Experimental study on shear resistance of self-stressing concrete filled circular steel tubes

This paper presents the results of shear tests on 27 self-stressing concrete filled steel tube (SSCFST) specimens and 8 conventional concrete filled steel tube (CFST) specimens. The main parameters in the tests were the self-stress and shear span to depth ratio. The experimental results indicate that the shear capacity of the CFST specimen is lower than that of the SSCFST specimen when 28-day cube strength of concrete core, shear span to depth ratio, yield strength and geometrical dimension of the steel tube are kept the same. The CFST/SSCFST specimen failed in shear when the shear span to depth ratio was smaller than 0.5 and failed in flexure when the shear span to depth ratio was 0.5 or higher. The bond between concrete core and steel tube also affected the shear capacities. Finally, an empirical equation for predicting the shear capacity of a SSCFST short beam is proposed.