Due to the earthquakes in Groningen, buildings are increasingly suffering damage. Not only do buildings suffer damage as a result, but even inside a building or warehouse, earthquakes can cause considerable damage. The Netherlands had not yet defined guidelines for earthquake-resistant construction. That is why the NEN, together with experts, developed the guideline NPR 9998. The guideline NPR 9998 was published on 18 December 2015. The final version of the guideline will be designated in the Building Decree Regulations in 2016. From then on, NPR 9998 will be mandatory. It is an aid in determining whether new or existing buildings in Groningen can withstand earthquakes. The guideline contains practical methods and calculation rules.
If we go back in time and think back to 13 April 1992, there was a strong earthquake in the Netherlands with a magnitude of 5.8 on the Richter Scale.
At the time, the earthquake was felt as far away as the Czech Republic, Switzerland, France and England and is, as far as we know, the strongest ever recorded in the Netherlands. Fortunately, damage was limited as the earthquake was 17 kilometres deep. The total damage at the time was estimated at €125 million. In contrast, a much less severe earthquake and but shallow quake can cause substantial damage. In Groningen, for example, shallow quakes, called induced quakes, cause substantial damage to buildings.
Because Nolte already supplied Mezzanine floors in other countries, where earthquakes are much more common and can also be stronger, Nolte already had a lot of experience with earthquake-resistant construction. An earthquake tool was developed to apply this correctly. In these countries, it is mandatory to take earthquake-resistant construction into account. Mezzanine floors must also be safe in the event of an earthquake.
It is becoming increasingly important to check offers of warehouse equipment, such as Mezzanine floors and warehouse racks, carefully for such components. Cheap then turns out to be expensive, especially if fatal accidents then happen because earthquake-proof construction has not been taken into account.
Recently, for instance, we were asked to explain this in Belgium. The company itself, with many international branches, was not familiar with this. And suppliers also appeared not to take it into account.
Perhaps the term “ductility” doesn’t mean anything to you yet. Ductility is the degree to which a material can deform without breaking. So how important is it not that the Mezzanine floor used is “ductile”?
The Mezzanine floor should then absorb precisely those forces without the steel structure collapsing. It should be remembered here that Mezzanine floors are not supported against the building or on the building itself. It seems so logical to build the mezzanine floor against the walls of the building with all its consequences. In the event of an earthquake, a collapse then occurs immediately if this is not taken into account.
But even wind loads can cause major problems. It blows in the Netherlands and this must also be taken into account when building a Mezzanine floor.