In the period from 2014 to 2018 IPSA INSTITUTE performed supervision of works on the Karaula Tunnel. The investment value of the project was €10 million and the client was the PC Roads of the Federation of Bosnia and Herzegovina.
The Karaula Tunnel is situated on the Karaula mountain pass on road M-18 between Olovo and Kladanj. By constructing the tunnel the road level has been lowered by approximately 100 m, thus significantly improving driving conditions on this section, especially in the winter period.
The tunnel is 902,13 m long, with new 1,1 km long road sections designed and constructed on both tunnel ends and connected with the existing road. The project has shortened the route by 2,5 km and significantly improved road characteristics. The design speed is 80 km/h (70 km/h). Emergency lanes were constructed on both tunnel ends. Tunnel excavation works were executed by applying the New Austrian Tunnelling Method (NATM), Apart from the main tunnel tube, a 2,25 x2,5m evacuation tube, functioning as an emergency pedestrian exit, was constructed. It measures 436m in length. Hydrant and emergency call niches were constructed at every 150 m in the tunnel. The tunnel tube comprises Five niches for electrical installations were constructed in the tunnel tube. One niche for electrical installations was constructed in the emergency exit tube. Retaining walls of significant length were constructed along the route. Furthermore, a few pipe culverts were installed for carrying accumulated water. The tunnel equipment was designed and installed in line with the latest European regulations for tunnels longer than 500m. A tank holding water for fire extinguishing purposes was installed at the south tunnel portal. Sub-stations were installed at both tunnel ends, with full equipment for controlling the tunnel safety system, lighting and ventilation installed in one of the sub-stations.
The project was implemented in line with FIDIC Conditions of Contract (Red Book).