Cracks and deformation occurred in grout-filled coupling sleeves of electric resistance welded steel tubes under monotonic tensile loading and tensile-compression cyclic loading are revealed by injecting epoxy resin into the cracks. Variables adopted in this study were types of loading, development length and shapes of circumferential ribs of reinforcing bars, strength of grout and some mechanical devices to improve bond characteristics.
Following test results are obtained.
(1) Cracks like cones at end zones of the sleeves, spaces behind circumferential ribs of reinforcing bars, horizontal cracks occurred at the tops of circumferential ribs, slip displacements at the ends of reinforcing bars and thinning of sectional areas of reinforcing bars in yielding zone are observed.
(2) Kinds of cracks and states of deformation observed in the splices under cycle loading are almost similar to those under monotonic tensile loading.
(3) Bond failure modes with or without yielding of reinforcing bars are seemed to be resulted from connection of horizontal cracks at the top of circumferential ribs.
(4) Some mechanical devices improved strength and deformation capacity of the splices.
