PSI - Issue 5

Hołowaty J. et al. / Procedia Structural Integrity 5 (2017) 1043 – 1050 Hołowaty / Structural Integrity Procedia 00 ( 2017) 000 – 000

1046

4

3. The bridges

The structural specifications of the five riveted railway bridges are given in Table 1 in chronological construction order. Two structures have truss spans on single track railway lines (Nos. 1 and 2), two structures have plate girders on double- (No. 5) and triple-track (No. 3) railway lines and there is one bridge with filler beam decks on a double track railway line (No. 4). The bridge lengths and number of spans differ, with length ranging from 16.10 m (No. 4) to 104.30 m (No. 1) and the number of spans from 1 (No. 2) to 3 (Nos. 1 and 5). Therefore, the number of primary girders is from two (No. 2) to twelve (Nos. 3 and 5) – Fig. 1. All the bri dges under analysis are described in Hołowaty (2013, 2016), where their material properties and weldability are discussed and details on a range of retrofitting projects are given. The problem of impact toughness for steels is only touched upon; therefore, more detailed information is given in this paper.

Fig. 1. Bridges Nos. 1  5 and cross section of bridge No. 4 (filler beam deck)

4. Chemical composition and mechanical data for steel

A spectroscopic chemical analysis of the steel was carried out on samples cut from a specific bridge member (col. 2). Their chemical compositions are given in Table 1. The table also gives the chemical contents for wrought steel and mild steel. Wrought and mild steels were used in bridge construction during the 19th century. The chemical content for S235 contemporary non-alloy structural steel (as per EN 10025:2004) is also given for comparison. The comparison of chemical content results in the conclusion that all the bridges were constructed from mild steels. In four structures (Nos. 2 ÷ 5), this is a low-carbon steel with carbon content from 0.016 to 0.037 %, manganese from 0.319 to 0.644 % and almost nil silicon content. Only truss bridge No. 1, dating from 1875, was constructed from a medium-carbon steel with a carbon content of 0.258 %, manganese 0.496 % and silicon 0.169 %. Similar steels were found in other structures on that railway line [Hołowaty and Wichtowski (2013)].