Acta Montanistica Slovaca Ročník 14 (2009), mimoriadne číslo 1, 79-85 79 Measurement of bridge body across the river Labe in Mělník Lukáš Vráblík 1 , Martin Štroner 2 a Rudolf Urban 3 Měření mostního tělesa přes řeku Labe v Mělníku Long-span concrete prestressed bridges are sensitive for long-term deflections growing. Bridge over the river Labe near Mělník is a typical example of this structural type. 15 years after bridge opening, midspan deflection still increases. Detail surveying of the superstructure was made to identify possible structure failure. Key words: prestressed concrete bridge, deformed structure Description of the bridge structure and its state Long span prestressed concrete bridge across the river Elbe in Mělník (fig. 1) is the main part of the bridging transferring the I/16 communication. It was designed as a through girder with span length 72,05 + 146,2 + 72,05 m. With the main span length 146,2 m it is still biggest overhung concrete bridge in operation in Czech republic. As well as other concrete bridges with large spans, this bridge is also characterized by permanent increase in deformations in time. The structure has been therefore permanently observed since its putting into operation in September 1994. The evaluation of monitoring results [4] clearly shows that even after almost 15 years since putting into operation it does not come to fixing of increase in deformations. Fig. 1. The bridge scheme. Long-term deformations are measured in fixed points on the structure (above supportings for analysis of their long-term settlement and in the intermediate points of the end span and middle span for observing long-term deformations of the prestrained concrete structure caused both by reological signs of concrete - creeping and shrinkage, and by other possible effects (e.g. decreases in prestress etc.). 1 Ing. Lukáš Vráblík, Ph.D., ČVUT in Prague, faculty of civil engineering, department of concrete and msonry structures, Thákurova 7, 166 29 Prague 6, lukas.vrablik@fsv.cvut.cz 2 Ing. Martin Štroner, Ph.D., ČVUT in Prague, faculty of civil engineering, department of special geodesy, Thákurova 7, 166 29 Prague 6, martin.stroner@fsv.cvut.cz 3 Ing. Rudolf Urban, ČVUT in Prague, faculty of civil engineering, department of special geodesy, Thákurova 7 166 29 Prague 6, rudolf.urban@fsv.cvut.cz (Reviewed and revised verzion 3. 11. 2009 )