# Analytical and Measured Effects of Short and Heavy Rail Cars on Railway Bridges in the USA
## 2 Modeling and Analysis of a Steel Railroad Bridge
### Description of Tested and Analyzed Bridges  
This study covered testing on two railway bridges. The first bridge is a ballasted deck bridge that contains two riveted truss spans with lengths of 33.5 m (110 ft) and 61 m (200 ft) [1; 2; 3]. The bridge is on a tangent alignment. Figure 3 presents the general dimensions of the bridge, and the colors on the diagram represent different cross-sections (symbol \"U\" refers to connection of upper chords, symbol \"L\" refers to connections of lower chords, and \"M\" is a connection on the middle of a diagonal).  
All member sections are built-up sections. Two types of sections dominate over the main truss members: two laced C-sections and an inverted U-section. Table 1 provides more information about the geometric properties of the main members within the trusses. The stringers and floor beams are riveted built-up 1.2-m (48-in.) deep girder sections.  
The second bridge has five ballasted riveted steel deck plate girder (DPG) spans on a curved alignment with north girders (G1) of 34.7 m (113 ft, 10 in.) overall length and 34 m (111 ft, 6 in.) between bearing centers, and south girders (G2) of 35 m (115 ft) overall length and 34.3 m (112 ft, 8 in.) between bearing centers [15]. Figure 4 illustrates detailed dimensions.  
\begin{table}
\begin{tabular}{c c c} \hline \hline  & **Bottom Chords and Diagonals** & **Top Chords and End Posts** \\ \hline \hline \multirow{4}{*}{Scheme of the cross-section} & \multirow{4}{*}{Upper Chords U1U3, U3U3: 2 PIs 2 \(\times\) 7/16} & \multirow{4}{*}{Upper Chords U1U3, U3U3: 2 Ls 4 \(\times\) 4 \(\times\) 1/2} \\  & & 2 Ls 6 \(\times\) 4 \(\times\) 1/2 \\ \cline{2-3}  & Bottom Chord L2L4 & \multirow{2}{*}{1 \(\text{Cov. Pl 27 }\times\) 5/8} \\  & 4 Ls 6 \(\times\) 4 \(\times\) 5/8 & 2 Web PIs 24 \(\times\) 5/8 \\ \cline{2-3}  & Diagonal U1L2: 4 Ls 6 \(\times\) 4\(\times\) 1/2 & Diagonal L0U1: 2 Ls 4 \(\times\) 4 \(\times\) 5/8 \\ \cline{2-3}  & Diagonal L2U3: 4 Ls 4 \(\times\) 4 \(\times\) 5/8 & 2 Ls 6 \(\times\) 4 \(\times\) 5/8 \\ \cline{2-3}  & 4 Ls 4 \(\times\) 4 \(\times\) 5/8 & 1 Cov. Pl 27 \(\times\) 5/8 \\ \cline{2-3}  & 2 PIs 18 \(\times\) 1/2 & 2 Web PIs 24 \(\times\) 3/4 \\ \cline{2-3}  & Diagonal U3L4 & \multirow{2}{*}{1 \(\text{Acs }4\times\) 4 \(\times\) 3/8} \\  & 4 Ls 4 \(\times\) 4 \(\times\) 3/8 & \\ \cline{2-3}  & 2 PIs 18 \(\times\) 1/2 & \\ \hline \multirow{4}{*}{33.5 m truss members} & \multirow{4}{*}{Bottom Chord L0L2: 4 Ls 4 \(\times\) 4\(\times\) 3/8} & \multirow{4}{*}{Upper Chords U1U3: 4 Ls 4 \(\times\) 4\(\times\) 3/8} \\  & 4 Ls 4 \(\times\) 4 \(\times\) 3/8 & 1 Cov. Pl 24 \(\times\) 1/2 \\ \cline{2-3}  & 2 PIs 18 \(\times\) 3/8 & 2 Web PIs 18 \(\times\) 3/8 \\ \cline{2-3}  & & Diagonal L0U1: 4 Ls 4 \(\times\) 4\(\times\) 3/8 \\ \cline{2-3}  & 2 Cs [EMAIL_ADDRESS] & 1 Cov. Pl 24 \(\times\) 1/2 \\ \cline{2-3}  & 2 Web PIs 18 \(\times\) 1/2 & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Geometry properties of truss members.  
Figure 3: Investigated truss bridge dimensions and strain gauge locations (1 ft = 0.305 m).