Kosovo Lepence Valley Passage Bridge
摘要
This paper describes an alternative design and construction solution for the Kosovo R6 Motorway Project from 2014 to 2019. Sections of the motorway cross mountainous terrain where extremely challenging geotechnical conditions were encountered. Following completion of detailed geotechnical investigations, preliminary results alerted the team to the presence of unstable zones that would require complex slope stability solutions along the alignment, thus increasing the schedule and cost of the project. After considering all challenges, an alternative alignment along a deep narrow valley of the Lepence River was selected, requiring a new 5.75-km-long bridge. To complete this bridge safely and within the schedule and budget, every stage of the execution was considered, planned, and occasionally extensively redesigned accordingly. Numerous different foundation types, piers, pier heads, and beams were designed. For the certainty of the solution, intensive geotechnical investigations were performed under the foundations. The solution required beam launchers from the two ends of the bridge to the center while installation with cranes from the center section in both directions. This was achieved by lowering the longitudinal profile at the bridge center section. Production of beams was carried out in four locations and work fronts. By using hybrid pre- and post-tensioned precast girders, the number of beams decreased. Use of single piers, each carrying a double carriageway, considerably reduced the number of piers. This well-coordinated design and construction plan, executed by an experienced design and build contractor resulted in safe, high-quality, and cost-effective work carried out according to the original project schedule.