Why does 往前走 have a repetitive meaning?
There isn't a repetitive meaning in 往前走. 

往: towards; in the direction of;

前: forward; ahead;

走: go; walk;

往前走: walk in the direction of 'ahead'

It might not be grammatical English, just to explain Chinese.

往 can be a preposition to mean towards and, as a verb, to go. In 往前走, it's used as a preposition.