Construction Techniques for Closure of Central Span of Jingyue Changjiang River Highway Bridge

The main bridge of Jingyue Changjiang River Highway Bridge is a hybrid girder cablestayed bridge with span arrangement of (100 + 298) m + 816 m + (80 + 75 + 75) m. The main girders of the bridge consist of the flat steel box girder and separated concrete edge box girders. The closure block for the steel box girder of the central span is 16. 4 m in length and 305 t in weight,which was lifted and installed by two sets of the deck cranes. The construction scheme for the closure of the central span was that of partial cutting and partial pushing of the girder and according to the statistic analysis method,the closure temperature was predicted to be 22 ℃ . Based on the prepared construction scheme and the temperature prediction,the unstressed material cutting length of the closure block was precisely calculated to be 16 454. 4 mm,considering numerous factors having influences on the closure and the block was precisely match prefabricated in the workshop. The hauling devices were arranged for adjusting the width of the closure gap,the location and geometric shapes of the closure block were adjusted,using the method of adjusting the closure joint width welding seam by welding seam and the central span was finally smoothly closed with high precision. Practice proves that the closure techniques applied to the bridge can lessen the dependence on the closure temperatures,shorten the construction time for the closure and raise the construction precision and quality.