Abstract:A series of tests (149 specimens) on single lap shear connections with self drilling/self tapping screws were carried out to investigate the effect of the end distance, screw spacing, pattern of screws arrangement and the number of screws, materials of sheets on shear connection strength. An analysis was made of the adaptability of the current design method provided by the Chinese “Technical code of cold formed thin wall steel structures” (GB 50018—2002) for load carrying capacity of self drilling/self tapping screw shear connections for steel sheets below 1.5 mm thick. Shear strength estimation methods for self drilling/self tapping screw connections based on different failure modes were studied. Based on a comparative study of test results, the proposed design method with a consideration of the influence of group effect was presented. Based on the analysis of mean stress of steel sheet net section, an estimation equation was presented to calculate the shear connection strength when tensile fracture of steel sheet occurred. Finally, a method to avoid shear fracture of screws was proposed according to Australian/New Zealand Standard “Cold formed steel structures” (AS/NZS 4600∶2005).
