Qinglong Isle Bridge, Yiyang, China: a lightweight composite-girder self-anchored suspension bridge

The Qinglong Isle Bridge is the world’s first self-anchored suspension bridge with a composite stiffening girder constructed using a steel double-box and ultra-high-performance concrete (UHPC). The bridge deck of the composite girder consists of a thin panel (10 cm thick) and longitudinal ribs (12 cm thick) and was constructed using UHPC with a high bending strength and high-durability. The self-weight of the UHPC deck is approximately 30% less than that of the deck of an ordinary concrete composite girder. This reduced self-weight leads to reduced work for other primary structures in the bridge. To improve the crack resistance of the cast-in-place (CiP) joints between the precast deck slabs, an innovative T-shaped design was adopted for the joints and CiP UHPC was subjected to high-temperature steam curing, which reduces the shrinkage and creep effect of UHPC materials in operation. The extensive use of UHPC materials in China has resulted in a gradual reduction in the overall unit price, thereby enhancing the economic viability of steel–UHPC composite girder in construction. Furthermore, the UHPC structure exhibits superior durability, which markedly diminishes the maintenance e