ABSTRACT
Previous chapters deal with ‘ber-reinforced polymer (FRP) deck-steel girder bridge systems. FRP decks can also be supported by FRP stringers. Therefore, in this chapter, a systematic approach for analysis and design of all FRP deckstringer bridges (Qiao et al. 2000) is presented. This approach (Figure 7.1) is based on analyses at the microlevel (material), macrolevel (structural component), and system level (structure) to design all FRP deck-stringer bridge systems. First, based on manufacturer’s information and material lay-up, ply properties are predicted by micromechanics. Once the ply stiffness properties are obtained, macromechanics is applied to compute the panel mechanical properties. Beam or stringer stiffness properties are then evaluated from mechanics of thin-walled laminated beams (MLB). Using elastic equivalence, apparent stiffness properties for composite cellular decks are formulated in terms of panel and single-cell beam stiffness properties, and their equivalent orthotropic material properties are further obtained. For design analysis of FRP deck-stringer bridge systems, an approximate series solution for the ‘rst-order shear deformation orthotropic plate theory is applied to develop simpli‘ed design equations, which account for load distribution factors for various load cases. As illustrated in Figure 7.1, the present systemic approach, which accounts for the microstructure of composite materials and geometric orthotropy of a deck system, can be used to design and optimize ef‘cient FRP deck and deck-stringer systems.
