Foundation works for construction of Danube Bridge II Vidin (Bulgaria)-Calafat (Romania)

The Foundations works of the bridge over the the Danube River II has involved a new technical challenge due to the cathartics of depth and diameter of the piles, and the logistical and human, due to the hard environmental conditions for the execution. This work, awarded to FCC. Construction company in its two contracts. Access to the bridge and Main Bridge has required on the differenced sites, the use of a wide range of foundation systems, since driven precast piles to in in situ pile with permanent casing, installed by vibrating systems and excavated with benoto grabs systems. The enormous responsibility of this phase is evident in the intense camping of characterization tests with static load tests, dynamic and Osterberg cells, as well as control the campaign with Cross-hole tests in 100% of the piles in situ executed, that has allowed no only ensure the highest level of quality on the foundation elements, but also to take the most of the mechanical characteristics of soils provided. The complexity of the execution of more than 24,000 ml pile executed along the more than 2 years duration of the work reach the maximum expression in the more than 6,900 ml of in situ pile made from marine resources, with a maximum depths up to 80 m with 2 m diameter pile. The article intends to give an overview of the site and the execution, associating the different foundation methods used, and the problems that were detected. (Author)