In current design of steel eccentrically braced frames (EBFs), the yielding link is coupled with the floor beam. This often results in oversized link elements, which leads to over-designed structures and foundations. In addition, the beams are expected to sustain significant damage through repeated inelastic deformations under design level earthquakes, and thus the structure may require extensive repair or need to be replaced. These drawbacks can be mitigated by designing EBFs with replaceable shear links. Two different replaceable link types with alternate section profiles, connection configurations, welding details and intermediate stiffener spacing were tested. A total of 13 cyclic quasi-static full-scale cyclic tests were performed, which included tests on eccentrically braced frames with the replaceable shear links, to study their inelastic seismic performance. The links exhibited a very good ductile behaviour, developing stable and repeatable yielding. Additional inelastic rotation capacity can be achieved with bolted replaceable links when allowing bolt bearing deformations to occur. The on-site replaceability of the link sections is confirmed even in the presence of residual deformations of 0.5% drift.

In my doctoral thesis I have investigated earthquake swarms from two com- pletely different tectonic areas, West Bohemia/Vogtland and Southwest Iceland, with the aim of gaining a deeper insight into the nature of earthquake swarms in diverse tectonic environments. I analysed swarm-like activities from West Bo- hemia and Southwest Iceland from the perspective of statistical characteristics (magnitude-frequency distribution, interevent time distribution), seismic moment release, and space-time distribution of events. I found that the ratio of small to large events and the event rates are similar for all the activities in both areas, while the rate of the seismic moment release is significantly higher for the South- west Icelandic swarms. Seismic moment released step by step is characterised for the West Bohemia swarms, whereas seismic moment released in one dominant short-term phase is typical of Southwest Icelandic earthquake swarms. All the West Bohemian swarms took place in a bounded focal zone Nový Kostel that is fairly complex, consisting of several fault segments. The Southwest Icelandic swarms are distributed at much larger area along the Mid Atlantic Ridge up to its branching in the Hengill triple junction, the individual swarms clearly reflect a tectonic structure of respective focal areas. I have...