This bridge symbolizes a key in the dreamer's life, which is a crucial decision.
Suddenly breaking the bridge usually means that the dreamer is a little anxious about the change of life. Another explanation is that this bridge also represents opportunity, and the bridge is broken, suggesting that the opportunity is about to be lost.
Grasping the railing, I finally climbed to the other side, suggesting that I will successfully seize the opportunity or successfully enter a new stage.