In a recent survey conducted by the Institute of Civil Engineering, the Architecture Studio Krištof and the Faculty of Arts at the University of Ljubljana, the experts examined possible solutions for earthquake reinforcement of the 15 most obviously problematic apartment blocks in the centre of Ljubljana that were built between the years 1959 and 1965, and for five of them they see no other solution than demolition and replacement construction.
The survey was commissioned by the Ljubljana City Government, with a focus on 15 buildings built before the first rules on earthquake-resistant construction were introduced following the 1963 earthquake in Skopje. In addition to the building standards, the criterion was also the height of the buildings, since the densest settlement would put most people at risk in the event of a collapse. The buildings in question are all towers between nine and 12 floor high, with only a few of them having even the minimum amount of reinforcement.
According to Marjana Lutman of the Institute of Civil Engineering, for ten of the buildings adequate earthquake safety can be achieved by internal or external fortification. For towers on Štefanova, Rozmanova, Pražakova and Cigaletova Street as well as Hrvatski trg, however, the experts see no other solution but demolition.
Amid mounting real estate prices in Ljubljana centre the question arises what exactly does this mean for the owners of apartments in these buildings?
For the national broadcaster’s MMC portal the city government explained that the results of the survey only indicate possible solutions, and that concern for the earthquake safety of buildings is primarily the responsibility of the owners. It is up to them to decide whether or not to accept the proposals.
However, interventions to increase seismic safety are associated with high costs. Both exterior and interior fortifications are expected to cost an average of € 5 million for each building, or more than € 110,000 for each housing unit. In contrast, the complete replacement of an old building with a new one would cost an average of almost € 8 million, which means up to € 180,000 per household.
Some apartment owners are convinced that the earthquake safety standards in the survey were unrealistic and that human factors could be taken into account in such cases, and so the criteria could be slightly adjusted. “Standard Eurocode 8 assumes 100% safety, but it does not hold that 100% safety must be maintained in order for a building to survive or fail in a major earthquake. We probably won’t just demolish the old city centre of Ljubljana just because it doesn’t meet the Eurocode 8 standard,”' stated an architect and resident of one of the endangered towers for MMC, Nika Grabar.
“Slovenia is located in a very earthquake-prone area, and according to some estimates there are more than 2000 earthquake safety inadequate buildings in Ljubljana and around 550 in Maribor, among them several schools and other public institutions,” stated Dr. Peter Fajfar of the Faculty of Civil Engineering and Geodesy for MMC. “There are 39 schools in Slovenia that were built at the most critical time, 14 of which are in Ljubljana. While considerable obstacles can be found with tackling this problem when it comes to private property in residential buildings, the state has no reason not to immediately undertake earthquake reinforcement measures when it comes to its own buildings,” he added.
All our stories about earthquakes and Slovenia can be found here