[R] dataframe rbind

[Troels Ring]

Dear friends - I have a very simple question -
I generate a number of dataframes with identical names and want to 
combine them into one large dataframe with the same names -
here is an example

DF <- data.frame(a=rnorm(10),b=runif(10),ID=0)
for (i in 1:10){
DF <- DF+rbind(data.frame(a=rnorm(10),b=runif(10),ID=i))}

- the dataframe do not grow as I thought it would.

How would I do this?

All best wishes
Troels Ring
Nephrology
Aalborg
Denmark