Shear strength of CFS shear walls with screw-rivet hybrid connections

• A novel CFS shear wall with screw-rivet (SR) hybrid connections was proposed. • The shear strength of multiple screw-rivet (SR) hybrid connections were tested. • The effects of fastener arrangement and number on shear performance and failure mechanisms were analyzed. • A calculation method based on the Group Effect for determining the shear strength of SR connections was proposed. • A calculation method for the shear strength of a CFS shear wall with SR connections was proposed. Numerous studies have demonstrated that the shear performance of cold-formed steel (CFS) shear walls is primarily influenced by the connection between the sheet sheathing and steel frame. The main connection type in CFS structures is self-drilling screws (SDS), which have high deformation capacity but low strength. Self-piercing rivets (SPR) have been found to improve the shear strength of CFS shear walls, but their deformation capacity is limited. Therefore, this paper presents a novel CFS shear wall with screw-rivet (SR) hybrid connections designed to enhance the shear performance of the wall by incorporating the properties and characteristics of both connection types. The influence of fastener arrangement on failure modes of the shear wall was studied and a hybrid connection type with better shear performance was proposed. Experimental investigation revealed that the shear strength of CFS shear walls with SR connections was primarily provided by the sheet sheathing through the diagonal tension field. However, the main failure mode was the failure of SR connections within the tension field. In view of this, the shear behaviour of SR connections was studied further. Shear tests were conducted on total of 42 specimens with two types of sheet combinations to assess the effects of fastener arrangement and number on shear performance and failure mechanisms. A calculation method based on the Group Effect was proposed for determining the shear strength of SR connections. Based on this, a calculation method for the shear strength of a CFS shear wall with SR connections combined with the effective strip method was proposed. The results indicated that the primary failure modes of SR connections were a combination of screw tilting and the rivet tail being pulled out from the lower sheet, and the bearing failure of the upper sheet. The sheet thickness combination was the main factor affecting the failure mode. Considering the Group Effect meant that the calculation method for the shear strength of SR connections was extremely accurate. Thus, SR connections can effectively improve the shear strength and deformation of a CFS shear wall compared to both a shear wall with SDS and a shear wall connected by SPR. The superior shear performance was observed in a shear wall in which screws were added continuously. The proposed calculation method for the shear strength of a CFS shear wall with SR connections was highly accurate, with an error of <5 %. A design example is presented to illustrate this.