Evaluation of Equivalent Bending Stiffness by Simplified Theoretical Solution for an FRP–aluminum Deck–truss Structure

Abstract

A hybrid Fiber-Reinforced Polymer (FRP)–aluminum spatial deck–truss structure that incorporates an innovative structural form and advanced extrusion-type FRP profiles has the advantages of a lightweight, high-bearing capacity, and faster installation. In this study, a design-oriented investigation was conducted with a simplified theoretical solution to conveniently evaluate the equivalent bending stiffness of the above-mentioned unique structure. The simplified theoretical solution was derived using the equivalent continuum beam method based on the homogenization concept and shearing equivalence principle. The theoretical prediction enabled a direct format and simple calculation process convenient for engineers in terms of the calculation and design. The theoretical solution was experimentally and numerically calibrated to ensure that the formulae have the satisfactory accuracy. The accuracy of the predicted bending stiffness exceeded 90%. The derivation procedures and formulae further indicated that the FRP web diagonals played a key role in resisting the global bending stiffness of the unique structure, and thus, the shear deformation should be considered in the structural design in terms of stiffness-driven. When compared with the conventional calculation method for obtaining the bending stiffness of steel solid-web beams and planar trusses, the proposed method was more accurate and applicable for the unique hybrid structures.