I accepted(but haven't signed contract) a job offer but I cannot go to anymore. Will I burn bridges with the company if I do this but I tell them I have a person that is a suitable replacement? Will this damage my reputation?
It depends on the reason you cannot go there anymore, whether you will burn bridges.
I wouldn't suggest another person as a suitable replacement, however, as it is a common scam in some parts of the world to do exactly as you describe in order to get someone in who simply doesn't know what they are doing, or worse.
No it will not unless you signed a contract. They should understand. If they do not understand, then they are a bad company, then you should be happy not working for them.