Analysis on the Long-Term Deflection in Prestressed Concrete Continuous Rigid Frame Box Girder Bridge

To find out the formation mechanism of excessive long-term deflection in a long-span prestressed concrete continuous rigid frame box girder bridge, a finite element method together with an empirical research are used to analyze the long-term deflection in the assistant shipping channel bridge of Humen bridge. The influences of several factors on long-term deflection at midspan in this bridge are demonstrated in detail. Finite element analysis results show that the midspan deflection value induced by concrete creep is limited and could not entirely account for actually observed deflection values in the running period. In addition to concrete creep, equivalent creep effect of traffic live loads applied at the deck, overweight in dead loads, and longitudinal prestress losses are also very significant factors leading to the excessive deflection at midspan. Considering these three factors, the calculated midspan deflection value could coincide with the measured one.