INGENIEUR
Figure 2: Badly rusted structure of the 16-year-
old bus
Figure 1: Collapsed roof of the bus flattened the
passengers’ cabin
Figure 3: Pillars welded together by manufacturer
Figure 4: The rusted structure at the welded
section
Figure 5: SEM image of sample from the bus
superstructure Figure 6: Grain structure of sample from the bus
superstructure
ring system (Figure 3 and Figure 4). The welding
section was identified as the weakest area,
serving as the failure modes at the time of the
accident. Further material analysis using Scanning
Electron Microscope (SEM) revealed that the bus
superstructure was constructed with much lower
grade material: cast iron (Figures 5 and 6). In this case, it can be stipulated that cast iron was
chosen to save cost. In addition, there was no
evidence to establish that the bus structure had
been coated to prevent rusting.
In another case involving a bus, eight of out 33
passengers died when the bus collided into the
rear end of a tanker. The main cause of the crash
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VOL
2018
VOL 76
55 OCTOBER-DECEMBER
JUNE 2013