Experimental and theoretical study of the torsional mechanism of a hybrid FRP aluminum triangular deck truss structure
This paper investigates the torsional mechanism of a hybrid FRP aluminum triangular deck truss structure composed of modular structural units. A pure torsion test was conducted on a 6 m cantilever specimen to characterize the structural responses. Based on the experimental results and structural layout, a simplified analytical model is established to predict the torsional stiffness of the hybrid triangular deck truss structure. The derivation procedures and formulae are experimentally calibrated, finding that the formulae can be conveniently used with satisfactory accuracy. It is ultimately confirmed that the torsional center of the entire triangular truss collocates with the center of the orthotropic deck. The external torsional moment is primarily resisted by the FRP lower chords and the aluminum longitudinal beams, particularly for the FRP lower chords which should be given a great consideration in the torsion design.