How to Make a Model Bridge Out of Cardboard

Cover your work surface with newspaper to protect the finish. Place the pizza box (in its closed state) on the work surface. Remove any stickers or pieces of papers from the pizza box. Paint the top and sides of the pizza box with blue paint to represent water. You may have to paint more than one coat to cover the writing on the box. Use multiple shades of blue to create waves and depth in the water. Let the paint dry completely.

Cut two of the thick mailing tubes in half with a serrated knife. You should have four 12-inch sections. Cut four 6-inch lengths from the third mailing tube. You can do this while the pizza box is drying.

Cut two oval pieces of cardboard 6 inches long by 2 1/2 inches wide. Place the end of one of the tubes on the cardboard and trace around it. Trace and cut a total of four circles.

Paint the rolls and cardboard pieces with the color you have chosen for your bridge. Let the paint dry throurghly.

Position the pizza box on your work surface so it looks like a diamond as opposed to a square. Place two of the short tubes on either side of the point. They should be sitting against the sides of the pizza box. These are your anchorages. Glue them to the side of the box with the hot glue gun. Hold the tube against the side of the box until the glue has set. Repeat for the point on the opposite side.

Place the long tubes on top of the box. Put one in front of each of the anchorages. Glue the tubes in place with hot glue. These are the towers.

Turn the box so the towers and anchorages are on the left and right side of the box. Cut a small slit in the right and left of the top edge of each tower. Make a 1/4-inch slit with a serrated knife. Cut a 1/4-inch slit in the top outside edge of the anchorages. These will give you a place to anchor the cables.

Tie a knot in the end of a chenille stick. Make a chain of four to five sticks by wrapping the ends of each stick tightly together. Slip the end of the chain into the slit in the left anchorage and pull so that the knot is in the inside to stop it from pulling out. Pull the chain up to the first tower. Slide the chain into the slits in either side of the tower and then drape across to the next tower. Be sure to allow the chenille sticks to drape to depict the cables on a suspension bridge. Bring the end of the chain down to the right anchorage, tie a knot in the end and slip it into the slit. Do the same for the other side of the bridge. Be sure to follow the shape of the side you completed so you have parallel cables.

Measure how long and wide you will need to make the deck of the bridge. Trace it onto a piece of cardboard and cut out. Paint or cover in construction paper. Let the paint or glue dry.

Prop your decking up underneath your bridge with any extra tubing you have. Bend the end of a chenille stick around the side cable on one side of the bridge. Pull the stick underneath the deck and up to the side cable on the other side. Wrap the tip around the side cable to secure. Cut off any excess stick with scissors. Repeat for the length of the bridge. Remove the extra tubing so the decking rests on the cables.

Glue the cardboard circles on the tops of the anchorages to cap them. Glue the ovals horizontally across the towers.