What Materials Will I Need to Build a Model Bridge Suspension?

Cable

• By far, the cables on a suspension bridge are the most impressive part of the bridge. In a full size bridge, the cables suspend the road above the water or other roadways. The tension in the cables hold the bridge up. Without the tension, the road would sag. When choosing a material for the cable for your suspension bridge, be sure to choose a string or rope that will not break easily. Dental floss, embroidery floss or fishing line work well when constructing a model suspension bridge.

Towers

• Depending on how long the bridge is, suspension bridges all have at least two towers. Many longer bridges, such as the Golden Gate, have several more towers placed strategically along the bridge. The towers are home to the ends of the cables. The towers help keep the cables pulled tightly, creating the tension that allows the bridge to suspend and not sag. When creating a model suspension bridge, try using materials that you can attach together to make the the towers as tall as you need them to be. For example, try using craft sticks, drinking straws or paper towel tubes when constructing the towers.

Anchors

• The anchors of the suspension bridge greatly increase the load a bridge is able to handle. In a real suspension bridge, anchors are often made from several hundred feet of concrete. The cables are pulled taut to the towers and are then attached directly to the anchors. The heavier and sturdier the anchors, the more weight your suspension bridge can handle. Try using wooden blocks of different sizes for your suspension bridge anchors. You may need to experiment with size, shape and weight before deciding on a wooden block that works well for your model bridge. You can also choose to use bricks or concrete blocks, depending on the weight your bridge will need to handle.

Other Materials

• In addition to materials for the cable, towers and anchors, you will need a few miscellaneous items in order to build your model suspension bridge. To construct the bridge properly, you will need masking tape, scissors and a ruler. When testing the bridge for strength, try using pennies or washers to add weight to the bridge and determine whether your anchors are sturdy enough. Try combining several different types of materials to see which suspension bridge holds the most weight. You may find that a combination of materials suspends more weight than simply using drinking straws and dental floss, for example.