Imagine you are a grown-up and you have a little brother or sister who doesn't have parents. They might feel sad and lonely because they don't have anyone to take care of them. This can make them feel like they are all alone in the world.
Now, let's think about a bridge. A bridge is something that is built to connect two places that are apart. Sometimes there are bridges that are no longer used, but they still stay there because nobody wants to knock them down. These bridges are called "orphan bridges."
So when we talk about an orphan bridge, we mean a bridge that is not being used anymore, like your little brother or sister who doesn't have parents. They are left all alone and nobody is taking care of them. Orphan bridges can be dangerous if they are not maintained because they can collapse or cause accidents.
Just like how we need to take care of our little brother or sister, we also need to take care of these orphan bridges. Engineers and experts work together to decide what to do with these bridges. Sometimes they are fixed up and made safe again, or they might be torn down and recycled. This is done so that nobody gets hurt and things can continue to run smoothly.