30 Damage to concrete structures
failure does not happen very often, making engineering structures highly
ranked within the list of most reliable man-made objects (more reliable
than chips and computers). However, in the event of structural failure, the
consequences can be very high, including human lives.
2.2 InaPProPrIate DIMensIons anD DetaIlIng
Allen (1979) collected information on 188 cases of failing concrete structures, 29 resulting in collapse and 118 in unacceptable serviceability issues
such as deterioration, excessive cracking, spalling, deflection or settlement.
It was concluded that about half of the errors were due to inappropriate design, and the other half due to faulty construction (see Chapter 3).
Within the group of collapsed structures, inadequate design (e.g. of formwork or temporary bracing) or inadequate detailing was responsible for
most of the cases. Many of the serviceability problems within the other
group were also due to improper design related to deflection, temperature effects, shrinkage, and creep. The conclusion that about half of the
structural failures are caused by errors in design or lack of design was
also reached by Ionită et al. (2009) within their analysis. They attribute
another quarter of the failures to errors on the construction site. Human
error is a major cause of structural failures, independent from the type of
material. Human errors can be due to ignorance (the designer is not aware
of the problem), due to carelessness (the designer is aware of the problem,
but does not care about it), or by intention (the designer is aware of the
problem, even cares about it, but takes the risk to oversimplify due to time
pressure or lack of budget) (Kaminetsky 1991). Ignorance and insufficient
knowledge are reported to be the main cause of human error, representing
about two thirds of the cases (Matousek and Schneider 1976, Kaminetsky
1991, Natarajan 2007).
To make mistakes is very human, as nicely illustrated for the case of
engineers by Petroski (1982). Human error cannot be totally avoided. On
the other hand, we cannot just sit back and give the fatalistic ‘that-is-life’
excuse. Efforts should be made to reduce the number of human errors
within structural design. As mentioned by Kaminetsky (1991), ‘training of
engineers and control in the design phase should have high priority, since
the most frequent errors are made in this phase’. Normal care and additional control are considered accurate measures to avoid almost all human
errors in structural design. Only about 10% of structural failures and errors
seem to be reasonably unavoidable (Kaminetsky, 1991). Structural collapse
due to inappropriate dimensions or detailing will be illustrated hereafter
by referring to three cases: the collapse of the Melle Bridge in Belgium, the
sinking of the Sleipner A offshore platform in Norway 1991, and the tumbling collapse of a 13-storey apartment building in Shanghai, China 2009.
failure does not happen very often, making engineering structures highly
ranked within the list of most reliable man-made objects (more reliable
than chips and computers). However, in the event of structural failure, the
consequences can be very high, including human lives.
2.2 InaPProPrIate DIMensIons anD DetaIlIng
Allen (1979) collected information on 188 cases of failing concrete structures, 29 resulting in collapse and 118 in unacceptable serviceability issues
such as deterioration, excessive cracking, spalling, deflection or settlement.
It was concluded that about half of the errors were due to inappropriate design, and the other half due to faulty construction (see Chapter 3).
Within the group of collapsed structures, inadequate design (e.g. of formwork or temporary bracing) or inadequate detailing was responsible for
most of the cases. Many of the serviceability problems within the other
group were also due to improper design related to deflection, temperature effects, shrinkage, and creep. The conclusion that about half of the
structural failures are caused by errors in design or lack of design was
also reached by Ionită et al. (2009) within their analysis. They attribute
another quarter of the failures to errors on the construction site. Human
error is a major cause of structural failures, independent from the type of
material. Human errors can be due to ignorance (the designer is not aware
of the problem), due to carelessness (the designer is aware of the problem,
but does not care about it), or by intention (the designer is aware of the
problem, even cares about it, but takes the risk to oversimplify due to time
pressure or lack of budget) (Kaminetsky 1991). Ignorance and insufficient
knowledge are reported to be the main cause of human error, representing
about two thirds of the cases (Matousek and Schneider 1976, Kaminetsky
1991, Natarajan 2007).
To make mistakes is very human, as nicely illustrated for the case of
engineers by Petroski (1982). Human error cannot be totally avoided. On
the other hand, we cannot just sit back and give the fatalistic ‘that-is-life’
excuse. Efforts should be made to reduce the number of human errors
within structural design. As mentioned by Kaminetsky (1991), ‘training of
engineers and control in the design phase should have high priority, since
the most frequent errors are made in this phase’. Normal care and additional control are considered accurate measures to avoid almost all human
errors in structural design. Only about 10% of structural failures and errors
seem to be reasonably unavoidable (Kaminetsky, 1991). Structural collapse
due to inappropriate dimensions or detailing will be illustrated hereafter
by referring to three cases: the collapse of the Melle Bridge in Belgium, the
sinking of the Sleipner A offshore platform in Norway 1991, and the tumbling collapse of a 13-storey apartment building in Shanghai, China 2009.