Algorithm of Composite Beam Synchronously Considering Geometrical Nonlinearity and Long Term Effects

Abstract:

Firstly, balance equation of composite beam element with interlayer slips under corotational coordinate system was deduced. Combining initial strain method,equivalent nodal force formulation of shrinkage and creep was obtained. Based on the corotational method, using the transformation matrices relating local and global quantities, a practical algorithm for analysis of composite beam with interlayer slips considering geometric nonlinearity, concrete shrinkage and creep synchronously was put forward. The advantage of this approach is that it leads to the separation of geometrical and material nonlinearities such as shrinkage and creep. The shrinkage and creep is only present at the level of the local element, whereas the geometrical nonlinearity is included in the transformation matrices. Finally, it was illustrated that the geometric nonlinearity is coupled with shrinkage and creep for composite beam with interlayer slip by an example.

Key words:composite beam; interlayer slips; shrinkage and creep; geometric nonlinearity; finite element