When you are working with Weldments and have the out of box installation for SolidWorks you may notice that there are very few Standards and Profiles in Weldments when you select a Structural Member.
SolidWorks does not install all the Standards and Profiles because of the size of installation and for that reason they provide you with a free download link in case you require other standards or profiles. To access the download link go to SolidWorks Task Pane and select the Design Library tab. From there expand the SolidWorks Content and select Weldments folder as shown below and it lists all the Standards that are available for download.
To download a particular standard click on it holding the Ctrl (Control) key on your keyboard. You can download the file and save it at any location and then unzip the file.
Once the file is unzipped go to SolidWorks Tools > Options and select the File Location from the system options tab. In the File location select the Weldment profiles option from the pull down menu. It also shows the default location of the Weldment profiles.
Now we will go to the location shown for Weldment profiles from the system options menu and copy-paste the unzipped file as shown below.
Once you are done with the above step you will see the profiles for that standard in the location like in this case we copied the ANSI Inch and now there are so many different types of profiles as shown below. After this all the profiles will automatically appear in the Structural member menu in the Weldments toolbar.