World's longest-span cable-stayed bridge undergoes load test before opening

NANJING -- The final pre-opening safety checks have begun on the Changtai Yangtze River Bridge, the world's longest-span cable-stayed bridge, as engineers launched a high-stakes week-long load testing campaign on the hybrid rail-road structure early Tuesday in East China's Jiangsu province.

A series of scientifically rigorous load tests will thoroughly evaluate the actual performance of this world-class multifunctional bridge, which will provide crucial data for its subsequent safe operation, according to the Jiangsu provincial transport engineering construction bureau, the bridge's developer.

Spanning 10.03 kilometers, this engineering milestone integrates highways, intercity railways, and local roads across two levels. Its main channel features a record-setting 1,208-meter central span supported by cables, while its two auxiliary channel bridges each boast 388-meter steel arch spans, the longest worldwide for their type.

All load testing occurs exclusively at night to avoid temperature fluctuations affecting the steel-based structure, with over 800 sensors deployed to track micrometer-level structural shifts, according to the bureau.

During the first night's static test, 30 four-axle trucks weighing 1,200 tonnes were positioned like "six vehicles side-by-side on the upper highway deck and four on the lower rail-road deck," according to technicians, mimicking the weight of 800 passenger cars. The trucks remained stationary for eight hours to measure structural responses.

Seven days of trials cover 119 static and 111 dynamic scenarios across all bridge sections. The most intense static test will mobilize 110 trucks weighing 4,400 tonnes simultaneously on the main span, according to the bureau.

Dynamic examinations later this week include simulated traffic flows with braking and bumping sequences.

Scheduled for completion by late 2025, the bridge will slash travel time between Changzhou and Taizhou in Jiangsu province from 80 minutes to 20 minutes, boosting development for the Yangtze economic belt and integration of the Yangtze River delta region.