# A Review of the Network Arch Bridge
## 3 Network Arch Bridges of Different Structural Systems around the World
### Network Arch Bridges in Numbers
Twenty-one structures are railway NABs, with spans varying from 78 m, to the Torikai-Ohashi bridge in Osaka, Japan, under construction at the time, with five network arch spans of \(85+130+195+130+85\) m. In the category of railway NABs was a carbon hanger network arch, with a span of 127 m.  
Of the 141 road structures, 10 were built to support one traffic lane; this category includes the slenderest NAB in the world, Brandanger Bridge, Figure 14; most of the structures, 97, were designed to support two or three traffic lanes, with or without pedestrian sidewalks; 32 were built to take four or five traffic lanes, and two of the structures ensure the crossing of more than six traffic lanes. The largest span network arch in the world, Bugrinsky Bridge, 380 m, was designed and built to support six road lanes, and Providence River Bridge in the United States of America carries 10 traffic lanes, five in each direction. Due to the large width of the bridge, 50 m, Providence River Bridge has three arch ribs instead of two. Extensive information on the design and construction of Providence River Bridge can be found in refs. [18; 45]. The characteristics of the network arches built in timber are given in Table 1. WB is the notation used for wind bracings between the arches from this point forward. Information regarding NABs built with the tie and the arch in concrete is given in Table 2. The presence of a bridge with the same name in Table 2, the Bijuli Bazar Bridge in Nepal, is no error, as two identical structures were identified in Kathmandu. \begin{table}
\begin{tabular}{c c c c c c c c} \hline
**Bridge Name** & **Location** & **Opening Year** & **Type** & **Span [m]** & **Arch** & **Tie** & **Lateral Buckling** \\ \hline \hline \multirow{2}{*}{Stein Bridge} & Alvdal, Norway & 2016 & Road & 88.2 & \multirow{2}{*}{Glulam, truss box} & \multirow{2}{*}{Concrete} & Arch inclined \\  & & & & & & & inward, WB \\ \hline \multirow{2}{*}{Vala Bridge} & \multirow{2}{*}{Ringube, Norway} & \multirow{2}{*}{2020} & \multirow{2}{*}{Pedestrian} & \multirow{2}{*}{52} & \multirow{2}{*}{Glulam, box} & \multirow{2}{*}{Concrete} & Arch inclined \\  & & & & & & & inward, WB \\ \hline \multirow{2}{*}{Hellefossbrua} & \multirow{2}{*}{Etnedal, Norway} & \multirow{2}{*}{2019} & Road & \multirow{2}{*}{70} & \multirow{2}{*}{Glulam, box} & \multirow{2}{*}{Concrete} & Arch inclined \\  & & & & & & inward, WB \\ \hline \multirow{2}{*}{Prestmyra bru} & \multirow{2}{*}{Elverum, Norway} & \multirow{2}{*}{2018} & Road & \multirow{2}{*}{34} & \multirow{2}{*}{Glulam, box} & \multirow{2}{*}{Concrete} & WB \\ \hline \end{tabular}
\end{table} 
Table 1: Timber Network Arches. The network arches with no WB are shown in Figure 18. The network arches were classified as vertical arches, arches inclined inward, arches inclined outward, one arch splitting in two legs near the ends of the arch, and one central arch. For all of the structures taken into consideration here, no upper WBs are presented. The purpose of the bridge, the number of lanes, the structural system used, and the span range in meters are given. The largest span in this category is 200.4 m, the Troja Bridge in Prague, Figure 11, already mentioned in Section 3.3. In Figures 18-22, the range span of each bridge structure is shown in green. The numbers presented in the  
Figure 19: Pedestrian network arch bridges. In bold are the number of structures of that type and the span range. The rest of the color code is taken as follows: bridges with a WB in orange, bridges without WB in light yellow; arches inclined inward in blue, one central arch in light blue and vertical arches in light red; structures with a steel arch and composite tie in light red, structures with a concrete arch and a concrete tie in light blue, composite tie in pink. In green is the span range for every type of bridge. Figure 20: Network arches with steel arches and steel ties/composite decks. In bold are the number of structures of that type and the span range.