171 Rockfall Hazard Management on Traffic Facilities in Croatia Dalibor Udovič (1) ; Željko Arbanas (2) ; Snježana Mihalić Arbanas (3) ; Mirko Grošić (4) (1) Monterra Ltd., Rijeka, Croatia, Vukovarska 76, dalibor.udovic@monterra.hr (2) University of Rijeka, Faculty of Civil Engineering, Rijeka, Croatia (3) University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Zagreb, Croatia (4) Geotech Ltd., Rijeka, Croatia Abstract Along the Croatian side of the Adriatic Coast some large rockfall on the steep limestone slopes occurred during last decade and caused serious damage on buildings and traffic facilities with injured persons. The main reasons for rockfall in limestone slopes near railways and roads occurring are unfavorable rock mass characteristics, rock mass weathering in combination with heavy rainfalls so as men influence during the facility constructions. The applied technologies of the slopes construction were very conservative and attained safety factors are very low. The technologies of rockfall protections during construction of the new roads in the last decades are significantly improved. The rockfall protection started with using of netting techniques with very low quality of the wire material. After some time, the double twisted netting with galvanic protection occurred as the most common type of the rockfall slope protection. On the more demanding slopes the shotcrete was used and still is regarding the quality of the rock mass in the slope that is needed to be protected. The new technologies are applied throughout construction of the support system including high load bearing meshes with reinforced geotechnical self-drilled anchors in combination with high performance rockfall barriers. After rockfall phenomena occurring on some particular locations, the projects of rockfall protection were conducted to ensure human lives and facilities from further rockfall occurrences. The process of rockfall protection started with rockfall hazard analyses to identify potential of rockfall occurrence so as possible accidental consequences, e.g. rockfall risk. On locations where hazard with related risk was determined the detailed field investigations were provided. Based on identified characteristics of possible unstable rock mass blocks analyses of motion and resulting paths were conducted. Trajectories, impact energy and height of bouncing are depending of slope geometry, slope surface roughness and rockfall block characteristics. Depending on these analyses rockfall protection measures were designed. Two design approaches were adopted, prevention of rockfall by removing of potentially unstable rock mass or by rock mass support system installation and by suspending of running rock fall mass with rockfall protection barriers. In this paper we will present experiences on rock fall hazard determination and rockfall protection design so as installation of rock fall system protection on some location on limestone slopes near the traffic facilities in Croatia. Keywords rockfall, hazard, risk, rockfall protection, rockfall hazard management Introduction Rockfall protection along the roads and railways in Croatia become very important in all designs of new facilities as well as remediation of old ones. The main reasons for occurring rockfalls in limestone slopes near railways and roads are unfavorable rock mass characteristics, rock mass weathering in combination with heavy rainfalls so as men influence during the facility constructions. After rockfall phenomena occurring (Fig. 1) on some particular location, the projects of rockfall protection were conducted to ensure human lives and facilities from further rockfall occurrences. The deformability and strength properties of the rock mass are determined from geotechnical field investigation and the use of the rock mass classification system. Depending on these analyses, rockfall protection measures were designed. Two design approaches were adopted, prevention of rockfall by removing of potentially unstable rock mass or by rock mass support system installation and by suspending of running rock fall mass with rockfall protection barriers (Arbanas et al. 2012). After adopting one of these approaches it is possible to make the geotechnical model for a rock slope and perform stability analyses. If a low initial factor of safety is obtained, the stability analysis should include a support system.