Please keep in mind that: The purpose of this section isn't the promotion of the software listed below, but the provision of free tools to engineers.
2D DWG/DXF editor with familiar graphical user interface and property window to view and edit DWG/DXF files.
A linear static structural analysis program for plane frames.
General purpose finite element analysis program designed for research and educational use.
Software for static and dynamic structural analysis of 2D and 3D frames and trusses with elastic and geometric stiffness.
Prestressed and reinforced beam capacity calculation software.
Static and dynamic analysis program for plane frames.
Yes, it isn't a civil engineering software, but it's a great free alternative to Microsoft Office.
SeismoStruct, Seismosignal, SeismoSpect and SeismoMatch are available in this link.