China’s 600-meter concrete arch bridge wins top award

At the Hongshui River in Guangxi, traffic now moves across a concrete arch with a 600-meter main span. The Tian’e Longtan Bridge in Tian’e County, Hechi, opened in 2024 with two-way, four-lane traffic, and has since been recognized by Xinhua News Agency as the world’s longest steel-reinforced concrete arch bridge by span. On August 24, the project received the top prize in Guangxi’s provincial science and technology awards.

The leap is measured against a previous record of 445 meters. For decades, engineers in Japan, Croatia and other bridge-building countries studied concrete arches approaching 600 meters, but completed projects there remained below 390 meters. Conventional concrete arches were widely considered difficult to extend beyond 400 meters, while concrete-filled steel tube arches faced challenges beyond 500 meters.

The team’s solution was to take weight out of the structure. The bridge’s own dead load accounts for over 90 percent of its total stress, and the concrete around the steel framework represents more than half of that weight. Engineers split the main arch into two ribs and removed sections that carried little stress, narrowing the arch from 23 meters to 13 meters. Concrete use dropped from about 40,000 cubic meters to 28,000 cubic meters, while the design used 22 percent less concrete per meter than 400-meter-class bridges at the same stress level.

Concrete that large also has to set without developing damaging cracks as temperatures and internal stresses change. The construction team developed new pouring methods to control those cracks, helping the project move beyond the limits associated with earlier long-span arches. The approach also reportedly saved 110 million yuan compared with a cable-stayed design; maintenance costs over the planned 100-year design life are expected to be 470 million yuan lower.

Concretely, the bridge gives China’s engineers a working, traffic-carrying example of a 600-meter concrete arch rather than a laboratory calculation. For future long-span projects, the practical gain is a lighter arch design, lower reported construction costs and a projected maintenance advantage, though those savings remain estimates and the engineering claims are presented through project and institutional reports rather than an independent cost review.