Explanation for Spine model - CSI Bridge

[SinaPeugeot]

Hi all!

I have a simple question. Could anybody explain what exactly is a spine model in programs like CSI Bridge?? I know that these elements, model the whole superstructure as a single frame element; But how does it calculate mechanical properties of the section - For example torsional constant or moments of inertia??
Also how does it account for load eccentricities?? Does it assumes the the ends of the spine is torsionaly fixed?? And what about the warping??

Many thanks

 

[rowingengineer]

sounds like a question for the software tech support.

http://www.nceng.com.au/

"A safe structure will be the one whose weakest link is never overloaded by the greatest force to which the structure is subjected” Petroski 1992