Behavior of headed shear studs in stub–girder stub assemblages

The paper summarizes the results of push-off tests conducted on 42 end stub assemblages. Written for conventional composite construction, the current Canadian Standards Association (CSA) standard on stud connectors offers little guidance for stub–girder design. A stud spacing of four times the stud diameter (the CSA requirement) does not appear to be adequate for a full development of the potential shear capacity of a stud connector in the stub–girder system. The required minimum stud spacing appears to be between five and six times the stud diameter for the case of 13 mm studs. Moreover, the CSA-recommended shear capacity of stud connector should be reduced to reflect the effect of prying forces. A modification factor of 0.9 is suggested for a 13 mm diameter stud connector. Test results for specimens with 19 mm studs indicated a further decrease in the shear capacity. However, a definite recommendation is postponed pending further tests.In addition to prying forces, stud configuration and spacing and the amount and location of transverse reinforcement must also be taken into account in determining the shear capacity of a stud connector. For a connection with 13 mm studs arranged in a single row, a reduction factor equal to stud spacing divided by six times the stud diameter is suggested when the stud spacing is less than six times the stud diameter. For a connection with staggered studs, the corresponding factor is obtained by dividing the stud spacing by five times the stud diameter when the stud spacing is less than five times the stud diameter. Key words: headed stud, shear capacity, minimum stud spacing, prying force.