Evaluation of the torsional mechanism by analytical solution for a hybrid fiber-reinforced polymer–aluminum triangular deck truss beam

Abstract

The hybrid fiber-reinforced polymer–aluminum triangular deck truss beam composed of modular structural units has the advantages of lightweight, high-bearing capacity, and faster installation. Although the analysis-oriented studies have been carried out by laboratory tests, numerical simulations, and theoretical analyses, the design-oriented study convenient for the application of the novel structure subjected to pure torsion is still lacking. Based on previous researches, some reasonable assumptions are presented to obtain a simplified analytical model. Analytical solutions of the torsional angle and torsional stiffness for the hybrid triangular deck truss beam subjected to pure torsion are derived. The derivation procedures and formulae are experimentally and numerically calibrated, finding that the formulae can be used to design with a satisfactory accuracy. The accuracy of the torsional stiffness predicted reaches to more than 90%. It is concluded that for the new hybrid triangular deck truss beam, the applied torsional moment is primarily resisted by the bending of its bilateral vierendeel trusses and the torsion of the fiber-reinforced polymer lower chords, which contribute approximately 37% and 62% for the total torsional stiffness, respectively.