Twin Bridges-Suspension Bridges

Advantages of suspension bridges:

Disadvantages of suspension bridges:


On a suspension bridge, there are towers that hold the cables. The towers allow the cable to span long distances. Anchors help to stabilize the bridge. Primitive suspension bridges were made of twisted grass and later bridges were made of iron chains. Today large suspension bridges are made of cables of thousands of wires which are tightly twisted together. Cables are secured on a heavy block (today made of concrete) to make sure they cannot break free. The anchors hold the cables that hold the bridges up.


The twin bridges in Lenape Park in Perkasie, PA are the only suspension bridges in the Pennridge School District.   These bridges were built by the WPA (Works Progress Administration) along with the island for the bridge bases, arched bridge on Walnut Street, a dam, and dredging the creek.

Cables for the suspension system are tied to a base on each side of the bridge.   The cables are attached to vertical metal rods.   Two pillars on each side of the bridge support the cable system.
Vertical rods are attached on both sides of the bridge to support beams.   As the cable gets closer to the pillar, the length of the vertical rod increases.   Note the triangulation at the side of the bridge supports to increase strength.
The triangular support is bolted to the beams that run under the bridge.   Trusses ("X" shaped) at the sides of the bridge also add strength to the bridge.   Notice the use of additional triangular braces under the bridge.


Suspension bridges can span distances up to 7,000 feet. This is much longer than other type of bridge. A suspension bridge suspends the road above the ground using cables that span across the whole bridge.

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