Seismic resilience of existing masonry building

Croatia is located on seismically active grounds. Its built heritage is with a large percentage of the existing built environment consisting of masonry structures built prior the first earthquake regulations, which therefore pose a serious threat for the inhabitants and society itself. Knowing this, it is of essence to know the vulnerability of the buildings, which most of the old city cores are built of. But knowing the structural vulnerability is just a small percentage of the work needed to increase the resilience of the buildings and the society. The engineer role is to formulate the platform emphasizing the mitigation of disaster effects while participating in the decision system managing the disaster leading to the conclusion that a minor investment to prevention is better than the one addressed to a cure. The current state of the structure is evaluated with a method which combines experimental data and engineering knowledge for evaluation of the seismic safety factors and expected structural performance under strong events. This method is also used for the choice of strengthening methods. The strengthening methods are evaluated balancing the costs and the benefits on the building resilience. When the building owner is aware of the potential risk, and is willing to prepare the structure to cope the serious earthquake hazard the whole risk mitigation process is to begin, which is presented in this article. It is presented on a masonry structure dating from the beginning of the 20th century and it is of major social value, and therefore high resilience is of essence. The presented risk mitigation process consists of structural vulnerability estimation, comparison of the cost of retrofit to those of loss and recovery of functionality in a disaster. The methods of mitigation and decisions based on resilience of this example building are presented.