Provide Analytical Relationship to Calculate the Stiffness of Composite Steel Shear Walls

Composite steel shear wall is an innovative lateral load-carrying system and consists of a steel plate with reinforced concrete cover in which the cover has been attached to its one side or both sides by shear connectors.
In composite steel shear wall, reinforced concrete cover causes to increase shear capacity of steel shear wall up to in-plane shear yield limit rather than tension along the diagonal tensile field by anchoring steel plate and preventing its buckling
In innovative composite steel shear wall system, a gap is created between concrete cover and boundary beams and columns. Tests on traditional and innovative composite steel shear wall show a slight failure in innovative system compared to traditional system.
In this paper, steel plate, concrete cover and frame were separated to calculate the stiffness of composite steel shear wall by their interaction (CPFI).
To evaluate the effect of concrete stiffness on composite steel shear wall stiffness, the gap between concrete cover and boundary members has been discussed, and then two relationships have been proposed to calculate the stiffness of composite steel shear wall.
The results show that the use of low yield stress steel plate with equivalent thickness to traditional steel plate will increase approximately 25% stiffness in composite steel shear wall. Also, concrete cover involvement in boundary members will increase the stiffness about 10%.