You need to find the next available empty row in the column and then paste the data into that column. The following example will give you an idea on how to achieve this -
Public Sub CopyRows()
Sheets("Sheet1").Select
' Find the last row of data
FinalRow = Range("A65536").End(xlUp).Row
' Loop through each row
For x = 2 To FinalRow
' Decide if to copy based on column H
ThisValue = Range("H" & x).Value
If ThisValue = "ir" Then
Range("A" & x & ":AG" & x).Copy
Sheets("a").Select
NextRow = Range("A65536").End(xlUp).Row + 1
Range("A" & NextRow).Select
ActiveSheet.Paste
Sheets("Sheet1").Select
ElseIf ThisValue = "RR" Then
Range("A" & x & ":AG" & x).Copy
Sheets("b").Select
NextRow = Range("A65536").End(xlUp).Row + 1
Range("A" & NextRow).Select
ActiveSheet.Paste
Sheets("Sheet1").Select
End If
Next x
End Sub