## 5 Conclusions  
This paper presents an analysis example of an adhesively connected GFRP bridge deck under bidirectional bending from traffic wheel loads, as per the Korean Highway Bridge Design Code. The FE analyses are performed considering the local behavior of the deck substrate and adhesive at the joints. The global deflection of the deck and the local deformation of the adhesive joint under SLS are determined. The local stresses are calculated to check the four failure modes of the adhesive joint: (1) TAF, (2) TAW, (3) SAF, and (4) FSD. The following conclusions are drawn:  
1. Analysis Method for Checking Joint Safety: The analysis method for checking the failures of the joints are newly presented for FRP decks under traffic loads. This method can be applied for designing and evaluating joints of other FRP decks. 2. Deflection: The deck deflects more under the single-wheel load of the rear axle than under the double-wheel loads of the middle axle. Thus, the former case governs the deflection limit in SLS. The GFRP decks do not satisfy the serviceability deflection limit for vehicular bridges (L/800); thus, it is necessary to increase the flexural stiffness or decrease the span in strong axis. 3. Local Deformation of Adhesive at Joints: The weak-axis tensile strains along the top and bottom surfaces of the deck tend to highly concentrate at the adhesives near the loading area. These concentrated tensile strains cause tensile failure of the adhesive and reflective cracks on the asphalt pavement. To avoid these problems, it is necessary to reduce the strain in the adhesive by selecting an adhesive with a higher stiffness or optimizing the joint configuration. 4. Tensile Failure of Adhesive at Joint Edge between Bonded Flanges (TAF): The maximum tensile stress occurs in the necking area, away from the deck surface. Tensile failure in the adhesive occurs under SLS and ULS. This adhesive tensile failure should be avoided by changing the lap joint shape to reduce tensile stresses. 5. Tensile Failure of Adhesive between Vertical Webs (TAW): Because the principal adhesive stresses are lower than the design tensile strength, the adhesive is safe against TAW. 6. Shear Failure of Adhesive between Flanges (SAF): For the deck subjected to the single-wheel load of the rear axle under ULS, the shear failure in adhesive occurs. To prevent this failure, it is necessary to reduce the shear stress by modifying the bonding configuration or selecting adhesives with higher shear strengths. 7. Failure of Deck Substrate at Discontinuous Dimension in Section (FSD): At the stepped lap joint in the flange, the maximum compressive and tensile stresses are slightly higher than the design strength of the deck substrate in ULS. At the corner between the flange and the web, the maximum compressive and tensile stresses are signifcantly greater than the design strength of the deck substrate in ULS. To prevent this failure, more fibers should be provided at these locations to increase the design strength of the deck substrate. 8. Limitation and future study: Because the test results are not sufficient to determine the orthotropic material properties for the 3D solid elements of the deck, it is necessary to perform all types of coupon tests to measure them, considering geometric (thickness change) and material (fiber amount change) discontinuities in the section. If failure at the bonding surface between the deck tubes and adhesive is to be considered, nonlinear tie elements or contact elements should be used, based on the corresponding test results. Conceptualization, S.-Z.P., S.-H.J., H.L. and K.-J.H. ; Data curation, S.-Z.P. and K.-J.H. ; Formal analysis, S.-Z.P., H.L. and K.-J.H. ; Funding acquisition, S.-H.J. ; Investigation, S.-Z.P. and H.L. ; Methodology, K.-J.H. ; Project administration, K.-J.H. ; Resources, S.-H.J. and K.-J.H. ; Supervision, K.-J.H. ; Writing--original draft, S.-Z.P., S.-H.J., H.L. and [PERSON]-J.H. ; Writing--review & editing, S.-Z.P., S.-H.J., H.L. and [PERSON]-J.H.