Free structural software? Is there such a thing? It is just knowing where to look. There are quite a few places now to obtain software. This page contains information on where to obtain free programs and fully working programs that the Author allows you to evaluate. All the software is fully working and no unusable or time limited demos are listed here.
Check out this website I found at
structural-engineering.fsnet.co.uk
Quite comprehensive list of free software available for checking and analysis of Truss and frame 3D Beam structures.