Application of Macro-Synthetic-Fiber-Reinforced Sprayed Concrete for Primary Lining Support on Highway Tunnel Project in Bosnia and Herzegovina

Abstract

The application of macro synthetic fiber reinforced sprayed concrete is seen by many design engineers as the alternative to steel reinforced sprayed concrete. The first applications of macro synthetic fiber reinforced sprayed concrete in Bosnia and Herzegovina were applied during the construction of the Sarajevo By-pass Motorway. The Project included a Motorway tunnel-system of three (3) double tubed, two-lane tunnels receptively 860m, 2776m and 402m in length, passing through an extensive and diverse geology. In this work application of macro synthetic fiber reinforced sprayed concrete will be presented, giving an inside in the underground condition, the concrete testing, measurements and calculations. The aspects related to the excavation work-cycles and time savings applying fiber reinforced sprayed concrete in the primary lining will also be presented. The Highway Tunnel ProjectThe Motorway Project is located on the route of the Pan European Corridor 5c: Budapest-Osijek-Ploce and is the most important Project for Bosnia and Herzegovina in the last decade.The construction works on the 20km long motorway section passing the capital city Sarajevo were significant for the city traffic itself.The Project started in May 2012 and the construction time was 28months. The length of the subsection "Lepenica-Tarcin" (Figure 1) was approximately 10km and included a number of different structures, whilst the construction of tunnels T2, T3 and T4 was the most significant part of the project. Especially the construction of the Tunnel T3 (later renamed as "Tunnel 25th of November") with an average length of 2776m being potentially on the "critical path". The construction of Tunnel T3 on the subsection "Lepenica-Tarcin" will be the subject of this work [1].