you can see it's more complicated because it's a greater distance," he said, pointing to the green truss in the middle of the bridge. "Back in the 1930s, when they built this, they didn't have beams long enough to spread this span, so they built a truss out of a bunch of smaller beams. The way the truss works is through an intricate combination of beams, which spread all of the weigh out."
The difference in construction, he said, can complicate how repairs are made. With the rest of the bridge -- a series of I-beams resting on cement piers -- half of the bridge can be shut down and traffic can flow along the remaining part.
"You can't take half [of the truss] down or the whole thing comes apart," Najimy said. "If we took one beam out, the whole [section] would crumble. So it is very difficult. We aren't replacing any of the big beams, but we are replacing some of the plates and bolts. We've designed this whole structure to hold it together. It's almost a truss inside of the truss, so we can disconnect a part of it and transfer the load to the temporary truss. It's a feat of engineering."
The city's six-week Imagi neering Summer Science Camp, which is being provided free-of-charge to 352 students in kindergarten through seventh grade at Brayton Elementary School, runs through Aug. 3.