PSI - Issue 5

G. Lesiuk et al. / Procedia Structural Integrity 5 (2017) 912–919 Lesiuk et al./ Structural Integrity Procedia 00 (2017) 000 – 000

913

2

1. Introduction

Fatigue and fatigue crack growth are one of the most frequent causes of machine or construction failures. On that canvas an application of CFRP patches to reinforce long-term operated structures made of steel, evaluated in fatigue crack growth context, seems to be a rational way to elongate their life time span and, hence, its further safe exploitation. The CFRP members also show an excellent impact resistance in various application: in mechanical and civil engineering (Khalili et al., 2009) as well in ballistic (Pach et al., 2017) area. Especially, this issue is vivid for stemming from 19 th and the beginning of 20 th century bridges which were usually built of components made of puddle or mild steels. According to Bień (2012), almost of 68% of currently exploited rail-road bridges are more than 50 years old and around 28% are over 100 years old since they were erected. Although fracture mechanics allows for effective and relatively sufficient estimation of subcritical fatigue growth period of pure metal alloy components without any reinforcement, it does not give answer for problems when reinforcement is applied. Therefore, many tests of many variants of reinforcement are needed to obtain reliable response how much they can elongate lifespan whether it is economically viable.

2. Experimental procedure

2.1. Material and specimen preparation

Material for investigation was gained from the railway old riveted, metallic bridge (1899-1902) located in Kluczbork (Poland, rail line 143 – 67.749km). The general view of the girder structure is shown in Fig. 1.

Fig. 1. General view of the structural element from Kluczbork bridge

According to the experimental program, the chemical analysis of the five components (C, Mn, Si, P, S) was carried out. The obtained results are presented in Table 1. The basic mechanical properties (according to static tensile test results) are collected in Table 2. In addition, the referenced values for typical old steel have been presented in the mentioned tables.