In the model, the total moment of the composite beam with interface slip consists of the local moment carried by superposition beam with free interface slip and the global moment carried by the composite beam without interface slip.

In the model an assumption was made that the total moment of a composite beam with interface slip was consisted of a global moment that was borne by a composite beam without interface slip and a local moment that was borne by a superposition beam with freely interface slip only.

In order to analyze the section stress considering the slip effect on the interface between concrete and steel,models for calculating global moment,local moment,elastic stress,and yield moment on composite steel-concrete beam section are created.

A semi-analytical method is developed to study the local bending and local buckling behavior of the structure based on the classical laminated plate theory.

Utilizing this method, the phenomena of local bending observed in experiments can theoretically be explained.

The empirical rules,which take into account the non neighbor interactions between the base pair steps,have been presented to predict the local bending of B DNA.