Concatenation - Nav Attr

Hello Team,

We got a requirement; where the field length is exceeding 70 characters from the Source. We have created to 2 infoObjects 60 and 60 (to hold more than 70 in future). They are Nav attributes and they hold characters not numbers.

Could anyone help how to concatenate them (Nav attr) at the query level? or is there any way to do the concatenation at the backend?

Thanks

San