Testing our “bridginess”
Last Thursday, the Green and Grow apprentices wrapped up an 8-week engineering curriculum by putting their skills to the test – the weight test! Using only manila folders, rubber cement and glue, groups of three apprentices constructed bridge models that had to withstand the weight of 5 kg (11 lbs) in order to pass “inspection”.
We could feel the excitement and anticipation in the room as the apprentices tentatively placed the weights, one by one, onto their bridges. YES! Every one of the bridges made the grade!
After passing the test, apprentices gleefully tested their bridges to failure, adding as much as 15.4 pounds before CRASH, the bridge was flattened and weights tumbled down – what engineers call “compression”. In addition to learning about tension and compression, the apprentices learned about the different parts of a bridge – including the struts, verticals, floor beams, lateral bracing, diagonals, decks, end posts and (whew!) abutments (the supports that border the bridge at each end).
Building a bridge model was just one part of the curriculum, designed by Dr. Brian Brenner of Tufts University, which also included geotechnical engineering, material science, traffic planning and construction planning. Many of the subjects were introduced by Big Dig engineers bringing the Green and Grow apprentices through an abbreviated version of the Dig history – a real behind the scenes advantage. Other interactive learning activities in the curriculum included a tour to the Leonard P. Zakim Bunker Hill Memorial Bridge, now one of Boston’s most defining features. The Greenway appropriately abuts the Zakim Bridge, extending what Brenner would call “bridginess” through downtown Boston, connecting people and places once divided by an elevated highway.