There is no limit on how many times a congressman can be re-elected to office. There isn't a term limit for senators either. How long they can stay in office depends on how happy their constituents are with them. Satisfied constituents will continue re-electing a congressman or senator.
There is no limit to the number of times that a member of the congress can be re elected. Congress is made up of the upper nd lower house. The upper house is composed of the senate. There are 100 senators, two from each state.