I made a small simple ppm that will do it for you if i understand correct what it should do if you have Platinum Edition, you dont tell what edition of TC you have
In case unpack the zip and place the ppm in;
C:\Users\Your Username\Documents\TurboCAD 2018 x64\Professional x64\Symbols\My Symbols
Open the Library Palette and find My Symbols folder and if TC was on, then click in there, then rigthclick and reload and it should turn up
It will have a ? mark, select it and rigthclick again and select rebuild thumbnail, and up on rigth side in that menu you can chose what view you want to use.
It is in metric, so if you use inch open the file and delete the first line "Units (1[mm])" or just change "mm" to "in", in case you maybe also want to change the Parametervalues on the top, ele it will be a pretty big beam
For change parameters befor inserting, Select it and change it's property or do it later in Selection Info Palette.
For inserting just drag it over if you are in wireframe mode, or you can click on "Insert" symbol on the top of the menu
V18, V19, V20, V21, 2015/ 16/ 17/ 18 Pro. Platinum
Deluxe V20, V21, 2015/ 16/ 17
Windows 10 Home Premium 64 bit, 32 GB
NVIDIA Geforce GTX 780m, 1 GB