RSTAB - Structural Frame & Truss Analysis is described as 'RSTAB is a powerful and intuitive software for verifiable structural analysis and effective design of beam, frame, and truss structures according to numerous standards'. There are more than 25 alternatives to RSTAB - Structural Frame & Truss Analysis for Windows, Linux, Online / Web-based and Mac. The best alternative is midas Civil. It's not free, so if you're looking for a free alternative, you could try SkyCiv Structural 3D or ClearCalcs. Other great apps like RSTAB - Structural Frame & Truss Analysis are midas Gen (Paid), RISA-3D (Paid), RISA-2D (Paid) and Etabs (Paid).
midas Gen is one-stop modeling, analysis and design solution for building and general structures. It features an intuitive UI, advanced analysis features, practical output and powerful design capacities using various standards
SkyCiv Structural 3D is a powerful structural analysis and design software on the cloud. Nothing to install or download and users can subscribe on a month-to-month basis so there's no life long commitment. It's also free to get started.
For nearly 30 years, ETABS has been recognized as the industry standard for Building Analysis and Design Software. Today, continuing in the same tradition, ETABS has evolved into a completely integrated building analysis and design environment.