Braila bridge: Design and construction of the cable system

The Braila bridge is a three-span suspension bridge spanning the Danube in Romania with a main span of 1120 meters, currently under construction. This bridge will be the first constructed long-span suspension bridge in Romania. The construction of the main cable system started in March 2021 and completed in December 2021. Strands of the main cable are erected by using low tension aerial spinning method by which wires are spanned one by one on site and then bound into a strand. It is of importance to assure the quality of strand/main cable on site, and two methodologies were adopted. One is to control the deflection of the catwalk by water counterweight. With the progress of wire spinning, the catwalk deflects due to increase of the weight of the spun wires. The excessive deflection makes the variation of wire length within a strand which causes unbalanced stress distribution within the cable, and thus shall be avoided. The other is to move the tower top saddle during construction. Due to asymmetric superimposed dead loads between the spans, the tension force is not balanced between main span and side span during the main cable construction, and it may cause a slippage of strand at saddles which results failing of designated geometry. Therefore, the position of tower saddle was adjusted to have the equilibrium by hydraulic jacks. Thanks to the measures above, the quality of the main cable was assured on site, and the construction was completed on schedule.