Construction Techniques for Closure of Main Bridge of South Feihe River Bridge in Hefei

The main bridge of the South Feihe River Bridge in Hefei is a prestressed concrete extradosed bridge with double pylons,single cable plane and with span arrangement(60+100+60) m.The box girder of the main bridge was constructed by the form traveler cantilever casting method and the closure segments of the side and central spans were constructed by the aid of the form traveler suspension supports.To choose the effective measures for the closure of the bridge,the influences of temperatures,loads and system transformation on the closure were analyzed,the finite element software was used to calculate the differential values of displacement of the structures before and after the counterweight were placed and it was determined that the closure should be carried out in the night time when the temperature was minimum.Before the closure,the unnecessary temporary loads on the deck were cleared away.After the side span was closed and the concrete strength reached the designed strength,the temporary anchoring of bearings of the main piers was released.The counterweight of sand bags used was 43.5 t and the closure of the bridge proceeded firstly from the side spans and then towards the central span.The closure practice of the bridge proved that the geometric shapes of the closure were smooth and the structure could satisfy the safe service requirements.