Downloading Revit Extensions for Autodesk Revit Structure 1.0 from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this software available.
We cannot guarantee that the program is safe to download as it will be downloaded from the developer's website. Before launching the program, check it with any free antivirus software. The latest version of the program is supported on PCs running Windows XP/Vista/7/8, both 32 and 64-bit. The most popular version of the software 1.0. This free program is a product of Autodesk, Inc. The software lies within Photo & Graphics Tools, more precisely 3D Design.
From the developer:
Revit Extensions extend the capabilities of Autodesk® Revit® Structure 2012 software in key areas, including structural analysis, modeling, concrete reinforcement, interoperability, and construction documentation. This download contains all previously released Revit Extensions and updates.
You may want to check out more software, such as Autodesk Robot Structural Analysis, Autodesk React Structures Tech Preview or Autodesk Revit Architecture 2011, which might be related to Revit Extensions for Autodesk Revit Structure.