When part of the Hongqi Bridge in Maerkang, Sichuan, collapsed in mid-November 2025, the images spread quickly online: twisted steel, a broken roadway, and a chunk of the newly built structure lying in the river below. What stood out just as strongly was the fact that nobody was hurt — a rare piece of good news in a serious infrastructure incident.

A Collapse That Came With Warning Signs

The day before the bridge failed, engineers noticed something worrying:
large cracks on the road surface and signs that the mountain slope beside the bridge was shifting. Local authorities reacted quickly, shutting the bridge to traffic and keeping people away. That decision almost certainly prevented casualties.

By the following day, the slope movement intensified. A landslide on one side of the bridge swept away the ground supporting the approach span. With nothing beneath it, a portion of the bridge dropped into the valley.

The Likely Reasons Behind the Failure

Early explanations point to one clear trigger: a landslide. The bridge sits in a steep, geologically complex area of Sichuan where slopes are naturally fragile and prone to movement.

Here are the main factors investigators are examining:

1. Slope Instability

The official explanation so far is straightforward:
The mountain beside the bridge shifted, causing the ground under the road and the approach to give way. These kinds of deep-seated slope deformations are not unusual in Western Sichuan’s fractured terrain.

2. Natural Geological Weakness

Maerkang is located in a region shaped by earthquakes, steep ravines and heavily fractured rock layers. Even with proper construction, the ground itself can become unstable, especially after heavy rain or long-term weathering.

3. Possible Influence of Human Activity

Some geologists and satellite-imagery analysts have raised a reasonable question:
Could nearby reservoir activity — specifically water-level changes from large hydro projects — have contributed to slope instability?

At this stage, this remains a hypothesis, not a confirmed cause. It is something the technical investigation will need to examine.

4. Construction and Oversight Factors

Although no official report has blamed the builders, the collapse has sparked a wider conversation:
Are major infrastructure projects in fragile mountain regions being built and monitored with enough geological caution?
Rapid development in such terrain is always a delicate balance between engineering ambition and natural risk.

A Young Bridge With a Sudden Failure

The Hongqi Bridge had been completed only months earlier and formed part of a key highway connecting Sichuan to the Tibetan Plateau. Its role was important, and the collapse has raised obvious questions about the long-term safety of large projects in similarly complex landscapes.

What Happens Next

Authorities have launched a detailed investigation, bringing in geological experts to study:

• the exact trigger point of the landslide
• soil and rock stability around the remaining structure
• satellite records of ground movement
• whether construction choices or reservoir water levels influenced the failure

Traffic has been rerouted while the area is stabilised, and further collapses are still being monitored.

Why This Incident Matters

The Hongqi Bridge collapse is more than a one-off accident. It highlights how ambitious infrastructure and fragile mountain geology can clash, especially as China continues building in remote areas.

It also shows the value of early detection: workers noticed the shift, the bridge was closed, and lives were likely saved.

Until full technical reports are released, we won’t have every detail. But what’s clear for now is this:
a landslide caused the structure to fall, and the quick reaction of engineers prevented a disaster from becoming a tragedy.