Mixed-mode I+II fracture characterization tests of steel-bonded joints were carried out with the dual actuator load apparatus using a previously developed data reduction scheme in order to obtain the fracture envelope. This test involves independent loading of the specimen arms of a clamped double cantilever beam, which allows for easy variation of the I+II mode mixity in fracture characterization through altering the applied displacement rates. Difficulties inherent to crack monitoring during its propagation and imperfections of initial crack manufacture are well managed with the proposed method. Three different cases corresponding to different mode mixities were tested. The experimental results revealed that a linear energetic criterion performs well in describing the fracture envelope of these bonded joints.