Confined masonry as practical seismic construction alternative-the experience from the 2014 Cephalonia Earthquake

摘要

During August 1953 three strong earthquakes of magnitude ranging from 6.3 to 7.2 shook the Ionian Island of Cephalonia (Kefalonia),Greece,and destroyed almost the entire building stock of the Island which consisted primarily of traditional unreinforced masonry (URM) houses.The authorities went on to restructuring of the building stock,using a structural system that is most like what is known today as confined masonry.They designed about 14 types of one-to two-storey buildings providing the engineers with detailed construction plans.These buildings are known as "Arogi" buildings (Arogi in Greek meaning Aid).On the 24th of January and 3rd of February 2014,two earthquakes of magnitude 6.1 and 6.0 struck the island,causing significant soil damages,developing excessively high ground accelerations.Surprisingly,no damage was reported in the "Arogi" buildings.The seismic behavior of the buildings is examined by FEM linear analysis and it is compared to that of URM structures.Computed results illustrate that the displacements of identical URM buildings would be about twice the magnitudes observed in the corresponding "Arogi" ones,with the implication that the earthquake sequence of 2014 would have caused critical damage should the type of structure be of the URM type.Furthermore,it is illustrated that this low cost alternative method of construction is a very effective means of producing earthquake resilient structures,whereas further reduction of seismic displacement may be achieved in the order of 50％ with commensurate effects on damage potential,when reinforced slabs are used to replace the timber roofs.