Doboj Bypass, of length of 5.5 km, represents the most complex section for execution of works, in the sense of engineering, due to very demanding terrain and poor geological conditions. This resulted in about 45% of its length being in structures. In this phase, the works are going on according to the planned schedule. More than 250 workers are engaged at the construction site. The works in the tunnel are organized 24 hours non-stop, in order to fulfil the required Time Schedule. <\/p>\n\n\n\n
The major part of the alignment is located in deep cuts, requiring slope stabilization works with piles, SN anchors and steel meshes. To stabilize slopes, it is necessary to drill 405 piles of length of l = 15.00 m, to drill over 10,000 anchors and install over 100,000 m2 of steel mesh. So far, more than 70% of the slope stabilization works have been completed. Currently, the works on the face stabilization of walls are being executed.<\/p>\n\n\n\n
Works in the Putnikovo brdo 1 (PB1) and Putnikovo brdo 2 (PB2) tunnels is certainly the biggest challenge and very unpredictable by its nature. The length of the step and the type of support depend on the geology that is controlled on a daily basis. The works are carried out in accordance with the New Austrian Tunneling Method (NATM), which implies changing of the support system and progress steps in accordance with the geological conditions at the site. The total length of tunnels to be excavated is approximately L = 3,610.40 m (both tunnels with separate tunnel pipes). So far, 54% of the length of tunnel PB1 or l = 1,2470.00 m has been excavated. Preparations are underway for the start of works on the secondary lining of the tunnel PB1.<\/p>\n\n\n\n
The Kostajnica Bridge, of length L = 328 m, is located at the beginning of this section and bridges the Bosna River and the Main Road M17. More than 93% of the works have been completed so far. Currently, the work is being carried out on the replacement of the bearing on the right (downstream) bridge and preparation for the final stages of works.<\/p>\n\n\n\n
Viaduct Putnikovo brdo is of length L = 288 m and bridges a natural valley between two hills. It is located between tunnels PB1 and PB2. The largest height of central piers is over 30 m. The founding is deep, with pile depth of 20 m. The span structure is carried out on a “scaffolding”, field by field. In the sense of stability, the upper slab represents a continuous support over 8 fields. The main support is a continuous beam of “pi” cross-section, of height h = 2 m. The viaduct consists of two completely separate structures for two-way traffic. So far, all piers have been completed and the construction of the span structure is underway, that is, 45% of the entire viaduct is completed. Currently, the works on the span structure of the right structure are underway.<\/p>\n\n\n\n
More than 85% of earthworks have been executed, and according to the current Time Schedule, the earthworks will be completed before the end of the year. At present, the works on construction of perimeter canals in cuts, subgrade construction and excavation of side cuts are ongoing.<\/p>\n\n\n\n
The following works shall be executed in order to complete the whole section: <\/p>\n\n\n\n
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