# Study on Shear Resistance and Structural Performance of Corrugated Steel-Concrete Composite Deck
## 3 Influence of the Structural Parameters of the Shear Stud on Its Shear Resistance
Comparative Study of the Flexural Load-Carrying Capacity of Combined Bridge Decks with Different Shear Keys in the Positive Section  
The previous section discussed the comparison of the slip and peel resistance between PBL open plate shear keys and pinned shear keys. The analysis was carried out in terms of the overall structural forces to investigate if there are differences between the two in terms of enhancing the overall force performance of the combined deck slabs. The positive section flexural load carrying capacity of the two sets of combined deck slabs from the finite element model analysis in the previous section was analyzed to produce the graphs shown in Table 9 and Figure 20.  
The ultimate load-carrying capacity of the corrugated steel-concrete deck with PBL shear keys is 747.3 kN, and the deflection under three times the wheel load is 1.82 mm;  
Figure 20: Load–displacement curves of PBL open steel plate with pinned shear key. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Shear Key Type** & **PBL Open Steel Plate A** & **Pins B** & **B/A** \\ \hline Load-bearing & & & \\ capacity (kN) & & & \\ Deflection (mm) & 1.82 & 1.90 & 1.04 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Comparison of the positive section force performance of the combined deck slab with two sets of shear keys. the two figures for the pinned deck are 740.6 kN and 1.90 mm, respectively. This shows that the ultimate load-carrying capacity of the PBL deck with perforated steel plates is not substantially higher than that of the shear studs and that the increase in the overall stiffness of the structure with perforated steel plates is also very limited, making the difference in deflection values between the two under the same load not significant. To study the effect of different forms of shear keys on the stresses in the concrete during the loading process, the concrete at point a, located at the same position around the shear key in the span (5 mm to the right of the shear key), was selected as the object of study in both sets of combined deck slabs to investigate the stress state during the loading process. The load-stress curve of the concrete at point a is shown in Figure 21.  
As can be seen from Figure 21, when the PBL open steel plate is used as the shear connection key, the stresses in the concrete around the shear key grow faster compared to the concrete around the pinned shear key. This means that the stresses in the concrete around the shear key reach their ultimate state when the external load P is around 500 kN. It is assumed that this phenomenon is due to the large stiffness gradient in the structure around the shear key caused by the addition of the perforated steel plate and the change in the local cross-sectional area of the concrete due to the perforation of the steel plate, which results in a local stress concentration in the concrete around the perforated steel plate of the PBL. Therefore, it can be concluded from the above analysis that there is little difference in the overall ultimate load-carrying capacity of the composite deck structure whether PBL perforated steel plates or pins are used as shear connection keys for the composite deck. And the point to be noted in the engineering design is: when using rigid shear keys such as PBL open-hole steel plates as the shear keys of the combined deck, attention should be paid to the phenomenon of local crushing of the concrete due to stress concentration.