A major construction milestone of Pelješac Bridge was reached at midnight on 29 July, 2021, as the deck was connected successfully. The extra-dosed cable-stayed bridge lies in the highly active seismic region with a designed ground acceleration ag= 0.34g, so the superstructure design of this bridge abandoned the regular concrete structure with poor plasticity, compared to concrete, steel has a better capability of shocks resistance and the designer adopted a steel box-shaped girder with a quantity of steel totaling 34,700t. This accounted for almost 50% of the entire bill of quantities, making the manufacture of the steel structure, its shipment, and on-site installation critical components of the project. Besides, the steel structure was designed with the strictest execution class EXC4 based on EN 1090-2. The specification requested near-perfect requirements for the appearance of the steel box girder. During the production, this project made extensive use of various welding robots and automatic or mechanical equipment. In addition, appropriate welding technology and manufacturing procedures ensured the quality level of EXC4. The global outbreak of the Covid-19 pandemic as force majeure had a serious impact on the steel structure production and transportation. Due to the shortage of cargo vessels the expense of ocean shipping increased dramatically. However, the contractor, China Road and Bridge Corporation (CRBC) overcame impossibilities beyond human control and utilized a simultaneous processing strategy by two manufacturers to decrease the construction period. At the meantime, CRBC relied on the shipment resource of its parent company China Communications Construction Company (CCCC) to deal with ship shortages in the global market. As a result, the steel structure fabrication and site installation were achieved in two years successfully. The acquired experience should be treated as a reference for similar mega sea-crossing bridge projects in future.

cable-stayed bridge; steel box girder; automatic welding; EXC4; Covid-19