# Load-Carrying Capacity of Bailey Bridge in Civil Applications
## 5 Results and Discussion
### Main Girders  
Load-carrying capacities of the main girders are given in Tables 3 and 4. Grey highlighted are the values which are less than 28 tons in the case of normal load-carrying capacity \(V_{n}\) and 40 tons in the case of exclusive load-carrying capacity \(V_{e}\), respectively. In addition, the values of \(V_{n}\) smaller than 22 tons and of \(V_{e}\) smaller than 32 tons are underlined to point out that they represent values very far from the required level defined at the beginning of the study. Thus, the applicability of main girders is clear from both tables. Table 3 presents the normal load-carrying capacities of members of Bailey bridge system. It can be seen that for the most cases the bottom chords and compressed truss elements of the BB panels (diagonals and verticals) do not meet the requirements for the assumed normal load-carrying capacity (\(V_{n}=28\) tons). Despite of that, these results do not lead to the conclusion that the BB system cannot be utilized for such variants and spans at all. These BB system configurations can still be utilized; however, the weight of the vehicles allowed to cross the bridge has to be limited to given levels. The similar conclusions can be derived for exclusive load-carrying capacity according to Table 4.  
In addition, the tables show the elements of the main girders that would need to be strengthened and thus ensure the use of the individual BB truss panels to the required or even higher level of load-carrying capacity. As a real example, the solution to satisfy demands on exclusive load-carrying capacity up to 40 tons for Bailey bridge TS-12 is shown in Figure 16. As a result of static analysis came the necessity to avoid the BB panels with diagonals and verticals made of I-profiles due to their insufficient capacity in comparison with the panels where U-profiles were used for diagonals and verticals. Anyway, this requirement is inevitable only for the panels near supports (first and last panels within span), and moreover only for the inner and the middle main girders' panels. Such a requirement arises from smaller compression capacity of I-sections used for diagonals and verticals due to its lower buckling resistance in comparison with common U-profiles. Thus, for the remaining 16 out of a total 24 panels, any panels can be applied. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Normal** & **Configuration** & **TS-12** & **TS-18** & **TS-21** & **DD-24** & **DD-27** & **TD-33** & **TD-36** \\ \cline{2-9}
**Load-Carrying** & **Span Length [m]** & **12.192** & **18.288** & **21.336** & **24.384** & **27.432** & **33.528** & **36.576** \\ \cline{2-9}
**[tons]** & **Predominant Stress** & \(V_{n}\) & \(V_{n}\) & \(V_{n}\) & \(V_{n}\) & \(V_{n}\) & \(V_{n}\) & \(V_{n}\) \\ \hline \multirow{3}{*}{Chords} & T + B (bottom) & 21.1 & 22.9 & 18.4 & 22.1 & 16.3 & 17.7 & 15.6 \\  & C (top) & 54.8 & 38.0 & 30.0 & 41.2 & 30.9 & 27.5 & 20.4 \\ \cline{1-1}  & C & 22.6 & 19.8 & 18.6 & 23.0 & 21.5 & 22.3 & 21.3 \\ \cline{1-1}  & T & 39.1 & 42.1 & 40.1 & 44.0 & 42.4 & 43.5 & 42.7 \\ \cline{1-1}  & C & 18.9 & 16.5 & 15.4 & 19.0 & 17.7 & 18.4 & 17.7 \\ \cline{1-1}  & T & 45.8 & 45.0 & 43.0 & 47.1 & 45.2 & 46.7 & 45.6 \\ \cline{1-1}  & C & 30.1 & 26.8 & 25.9 & 27.7 & 25.0 & 24.8 & 25.0 \\ \cline{1-1}  & T & 40.0 & 40.3 & 38.6 & 40.0 & 40.4 & 41.0 & 41.2 \\ \cline{1-1}  & C & 25.4 & 22.4 & 21.7 & 22.7 & 20.1 & 20.6 & 19.9 \\ \cline{1-1}  & T & 42.3 & 42.5 & 42.2 & 43.6 & 44.1 & 44.6 & 44.9 \\ \cline{1-1}  & C & 31.3 & 34.3 & 31.3 & 37.2 & 37.2 & 40.7 & 43.5 \\ \cline{1-1}  & T & 92.6 & 91.4 & 67.3 & 95.2 & 79.4 & 83.6 & 80.0 \\ \cline{1-1}  & End posts & C & 65.3 & 62.4 & 62.4 & 46.5 & 44.5 & 53.5 & 52.2 \\ \cline{1-1}  & Sway braces & T & 66.1 & 58.1 & 54.0 & 61.0 & 55.5 & 51.7 & 47.0 \\ \cline{1-1}  & Pin joint & S + B & 92.4 & 64.1 & 51.4 & 58.7 & 47.6 & 44.5 & 35.2 \\ \cline{1-1}  & Chord bolts & S + T & & & & 66.7 & 61.8 & 63.7 & 60.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Normal load-carrying capacities of main girders parts.