36 Damage to concrete structures
too few and too thin. […] in Japan where there are frequent earthquakes,
the posts would be around 2 meters in diameter; but those of the collapsed
building are about 50–60 centimeters; in addition, those posts are all hollow, where they should be solid’.
However, following the conclusion of an official investigation into the
collapse of the building, the accident was determined to be due to improper
construction activities related to the completion of an underground car
park. Earth was excavated to make a 4.6-meter deep pit at one side of the
building, and was being stored to heights of up to 10 meters on the other
side of the structure. The weight of the excavated earth created a shear
mode failure in the soil structure, damaging the foundation piles and causing them to fail. This situation may have been aggravated by several days of
heavy rain.Probably the combination of inappropriate design of the foundation and improper excavation activities leading to an increased loading
on the foundation piles caused the collapse to happen. As in many cases,
here the problem could have been avoided by a better organised quality
control during structural design and construction.
2.3 Wrong estIMatIon of loaDIng
In the previously considered case of the Sleipner A platform, it was mentioned that the internal shear forces were underestimated during the design
stage, although the external loading—the hydrostatic pressure—was correctly identified. In some cases, it might be difficult to correctly define the
external loading on a structure. In some cases, inaccurate estimation of the
loading might be due to the stochastic nature of external loading like wind
pressure and earthquakes. In the case of new structures pushing the limits
of earlier experience, like record span cable bridges or dazzling high skyscrapers, extrapolation of deemed-to-satisfy rules might not be sufficient
as new and up-to-then unknown phenomenona might occur. In rare cases,
wrong estimation of loading might simply have to do with erroneous static
analysis. All of this will be illustrated by means of some case studies.
2.3.1 roof collapses due to snow loading
in belgium, winter 2010-2011
Belgium has a moderate climate with rather cool summers and soft winters. For several decades, no significant snow precipitated during winters in
Belgium. Due to this experience, snow loading was generally considered as
a very low risk, and not much attention was paid to special measures like
removal of melting water once the snow starts to melt.
Unfortunately, the 2010–2011 winter in Belgium was quite severe
(according to local standards). In December 2010, 23 days of snow were
too few and too thin. […] in Japan where there are frequent earthquakes,
the posts would be around 2 meters in diameter; but those of the collapsed
building are about 50–60 centimeters; in addition, those posts are all hollow, where they should be solid’.
However, following the conclusion of an official investigation into the
collapse of the building, the accident was determined to be due to improper
construction activities related to the completion of an underground car
park. Earth was excavated to make a 4.6-meter deep pit at one side of the
building, and was being stored to heights of up to 10 meters on the other
side of the structure. The weight of the excavated earth created a shear
mode failure in the soil structure, damaging the foundation piles and causing them to fail. This situation may have been aggravated by several days of
heavy rain.Probably the combination of inappropriate design of the foundation and improper excavation activities leading to an increased loading
on the foundation piles caused the collapse to happen. As in many cases,
here the problem could have been avoided by a better organised quality
control during structural design and construction.
2.3 Wrong estIMatIon of loaDIng
In the previously considered case of the Sleipner A platform, it was mentioned that the internal shear forces were underestimated during the design
stage, although the external loading—the hydrostatic pressure—was correctly identified. In some cases, it might be difficult to correctly define the
external loading on a structure. In some cases, inaccurate estimation of the
loading might be due to the stochastic nature of external loading like wind
pressure and earthquakes. In the case of new structures pushing the limits
of earlier experience, like record span cable bridges or dazzling high skyscrapers, extrapolation of deemed-to-satisfy rules might not be sufficient
as new and up-to-then unknown phenomenona might occur. In rare cases,
wrong estimation of loading might simply have to do with erroneous static
analysis. All of this will be illustrated by means of some case studies.
2.3.1 roof collapses due to snow loading
in belgium, winter 2010-2011
Belgium has a moderate climate with rather cool summers and soft winters. For several decades, no significant snow precipitated during winters in
Belgium. Due to this experience, snow loading was generally considered as
a very low risk, and not much attention was paid to special measures like
removal of melting water once the snow starts to melt.
Unfortunately, the 2010–2011 winter in Belgium was quite severe
(according to local standards). In December 2010, 23 days of snow were