Before you hand out the supplies and let your students have a go at bridge building, there are a few things you’ll want to consider. A little historical information will equip them to handle the project and open their minds to get creative. Check out these fun facts about vertical-lift bridges for students.
Defense Purposes
We know bridges are meant as a mode of transportation over a body of water. But vertical bridges are sometimes a form of drawbridge, and their original purpose was defense.
During medieval times, castles had a bridge over a ditch or moat. When enemies would approach, the inhabitants would either destroy or raise the bridge to prevent the enemy from entering the castle. It was the first line of defense because it immediately cut off access to the castle. From here, soldiers would regroup and strategize their next plan of defense.
Use Towers
Vertical-lift bridges are normally accompanied by towers. Because of the height of the towers, the vertical lift can only go as high as the towers will permit. Even with the towers, some of the bridges use hydraulic jacks located below the deck.
The hydraulic jacks provide vertical motion and power to raise or lower the frame with or without a snub load. The hydraulic fluid is the main source of power, and it consists of a pair of cylinders in different sizes, connected by a pipe and hydraulic oil.
Equal With the Deck
The great thing about vertical-lift bridges is the counterweights only have to be equal to the weight of the deck. Other bridges, like the bascule bridge, must weigh several times as much as the span being lifted. It makes it easier for students to gauge and calculate how heavy their bridge needs to be.
Because of this benefit the vertical-lift bridge offers, students can use heavier materials to build the deck. Note that you see most of these bridges near railroad tracks. Check out some of our bridge-building kits to get your students started off right. Here at AC Supply, we have all the equipment you’ll need.
Height Restrictions
As previously mentioned, the vertical lift is accompanied by towers. So, there are height restrictions for these bridges. Because the deck remains suspended above the passageway, there’s a height restriction for the vessel passing underneath it.
Remind your students that the towers will be their point of focus when it comes to height. It also helps them to gauge what items they plan to pass underneath the bridge. The height restrictions will work as a guide so they don’t get too far off course.
These fun facts about vertical-lift bridges are just a few tidbits we relay to all our customers. If you want more interesting information about bridges or model rockets, visit our website.