iStructural : web based structural engineering software

At http://www.istructural.com you can check out a structural engineering software that is completely web-based and runs on most computers and operating systems. It has free and non-free account types and provides different systems. Check out the demo to see if this fits your needs (which can not save and has fixed values). Beware that most examples use US units, but you can define a project with SI if you want.

The demo has two main example calculations with which you can play around.