World's highest bridge passes stress test

A fleet of 96 trucks weighing a whopping total of 3,360 metric tons drove down the world's highest bridge under construction — the Huajiang Grand Canyon Bridge in Guizhou province — on Monday to test its load-bearing capacity.

The simulated traffic congestion was the final structural performance test for key bridge components under heavy load, marking a crucial step toward the bridge's opening in September.

After five days of intensive and orderly inspections, the load test — a comprehensive "physical examination" essential for verifying the bridge's structural safety and load-bearing capacity — was completed successfully.

"Preliminary analysis of the load test data shows that all measured indicators responded normally," said Han Hongju, deputy general manager and chief engineer of Guizhou Communications Investment Group, the company that built the bridge.

Stretching 2,890 meters in total length with a main span of 1,420 meters, the bridge towers 625 meters above the Beipan River.

Once open, it will be the world's highest bridge and longest bridge span in mountainous terrain.

To describe the world-class project, the builders used a vivid analogy of two "sky-high trees" 1,420 meters apart, connected by a giant "clothesline" that is 2,378 meters long and nearly 1 meter thick.

From this "clothesline", 91 pairs of "hangers" are suspended vertically, spaced 15.4 meters apart. Below these hangs a large "clothes-drying platform" — the bridge deck — which is 8 meters high, 30.5 meters wide, and weighs approximately 22,000 tons.

The "sky-high tree" on the Liu-zhi side in Anshun city stands 262 meters tall, while the one on the Anlong side in the Qianxinan Bouyei and Miao autonomous prefecture touches 204 meters. At the top of each "tree", a "saddle" is installed to ensure the "clothesline" performs smoothly and is firmly anchored.

In technical terms, the "clothesline" refers to the main cable, the "hangers" are the suspenders, the "sky-high trees" are the main towers, the "saddles" are the cable saddles, and the "clothes-drying platform" is the main girder.

The test was designed based on the bridge's intended vehicle load capacity. Through both dynamic and static assessments, the performance of the four major systems was thoroughly evaluated.

Originally scheduled to be conducted from Thursday to Saturday, the static load test was rescheduled due to unpredictable weather conditions. The tests were finally carried out from Thursday to Monday, with a break in work on Saturday.

Lei Min, technical director of the Bridge and Tunnel Division of Gui-zhou Shunkang Testing, said that three weight classes — 18, 48 and 96 trucks, with each weighing 35 tons — were used sequentially, with the maximum load reaching 3,360 tons, to test the bridge's load-bearing capacity.

"This approach simulated varying traffic volumes and load distributions while ensuring there was no damage to the bridge structure," he said.

Construction of the bridge began in January 2022, and the bridge is expected to open to traffic in late September.

A key project component of the Liuzhi-Anlong Expressway, the bridge will reduce travel time between the two sides of the canyon from two hours to just two minutes.

It is also expected to enhance regional tourism by linking attractions such as the Huangguoshu Waterfall, Longgong Cave and Wanfenglin scenic area, helping create a world-class tourism destination.

"The bridge itself is a world-class attraction," said Zhang Xiangyu, a member of the bridge and tourism integration team at Guizhou Communications Investment Group.

The builders have integrated modern facilities as well as experience-based activities such as bungee jumping, paragliding and rope swinging from the bridge structure, Zhang said.

Contact the writers at yangjun@chinadaily.com.cn