To download the CA Concatenate utility, please follow the below..
From the
https://support.broadcom.com/ main page click on Mainframe Software
On the Mainframe Software Support page, scroll down and click on "View Installation and Maintenance Tools" under "Installation and Maintenance Tools".
On the page that is now open, you will find a link for "Freeware Utilities / Toolbox" Where you can then download the tool.