This study evaluated a special type of stiffened plate that eliminates the weaknesses of previous stiffened systems, such as early out-of-plane buckling, low ultimate shear capacity, lack of symmetry and stability in the hysteresis curves of shear force displacement. Consequently, folded sheet trapezoidal stiffeners connected to the basic plate by screws were used in order to obtain the values of the ultimate capacity and failure modes under quasi-static cyclic loads. An experimental analysis was performed on three types of steel plate shear walls including unstiffened by two different dimension stiffeners. The results indicated that the appropriate behavior in the stiffened wall using folded-shape specimens significantly amplified the ultimate capacity of the system and enhanced the symmetry and stability of the hysteresis curves of the force-displacement. Energy absorption also increased substantially.
